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MaxScale/server/modules/routing/schemarouter/schemarouter.c
Markus Mäkelä 63c803a818 MXS-1379: Route conflicting queries to current shard 
All conflicting queries are routed to the shard which contains the
currently active database.
2017-09-01 11:28:21 +03:00

4317 lines
134 KiB
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/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2019-07-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include "schemarouter.h"
#include <stdio.h>
#include <strings.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <maxscale/router.h>
#include "sharding_common.h"
#include <maxscale/secrets.h>
#include <mysql.h>
#include <maxscale/log_manager.h>
#include <maxscale/query_classifier.h>
#include <maxscale/dcb.h>
#include <maxscale/spinlock.h>
#include <maxscale/modinfo.h>
#include <maxscale/modutil.h>
#include <maxscale/protocol/mysql.h>
#include <maxscale/alloc.h>
#include <maxscale/poll.h>
#include <pcre.h>
#define DEFAULT_REFRESH_INTERVAL "300"
/** Size of the hashtable used to store ignored databases */
#define SCHEMAROUTER_HASHSIZE 100
/** Hashtable size for the per user shard maps */
#define SCHEMAROUTER_USERHASH_SIZE 10
/**
* @file schemarouter.c The entry points for the simple sharding
* router module.
*.
* @verbatim
* Revision History
*
* Date Who Description
* 01/12/2014 Vilho Raatikka/Markus Mäkelä Initial implementation
* 09/09/2015 Martin Brampton Modify error handler
* 25/09/2015 Martin Brampton Block callback processing when no router session in the DCB
*
* @endverbatim
*/
static MXS_ROUTER* createInstance(SERVICE *service, char **options);
static MXS_ROUTER_SESSION* newSession(MXS_ROUTER *instance, MXS_SESSION *session);
static void closeSession(MXS_ROUTER *instance, MXS_ROUTER_SESSION *session);
static void freeSession(MXS_ROUTER *instance, MXS_ROUTER_SESSION *session);
static int routeQuery(MXS_ROUTER *instance, MXS_ROUTER_SESSION *session, GWBUF *queue);
static void diagnostic(MXS_ROUTER *instance, DCB *dcb);
static void clientReply(MXS_ROUTER* instance,
MXS_ROUTER_SESSION* router_session,
GWBUF* queue,
DCB* backend_dcb);
static void handleError(MXS_ROUTER* instance,
MXS_ROUTER_SESSION* router_session,
GWBUF* errmsgbuf,
DCB* backend_dcb,
mxs_error_action_t action,
bool* succp);
static backend_ref_t* get_bref_from_dcb(ROUTER_CLIENT_SES* rses, DCB* dcb);
static route_target_t get_shard_route_target(qc_query_type_t qtype,
bool trx_active,
HINT* hint);
static uint64_t getCapabilities(MXS_ROUTER* instance);
static bool connect_backend_servers(backend_ref_t* backend_ref,
int router_nservers,
MXS_SESSION* session,
ROUTER_INSTANCE* router);
static bool get_shard_dcb(DCB** dcb,
ROUTER_CLIENT_SES* rses,
char* name);
static bool rses_begin_locked_router_action(ROUTER_CLIENT_SES* rses);
static void rses_end_locked_router_action(ROUTER_CLIENT_SES* rses);
static void mysql_sescmd_done(mysql_sescmd_t* sescmd);
static mysql_sescmd_t* mysql_sescmd_init(rses_property_t* rses_prop,
GWBUF* sescmd_buf,
unsigned char packet_type,
ROUTER_CLIENT_SES* rses);
static rses_property_t* mysql_sescmd_get_property(mysql_sescmd_t* scmd);
static rses_property_t* rses_property_init(rses_property_type_t prop_type);
static void rses_property_add(ROUTER_CLIENT_SES* rses,
rses_property_t* prop);
static void rses_property_done(rses_property_t* prop);
static mysql_sescmd_t* rses_property_get_sescmd(rses_property_t* prop);
static bool execute_sescmd_history(backend_ref_t* bref);
static bool execute_sescmd_in_backend(backend_ref_t* backend_ref);
static void sescmd_cursor_reset(sescmd_cursor_t* scur);
static bool sescmd_cursor_history_empty(sescmd_cursor_t* scur);
static void sescmd_cursor_set_active(sescmd_cursor_t* sescmd_cursor,
bool value);
static bool sescmd_cursor_is_active(sescmd_cursor_t* sescmd_cursor);
static GWBUF* sescmd_cursor_clone_querybuf(sescmd_cursor_t* scur);
static mysql_sescmd_t* sescmd_cursor_get_command(sescmd_cursor_t* scur);
static bool sescmd_cursor_next(sescmd_cursor_t* scur);
static GWBUF* sescmd_cursor_process_replies(GWBUF* replybuf, backend_ref_t* bref);
static void tracelog_routed_query(ROUTER_CLIENT_SES* rses,
char* funcname,
backend_ref_t* bref,
GWBUF* buf);
static bool route_session_write(ROUTER_CLIENT_SES* router_client_ses,
GWBUF* querybuf,
ROUTER_INSTANCE* inst,
unsigned char packet_type,
qc_query_type_t qtype);
static void bref_clear_state(backend_ref_t* bref, bref_state_t state);
static void bref_set_state(backend_ref_t* bref, bref_state_t state);
static sescmd_cursor_t* backend_ref_get_sescmd_cursor (backend_ref_t* bref);
static int router_handle_state_switch(DCB* dcb, DCB_REASON reason, void* data);
static bool handle_error_new_connection(ROUTER_INSTANCE* inst,
ROUTER_CLIENT_SES* rses,
DCB* backend_dcb,
GWBUF* errmsg);
static void handle_error_reply_client(MXS_SESSION* ses,
ROUTER_CLIENT_SES* rses,
DCB* backend_dcb,
GWBUF* errmsg);
static SPINLOCK instlock;
static ROUTER_INSTANCE* instances;
bool detect_show_shards(GWBUF* query);
int process_show_shards(ROUTER_CLIENT_SES* rses);
static int hashkeyfun(const void* key);
static int hashcmpfun(const void *, const void *);
void write_error_to_client(DCB* dcb, int errnum, const char* mysqlstate, const char* errmsg);
int inspect_backend_mapping_states(ROUTER_CLIENT_SES *router_cli_ses,
backend_ref_t *bref,
GWBUF** wbuf);
bool handle_default_db(ROUTER_CLIENT_SES *router_cli_ses);
void route_queued_query(ROUTER_CLIENT_SES *router_cli_ses);
void synchronize_shard_map(ROUTER_CLIENT_SES *client);
static int hashkeyfun(const void* key)
{
if (key == NULL)
{
return 0;
}
int hash = 0, c = 0;
const char* ptr = (const char*)key;
while ((c = *ptr++))
{
hash = c + (hash << 6) + (hash << 16) - hash;
}
return hash;
}
static int hashcmpfun(const void* v1, const void* v2)
{
const char* i1 = (const char*) v1;
const char* i2 = (const char*) v2;
return strcmp(i1, i2);
}
void keyfreefun(void* data)
{
MXS_FREE(data);
}
/**
* Allocate a shard map and initialize it.
* @return Pointer to new shard_map_t or NULL if memory allocation failed
*/
shard_map_t* shard_map_alloc()
{
shard_map_t *rval = (shard_map_t*) MXS_MALLOC(sizeof(shard_map_t));
if (rval)
{
if ((rval->hash = hashtable_alloc(SCHEMAROUTER_HASHSIZE, hashkeyfun, hashcmpfun)))
{
HASHCOPYFN kcopy = (HASHCOPYFN)strdup;
hashtable_memory_fns(rval->hash, kcopy, kcopy, keyfreefun, keyfreefun);
spinlock_init(&rval->lock);
rval->last_updated = 0;
rval->state = SHMAP_UNINIT;
}
else
{
MXS_FREE(rval);
rval = NULL;
}
}
return rval;
}
/**
* Convert a length encoded string into a C string.
* @param data Pointer to the first byte of the string
* @return Pointer to the newly allocated string or NULL if the value is NULL or an error occurred
*/
char* get_lenenc_str(void* data)
{
unsigned char* ptr = (unsigned char*)data;
char* rval;
uintptr_t size;
long offset;
if (data == NULL)
{
return NULL;
}
if (*ptr < 251)
{
size = (uintptr_t) * ptr;
offset = 1;
}
else
{
switch (*(ptr))
{
case 0xfb:
return NULL;
case 0xfc:
size = *(ptr + 1) + (*(ptr + 2) << 8);
offset = 2;
break;
case 0xfd:
size = *ptr + (*(ptr + 2) << 8) + (*(ptr + 3) << 16);
offset = 3;
break;
case 0xfe:
size = *ptr + ((*(ptr + 2) << 8)) + (*(ptr + 3) << 16) +
(*(ptr + 4) << 24) + ((uintptr_t) * (ptr + 5) << 32) +
((uintptr_t) * (ptr + 6) << 40) +
((uintptr_t) * (ptr + 7) << 48) + ((uintptr_t) * (ptr + 8) << 56);
offset = 8;
break;
default:
return NULL;
}
}
rval = MXS_MALLOC(sizeof(char) * (size + 1));
if (rval)
{
memcpy(rval, ptr + offset, size);
memset(rval + size, 0, 1);
}
return rval;
}
/**
* Parses a response set to a SHOW DATABASES query and inserts them into the
* router client session's database hashtable. The name of the database is used
* as the key and the unique name of the server is the value. The function
* currently supports only result sets that span a single SQL packet.
* @param rses Router client session
* @param target Target server where the database is
* @param buf GWBUF containing the result set
* @return 1 if a complete response was received, 0 if a partial response was received
* and -1 if a database was found on more than one server.
*/
showdb_response_t parse_showdb_response(ROUTER_CLIENT_SES* rses, backend_ref_t* bref, GWBUF** buffer)
{
unsigned char* ptr;
char* target = bref->bref_backend->server->unique_name;
GWBUF* buf;
bool duplicate_found = false;
showdb_response_t rval = SHOWDB_PARTIAL_RESPONSE;
if (buffer == NULL || *buffer == NULL)
{
return SHOWDB_FATAL_ERROR;
}
/** TODO: Don't make the buffer contiguous but process it as a buffer chain */
*buffer = gwbuf_make_contiguous(*buffer);
buf = modutil_get_complete_packets(buffer);
if (buf == NULL)
{
return SHOWDB_PARTIAL_RESPONSE;
}
ptr = (unsigned char*) buf->start;
if (PTR_IS_ERR(ptr))
{
MXS_INFO("SHOW DATABASES returned an error.");
gwbuf_free(buf);
return SHOWDB_FATAL_ERROR;
}
if (bref->n_mapping_eof == 0)
{
/** Skip column definitions */
while (ptr < (unsigned char*) buf->end && !PTR_IS_EOF(ptr))
{
ptr += gw_mysql_get_byte3(ptr) + 4;
}
if (ptr >= (unsigned char*) buf->end)
{
MXS_INFO("Malformed packet for SHOW DATABASES.");
*buffer = gwbuf_append(buf, *buffer);
return SHOWDB_FATAL_ERROR;
}
atomic_add(&bref->n_mapping_eof, 1);
/** Skip first EOF packet */
ptr += gw_mysql_get_byte3(ptr) + 4;
}
spinlock_acquire(&rses->shardmap->lock);
while (ptr < (unsigned char*) buf->end && !PTR_IS_EOF(ptr))
{
int payloadlen = gw_mysql_get_byte3(ptr);
int packetlen = payloadlen + 4;
char* data = get_lenenc_str(ptr + 4);
if (data)
{
if (hashtable_add(rses->shardmap->hash, data, target))
{
MXS_INFO("<%s, %s>", target, data);
}
else
{
if (!(hashtable_fetch(rses->router->ignored_dbs, data) ||
(rses->router->ignore_regex &&
pcre2_match(rses->router->ignore_regex, (PCRE2_SPTR)data,
PCRE2_ZERO_TERMINATED, 0, 0,
rses->router->ignore_match_data, NULL) >= 0)))
{
duplicate_found = true;
MXS_ERROR("Database '%s' found on servers '%s' and '%s' for user %s@%s.",
data, target,
(char*)hashtable_fetch(rses->shardmap->hash, data),
rses->rses_client_dcb->user,
rses->rses_client_dcb->remote);
}
else if (rses->router->preferred_server &&
strcmp(target, rses->router->preferred_server->unique_name) == 0)
{
/** In conflict situations, use the preferred server */
MXS_INFO("Forcing location of '%s' from '%s' to ''%s",
data, (char*)hashtable_fetch(rses->shardmap->hash,
data), target);
hashtable_delete(rses->shardmap->hash, data);
hashtable_add(rses->shardmap->hash, data, target);
}
}
MXS_FREE(data);
}
ptr += packetlen;
}
spinlock_release(&rses->shardmap->lock);
if (ptr < (unsigned char*) buf->end && PTR_IS_EOF(ptr) && bref->n_mapping_eof == 1)
{
atomic_add(&bref->n_mapping_eof, 1);
MXS_INFO("SHOW DATABASES fully received from %s.",
bref->bref_backend->server->unique_name);
}
else
{
MXS_INFO("SHOW DATABASES partially received from %s.",
bref->bref_backend->server->unique_name);
}
gwbuf_free(buf);
if (duplicate_found)
{
rval = SHOWDB_DUPLICATE_DATABASES;
}
else if (bref->n_mapping_eof == 2)
{
rval = SHOWDB_FULL_RESPONSE;
}
return rval;
}
/**
* Initiate the generation of the database hash table by sending a
* SHOW DATABASES query to each valid backend server. This sets the session
* into the mapping state where it queues further queries until all the database
* servers have returned a result.
* @param inst Router instance
* @param session Router client session
* @return 1 if all writes to backends were succesful and 0 if one or more errors occurred
*/
int gen_databaselist(ROUTER_INSTANCE* inst, ROUTER_CLIENT_SES* session)
{
DCB* dcb;
const char* query = "SHOW DATABASES";
GWBUF *buffer, *clone;
int i, rval = 0;
unsigned int len;
for (i = 0; i < session->rses_nbackends; i++)
{
session->rses_backend_ref[i].bref_mapped = false;
session->rses_backend_ref[i].n_mapping_eof = 0;
}
session->init |= INIT_MAPPING;
session->init &= ~INIT_UNINT;
len = strlen(query) + 1;
buffer = gwbuf_alloc(len + 4);
*((unsigned char*)buffer->start) = len;
*((unsigned char*)buffer->start + 1) = len >> 8;
*((unsigned char*)buffer->start + 2) = len >> 16;
*((unsigned char*)buffer->start + 3) = 0x0;
*((unsigned char*)buffer->start + 4) = 0x03;
memcpy(buffer->start + 5, query, strlen(query));
for (i = 0; i < session->rses_nbackends; i++)
{
if (BREF_IS_IN_USE(&session->rses_backend_ref[i]) &&
!BREF_IS_CLOSED(&session->rses_backend_ref[i]) &
SERVER_IS_RUNNING(session->rses_backend_ref[i].bref_backend->server))
{
clone = gwbuf_clone(buffer);
dcb = session->rses_backend_ref[i].bref_dcb;
rval |= !dcb->func.write(dcb, clone);
MXS_DEBUG("Wrote SHOW DATABASES to %s for session %p: returned %d",
session->rses_backend_ref[i].bref_backend->server->unique_name,
session->rses_client_dcb->session,
rval);
}
}
gwbuf_free(buffer);
return !rval;
}
/**
* Check the hashtable for the right backend for this query.
* @param router Router instance
* @param client Client router session
* @param buffer Query to inspect
* @return Name of the backend or NULL if the query contains no known databases.
*/
char* get_shard_target_name(ROUTER_INSTANCE* router,
ROUTER_CLIENT_SES* client,
GWBUF* buffer,
qc_query_type_t qtype)
{
int sz = 0, i, j;
char** dbnms = NULL;
char* rval = NULL, *query, *tmp = NULL;
bool has_dbs = false; /**If the query targets any database other than the current one*/
bool uses_implicit_databases = false;
dbnms = qc_get_table_names(buffer, &sz, true);
for (i = 0; i < sz; i++)
{
if (strchr(dbnms[i], '.') == NULL)
{
uses_implicit_databases = true;
}
MXS_FREE(dbnms[i]);
}
MXS_FREE(dbnms);
HASHTABLE* ht = client->shardmap->hash;
if (uses_implicit_databases)
{
MXS_INFO("Query implicitly uses the current database");
return (char*)hashtable_fetch(ht, client->current_db);
}
dbnms = qc_get_database_names(buffer, &sz);
if (sz > 0)
{
bool conflict = false;
for (i = 0; i < sz; i++)
{
char* name;
if ((name = (char*)hashtable_fetch(ht, dbnms[i])))
{
if (strcmp(dbnms[i], "information_schema") == 0 && rval == NULL)
{
has_dbs = false;
}
else
{
/** Warn about improper usage of the router */
if (rval && strcmp(name, rval) != 0)
{
MXS_WARNING("Query targets databases on servers '%s' and '%s'. "
"Cross database queries across servers are not supported. "
"Routing query to server with the current active database.",
rval, name);
conflict = true;
}
else if (rval == NULL)
{
rval = name;
has_dbs = true;
MXS_INFO("Query targets database '%s' on server '%s'", dbnms[i], rval);
}
}
}
MXS_FREE(dbnms[i]);
}
MXS_FREE(dbnms);
if (conflict)
{
return (char*)hashtable_fetch(ht, client->current_db);
}
}
/* Check if the query is a show tables query with a specific database */
if (qc_query_is_type(qtype, QUERY_TYPE_SHOW_TABLES))
{
query = modutil_get_SQL(buffer);
if ((tmp = strcasestr(query, "from")))
{
const char *delim = "` \n\t;";
char *saved, *tok = strtok_r(tmp, delim, &saved);
tok = strtok_r(NULL, delim, &saved);
ss_dassert(tok != NULL);
tmp = (char*) hashtable_fetch(ht, tok);
if (tmp)
{
MXS_INFO("SHOW TABLES with specific database '%s' on server '%s'", tok, tmp);
}
}
MXS_FREE(query);
if (tmp == NULL)
{
rval = (char*) hashtable_fetch(ht, client->current_db);
MXS_INFO("SHOW TABLES query, current database '%s' on server '%s'",
client->current_db, rval);
}
else
{
rval = tmp;
has_dbs = true;
}
}
else
{
if (buffer->hint && buffer->hint->type == HINT_ROUTE_TO_NAMED_SERVER)
{
for (i = 0; i < client->rses_nbackends; i++)
{
char *srvnm = client->rses_backend_ref[i].bref_backend->server->unique_name;
if (strcmp(srvnm, buffer->hint->data) == 0)
{
rval = srvnm;
MXS_INFO("Routing hint found (%s)", srvnm);
}
}
}
if (rval == NULL && !has_dbs && client->current_db[0] != '\0')
{
/**
* If the target name has not been found and the session has an
* active database, set is as the target
*/
rval = (char*) hashtable_fetch(ht, client->current_db);
if (rval)
{
MXS_INFO("Using active database '%s'", client->current_db);
}
}
}
return rval;
}
/**
* Check if the backend is still running. If the backend is not running the
* hashtable is updated with up-to-date values.
* @param router Router instance
* @param shard Shard to check
* @return True if the backend server is running
*/
bool check_shard_status(ROUTER_INSTANCE* router, char* shard)
{
for (SERVER_REF *ref = router->service->dbref; ref; ref = ref->next)
{
if (strcmp(ref->server->unique_name, shard) == 0 &&
SERVER_IS_RUNNING(ref->server))
{
return true;
}
}
return false;
}
/**
* The module entry point routine. It is this routine that
* must populate the structure that is referred to as the
* "module object", this is a structure with the set of
* external entry points for this module.
*
* @return The module object
*/
MXS_MODULE* MXS_CREATE_MODULE()
{
MXS_NOTICE("Initializing Schema Sharding Router.");
spinlock_init(&instlock);
instances = NULL;
static MXS_ROUTER_OBJECT MyObject =
{
createInstance,
newSession,
closeSession,
freeSession,
routeQuery,
diagnostic,
clientReply,
handleError,
getCapabilities,
NULL
};
static MXS_MODULE info =
{
MXS_MODULE_API_ROUTER,
MXS_MODULE_BETA_RELEASE,
MXS_ROUTER_VERSION,
"A database sharding router for simple sharding",
"V1.0.0",
&MyObject,
NULL, /* Process init. */
NULL, /* Process finish. */
NULL, /* Thread init. */
NULL, /* Thread finish. */
{
{"ignore_databases", MXS_MODULE_PARAM_STRING},
{"ignore_databases_regex", MXS_MODULE_PARAM_STRING},
{"max_sescmd_history", MXS_MODULE_PARAM_COUNT, "0"},
{"disable_sescmd_history", MXS_MODULE_PARAM_BOOL, "false"},
{"refresh_databases", MXS_MODULE_PARAM_BOOL, "true"},
{"refresh_interval", MXS_MODULE_PARAM_COUNT, DEFAULT_REFRESH_INTERVAL},
{"debug", MXS_MODULE_PARAM_BOOL, "false"},
{"preferred_server", MXS_MODULE_PARAM_SERVER},
{MXS_END_MODULE_PARAMS}
}
};
return &info;
}
/**
* Create an instance of schemarouter router within the MaxScale.
*
*
* @param service The service this router is being create for
* @param options The options for this query router
*
* @return NULL in failure, pointer to router in success.
*/
static MXS_ROUTER* createInstance(SERVICE *service, char **options)
{
ROUTER_INSTANCE* router;
MXS_CONFIG_PARAMETER* conf;
MXS_CONFIG_PARAMETER* param;
if ((router = MXS_CALLOC(1, sizeof(ROUTER_INSTANCE))) == NULL)
{
return NULL;
}
if ((router->ignored_dbs = hashtable_alloc(SCHEMAROUTER_HASHSIZE, hashkeyfun, hashcmpfun)) == NULL)
{
MXS_ERROR("Memory allocation failed when allocating schemarouter database ignore list.");
MXS_FREE(router);
return NULL;
}
hashtable_memory_fns(router->ignored_dbs, hashtable_item_strdup, NULL, hashtable_item_free, NULL);
if ((router->shard_maps = hashtable_alloc(SCHEMAROUTER_USERHASH_SIZE, hashkeyfun, hashcmpfun)) == NULL)
{
MXS_ERROR("Memory allocation failed when allocating schemarouter database ignore list.");
hashtable_free(router->ignored_dbs);
MXS_FREE(router);
return NULL;
}
hashtable_memory_fns(router->shard_maps, hashtable_item_strdup, NULL, keyfreefun, NULL);
/** Add default system databases to ignore */
hashtable_add(router->ignored_dbs, "mysql", "");
hashtable_add(router->ignored_dbs, "information_schema", "");
hashtable_add(router->ignored_dbs, "performance_schema", "");
router->service = service;
router->schemarouter_config.max_sescmd_hist = 0;
router->schemarouter_config.last_refresh = time(NULL);
router->stats.longest_sescmd = 0;
router->stats.n_hist_exceeded = 0;
router->stats.n_queries = 0;
router->stats.n_sescmd = 0;
router->stats.ses_longest = 0;
router->stats.ses_shortest = (double)((unsigned long)(~0));
spinlock_init(&router->lock);
conf = service->svc_config_param;
router->schemarouter_config.refresh_databases = config_get_bool(conf, "refresh_databases");
router->schemarouter_config.refresh_min_interval = config_get_integer(conf, "refresh_interval");
router->schemarouter_config.max_sescmd_hist = config_get_integer(conf, "max_sescmd_history");
router->schemarouter_config.disable_sescmd_hist = config_get_bool(conf, "disable_sescmd_history");
router->schemarouter_config.debug = config_get_bool(conf, "debug");
router->preferred_server = config_get_server(conf, "preferred_server");
if ((config_get_param(conf, "auth_all_servers")) == NULL)
{
MXS_NOTICE("Authentication data is fetched from all servers. To disable this "
"add 'auth_all_servers=0' to the service.");
service->users_from_all = true;
}
if ((param = config_get_param(conf, "ignore_databases_regex")))
{
int errcode;
PCRE2_SIZE erroffset;
pcre2_code* re = pcre2_compile((PCRE2_SPTR)param->value, PCRE2_ZERO_TERMINATED, 0,
&errcode, &erroffset, NULL);
if (re == NULL)
{
PCRE2_UCHAR errbuf[512];
pcre2_get_error_message(errcode, errbuf, sizeof(errbuf));
MXS_ERROR("Regex compilation failed at %d for regex '%s': %s",
(int)erroffset, param->value, errbuf);
hashtable_free(router->ignored_dbs);
MXS_FREE(router);
return NULL;
}
pcre2_match_data* match_data = pcre2_match_data_create_from_pattern(re, NULL);
if (match_data == NULL)
{
MXS_ERROR("PCRE2 match data creation failed. This"
" is most likely caused by a lack of available memory.");
pcre2_code_free(re);
hashtable_free(router->ignored_dbs);
MXS_FREE(router);
return NULL;
}
router->ignore_regex = re;
router->ignore_match_data = match_data;
}
if ((param = config_get_param(conf, "ignore_databases")))
{
char val[strlen(param->value) + 1];
strcpy(val, param->value);
const char *sep = ", \t";
char *sptr;
char *tok = strtok_r(val, sep, &sptr);
while (tok)
{
hashtable_add(router->ignored_dbs, tok, "");
tok = strtok_r(NULL, sep, &sptr);
}
}
bool failure = false;
for (int i = 0; options && options[i]; i++)
{
char* value = strchr(options[i], '=');
if (value == NULL)
{
MXS_ERROR("Unknown router options for %s", options[i]);
failure = true;
break;
}
*value = '\0';
value++;
if (strcmp(options[i], "max_sescmd_history") == 0)
{
router->schemarouter_config.max_sescmd_hist = atoi(value);
}
else if (strcmp(options[i], "disable_sescmd_history") == 0)
{
router->schemarouter_config.disable_sescmd_hist = config_truth_value(value);
}
else if (strcmp(options[i], "refresh_databases") == 0)
{
router->schemarouter_config.refresh_databases = config_truth_value(value);
}
else if (strcmp(options[i], "refresh_interval") == 0)
{
router->schemarouter_config.refresh_min_interval = atof(value);
}
else if (strcmp(options[i], "debug") == 0)
{
router->schemarouter_config.debug = config_truth_value(value);
}
else
{
MXS_ERROR("Unknown router options for %s", options[i]);
failure = true;
break;
}
}
/** Setting a limit to the history size is not needed if it is disabled.*/
if (router->schemarouter_config.disable_sescmd_hist && router->schemarouter_config.max_sescmd_hist > 0)
{
router->schemarouter_config.max_sescmd_hist = 0;
}
if (failure)
{
MXS_FREE(router);
router = NULL;
}
return (MXS_ROUTER *)router;
}
/**
* Check if the shard map is out of date and update its state if necessary.
* @param router Router instance
* @param map Shard map to update
* @return Current state of the shard map
*/
enum shard_map_state shard_map_update_state(shard_map_t *self, ROUTER_INSTANCE* router)
{
spinlock_acquire(&self->lock);
double tdiff = difftime(time(NULL), self->last_updated);
if (tdiff > router->schemarouter_config.refresh_min_interval)
{
self->state = SHMAP_STALE;
}
enum shard_map_state state = self->state;
spinlock_release(&self->lock);
return state;
}
/**
* Associate a new session with this instance of the router.
*
* The session is used to store all the data required for a particular
* client connection.
*
* @param instance The router instance data
* @param session The session itself
* @return Session specific data for this session
*/
static MXS_ROUTER_SESSION* newSession(MXS_ROUTER* router_inst, MXS_SESSION* session)
{
backend_ref_t* backend_ref; /*< array of backend references (DCB, BACKEND, cursor) */
ROUTER_CLIENT_SES* client_rses = NULL;
ROUTER_INSTANCE* router = (ROUTER_INSTANCE *)router_inst;
bool succp;
int router_nservers = 0; /*< # of servers in total */
char db[MYSQL_DATABASE_MAXLEN + 1] = "";
MySQLProtocol* protocol = session->client_dcb->protocol;
MYSQL_session* data = session->client_dcb->data;
bool using_db = false;
bool have_db = false;
/* To enable connecting directly to a sharded database we first need
* to disable it for the client DCB's protocol so that we can connect to them*/
if (protocol->client_capabilities & GW_MYSQL_CAPABILITIES_CONNECT_WITH_DB &&
(have_db = strnlen(data->db, MYSQL_DATABASE_MAXLEN) > 0))
{
protocol->client_capabilities &= ~GW_MYSQL_CAPABILITIES_CONNECT_WITH_DB;
strcpy(db, data->db);
*data->db = 0;
using_db = true;
MXS_INFO("Client logging in directly to a database '%s', "
"postponing until databases have been mapped.", db);
}
if (!have_db)
{
MXS_INFO("Client'%s' connecting with empty database.", data->user);
}
client_rses = (ROUTER_CLIENT_SES *)MXS_CALLOC(1, sizeof(ROUTER_CLIENT_SES));
if (client_rses == NULL)
{
return NULL;
}
#if defined(SS_DEBUG)
client_rses->rses_chk_top = CHK_NUM_ROUTER_SES;
client_rses->rses_chk_tail = CHK_NUM_ROUTER_SES;
#endif
client_rses->router = router;
client_rses->rses_mysql_session = (MYSQL_session*)session->client_dcb->data;
client_rses->rses_client_dcb = (DCB*)session->client_dcb;
spinlock_acquire(&router->lock);
shard_map_t *map = hashtable_fetch(router->shard_maps, session->client_dcb->user);
enum shard_map_state state;
if (map)
{
state = shard_map_update_state(map, router);
}
spinlock_release(&router->lock);
if (map == NULL || state != SHMAP_READY)
{
if ((map = shard_map_alloc()) == NULL)
{
MXS_ERROR("Failed to allocate enough memory to create"
"new shard mapping. Session will be closed.");
MXS_FREE(client_rses);
return NULL;
}
client_rses->init = INIT_UNINT;
}
else
{
client_rses->init = INIT_READY;
atomic_add(&router->stats.shmap_cache_hit, 1);
}
client_rses->shardmap = map;
memcpy(&client_rses->rses_config, &router->schemarouter_config, sizeof(schemarouter_config_t));
client_rses->n_sescmd = 0;
client_rses->rses_config.last_refresh = time(NULL);
if (using_db)
{
client_rses->init |= INIT_USE_DB;
}
/**
* Set defaults to session variables.
*/
client_rses->rses_autocommit_enabled = true;
client_rses->rses_transaction_active = false;
/**
* Instead of calling this, ensure that there is at least one
* responding server.
*/
router_nservers = router->service->n_dbref;
/**
* Create backend reference objects for this session.
*/
backend_ref = (backend_ref_t *)MXS_CALLOC(router_nservers, sizeof(backend_ref_t));
if (backend_ref == NULL)
{
MXS_FREE(client_rses);
return NULL;
}
/**
* Initialize backend references with BACKEND ptr.
* Initialize session command cursors for each backend reference.
*/
int i = 0;
for (SERVER_REF *ref = router->service->dbref; ref; ref = ref->next)
{
if (ref->active)
{
#if defined(SS_DEBUG)
backend_ref[i].bref_chk_top = CHK_NUM_BACKEND_REF;
backend_ref[i].bref_chk_tail = CHK_NUM_BACKEND_REF;
backend_ref[i].bref_sescmd_cur.scmd_cur_chk_top = CHK_NUM_SESCMD_CUR;
backend_ref[i].bref_sescmd_cur.scmd_cur_chk_tail = CHK_NUM_SESCMD_CUR;
#endif
backend_ref[i].bref_state = 0;
backend_ref[i].n_mapping_eof = 0;
backend_ref[i].map_queue = NULL;
backend_ref[i].bref_backend = ref;
/** store pointers to sescmd list to both cursors */
backend_ref[i].bref_sescmd_cur.scmd_cur_rses = client_rses;
backend_ref[i].bref_sescmd_cur.scmd_cur_active = false;
backend_ref[i].bref_sescmd_cur.scmd_cur_ptr_property =
&client_rses->rses_properties[RSES_PROP_TYPE_SESCMD];
backend_ref[i].bref_sescmd_cur.scmd_cur_cmd = NULL;
i++;
}
}
if (i < router_nservers)
{
router_nservers = i;
}
spinlock_init(&client_rses->rses_lock);
client_rses->rses_backend_ref = backend_ref;
client_rses->rses_nbackends = router_nservers;
/**
* Find a backend servers to connect to.
* This command requires that rsession's lock is held.
*/
if (!(succp = rses_begin_locked_router_action(client_rses)))
{
MXS_FREE(client_rses->rses_backend_ref);
MXS_FREE(client_rses);
return NULL;
}
/**
* Connect to all backend servers
*/
succp = connect_backend_servers(backend_ref, router_nservers, session, router);
rses_end_locked_router_action(client_rses);
if (!succp || !(succp = rses_begin_locked_router_action(client_rses)))
{
MXS_FREE(client_rses->rses_backend_ref);
MXS_FREE(client_rses);
return NULL;
}
if (db[0])
{
/* Store the database the client is connecting to */
snprintf(client_rses->connect_db, MYSQL_DATABASE_MAXLEN + 1, "%s", db);
}
rses_end_locked_router_action(client_rses);
atomic_add(&router->stats.sessions, 1);
return (void *)client_rses;
}
/**
* Close a session with the router, this is the mechanism
* by which a router may cleanup data structure etc.
*
* @param instance The router instance data
* @param session The session being closed
*/
static void closeSession(MXS_ROUTER* instance, MXS_ROUTER_SESSION* router_session)
{
ROUTER_CLIENT_SES* router_cli_ses;
ROUTER_INSTANCE* inst;
backend_ref_t* backend_ref;
MXS_DEBUG("%lu [schemarouter:closeSession]", pthread_self());
/**
* router session can be NULL if newSession failed and it is discarding
* its connections and DCB's.
*/
if (router_session == NULL)
{
return;
}
router_cli_ses = (ROUTER_CLIENT_SES *)router_session;
CHK_CLIENT_RSES(router_cli_ses);
inst = router_cli_ses->router;
backend_ref = router_cli_ses->rses_backend_ref;
/**
* Lock router client session for secure read and update.
*/
if (!router_cli_ses->rses_closed && rses_begin_locked_router_action(router_cli_ses))
{
int i;
/**
* This sets router closed. Nobody is allowed to use router
* whithout checking this first.
*/
router_cli_ses->rses_closed = true;
for (i = 0; i < router_cli_ses->rses_nbackends; i++)
{
backend_ref_t* bref = &backend_ref[i];
DCB* dcb = bref->bref_dcb;
/** Close those which had been connected */
if (BREF_IS_IN_USE(bref))
{
CHK_DCB(dcb);
#if defined(SS_DEBUG)
/**
* session must be moved to SESSION_STATE_STOPPING state before
* router session is closed.
*/
if (dcb->session != NULL)
{
ss_dassert(dcb->session->state == SESSION_STATE_STOPPING);
}
#endif
/** Clean operation counter in bref and in SERVER */
while (BREF_IS_WAITING_RESULT(bref))
{
bref_clear_state(bref, BREF_WAITING_RESULT);
}
bref_clear_state(bref, BREF_IN_USE);
bref_set_state(bref, BREF_CLOSED);
/**
* closes protocol and dcb
*/
dcb_close(dcb);
/** decrease server current connection counters */
atomic_add(&bref->bref_backend->connections, -1);
}
}
gwbuf_free(router_cli_ses->queue);
/** Unlock */
rses_end_locked_router_action(router_cli_ses);
spinlock_acquire(&inst->lock);
if (inst->stats.longest_sescmd < router_cli_ses->stats.longest_sescmd)
{
inst->stats.longest_sescmd = router_cli_ses->stats.longest_sescmd;
}
double ses_time = difftime(time(NULL), router_cli_ses->rses_client_dcb->session->stats.connect);
if (inst->stats.ses_longest < ses_time)
{
inst->stats.ses_longest = ses_time;
}
if (inst->stats.ses_shortest > ses_time && inst->stats.ses_shortest > 0)
{
inst->stats.ses_shortest = ses_time;
}
inst->stats.ses_average =
(ses_time + ((inst->stats.sessions - 1) * inst->stats.ses_average)) /
(inst->stats.sessions);
spinlock_release(&inst->lock);
}
}
static void freeSession(MXS_ROUTER* router_instance, MXS_ROUTER_SESSION* router_client_session)
{
ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_client_session;
for (int i = 0; i < router_cli_ses->rses_nbackends; i++)
{
gwbuf_free(router_cli_ses->rses_backend_ref[i].bref_pending_cmd);
}
/**
* For each property type, walk through the list, finalize properties
* and free the allocated memory.
*/
for (int i = RSES_PROP_TYPE_FIRST; i < RSES_PROP_TYPE_COUNT; i++)
{
rses_property_t* p = router_cli_ses->rses_properties[i];
rses_property_t* q = p;
while (p != NULL)
{
q = p->rses_prop_next;
rses_property_done(p);
p = q;
}
}
/*
* We are no longer in the linked list, free
* all the memory and other resources associated
* to the client session.
*/
MXS_FREE(router_cli_ses->rses_backend_ref);
MXS_FREE(router_cli_ses);
return;
}
/**
* Provide the router with a pointer to a suitable backend dcb.
*
* Detect failures in server statuses and reselect backends if necessary
* If name is specified, server name becomes primary selection criteria.
* Similarly, if max replication lag is specified, skip backends which lag too
* much.
*
* @param p_dcb Address of the pointer to the resulting DCB
* @param rses Pointer to router client session
* @param btype Backend type
* @param name Name of the backend which is primarily searched. May be NULL.
*
* @return True if proper DCB was found, false otherwise.
*/
static bool get_shard_dcb(DCB** p_dcb,
ROUTER_CLIENT_SES* rses,
char* name)
{
backend_ref_t* backend_ref;
int i;
bool succp = false;
CHK_CLIENT_RSES(rses);
ss_dassert(p_dcb != NULL && *(p_dcb) == NULL);
if (p_dcb == NULL || name == NULL)
{
goto return_succp;
}
backend_ref = rses->rses_backend_ref;
for (i = 0; i < rses->rses_nbackends; i++)
{
SERVER_REF* b = backend_ref[i].bref_backend;
/**
* To become chosen:
* backend must be in use, name must match, and
* the backend state must be RUNNING
*/
if (BREF_IS_IN_USE((&backend_ref[i])) &&
(strncasecmp(name, b->server->unique_name, PATH_MAX) == 0) &&
SERVER_IS_RUNNING(b->server))
{
*p_dcb = backend_ref[i].bref_dcb;
succp = true;
ss_dassert(backend_ref[i].bref_dcb->state != DCB_STATE_ZOMBIE);
goto return_succp;
}
}
return_succp:
return succp;
}
/**
* Examine the query type, transaction state and routing hints. Find out the
* target for query routing.
*
* @param qtype Type of query
* @param trx_active Is transacation active or not
* @param hint Pointer to list of hints attached to the query buffer
*
* @return bitfield including the routing target, or the target server name
* if the query would otherwise be routed to slave.
*/
static route_target_t get_shard_route_target(qc_query_type_t qtype,
bool trx_active, /*< !!! turha ? */
HINT* hint) /*< !!! turha ? */
{
route_target_t target = TARGET_UNDEFINED;
/**
* These queries are not affected by hints
*/
if (qc_query_is_type(qtype, QUERY_TYPE_SESSION_WRITE) ||
qc_query_is_type(qtype, QUERY_TYPE_PREPARE_STMT) ||
qc_query_is_type(qtype, QUERY_TYPE_PREPARE_NAMED_STMT) ||
qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_WRITE) ||
/** enable or disable autocommit are always routed to all */
qc_query_is_type(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT) ||
qc_query_is_type(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT))
{
/** hints don't affect on routing */
target = TARGET_ALL;
}
else if (qc_query_is_type(qtype, QUERY_TYPE_SYSVAR_READ) ||
qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_READ))
{
target = TARGET_ANY;
}
#if defined(SS_DEBUG)
MXS_INFO("Selected target type \"%s\"", STRTARGET(target));
#endif
return target;
}
/**
* Check if the query is a DROP TABLE... query and
* if it targets a temporary table, remove it from the hashtable.
* @param instance Router instance
* @param router_session Router client session
* @param querybuf GWBUF containing the query
* @param type The type of the query resolved so far
*/
void check_drop_tmp_table(MXS_ROUTER* instance,
void* router_session,
GWBUF* querybuf,
qc_query_type_t type)
{
int tsize = 0, klen = 0, i;
char** tbl = NULL;
char *hkey, *dbname;
ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session;
rses_property_t* rses_prop_tmp;
rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES];
dbname = router_cli_ses->current_db;
if (qc_is_drop_table_query(querybuf))
{
tbl = qc_get_table_names(querybuf, &tsize, false);
if (tbl != NULL)
{
for (i = 0; i < tsize; i++)
{
klen = strlen(dbname) + strlen(tbl[i]) + 2;
hkey = MXS_CALLOC(klen, sizeof(char));
MXS_ABORT_IF_NULL(hkey);
strcpy(hkey, dbname);
strcat(hkey, ".");
strcat(hkey, tbl[i]);
if (rses_prop_tmp && rses_prop_tmp->rses_prop_data.temp_tables)
{
if (hashtable_delete(rses_prop_tmp->rses_prop_data.temp_tables,
(void *)hkey))
{
MXS_INFO("Temporary table dropped: %s", hkey);
}
}
MXS_FREE(tbl[i]);
MXS_FREE(hkey);
}
MXS_FREE(tbl);
}
}
}
/**
* Check if the query targets a temporary table.
* @param instance Router instance
* @param router_session Router client session
* @param querybuf GWBUF containing the query
* @param type The type of the query resolved so far
* @return The type of the query
*/
qc_query_type_t is_read_tmp_table(MXS_ROUTER* instance,
void* router_session,
GWBUF* querybuf,
qc_query_type_t type)
{
bool target_tmp_table = false;
int tsize = 0, klen = 0, i;
char** tbl = NULL;
char *hkey, *dbname;
ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session;
qc_query_type_t qtype = type;
rses_property_t* rses_prop_tmp;
rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES];
dbname = router_cli_ses->current_db;
if (qc_query_is_type(qtype, QUERY_TYPE_READ) ||
qc_query_is_type(qtype, QUERY_TYPE_LOCAL_READ) ||
qc_query_is_type(qtype, QUERY_TYPE_USERVAR_READ) ||
qc_query_is_type(qtype, QUERY_TYPE_SYSVAR_READ) ||
qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_READ))
{
tbl = qc_get_table_names(querybuf, &tsize, false);
if (tbl != NULL && tsize > 0)
{
/** Query targets at least one table */
for (i = 0; i < tsize && !target_tmp_table && tbl[i]; i++)
{
klen = strlen(dbname) + strlen(tbl[i]) + 2;
hkey = MXS_CALLOC(klen, sizeof(char));
MXS_ABORT_IF_NULL(hkey);
strcpy(hkey, dbname);
strcat(hkey, ".");
strcat(hkey, tbl[i]);
if (rses_prop_tmp && rses_prop_tmp->rses_prop_data.temp_tables)
{
if ((target_tmp_table =
(bool)hashtable_fetch(rses_prop_tmp->rses_prop_data.temp_tables, (void *)hkey)))
{
/**Query target is a temporary table*/
qtype = QUERY_TYPE_READ_TMP_TABLE;
MXS_INFO("Query targets a temporary table: %s", hkey);
}
}
MXS_FREE(hkey);
}
}
}
if (tbl != NULL)
{
for (i = 0; i < tsize; i++)
{
MXS_FREE(tbl[i]);
}
MXS_FREE(tbl);
}
return qtype;
}
/**
* If query is of type QUERY_TYPE_CREATE_TMP_TABLE then find out
* the database and table name, create a hashvalue and
* add it to the router client session's property. If property
* doesn't exist then create it first.
* @param instance Router instance
* @param router_session Router client session
* @param querybuf GWBUF containing the query
* @param type The type of the query resolved so far
*/
void check_create_tmp_table(MXS_ROUTER* instance,
void* router_session,
GWBUF* querybuf,
qc_query_type_t type)
{
int klen = 0;
char *hkey, *dbname;
ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session;
rses_property_t* rses_prop_tmp;
HASHTABLE* h;
rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES];
dbname = router_cli_ses->current_db;
if (qc_query_is_type(type, QUERY_TYPE_CREATE_TMP_TABLE))
{
bool is_temp = true;
char* tblname = NULL;
tblname = qc_get_created_table_name(querybuf);
if (tblname && strlen(tblname) > 0)
{
klen = strlen(dbname) + strlen(tblname) + 2;
hkey = MXS_CALLOC(klen, sizeof(char));
MXS_ABORT_IF_NULL(hkey);
strcpy(hkey, dbname);
strcat(hkey, ".");
strcat(hkey, tblname);
}
else
{
hkey = NULL;
}
if (rses_prop_tmp == NULL)
{
if ((rses_prop_tmp =
(rses_property_t*)MXS_CALLOC(1, sizeof(rses_property_t))))
{
#if defined(SS_DEBUG)
rses_prop_tmp->rses_prop_chk_top = CHK_NUM_ROUTER_PROPERTY;
rses_prop_tmp->rses_prop_chk_tail = CHK_NUM_ROUTER_PROPERTY;
#endif
rses_prop_tmp->rses_prop_rsession = router_cli_ses;
rses_prop_tmp->rses_prop_refcount = 1;
rses_prop_tmp->rses_prop_next = NULL;
rses_prop_tmp->rses_prop_type = RSES_PROP_TYPE_TMPTABLES;
router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES] = rses_prop_tmp;
}
}
if (rses_prop_tmp)
{
if (rses_prop_tmp->rses_prop_data.temp_tables == NULL)
{
h = hashtable_alloc(SCHEMAROUTER_HASHSIZE, hashkeyfun, hashcmpfun);
hashtable_memory_fns(h,
hashtable_item_strdup, hashtable_item_strdup,
hashtable_item_free, hashtable_item_free);
if (h != NULL)
{
rses_prop_tmp->rses_prop_data.temp_tables = h;
}
else
{
MXS_ERROR("Failed to allocate a new hashtable.");
}
}
if (hkey && rses_prop_tmp->rses_prop_data.temp_tables &&
hashtable_add(rses_prop_tmp->rses_prop_data.temp_tables,
(void *)hkey,
(void *)is_temp) == 0) /*< Conflict in hash table */
{
MXS_INFO("Temporary table conflict in hashtable: %s", hkey);
}
#if defined(SS_DEBUG)
{
bool retkey = hashtable_fetch(rses_prop_tmp->rses_prop_data.temp_tables, hkey);
if (retkey)
{
MXS_INFO("Temporary table added: %s", hkey);
}
}
#endif
}
MXS_FREE(hkey);
MXS_FREE(tblname);
}
}
int cmpfn(const void* a, const void *b)
{
return strcmp(*(char* const *)a, *(char* const *)b);
}
/** Internal structure used to stream the list of databases */
struct string_array
{
char** array;
int position;
int size;
};
/**
* Callback for the database list streaming.
* @param rset Result set which is being processed
* @param data Pointer to struct string_array containing the database names
* @return New resultset row or NULL if no more data is available. If memory allocation
* failed, NULL is returned.
*/
RESULT_ROW *result_set_cb(struct resultset * rset, void *data)
{
RESULT_ROW *row = NULL;
struct string_array *strarray = (struct string_array*) data;
if (strarray->position < strarray->size && (row = resultset_make_row(rset)))
{
if (resultset_row_set(row, 0, strarray->array[strarray->position++]) == 0)
{
resultset_free_row(row);
row = NULL;
}
}
return row;
}
/**
* Generates a custom SHOW DATABASES result set from all the databases in the
* hashtable. Only backend servers that are up and in a proper state are listed
* in it.
* @param router Router instance
* @param client Router client session
* @return True if the sending of the database list was successful, otherwise false
*/
bool send_database_list(ROUTER_INSTANCE* router, ROUTER_CLIENT_SES* client)
{
bool rval = false;
spinlock_acquire(&client->shardmap->lock);
if (client->shardmap->state != SHMAP_UNINIT)
{
struct string_array strarray;
const int size = hashtable_size(client->shardmap->hash);
strarray.array = MXS_MALLOC(size * sizeof(char*));
MXS_ABORT_IF_NULL(strarray.array);
strarray.position = 0;
HASHITERATOR *iter = hashtable_iterator(client->shardmap->hash);
RESULTSET* resultset = resultset_create(result_set_cb, &strarray);
if (strarray.array && iter && resultset)
{
char *key;
int i = 0;
while ((key = hashtable_next(iter)))
{
char *value = hashtable_fetch(client->shardmap->hash, key);
SERVER * server = server_find_by_unique_name(value);
if (SERVER_IS_RUNNING(server))
{
strarray.array[i++] = key;
}
}
strarray.size = i;
qsort(strarray.array, strarray.size, sizeof(char*), cmpfn);
if (resultset_add_column(resultset, "Database", MYSQL_DATABASE_MAXLEN,
COL_TYPE_VARCHAR))
{
resultset_stream_mysql(resultset, client->rses_client_dcb);
rval = true;
}
}
resultset_free(resultset);
hashtable_iterator_free(iter);
MXS_FREE(strarray.array);
}
spinlock_release(&client->shardmap->lock);
return rval;
}
/**
* The main routing entry, this is called with every packet that is
* received and has to be forwarded to the backend database.
*
* The routeQuery will make the routing decision based on the contents
* of the instance, session and the query itself in the queue. The
* data in the queue may not represent a complete query, it represents
* the data that has been received. The query router itself is responsible
* for buffering the partial query, a later call to the query router will
* contain the remainder, or part thereof of the query.
*
* @param instance The query router instance
* @param router_session The session associated with the client
* @param querybuf MaxScale buffer queue with received packet
*
* @return if succeed 1, otherwise 0
* If routeQuery fails, it means that router session has failed.
* In any tolerated failure, handleError is called and if necessary,
* an error message is sent to the client.
*
*/
static int routeQuery(MXS_ROUTER* instance,
MXS_ROUTER_SESSION* router_session,
GWBUF* qbuf)
{
qc_query_type_t qtype = QUERY_TYPE_UNKNOWN;
mysql_server_cmd_t packet_type;
uint8_t* packet;
int i, ret = 0;
DCB* target_dcb = NULL;
ROUTER_INSTANCE* inst = (ROUTER_INSTANCE *)instance;
ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session;
bool rses_is_closed = false;
bool change_successful = false;
route_target_t route_target = TARGET_UNDEFINED;
bool succp = false;
char* tname = NULL;
char* targetserver = NULL;
GWBUF* querybuf = qbuf;
char db[MYSQL_DATABASE_MAXLEN + 1];
char errbuf[26 + MYSQL_DATABASE_MAXLEN];
CHK_CLIENT_RSES(router_cli_ses);
ss_dassert(!GWBUF_IS_TYPE_UNDEFINED(querybuf));
if (!rses_begin_locked_router_action(router_cli_ses))
{
MXS_INFO("Route query aborted! Routing session is closed <");
ret = 0;
goto retblock;
}
if (!(rses_is_closed = router_cli_ses->rses_closed))
{
if (router_cli_ses->init & INIT_UNINT)
{
/* Generate database list */
gen_databaselist(inst, router_cli_ses);
}
/**
* If the databases are still being mapped or if the client connected
* with a default database but no database mapping was performed we need
* to store the query. Once the databases have been mapped and/or the
* default database is taken into use we can send the query forward.
*/
if (router_cli_ses->init & (INIT_MAPPING | INIT_USE_DB))
{
int init_rval = 1;
char* querystr = modutil_get_SQL(querybuf);
MXS_INFO("Storing query for session %p: %s",
router_cli_ses->rses_client_dcb->session,
querystr);
MXS_FREE(querystr);
querybuf = gwbuf_make_contiguous(querybuf);
GWBUF* ptr = router_cli_ses->queue;
while (ptr && ptr->next)
{
ptr = ptr->next;
}
if (ptr == NULL)
{
router_cli_ses->queue = querybuf;
}
else
{
ptr->next = querybuf;
}
if (router_cli_ses->init == (INIT_READY | INIT_USE_DB))
{
/**
* This state is possible if a client connects with a default database
* and the shard map was found from the router cache
*/
if (!handle_default_db(router_cli_ses))
{
init_rval = 0;
}
}
rses_end_locked_router_action(router_cli_ses);
return init_rval;
}
}
rses_end_locked_router_action(router_cli_ses);
packet = GWBUF_DATA(querybuf);
packet_type = packet[4];
if (rses_is_closed)
{
/**
* MYSQL_COM_QUIT may have sent by client and as a part of backend
* closing procedure.
*/
if (packet_type != MYSQL_COM_QUIT)
{
char* query_str = modutil_get_query(querybuf);
MXS_ERROR("Can't route %s:%s:\"%s\" to "
"backend server. Router is closed.",
STRPACKETTYPE(packet_type),
STRQTYPE(qtype),
(query_str == NULL ? "(empty)" : query_str));
MXS_FREE(query_str);
}
ret = 0;
goto retblock;
}
/** If buffer is not contiguous, make it such */
if (querybuf->next != NULL)
{
querybuf = gwbuf_make_contiguous(querybuf);
}
if (detect_show_shards(querybuf))
{
process_show_shards(router_cli_ses);
ret = 1;
goto retblock;
}
qc_query_op_t op = QUERY_OP_UNDEFINED;
switch (packet_type)
{
case MYSQL_COM_QUIT: /*< 1 QUIT will close all sessions */
case MYSQL_COM_INIT_DB: /*< 2 DDL must go to the master */
case MYSQL_COM_REFRESH: /*< 7 - I guess this is session but not sure */
case MYSQL_COM_DEBUG: /*< 0d all servers dump debug info to stdout */
case MYSQL_COM_PING: /*< 0e all servers are pinged */
case MYSQL_COM_CHANGE_USER: /*< 11 all servers change it accordingly */
case MYSQL_COM_STMT_CLOSE: /*< free prepared statement */
case MYSQL_COM_STMT_SEND_LONG_DATA: /*< send data to column */
case MYSQL_COM_STMT_RESET: /*< resets the data of a prepared statement */
qtype = QUERY_TYPE_SESSION_WRITE;
break;
case MYSQL_COM_CREATE_DB: /**< 5 DDL must go to the master */
case MYSQL_COM_DROP_DB: /**< 6 DDL must go to the master */
qtype = QUERY_TYPE_WRITE;
break;
case MYSQL_COM_QUERY:
qtype = qc_get_type_mask(querybuf);
op = qc_get_operation(querybuf);
break;
case MYSQL_COM_STMT_PREPARE:
qtype = qc_get_type_mask(querybuf);
qtype |= QUERY_TYPE_PREPARE_STMT;
break;
case MYSQL_COM_STMT_EXECUTE:
/** Parsing is not needed for this type of packet */
qtype = QUERY_TYPE_EXEC_STMT;
break;
case MYSQL_COM_SHUTDOWN: /**< 8 where should shutdown be routed ? */
case MYSQL_COM_STATISTICS: /**< 9 ? */
case MYSQL_COM_PROCESS_INFO: /**< 0a ? */
case MYSQL_COM_CONNECT: /**< 0b ? */
case MYSQL_COM_PROCESS_KILL: /**< 0c ? */
case MYSQL_COM_TIME: /**< 0f should this be run in gateway ? */
case MYSQL_COM_DELAYED_INSERT: /**< 10 ? */
case MYSQL_COM_DAEMON: /**< 1d ? */
default:
break;
} /**< switch by packet type */
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))
{
uint8_t* packet = GWBUF_DATA(querybuf);
unsigned char ptype = packet[4];
size_t len = MXS_MIN(GWBUF_LENGTH(querybuf),
MYSQL_GET_PAYLOAD_LEN((unsigned char *)querybuf->start) - 1);
char* data = (char*)&packet[5];
char* contentstr = strndup(data, len);
char* qtypestr = qc_typemask_to_string(qtype);
MXS_INFO("> Cmd: %s, type: %s, "
"stmt: %s%s %s",
STRPACKETTYPE(ptype),
(qtypestr == NULL ? "N/A" : qtypestr),
contentstr,
(querybuf->hint == NULL ? "" : ", Hint:"),
(querybuf->hint == NULL ? "" : STRHINTTYPE(querybuf->hint->type)));
MXS_FREE(contentstr);
MXS_FREE(qtypestr);
}
/**
* Find out whether the query should be routed to single server or to
* all of them.
*/
if (packet_type == MYSQL_COM_INIT_DB || op == QUERY_OP_CHANGE_DB)
{
spinlock_acquire(&router_cli_ses->shardmap->lock);
change_successful = change_current_db(router_cli_ses->current_db,
router_cli_ses->shardmap->hash,
querybuf);
spinlock_release(&router_cli_ses->shardmap->lock);
if (!change_successful)
{
time_t now = time(NULL);
if (router_cli_ses->rses_config.refresh_databases &&
difftime(now, router_cli_ses->rses_config.last_refresh) >
router_cli_ses->rses_config.refresh_min_interval)
{
spinlock_acquire(&router_cli_ses->shardmap->lock);
router_cli_ses->shardmap->state = SHMAP_STALE;
spinlock_release(&router_cli_ses->shardmap->lock);
rses_begin_locked_router_action(router_cli_ses);
router_cli_ses->rses_config.last_refresh = now;
router_cli_ses->queue = querybuf;
int rc_refresh = 1;
if ((router_cli_ses->shardmap = shard_map_alloc()))
{
gen_databaselist(inst, router_cli_ses);
}
else
{
rc_refresh = 0;
}
rses_end_locked_router_action(router_cli_ses);
return rc_refresh;
}
extract_database(querybuf, db);
snprintf(errbuf, 25 + MYSQL_DATABASE_MAXLEN, "Unknown database: %s", db);
if (router_cli_ses->rses_config.debug)
{
sprintf(errbuf + strlen(errbuf),
" ([%lu]: DB change failed)",
router_cli_ses->rses_client_dcb->session->ses_id);
}
write_error_to_client(router_cli_ses->rses_client_dcb,
SCHEMA_ERR_DBNOTFOUND,
SCHEMA_ERRSTR_DBNOTFOUND,
errbuf);
MXS_ERROR("Changing database failed.");
ret = 1;
goto retblock;
}
}
/** Create the response to the SHOW DATABASES from the mapped databases */
if (qc_query_is_type(qtype, QUERY_TYPE_SHOW_DATABASES))
{
if (send_database_list(inst, router_cli_ses))
{
ret = 1;
}
goto retblock;
}
route_target = get_shard_route_target(qtype,
router_cli_ses->rses_transaction_active,
querybuf->hint);
if (packet_type == MYSQL_COM_INIT_DB || op == QUERY_OP_CHANGE_DB)
{
route_target = TARGET_UNDEFINED;
spinlock_acquire(&router_cli_ses->shardmap->lock);
tname = hashtable_fetch(router_cli_ses->shardmap->hash, router_cli_ses->current_db);
if (tname)
{
MXS_INFO("INIT_DB for database '%s' on server '%s'",
router_cli_ses->current_db, tname);
route_target = TARGET_NAMED_SERVER;
targetserver = MXS_STRDUP_A(tname);
}
else
{
MXS_INFO("INIT_DB with unknown database");
}
spinlock_release(&router_cli_ses->shardmap->lock);
}
else if (route_target != TARGET_ALL)
{
/** If no database is found in the query and there is no active database
* or hints in the query we need to route the query to the first available
* server. This isn't ideal for monitoring server status but works if
* we just want the server to send an error back. */
spinlock_acquire(&router_cli_ses->shardmap->lock);
if ((tname = get_shard_target_name(inst, router_cli_ses, querybuf, qtype)) != NULL)
{
bool shard_ok = check_shard_status(inst, tname);
if (shard_ok)
{
route_target = TARGET_NAMED_SERVER;
targetserver = MXS_STRDUP_A(tname);
}
else
{
MXS_INFO("Backend server '%s' is not in a viable state", tname);
/**
* Shard is not a viable target right now so we check
* for an alternate backend with the database. If this is not found
* the target is undefined and an error will be returned to the client.
*/
}
}
spinlock_release(&router_cli_ses->shardmap->lock);
}
if (TARGET_IS_UNDEFINED(route_target))
{
spinlock_acquire(&router_cli_ses->shardmap->lock);
tname = get_shard_target_name(inst, router_cli_ses, querybuf, qtype);
if ((tname == NULL &&
packet_type != MYSQL_COM_INIT_DB &&
router_cli_ses->current_db[0] == '\0') ||
packet_type == MYSQL_COM_FIELD_LIST ||
(router_cli_ses->current_db[0] != '\0'))
{
/**
* No current database and no databases in query or
* the database is ignored, route to first available backend.
*/
route_target = TARGET_ANY;
MXS_INFO("Routing query to first available backend.");
}
else
{
if (tname)
{
targetserver = MXS_STRDUP_A(tname);
}
if (!change_successful)
{
/**
* Bad shard status. The changing of the database
* was not successful and the error message was already sent.
*/
ret = 1;
}
else
{
MXS_ERROR("Error : Router internal failure (schemarouter)");
/** Something else went wrong, terminate connection */
ret = 0;
}
spinlock_release(&router_cli_ses->shardmap->lock);
goto retblock;
}
spinlock_release(&router_cli_ses->shardmap->lock);
}
if (TARGET_IS_ALL(route_target))
{
/**
* It is not sure if the session command in question requires
* response. Statement is examined in route_session_write.
* Router locking is done inside the function.
*/
succp = route_session_write(router_cli_ses,
gwbuf_clone(querybuf),
inst,
packet_type,
qtype);
if (succp)
{
atomic_add(&inst->stats.n_sescmd, 1);
atomic_add(&inst->stats.n_queries, 1);
ret = 1;
}
goto retblock;
}
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
MXS_INFO("Route query aborted! Routing session is closed <");
ret = 0;
goto retblock;
}
if (TARGET_IS_ANY(route_target))
{
for (int i = 0; i < router_cli_ses->rses_nbackends; i++)
{
SERVER *server = router_cli_ses->rses_backend_ref[i].bref_backend->server;
if (SERVER_IS_RUNNING(server))
{
route_target = TARGET_NAMED_SERVER;
targetserver = MXS_STRDUP_A(server->unique_name);
break;
}
}
if (TARGET_IS_ANY(route_target))
{
/**No valid backends alive*/
MXS_ERROR("Failed to route query, no backends are available.");
rses_end_locked_router_action(router_cli_ses);
ret = 0;
goto retblock;
}
}
/**
* Query is routed to one of the backends
*/
if (TARGET_IS_NAMED_SERVER(route_target) && targetserver != NULL)
{
/**
* Search backend server by name or replication lag.
* If it fails, then try to find valid slave or master.
*/
succp = get_shard_dcb(&target_dcb, router_cli_ses, targetserver);
if (!succp)
{
MXS_INFO("Was supposed to route to named server "
"%s but couldn't find the server in a "
"suitable state.", targetserver);
}
}
if (succp) /*< Have DCB of the target backend */
{
backend_ref_t* bref;
sescmd_cursor_t* scur;
bref = get_bref_from_dcb(router_cli_ses, target_dcb);
scur = &bref->bref_sescmd_cur;
MXS_INFO("Route query to \t[%s]:%d <",
bref->bref_backend->server->name,
bref->bref_backend->server->port);
/**
* Store current stmt if execution of previous session command
* haven't completed yet. Note that according to MySQL protocol
* there can only be one such non-sescmd stmt at the time.
*/
if (sescmd_cursor_is_active(scur))
{
ss_dassert((bref->bref_pending_cmd == NULL ||
router_cli_ses->rses_closed));
bref->bref_pending_cmd = gwbuf_clone(querybuf);
rses_end_locked_router_action(router_cli_ses);
ret = 1;
goto retblock;
}
if ((ret = target_dcb->func.write(target_dcb, gwbuf_clone(querybuf))) == 1)
{
backend_ref_t* bref;
atomic_add(&inst->stats.n_queries, 1);
/**
* Add one query response waiter to backend reference
*/
bref = get_bref_from_dcb(router_cli_ses, target_dcb);
bref_set_state(bref, BREF_QUERY_ACTIVE);
bref_set_state(bref, BREF_WAITING_RESULT);
}
else
{
MXS_ERROR("Routing query failed.");
}
}
rses_end_locked_router_action(router_cli_ses);
retblock:
MXS_FREE(targetserver);
gwbuf_free(querybuf);
return ret;
}
/**
* @node Acquires lock to router client session if it is not closed.
*
* Parameters:
* @param rses - in, use
*
*
* @return true if router session was not closed. If return value is true
* it means that router is locked, and must be unlocked later. False, if
* router was closed before lock was acquired.
*
*
* @details (write detailed description here)
*
*/
static bool rses_begin_locked_router_action(
ROUTER_CLIENT_SES* rses)
{
bool succp = false;
CHK_CLIENT_RSES(rses);
if (rses->rses_closed)
{
goto return_succp;
}
spinlock_acquire(&rses->rses_lock);
if (rses->rses_closed)
{
spinlock_release(&rses->rses_lock);
goto return_succp;
}
succp = true;
return_succp:
return succp;
}
/** to be inline'd */
/**
* @node Releases router client session lock.
*
* Parameters:
* @param rses - <usage>
* <description>
*
* @return void
*
*
* @details (write detailed description here)
*
*/
static void rses_end_locked_router_action(ROUTER_CLIENT_SES* rses)
{
CHK_CLIENT_RSES(rses);
spinlock_release(&rses->rses_lock);
}
/**
* Diagnostics routine
*
* Print query router statistics to the DCB passed in
*
* @param instance The router instance
* @param dcb The DCB for diagnostic output
*/
static void diagnostic(MXS_ROUTER *instance, DCB *dcb)
{
ROUTER_INSTANCE *router = (ROUTER_INSTANCE *)instance;
int i = 0;
double sescmd_pct = router->stats.n_sescmd != 0 ?
100.0 * ((double)router->stats.n_sescmd / (double)router->stats.n_queries) :
0.0;
/** Session command statistics */
dcb_printf(dcb, "\n\33[1;4mSession Commands\33[0m\n");
dcb_printf(dcb, "Total number of queries: %d\n",
router->stats.n_queries);
dcb_printf(dcb, "Percentage of session commands: %.2f\n",
sescmd_pct);
dcb_printf(dcb, "Longest chain of stored session commands: %d\n",
router->stats.longest_sescmd);
dcb_printf(dcb, "Session command history limit exceeded: %d times\n",
router->stats.n_hist_exceeded);
if (!router->schemarouter_config.disable_sescmd_hist)
{
dcb_printf(dcb, "Session command history: enabled\n");
if (router->schemarouter_config.max_sescmd_hist == 0)
{
dcb_printf(dcb, "Session command history limit: unlimited\n");
}
else
{
dcb_printf(dcb, "Session command history limit: %d\n",
router->schemarouter_config.max_sescmd_hist);
}
}
else
{
dcb_printf(dcb, "Session command history: disabled\n");
}
/** Session time statistics */
if (router->stats.sessions > 0)
{
dcb_printf(dcb, "\n\33[1;4mSession Time Statistics\33[0m\n");
dcb_printf(dcb, "Longest session: %.2lf seconds\n", router->stats.ses_longest);
dcb_printf(dcb, "Shortest session: %.2lf seconds\n", router->stats.ses_shortest);
dcb_printf(dcb, "Average session length: %.2lf seconds\n", router->stats.ses_average);
}
dcb_printf(dcb, "Shard map cache hits: %d\n", router->stats.shmap_cache_hit);
dcb_printf(dcb, "Shard map cache misses: %d\n", router->stats.shmap_cache_miss);
dcb_printf(dcb, "\n");
}
/**
* Client Reply routine
*
* The routine will reply to client for session change with master server data
*
* @param instance The router instance
* @param router_session The router session
* @param backend_dcb The backend DCB
* @param queue The GWBUF with reply data
*/
static void clientReply(MXS_ROUTER* instance,
MXS_ROUTER_SESSION* router_session,
GWBUF* buffer,
DCB* backend_dcb)
{
DCB* client_dcb;
ROUTER_CLIENT_SES* router_cli_ses;
sescmd_cursor_t* scur = NULL;
backend_ref_t* bref;
GWBUF* writebuf = buffer;
router_cli_ses = (ROUTER_CLIENT_SES *) router_session;
CHK_CLIENT_RSES(router_cli_ses);
/**
* Lock router client session for secure read of router session members.
* Note that this could be done without lock by using version #
*/
if (!rses_begin_locked_router_action(router_cli_ses))
{
while ((writebuf = gwbuf_consume(writebuf, gwbuf_length(writebuf))));
return;
}
/** Holding lock ensures that router session remains open */
ss_dassert(backend_dcb->session != NULL);
client_dcb = backend_dcb->session->client_dcb;
/** Unlock */
rses_end_locked_router_action(router_cli_ses);
if (client_dcb == NULL || !rses_begin_locked_router_action(router_cli_ses))
{
while ((writebuf = gwbuf_consume(writebuf, gwbuf_length(writebuf))));
return;
}
bref = get_bref_from_dcb(router_cli_ses, backend_dcb);
if (bref == NULL)
{
/** Unlock router session */
rses_end_locked_router_action(router_cli_ses);
while ((writebuf = gwbuf_consume(writebuf, gwbuf_length(writebuf))))
{
;
}
return;
}
MXS_DEBUG("Reply from [%s] session [%p]"
" mapping [%s] queries queued [%s]",
bref->bref_backend->server->unique_name,
router_cli_ses->rses_client_dcb->session,
router_cli_ses->init & INIT_MAPPING ? "true" : "false",
router_cli_ses->queue == NULL ? "none" :
router_cli_ses->queue->next ? "multiple" : "one");
if (router_cli_ses->init & INIT_MAPPING)
{
int rc = inspect_backend_mapping_states(router_cli_ses, bref, &writebuf);
while (writebuf && (writebuf = gwbuf_consume(writebuf, gwbuf_length(writebuf))))
{
;
}
if (rc == 1)
{
spinlock_acquire(&router_cli_ses->shardmap->lock);
router_cli_ses->shardmap->state = SHMAP_READY;
router_cli_ses->shardmap->last_updated = time(NULL);
spinlock_release(&router_cli_ses->shardmap->lock);
rses_end_locked_router_action(router_cli_ses);
synchronize_shard_map(router_cli_ses);
if (!rses_begin_locked_router_action(router_cli_ses))
{
return;
}
/*
* Check if the session is reconnecting with a database name
* that is not in the hashtable. If the database is not found
* then close the session.
*/
router_cli_ses->init &= ~INIT_MAPPING;
if (router_cli_ses->init & INIT_USE_DB)
{
bool success = handle_default_db(router_cli_ses);
rses_end_locked_router_action(router_cli_ses);
if (!success)
{
dcb_close(router_cli_ses->rses_client_dcb);
}
return;
}
if (router_cli_ses->queue)
{
ss_dassert(router_cli_ses->init == INIT_READY);
route_queued_query(router_cli_ses);
}
MXS_DEBUG("session [%p] database map finished.",
router_cli_ses);
}
rses_end_locked_router_action(router_cli_ses);
if (rc == -1)
{
dcb_close(router_cli_ses->rses_client_dcb);
}
return;
}
if (router_cli_ses->init & INIT_USE_DB)
{
MXS_DEBUG("Reply to USE '%s' received for session %p",
router_cli_ses->connect_db,
router_cli_ses->rses_client_dcb->session);
router_cli_ses->init &= ~INIT_USE_DB;
strcpy(router_cli_ses->current_db, router_cli_ses->connect_db);
ss_dassert(router_cli_ses->init == INIT_READY);
if (router_cli_ses->queue)
{
route_queued_query(router_cli_ses);
}
rses_end_locked_router_action(router_cli_ses);
if (writebuf)
{
while ((writebuf = gwbuf_consume(writebuf, gwbuf_length(writebuf))))
{
;
}
}
return;
}
if (router_cli_ses->queue)
{
ss_dassert(router_cli_ses->init == INIT_READY);
route_queued_query(router_cli_ses);
rses_end_locked_router_action(router_cli_ses);
return;
}
CHK_BACKEND_REF(bref);
scur = &bref->bref_sescmd_cur;
/**
* Active cursor means that reply is from session command
* execution.
*/
if (sescmd_cursor_is_active(scur))
{
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_ERR) &&
MYSQL_IS_ERROR_PACKET(((uint8_t *) GWBUF_DATA(writebuf))))
{
uint8_t* buf = (uint8_t *) GWBUF_DATA((scur->scmd_cur_cmd->my_sescmd_buf));
uint8_t* replybuf = (uint8_t *) GWBUF_DATA(writebuf);
size_t len = MYSQL_GET_PAYLOAD_LEN(buf);
size_t replylen = MYSQL_GET_PAYLOAD_LEN(replybuf);
char* cmdstr = strndup(&((char *) buf)[5], len - 4);
char* err = strndup(&((char *) replybuf)[8], 5);
char* replystr = strndup(&((char *) replybuf)[13],
replylen - 4 - 5);
ss_dassert(len + 4 == GWBUF_LENGTH(scur->scmd_cur_cmd->my_sescmd_buf));
MXS_ERROR("Failed to execute %s in [%s]:%d. %s %s",
cmdstr,
bref->bref_backend->server->name,
bref->bref_backend->server->port,
err,
replystr);
MXS_FREE(cmdstr);
MXS_FREE(err);
MXS_FREE(replystr);
}
if (GWBUF_IS_TYPE_SESCMD_RESPONSE(writebuf))
{
/**
* Discard all those responses that have already been sent to
* the client. Return with buffer including response that
* needs to be sent to client or NULL.
*/
writebuf = sescmd_cursor_process_replies(writebuf, bref);
}
/**
* If response will be sent to client, decrease waiter count.
* This applies to session commands only. Counter decrement
* for other type of queries is done outside this block.
*/
if (writebuf != NULL && client_dcb != NULL)
{
/** Set response status as replied */
bref_clear_state(bref, BREF_WAITING_RESULT);
}
}
/**
* Clear BREF_QUERY_ACTIVE flag and decrease waiter counter.
* This applies for queries other than session commands.
*/
else if (BREF_IS_QUERY_ACTIVE(bref))
{
bref_clear_state(bref, BREF_QUERY_ACTIVE);
/** Set response status as replied */
bref_clear_state(bref, BREF_WAITING_RESULT);
}
if (writebuf != NULL && client_dcb != NULL)
{
unsigned char* cmd = (unsigned char*) writebuf->start;
int state = router_cli_ses->init;
/** Write reply to client DCB */
MXS_INFO("returning reply [%s] "
"state [%s] session [%p]",
PTR_IS_ERR(cmd) ? "ERR" : PTR_IS_OK(cmd) ? "OK" : "RSET",
state & INIT_UNINT ? "UNINIT" : state & INIT_MAPPING ? "MAPPING" : "READY",
router_cli_ses->rses_client_dcb->session);
MXS_SESSION_ROUTE_REPLY(backend_dcb->session, writebuf);
}
/** Unlock router session */
rses_end_locked_router_action(router_cli_ses);
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
/** Log to debug that router was closed */
return;
}
/** There is one pending session command to be executed. */
if (sescmd_cursor_is_active(scur))
{
MXS_INFO("Backend [%s]:%d processed reply and starts to execute "
"active cursor.",
bref->bref_backend->server->name,
bref->bref_backend->server->port);
execute_sescmd_in_backend(bref);
}
else if (bref->bref_pending_cmd != NULL) /*< non-sescmd is waiting to be routed */
{
int ret;
CHK_GWBUF(bref->bref_pending_cmd);
if ((ret = bref->bref_dcb->func.write(bref->bref_dcb,
gwbuf_clone(bref->bref_pending_cmd))) == 1)
{
ROUTER_INSTANCE* inst = (ROUTER_INSTANCE *) instance;
atomic_add(&inst->stats.n_queries, 1);
/**
* Add one query response waiter to backend reference
*/
bref_set_state(bref, BREF_QUERY_ACTIVE);
bref_set_state(bref, BREF_WAITING_RESULT);
}
else
{
char* sql = modutil_get_SQL(bref->bref_pending_cmd);
if (sql)
{
MXS_ERROR("Routing query \"%s\" failed.", sql);
MXS_FREE(sql);
}
else
{
MXS_ERROR("Routing query failed.");
}
}
gwbuf_free(bref->bref_pending_cmd);
bref->bref_pending_cmd = NULL;
}
/** Unlock router session */
rses_end_locked_router_action(router_cli_ses);
return;
}
/** Compare number of connections from this router in backend servers */
int bref_cmp_router_conn(const void* bref1, const void* bref2)
{
SERVER_REF* b1 = ((backend_ref_t *)bref1)->bref_backend;
SERVER_REF* b2 = ((backend_ref_t *)bref2)->bref_backend;
return ((1000 * b1->connections) / b1->weight)
- ((1000 * b2->connections) / b2->weight);
}
/** Compare number of global connections in backend servers */
int bref_cmp_global_conn(const void* bref1, const void* bref2)
{
SERVER_REF* b1 = ((backend_ref_t *)bref1)->bref_backend;
SERVER_REF* b2 = ((backend_ref_t *)bref2)->bref_backend;
return ((1000 * b1->server->stats.n_current) / b1->weight)
- ((1000 * b2->server->stats.n_current) / b2->weight);
}
/** Compare replication lag between backend servers */
int bref_cmp_behind_master(const void* bref1, const void* bref2)
{
SERVER_REF* b1 = ((backend_ref_t *)bref1)->bref_backend;
SERVER_REF* b2 = ((backend_ref_t *)bref2)->bref_backend;
return b1->server->rlag - b2->server->rlag;
}
/** Compare number of current operations in backend servers */
int bref_cmp_current_load(const void* bref1, const void* bref2)
{
SERVER_REF* b1 = ((backend_ref_t *)bref1)->bref_backend;
SERVER_REF* b2 = ((backend_ref_t *)bref2)->bref_backend;
return ((1000 * b1->server->stats.n_current_ops) - b1->weight)
- ((1000 * b2->server->stats.n_current_ops) - b2->weight);
}
static void bref_clear_state(backend_ref_t* bref, bref_state_t state)
{
if (bref == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return;
}
if (state != BREF_WAITING_RESULT)
{
bref->bref_state &= ~state;
}
else
{
int prev1;
int prev2;
/** Decrease waiter count */
prev1 = atomic_add(&bref->bref_num_result_wait, -1);
if (prev1 <= 0)
{
atomic_add(&bref->bref_num_result_wait, 1);
}
else
{
/** Decrease global operation count */
prev2 = atomic_add(&bref->bref_backend->server->stats.n_current_ops, -1);
ss_dassert(prev2 > 0);
if (prev2 <= 0)
{
MXS_ERROR("[%s] Error: negative current operation count in backend %s:%u",
__FUNCTION__,
bref->bref_backend->server->name,
bref->bref_backend->server->port);
}
}
}
}
static void bref_set_state(backend_ref_t* bref, bref_state_t state)
{
if (bref == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return;
}
if (state != BREF_WAITING_RESULT)
{
bref->bref_state |= state;
}
else
{
int prev1;
int prev2;
/** Increase waiter count */
prev1 = atomic_add(&bref->bref_num_result_wait, 1);
ss_dassert(prev1 >= 0);
if (prev1 < 0)
{
MXS_ERROR("[%s] Error: negative number of connections waiting "
"for results in backend %s:%u",
__FUNCTION__,
bref->bref_backend->server->name,
bref->bref_backend->server->port);
}
/** Increase global operation count */
prev2 = atomic_add(&bref->bref_backend->server->stats.n_current_ops, 1);
ss_dassert(prev2 >= 0);
if (prev2 < 0)
{
MXS_ERROR("[%s] Error: negative current operation count in backend %s:%u",
__FUNCTION__,
bref->bref_backend->server->name,
bref->bref_backend->server->port);
}
}
}
/**
* @node Search all RUNNING backend servers and connect
*
* Parameters:
* @param backend_ref - in, use, out
* Pointer to backend server reference object array.
* NULL is not allowed.
*
* @param router_nservers - in, use
* Number of backend server pointers pointed to by b.
*
* @param session - in, use
* MaxScale session pointer used when connection to backend is established.
*
* @param router - in, use
* Pointer to router instance. Used when server states are qualified.
*
* @return true, if at least one master and one slave was found.
*
*
* @details It is assumed that there is only one available server.
* There will be exactly as many backend references than there are
* connections because all servers are supposed to be operational. It is,
* however, possible that there are less available servers than expected.
*/
static bool connect_backend_servers(backend_ref_t* backend_ref,
int router_nservers,
MXS_SESSION* session,
ROUTER_INSTANCE* router)
{
bool succp = true;
/*
bool is_synced_master;
bool master_connected = true;
*/
int servers_found = 0;
int servers_connected = 0;
int slaves_connected = 0;
int i;
/*
select_criteria_t select_criteria = LEAST_GLOBAL_CONNECTIONS;
*/
#if defined(EXTRA_SS_DEBUG)
MXS_INFO("Servers and conns before ordering:");
for (i = 0; i < router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
MXS_INFO("bref %p %d %s %d:%d",
&backend_ref[i],
backend_ref[i].bref_state,
b->backend_server->name,
b->backend_server->port,
b->backend_conn_count);
}
#endif
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))
{
MXS_INFO("Servers and connection counts:");
for (i = 0; i < router_nservers; i++)
{
SERVER_REF* b = backend_ref[i].bref_backend;
MXS_INFO("MaxScale connections : %d (%d) in \t[%s]:%d %s",
b->connections,
b->server->stats.n_current,
b->server->name,
b->server->port,
STRSRVSTATUS(b->server));
}
} /*< log only */
/**
* Scan server list and connect each of them. None should fail or session
* can't be established.
*/
for (i = 0; i < router_nservers; i++)
{
SERVER_REF* b = backend_ref[i].bref_backend;
if (SERVER_IS_RUNNING(b->server))
{
servers_found += 1;
/** Server is already connected */
if (BREF_IS_IN_USE((&backend_ref[i])))
{
slaves_connected += 1;
}
/** New server connection */
else
{
backend_ref[i].bref_dcb = dcb_connect(b->server,
session,
b->server->protocol);
if (backend_ref[i].bref_dcb != NULL)
{
servers_connected += 1;
/**
* Start executing session command
* history.
*/
execute_sescmd_history(&backend_ref[i]);
/**
* When server fails, this callback
* is called.
* !!! Todo, routine which removes
* corresponding entries from the hash
* table.
*/
backend_ref[i].bref_state = 0;
bref_set_state(&backend_ref[i], BREF_IN_USE);
/**
* Increase backend connection counter.
* Server's stats are _increased_ in
* dcb.c:dcb_alloc !
* But decreased in the calling function
* of dcb_close.
*/
atomic_add(&b->connections, 1);
dcb_add_callback(backend_ref[i].bref_dcb,
DCB_REASON_NOT_RESPONDING,
&router_handle_state_switch,
(void *)&backend_ref[i]);
}
else
{
succp = false;
MXS_ERROR("Unable to establish "
"connection with slave [%s]:%d",
b->server->name,
b->server->port);
/* handle connect error */
break;
}
}
}
} /*< for */
#if defined(EXTRA_SS_DEBUG)
MXS_INFO("Servers and conns after ordering:");
for (i = 0; i < router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
MXS_INFO("bref %p %d %s %d:%d",
&backend_ref[i],
backend_ref[i].bref_state,
b->backend_server->name,
b->backend_server->port,
b->backend_conn_count);
}
#endif
/**
* Successful cases
*/
if (servers_connected == router_nservers)
{
succp = true;
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))
{
for (i = 0; i < router_nservers; i++)
{
SERVER_REF* b = backend_ref[i].bref_backend;
if (BREF_IS_IN_USE((&backend_ref[i])))
{
MXS_INFO("Connected %s in \t[%s]:%d",
STRSRVSTATUS(b->server),
b->server->name,
b->server->port);
}
} /* for */
}
}
return succp;
}
/**
* Create a generic router session property strcture.
*/
static rses_property_t* rses_property_init(rses_property_type_t prop_type)
{
rses_property_t* prop;
prop = (rses_property_t*)MXS_CALLOC(1, sizeof(rses_property_t));
if (prop == NULL)
{
goto return_prop;
}
prop->rses_prop_type = prop_type;
#if defined(SS_DEBUG)
prop->rses_prop_chk_top = CHK_NUM_ROUTER_PROPERTY;
prop->rses_prop_chk_tail = CHK_NUM_ROUTER_PROPERTY;
#endif
return_prop:
CHK_RSES_PROP(prop);
return prop;
}
/**
* Property is freed at the end of router client session.
*/
static void rses_property_done(rses_property_t* prop)
{
CHK_RSES_PROP(prop);
switch (prop->rses_prop_type)
{
case RSES_PROP_TYPE_SESCMD:
mysql_sescmd_done(&prop->rses_prop_data.sescmd);
break;
case RSES_PROP_TYPE_TMPTABLES:
hashtable_free(prop->rses_prop_data.temp_tables);
break;
default:
MXS_DEBUG("%lu [rses_property_done] Unknown property type %d "
"in property %p",
pthread_self(),
prop->rses_prop_type,
prop);
ss_dassert(false);
break;
}
MXS_FREE(prop);
}
/**
* Add property to the router_client_ses structure's rses_properties
* array. The slot is determined by the type of property.
* In each slot there is a list of properties of similar type.
*
* Router client session must be locked.
*/
static void rses_property_add(ROUTER_CLIENT_SES* rses,
rses_property_t* prop)
{
rses_property_t* p;
CHK_CLIENT_RSES(rses);
CHK_RSES_PROP(prop);
ss_dassert(SPINLOCK_IS_LOCKED(&rses->rses_lock));
prop->rses_prop_rsession = rses;
p = rses->rses_properties[prop->rses_prop_type];
if (p == NULL)
{
rses->rses_properties[prop->rses_prop_type] = prop;
}
else
{
while (p->rses_prop_next != NULL)
{
p = p->rses_prop_next;
}
p->rses_prop_next = prop;
}
}
/**
* Router session must be locked.
* Return session command pointer if succeed, NULL if failed.
*/
static mysql_sescmd_t* rses_property_get_sescmd(rses_property_t* prop)
{
mysql_sescmd_t* sescmd;
CHK_RSES_PROP(prop);
ss_dassert(prop->rses_prop_rsession == NULL ||
SPINLOCK_IS_LOCKED(&prop->rses_prop_rsession->rses_lock));
sescmd = &prop->rses_prop_data.sescmd;
if (sescmd != NULL)
{
CHK_MYSQL_SESCMD(sescmd);
}
return sescmd;
}
/**
* Create session command property.
*/
static mysql_sescmd_t* mysql_sescmd_init(rses_property_t* rses_prop,
GWBUF* sescmd_buf,
unsigned char packet_type,
ROUTER_CLIENT_SES* rses)
{
mysql_sescmd_t* sescmd;
CHK_RSES_PROP(rses_prop);
/** Can't call rses_property_get_sescmd with uninitialized sescmd */
sescmd = &rses_prop->rses_prop_data.sescmd;
sescmd->my_sescmd_prop = rses_prop; /*< reference to owning property */
#if defined(SS_DEBUG)
sescmd->my_sescmd_chk_top = CHK_NUM_MY_SESCMD;
sescmd->my_sescmd_chk_tail = CHK_NUM_MY_SESCMD;
#endif
/** Set session command buffer */
sescmd->my_sescmd_buf = sescmd_buf;
sescmd->my_sescmd_packet_type = packet_type;
sescmd->position = atomic_add(&rses->pos_generator, 1);
return sescmd;
}
static void mysql_sescmd_done(mysql_sescmd_t* sescmd)
{
CHK_RSES_PROP(sescmd->my_sescmd_prop);
gwbuf_free(sescmd->my_sescmd_buf);
memset(sescmd, 0, sizeof(mysql_sescmd_t));
}
/**
* All cases where backend message starts at least with one response to session
* command are handled here.
* Read session commands from property list. If command is already replied,
* discard packet. Else send reply to client. In both cases move cursor forward
* until all session command replies are handled.
*
* Cases that are expected to happen and which are handled:
* s = response not yet replied to client, S = already replied response,
* q = query
* 1. q+ for example : select * from mysql.user
* 2. s+ for example : set autocommit=1
* 3. S+
* 4. sq+
* 5. Sq+
* 6. Ss+
* 7. Ss+q+
* 8. S+q+
* 9. s+q+
*/
static GWBUF* sescmd_cursor_process_replies(GWBUF* replybuf,
backend_ref_t* bref)
{
mysql_sescmd_t* scmd;
sescmd_cursor_t* scur;
scur = &bref->bref_sescmd_cur;
ss_dassert(SPINLOCK_IS_LOCKED(&(scur->scmd_cur_rses->rses_lock)));
scmd = sescmd_cursor_get_command(scur);
CHK_GWBUF(replybuf);
/**
* Walk through packets in the message and the list of session
* commands.
*/
while (scmd != NULL && replybuf != NULL)
{
scur->position = scmd->position;
/** Faster backend has already responded to client : discard */
if (scmd->my_sescmd_is_replied)
{
bool last_packet = false;
CHK_GWBUF(replybuf);
while (!last_packet)
{
int buflen;
buflen = GWBUF_LENGTH(replybuf);
last_packet = GWBUF_IS_TYPE_RESPONSE_END(replybuf);
/** discard packet */
replybuf = gwbuf_consume(replybuf, buflen);
}
/** Set response status received */
bref_clear_state(bref, BREF_WAITING_RESULT);
}
/** Response is in the buffer and it will be sent to client. */
else if (replybuf != NULL)
{
/** Mark the rest session commands as replied */
scmd->my_sescmd_is_replied = true;
}
if (sescmd_cursor_next(scur))
{
scmd = sescmd_cursor_get_command(scur);
}
else
{
scmd = NULL;
/** All session commands are replied */
scur->scmd_cur_active = false;
}
}
ss_dassert(replybuf == NULL || *scur->scmd_cur_ptr_property == NULL);
return replybuf;
}
/**
* Get the address of current session command.
*
* Router session must be locked */
static mysql_sescmd_t* sescmd_cursor_get_command(sescmd_cursor_t* scur)
{
mysql_sescmd_t* scmd;
ss_dassert(SPINLOCK_IS_LOCKED(&(scur->scmd_cur_rses->rses_lock)));
scur->scmd_cur_cmd = rses_property_get_sescmd(*scur->scmd_cur_ptr_property);
CHK_MYSQL_SESCMD(scur->scmd_cur_cmd);
scmd = scur->scmd_cur_cmd;
return scmd;
}
/** router must be locked */
static bool sescmd_cursor_is_active(sescmd_cursor_t* sescmd_cursor)
{
bool succp;
ss_dassert(SPINLOCK_IS_LOCKED(&sescmd_cursor->scmd_cur_rses->rses_lock));
succp = sescmd_cursor->scmd_cur_active;
return succp;
}
/** router must be locked */
static void sescmd_cursor_set_active(sescmd_cursor_t* sescmd_cursor,
bool value)
{
ss_dassert(SPINLOCK_IS_LOCKED(&sescmd_cursor->scmd_cur_rses->rses_lock));
/** avoid calling unnecessarily */
ss_dassert(sescmd_cursor->scmd_cur_active != value);
sescmd_cursor->scmd_cur_active = value;
}
/**
* Clone session command's command buffer.
* Router session must be locked
*/
static GWBUF* sescmd_cursor_clone_querybuf(sescmd_cursor_t* scur)
{
GWBUF* buf;
ss_dassert(scur->scmd_cur_cmd != NULL);
buf = gwbuf_clone(scur->scmd_cur_cmd->my_sescmd_buf);
CHK_GWBUF(buf);
return buf;
}
static bool sescmd_cursor_history_empty(sescmd_cursor_t* scur)
{
bool succp;
CHK_SESCMD_CUR(scur);
if (scur->scmd_cur_rses->rses_properties[RSES_PROP_TYPE_SESCMD] == NULL)
{
succp = true;
}
else
{
succp = false;
}
return succp;
}
static void sescmd_cursor_reset(sescmd_cursor_t* scur)
{
ROUTER_CLIENT_SES* rses;
CHK_SESCMD_CUR(scur);
CHK_CLIENT_RSES(scur->scmd_cur_rses);
rses = scur->scmd_cur_rses;
scur->scmd_cur_ptr_property = &rses->rses_properties[RSES_PROP_TYPE_SESCMD];
CHK_RSES_PROP((*scur->scmd_cur_ptr_property));
scur->scmd_cur_active = false;
scur->scmd_cur_cmd = &(*scur->scmd_cur_ptr_property)->rses_prop_data.sescmd;
}
static bool execute_sescmd_history(backend_ref_t* bref)
{
bool succp;
sescmd_cursor_t* scur;
CHK_BACKEND_REF(bref);
scur = &bref->bref_sescmd_cur;
CHK_SESCMD_CUR(scur);
if (!sescmd_cursor_history_empty(scur))
{
sescmd_cursor_reset(scur);
succp = execute_sescmd_in_backend(bref);
}
else
{
succp = true;
}
return succp;
}
/**
* If session command cursor is passive, sends the command to backend for
* execution.
*
* Returns true if command was sent or added successfully to the queue.
* Returns false if command sending failed or if there are no pending session
* commands.
*
* Router session must be locked.
*/
static bool execute_sescmd_in_backend(backend_ref_t* backend_ref)
{
DCB* dcb;
bool succp;
int rc = 0;
sescmd_cursor_t* scur;
if (BREF_IS_CLOSED(backend_ref))
{
succp = false;
goto return_succp;
}
dcb = backend_ref->bref_dcb;
CHK_DCB(dcb);
CHK_BACKEND_REF(backend_ref);
/**
* Get cursor pointer and copy of command buffer to cursor.
*/
scur = &backend_ref->bref_sescmd_cur;
/** Return if there are no pending ses commands */
if (sescmd_cursor_get_command(scur) == NULL)
{
succp = false;
MXS_INFO("Cursor had no pending session commands.");
goto return_succp;
}
if (!sescmd_cursor_is_active(scur))
{
/** Cursor is left active when function returns. */
sescmd_cursor_set_active(scur, true);
}
switch (scur->scmd_cur_cmd->my_sescmd_packet_type)
{
case MYSQL_COM_CHANGE_USER:
/** This makes it possible to handle replies correctly */
gwbuf_set_type(scur->scmd_cur_cmd->my_sescmd_buf, GWBUF_TYPE_SESCMD);
rc = dcb->func.auth(dcb,
NULL,
dcb->session,
sescmd_cursor_clone_querybuf(scur));
break;
case MYSQL_COM_QUERY:
default:
/**
* Mark session command buffer, it triggers writing
* MySQL command to protocol
*/
gwbuf_set_type(scur->scmd_cur_cmd->my_sescmd_buf, GWBUF_TYPE_SESCMD);
rc = dcb->func.write(dcb, sescmd_cursor_clone_querybuf(scur));
break;
}
if (rc == 1)
{
succp = true;
}
else
{
succp = false;
}
return_succp:
return succp;
}
/**
* Moves cursor to next property and copied address of its sescmd to cursor.
* Current propery must be non-null.
* If current property is the last on the list, *scur->scmd_ptr_property == NULL
*
* Router session must be locked
*/
static bool sescmd_cursor_next(sescmd_cursor_t* scur)
{
bool succp = false;
rses_property_t* prop_curr;
rses_property_t* prop_next;
ss_dassert(scur != NULL);
ss_dassert(*(scur->scmd_cur_ptr_property) != NULL);
ss_dassert(SPINLOCK_IS_LOCKED(&(*(scur->scmd_cur_ptr_property))->rses_prop_rsession->rses_lock));
/** Illegal situation */
if (scur == NULL ||
*scur->scmd_cur_ptr_property == NULL ||
scur->scmd_cur_cmd == NULL)
{
/** Log error */
goto return_succp;
}
prop_curr = *(scur->scmd_cur_ptr_property);
CHK_MYSQL_SESCMD(scur->scmd_cur_cmd);
ss_dassert(prop_curr == mysql_sescmd_get_property(scur->scmd_cur_cmd));
CHK_RSES_PROP(prop_curr);
/** Copy address of pointer to next property */
scur->scmd_cur_ptr_property = &(prop_curr->rses_prop_next);
prop_next = *scur->scmd_cur_ptr_property;
ss_dassert(prop_next == *(scur->scmd_cur_ptr_property));
/** If there is a next property move forward */
if (prop_next != NULL)
{
CHK_RSES_PROP(prop_next);
CHK_RSES_PROP((*(scur->scmd_cur_ptr_property)));
/** Get pointer to next property's sescmd */
scur->scmd_cur_cmd = rses_property_get_sescmd(prop_next);
ss_dassert(prop_next == scur->scmd_cur_cmd->my_sescmd_prop);
CHK_MYSQL_SESCMD(scur->scmd_cur_cmd);
CHK_RSES_PROP(scur->scmd_cur_cmd->my_sescmd_prop);
}
else
{
/** No more properties, can't proceed. */
goto return_succp;
}
if (scur->scmd_cur_cmd != NULL)
{
succp = true;
}
else
{
ss_dassert(false); /*< Log error, sescmd shouldn't be NULL */
}
return_succp:
return succp;
}
static rses_property_t* mysql_sescmd_get_property(mysql_sescmd_t* scmd)
{
CHK_MYSQL_SESCMD(scmd);
return scmd->my_sescmd_prop;
}
/**
* @brief Get router capabilities
*
* @return Always RCAP_TYPE_CONTIGUOUS_INPUT
*/
static uint64_t getCapabilities(MXS_ROUTER* instance)
{
return RCAP_TYPE_CONTIGUOUS_INPUT;
}
/**
* Execute in backends used by current router session.
* Save session variable commands to router session property
* struct. Thus, they can be replayed in backends which are
* started and joined later.
*
* Suppress redundant OK packets sent by backends.
*
* The first OK packet is replied to the client.
* Return true if succeed, false is returned if router session was closed or
* if execute_sescmd_in_backend failed.
*/
static bool route_session_write(ROUTER_CLIENT_SES* router_cli_ses,
GWBUF* querybuf,
ROUTER_INSTANCE* inst,
unsigned char packet_type,
qc_query_type_t qtype)
{
bool succp = false;
rses_property_t* prop;
backend_ref_t* backend_ref;
int i;
MXS_INFO("Session write, routing to all servers.");
backend_ref = router_cli_ses->rses_backend_ref;
/**
* These are one-way messages and server doesn't respond to them.
* Therefore reply processing is unnecessary and session
* command property is not needed. It is just routed to all available
* backends.
*/
if (packet_type == MYSQL_COM_STMT_SEND_LONG_DATA ||
packet_type == MYSQL_COM_QUIT ||
packet_type == MYSQL_COM_STMT_CLOSE)
{
int rc;
succp = true;
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
succp = false;
goto return_succp;
}
for (i = 0; i < router_cli_ses->rses_nbackends; i++)
{
DCB* dcb = backend_ref[i].bref_dcb;
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))
{
MXS_INFO("Route query to %s\t[%s]:%d%s",
(SERVER_IS_MASTER(backend_ref[i].bref_backend->server) ?
"master" : "slave"),
backend_ref[i].bref_backend->server->name,
backend_ref[i].bref_backend->server->port,
(i + 1 == router_cli_ses->rses_nbackends ? " <" : ""));
}
if (BREF_IS_IN_USE((&backend_ref[i])))
{
rc = dcb->func.write(dcb, gwbuf_clone(querybuf));
if (rc != 1)
{
succp = false;
}
}
}
rses_end_locked_router_action(router_cli_ses);
gwbuf_free(querybuf);
goto return_succp;
}
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
succp = false;
goto return_succp;
}
if (router_cli_ses->rses_nbackends <= 0)
{
succp = false;
goto return_succp;
}
if (router_cli_ses->rses_config.max_sescmd_hist > 0 &&
router_cli_ses->n_sescmd >= router_cli_ses->rses_config.max_sescmd_hist)
{
MXS_ERROR("Router session exceeded session command history limit of %d. "
"Closing router session.",
router_cli_ses->rses_config.max_sescmd_hist);
gwbuf_free(querybuf);
atomic_add(&router_cli_ses->router->stats.n_hist_exceeded, 1);
rses_end_locked_router_action(router_cli_ses);
router_cli_ses->rses_client_dcb->func.hangup(router_cli_ses->rses_client_dcb);
goto return_succp;
}
if (router_cli_ses->rses_config.disable_sescmd_hist)
{
rses_property_t *prop, *tmp;
backend_ref_t* bref;
bool conflict;
prop = router_cli_ses->rses_properties[RSES_PROP_TYPE_SESCMD];
while (prop)
{
conflict = false;
for (i = 0; i < router_cli_ses->rses_nbackends; i++)
{
bref = &backend_ref[i];
if (BREF_IS_IN_USE(bref))
{
if (bref->bref_sescmd_cur.position <= prop->rses_prop_data.sescmd.position)
{
conflict = true;
break;
}
}
}
if (conflict)
{
break;
}
tmp = prop;
router_cli_ses->rses_properties[RSES_PROP_TYPE_SESCMD] = prop->rses_prop_next;
rses_property_done(tmp);
prop = router_cli_ses->rses_properties[RSES_PROP_TYPE_SESCMD];
}
}
/**
*
* Additional reference is created to querybuf to
* prevent it from being released before properties
* are cleaned up as a part of router session clean-up.
*/
prop = rses_property_init(RSES_PROP_TYPE_SESCMD);
mysql_sescmd_init(prop, querybuf, packet_type, router_cli_ses);
/** Add sescmd property to router client session */
rses_property_add(router_cli_ses, prop);
atomic_add(&router_cli_ses->stats.longest_sescmd, 1);
atomic_add(&router_cli_ses->n_sescmd, 1);
for (i = 0; i < router_cli_ses->rses_nbackends; i++)
{
if (BREF_IS_IN_USE((&backend_ref[i])))
{
sescmd_cursor_t* scur;
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))
{
MXS_INFO("Route query to %s\t[%s]:%d%s",
(SERVER_IS_MASTER(backend_ref[i].bref_backend->server) ?
"master" : "slave"),
backend_ref[i].bref_backend->server->name,
backend_ref[i].bref_backend->server->port,
(i + 1 == router_cli_ses->rses_nbackends ? " <" : ""));
}
scur = backend_ref_get_sescmd_cursor(&backend_ref[i]);
/**
* Add one waiter to backend reference.
*/
bref_set_state(get_bref_from_dcb(router_cli_ses,
backend_ref[i].bref_dcb),
BREF_WAITING_RESULT);
/**
* Start execution if cursor is not already executing.
* Otherwise, cursor will execute pending commands
* when it completes with previous commands.
*/
if (sescmd_cursor_is_active(scur))
{
succp = true;
MXS_INFO("Backend [%s]:%d already executing sescmd.",
backend_ref[i].bref_backend->server->name,
backend_ref[i].bref_backend->server->port);
}
else
{
succp = execute_sescmd_in_backend(&backend_ref[i]);
if (!succp)
{
MXS_ERROR("Failed to execute session "
"command in [%s]:%d",
backend_ref[i].bref_backend->server->name,
backend_ref[i].bref_backend->server->port);
}
}
}
else
{
succp = false;
}
}
/** Unlock router session */
rses_end_locked_router_action(router_cli_ses);
return_succp:
return succp;
}
/**
* Error Handler routine to resolve _backend_ failures. If it succeeds then there
* are enough operative backends available and connected. Otherwise it fails,
* and session is terminated.
*
* @param instance The router instance
* @param router_session The router session
* @param errmsgbuf The error message to reply
* @param backend_dcb The backend DCB
* @param action The action: ERRACT_NEW_CONNECTION or ERRACT_REPLY_CLIENT
* @param succp Result of action: true iff router can continue
*
* Even if succp == true connecting to new slave may have failed. succp is to
* tell whether router has enough master/slave connections to continue work.
*/
static void handleError(MXS_ROUTER* instance,
MXS_ROUTER_SESSION* router_session,
GWBUF* errmsgbuf,
DCB* problem_dcb,
mxs_error_action_t action,
bool* succp)
{
MXS_SESSION* session;
ROUTER_INSTANCE* inst = (ROUTER_INSTANCE *)instance;
ROUTER_CLIENT_SES* rses = (ROUTER_CLIENT_SES *)router_session;
CHK_DCB(problem_dcb);
/** Don't handle same error twice on same DCB */
if (problem_dcb->dcb_errhandle_called)
{
/** we optimistically assume that previous call succeed */
*succp = true;
return;
}
else
{
problem_dcb->dcb_errhandle_called = true;
}
session = problem_dcb->session;
if (session == NULL || rses == NULL)
{
*succp = false;
}
else if (DCB_ROLE_CLIENT_HANDLER == problem_dcb->dcb_role)
{
*succp = false;
}
else
{
CHK_SESSION(session);
CHK_CLIENT_RSES(rses);
switch (action)
{
case ERRACT_NEW_CONNECTION:
{
if (!rses_begin_locked_router_action(rses))
{
*succp = false;
break;
}
/**
* This is called in hope of getting replacement for
* failed slave(s).
*/
*succp = handle_error_new_connection(inst,
rses,
problem_dcb,
errmsgbuf);
rses_end_locked_router_action(rses);
break;
}
case ERRACT_REPLY_CLIENT:
{
handle_error_reply_client(session,
rses,
problem_dcb,
errmsgbuf);
*succp = false; /*< no new backend servers were made available */
break;
}
default:
*succp = false;
break;
}
}
dcb_close(problem_dcb);
}
static void handle_error_reply_client(MXS_SESSION* ses,
ROUTER_CLIENT_SES* rses,
DCB* backend_dcb,
GWBUF* errmsg)
{
mxs_session_state_t sesstate;
DCB* client_dcb;
backend_ref_t* bref;
sesstate = ses->state;
client_dcb = ses->client_dcb;
/**
* If bref exists, mark it closed
*/
if ((bref = get_bref_from_dcb(rses, backend_dcb)) != NULL)
{
CHK_BACKEND_REF(bref);
bref_clear_state(bref, BREF_IN_USE);
bref_set_state(bref, BREF_CLOSED);
}
if (sesstate == SESSION_STATE_ROUTER_READY)
{
CHK_DCB(client_dcb);
client_dcb->func.write(client_dcb, gwbuf_clone(errmsg));
}
}
/**
* Check if a router session has servers in use
* @param rses Router client session
* @return True if session has a single backend server in use that is running.
* False if no backends are in use or running.
*/
bool have_servers(ROUTER_CLIENT_SES* rses)
{
int i;
for (i = 0; i < rses->rses_nbackends; i++)
{
if (BREF_IS_IN_USE(&rses->rses_backend_ref[i]) &&
!BREF_IS_CLOSED(&rses->rses_backend_ref[i]))
{
return true;
}
}
return false;
}
/**
* Check if there is backend reference pointing at failed DCB, and reset its
* flags. Then clear DCB's callback and finally try to reconnect.
*
* This must be called with router lock.
*
* @param inst router instance
* @param rses router client session
* @param dcb failed DCB
* @param errmsg error message which is sent to client if it is waiting
*
* @return true if there are enough backend connections to continue, false if not
*/
static bool handle_error_new_connection(ROUTER_INSTANCE* inst,
ROUTER_CLIENT_SES* rses,
DCB* backend_dcb,
GWBUF* errmsg)
{
MXS_SESSION* ses;
unsigned char cmd = *((unsigned char*)errmsg->start + 4);
backend_ref_t* bref;
bool succp;
ss_dassert(SPINLOCK_IS_LOCKED(&rses->rses_lock));
ses = backend_dcb->session;
CHK_SESSION(ses);
/**
* If bref == NULL it has been replaced already with another one.
*/
if ((bref = get_bref_from_dcb(rses, backend_dcb)) == NULL)
{
succp = false;
goto return_succp;
}
CHK_BACKEND_REF(bref);
/**
* If query was sent through the bref and it is waiting for reply from
* the backend server it is necessary to send an error to the client
* because it is waiting for reply.
*/
if (BREF_IS_WAITING_RESULT(bref))
{
DCB* client_dcb;
client_dcb = ses->client_dcb;
client_dcb->func.write(client_dcb, gwbuf_clone(errmsg));
bref_clear_state(bref, BREF_WAITING_RESULT);
}
bref_clear_state(bref, BREF_IN_USE);
bref_set_state(bref, BREF_CLOSED);
/**
* Error handler is already called for this DCB because
* it's not polling anymore. It can be assumed that
* it succeed because rses isn't closed.
*/
if (backend_dcb->state != DCB_STATE_POLLING)
{
succp = true;
goto return_succp;
}
/**
* Remove callback because this DCB won't be used
* unless it is reconnected later, and then the callback
* is set again.
*/
dcb_remove_callback(backend_dcb,
DCB_REASON_NOT_RESPONDING,
&router_handle_state_switch,
(void *)bref);
/**
* Try to get replacement slave or at least the minimum
* number of slave connections for router session.
*/
succp = connect_backend_servers(rses->rses_backend_ref,
rses->rses_nbackends,
ses,
inst);
if (!have_servers(rses))
{
MXS_ERROR("No more valid servers, closing session");
succp = false;
goto return_succp;
}
return_succp:
return succp;
}
/**
* Finds out if there is a backend reference pointing at the DCB given as
* parameter.
* @param rses router client session
* @param dcb DCB
*
* @return backend reference pointer if succeed or NULL
*/
static backend_ref_t* get_bref_from_dcb(ROUTER_CLIENT_SES* rses,
DCB* dcb)
{
backend_ref_t* bref;
int i = 0;
CHK_DCB(dcb);
CHK_CLIENT_RSES(rses);
bref = rses->rses_backend_ref;
while (i < rses->rses_nbackends)
{
if (bref->bref_dcb == dcb)
{
break;
}
bref++;
i += 1;
}
if (i == rses->rses_nbackends)
{
bref = NULL;
}
return bref;
}
/**
* Calls hang-up function for DCB if it is not both running and in
* master/slave/joined/ndb role. Called by DCB's callback routine.
* @param dcb Backend server DCB
* @param reason The reason this DCB callback was called
* @param data Data pointer assigned in the add_callback function call
* @return Always 1
*/
static int router_handle_state_switch(DCB* dcb,
DCB_REASON reason,
void* data)
{
backend_ref_t* bref;
int rc = 1;
SERVER* srv;
CHK_DCB(dcb);
if (NULL == dcb->session->router_session)
{
/*
* The following processing will fail if there is no router session,
* because the "data" parameter will not contain meaningful data,
* so we have no choice but to stop here.
*/
return 0;
}
bref = (backend_ref_t *) data;
CHK_BACKEND_REF(bref);
srv = bref->bref_backend->server;
if (SERVER_IS_RUNNING(srv))
{
goto return_rc;
}
switch (reason)
{
case DCB_REASON_NOT_RESPONDING:
atomic_add(&bref->bref_backend->connections, -1);
MXS_INFO("server %s not responding", srv->unique_name);
dcb->func.hangup(dcb);
break;
default:
break;
}
return_rc:
return rc;
}
static sescmd_cursor_t* backend_ref_get_sescmd_cursor(backend_ref_t* bref)
{
sescmd_cursor_t* scur;
CHK_BACKEND_REF(bref);
scur = &bref->bref_sescmd_cur;
CHK_SESCMD_CUR(scur);
return scur;
}
/**
* Detect if a query contains a SHOW SHARDS query.
* @param query Query to inspect
* @return true if the query is a SHOW SHARDS query otherwise false
*/
bool detect_show_shards(GWBUF* query)
{
bool rval = false;
char *querystr, *tok, *sptr;
if (query == NULL)
{
MXS_ERROR("NULL value passed at %s:%d", __FILE__, __LINE__);
return false;
}
if (!modutil_is_SQL(query) && !modutil_is_SQL_prepare(query))
{
return false;
}
if ((querystr = modutil_get_SQL(query)) == NULL)
{
MXS_ERROR("Failure to parse SQL at %s:%d", __FILE__, __LINE__);
return false;
}
tok = strtok_r(querystr, " ", &sptr);
if (tok && strcasecmp(tok, "show") == 0)
{
tok = strtok_r(NULL, " ", &sptr);
if (tok && strcasecmp(tok, "shards") == 0)
{
rval = true;
}
}
MXS_FREE(querystr);
return rval;
}
struct shard_list
{
HASHITERATOR* iter;
ROUTER_CLIENT_SES* rses;
RESULTSET* rset;
};
/**
* Callback for the shard list result set creation
*/
RESULT_ROW* shard_list_cb(struct resultset* rset, void* data)
{
char *key, *value;
struct shard_list *sl = (struct shard_list*)data;
RESULT_ROW* rval = NULL;
if ((key = hashtable_next(sl->iter)) &&
(value = hashtable_fetch(sl->rses->shardmap->hash, key)))
{
if ((rval = resultset_make_row(sl->rset)))
{
resultset_row_set(rval, 0, key);
resultset_row_set(rval, 1, value);
}
}
return rval;
}
/**
* Send a result set of all shards and their locations to the client.
* @param rses Router client session
* @return 0 on success, -1 on error
*/
int process_show_shards(ROUTER_CLIENT_SES* rses)
{
int rval = 0;
spinlock_acquire(&rses->shardmap->lock);
if (rses->shardmap->state != SHMAP_UNINIT)
{
HASHITERATOR* iter = hashtable_iterator(rses->shardmap->hash);
struct shard_list sl;
if (iter)
{
sl.iter = iter;
sl.rses = rses;
if ((sl.rset = resultset_create(shard_list_cb, &sl)) == NULL)
{
MXS_ERROR("[%s] Error: Failed to create resultset.", __FUNCTION__);
rval = -1;
}
else
{
resultset_add_column(sl.rset, "Database", MYSQL_DATABASE_MAXLEN, COL_TYPE_VARCHAR);
resultset_add_column(sl.rset, "Server", MYSQL_DATABASE_MAXLEN, COL_TYPE_VARCHAR);
resultset_stream_mysql(sl.rset, rses->rses_client_dcb);
resultset_free(sl.rset);
hashtable_iterator_free(iter);
}
}
else
{
MXS_ERROR("hashtable_iterator creation failed. "
"This is caused by a memory allocation failure.");
rval = -1;
}
}
spinlock_release(&rses->shardmap->lock);
return rval;
}
/**
*
* @param dcb
* @param errnum
* @param mysqlstate
* @param errmsg
*/
void write_error_to_client(DCB* dcb, int errnum, const char* mysqlstate, const char* errmsg)
{
GWBUF* errbuff = modutil_create_mysql_err_msg(1, 0, errnum, mysqlstate, errmsg);
if (errbuff)
{
if (dcb->func.write(dcb, errbuff) != 1)
{
MXS_ERROR("Failed to write error packet to client.");
}
}
else
{
MXS_ERROR("Memory allocation failed when creating error packet.");
}
}
/**
*
* @param router_cli_ses
* @return
*/
bool handle_default_db(ROUTER_CLIENT_SES *router_cli_ses)
{
bool rval = false;
char* target = NULL;
spinlock_acquire(&router_cli_ses->shardmap->lock);
if (router_cli_ses->shardmap->state != SHMAP_UNINIT)
{
target = hashtable_fetch(router_cli_ses->shardmap->hash, router_cli_ses->connect_db);
}
spinlock_release(&router_cli_ses->shardmap->lock);
if (target)
{
/* Send a COM_INIT_DB packet to the server with the right database
* and set it as the client's active database */
unsigned int qlen = strlen(router_cli_ses->connect_db);
GWBUF* buffer = gwbuf_alloc(qlen + 5);
if (buffer)
{
gw_mysql_set_byte3((unsigned char*) buffer->start, qlen + 1);
gwbuf_set_type(buffer, GWBUF_TYPE_MYSQL);
*((unsigned char*) buffer->start + 3) = 0x0;
*((unsigned char*) buffer->start + 4) = 0x2;
memcpy(buffer->start + 5, router_cli_ses->connect_db, qlen);
DCB* dcb = NULL;
if (get_shard_dcb(&dcb, router_cli_ses, target))
{
dcb->func.write(dcb, buffer);
MXS_DEBUG("USE '%s' sent to %s for session %p",
router_cli_ses->connect_db,
target,
router_cli_ses->rses_client_dcb->session);
rval = true;
}
else
{
MXS_INFO("Couldn't find target DCB for '%s'.", target);
}
}
else
{
MXS_ERROR("Buffer allocation failed.");
}
}
else
{
/** Unknown database, hang up on the client*/
MXS_INFO("Connecting to a non-existent database '%s'",
router_cli_ses->connect_db);
char errmsg[128 + MYSQL_DATABASE_MAXLEN + 1];
sprintf(errmsg, "Unknown database '%s'", router_cli_ses->connect_db);
if (router_cli_ses->rses_config.debug)
{
sprintf(errmsg + strlen(errmsg), " ([%lu]: DB not found on connect)",
router_cli_ses->rses_client_dcb->session->ses_id);
}
write_error_to_client(router_cli_ses->rses_client_dcb,
SCHEMA_ERR_DBNOTFOUND,
SCHEMA_ERRSTR_DBNOTFOUND,
errmsg);
}
return rval;
}
void route_queued_query(ROUTER_CLIENT_SES *router_cli_ses)
{
GWBUF* tmp = router_cli_ses->queue;
router_cli_ses->queue = router_cli_ses->queue->next;
tmp->next = NULL;
#ifdef SS_DEBUG
char* querystr = modutil_get_SQL(tmp);
MXS_DEBUG("Sending queued buffer for session %p: %s",
router_cli_ses->rses_client_dcb->session,
querystr);
MXS_FREE(querystr);
#endif
poll_add_epollin_event_to_dcb(router_cli_ses->rses_client_dcb, tmp);
}
/**
*
* @param router_cli_ses Router client session
* @return 1 if mapping is done, 0 if it is still ongoing and -1 on error
*/
int inspect_backend_mapping_states(ROUTER_CLIENT_SES *router_cli_ses,
backend_ref_t *bref,
GWBUF** wbuf)
{
bool mapped = true;
GWBUF* writebuf = *wbuf;
backend_ref_t* bkrf = router_cli_ses->rses_backend_ref;
for (int i = 0; i < router_cli_ses->rses_nbackends; i++)
{
if (bref->bref_dcb == bkrf[i].bref_dcb && !BREF_IS_MAPPED(&bkrf[i]))
{
if (bref->map_queue)
{
writebuf = gwbuf_append(bref->map_queue, writebuf);
bref->map_queue = NULL;
}
showdb_response_t rc = parse_showdb_response(router_cli_ses,
&router_cli_ses->rses_backend_ref[i],
&writebuf);
if (rc == SHOWDB_FULL_RESPONSE)
{
router_cli_ses->rses_backend_ref[i].bref_mapped = true;
MXS_DEBUG("Received SHOW DATABASES reply from %s for session %p",
router_cli_ses->rses_backend_ref[i].bref_backend->server->unique_name,
router_cli_ses->rses_client_dcb->session);
}
else if (rc == SHOWDB_PARTIAL_RESPONSE)
{
bref->map_queue = writebuf;
writebuf = NULL;
MXS_DEBUG("Received partial SHOW DATABASES reply from %s for session %p",
router_cli_ses->rses_backend_ref[i].bref_backend->server->unique_name,
router_cli_ses->rses_client_dcb->session);
}
else
{
DCB* client_dcb = NULL;
if ((router_cli_ses->init & INIT_FAILED) == 0)
{
if (rc == SHOWDB_DUPLICATE_DATABASES)
{
MXS_ERROR("Duplicate databases found, closing session.");
}
else
{
MXS_ERROR("Fatal error when processing SHOW DATABASES response, closing session.");
}
client_dcb = router_cli_ses->rses_client_dcb;
/** This is the first response to the database mapping which
* has duplicate database conflict. Set the initialization bitmask
* to INIT_FAILED */
router_cli_ses->init |= INIT_FAILED;
/** Send the client an error about duplicate databases
* if there is a queued query from the client. */
if (router_cli_ses->queue)
{
GWBUF* error = modutil_create_mysql_err_msg(1, 0,
SCHEMA_ERR_DUPLICATEDB,
SCHEMA_ERRSTR_DUPLICATEDB,
"Error: duplicate databases "
"found on two different shards.");
if (error)
{
client_dcb->func.write(client_dcb, error);
}
else
{
MXS_ERROR("Creating buffer for error message failed.");
}
}
}
*wbuf = writebuf;
return -1;
}
}
if (BREF_IS_IN_USE(&bkrf[i]) && !BREF_IS_MAPPED(&bkrf[i]))
{
mapped = false;
MXS_DEBUG("Still waiting for reply to SHOW DATABASES from %s for session %p",
bkrf[i].bref_backend->server->unique_name,
router_cli_ses->rses_client_dcb->session);
}
}
*wbuf = writebuf;
return mapped ? 1 : 0;
}
/**
* Replace a shard map with another one. This function copies the contents of
* the source shard map to the target and frees the source memory.
* @param target Target shard map to replace
* @param source Source shard map to use
*/
void replace_shard_map(shard_map_t **target, shard_map_t **source)
{
shard_map_t *tgt = *target;
shard_map_t *src = *source;
tgt->last_updated = src->last_updated;
tgt->state = src->state;
hashtable_free(tgt->hash);
tgt->hash = src->hash;
MXS_FREE(src);
*source = NULL;
}
/**
* Synchronize the router client session shard map with the global shard map for
* this user.
*
* If the router doesn't have a shard map for this user then the current shard map
* of the client session is added to the router. If the shard map in the router is
* out of date, its contents are replaced with the contents of the current client
* session. If the router has a usable shard map, the current shard map of the client
* is discarded and the router's shard map is used.
* @param client Router session
*/
void synchronize_shard_map(ROUTER_CLIENT_SES *client)
{
spinlock_acquire(&client->router->lock);
client->router->stats.shmap_cache_miss++;
shard_map_t *map = hashtable_fetch(client->router->shard_maps,
client->rses_client_dcb->user);
if (map)
{
spinlock_acquire(&map->lock);
if (map->state == SHMAP_STALE)
{
replace_shard_map(&map, &client->shardmap);
}
else if (map->state != SHMAP_READY)
{
MXS_WARNING("Shard map state is not ready but"
"it is in use. Replacing it with a newer one.");
replace_shard_map(&map, &client->shardmap);
}
else
{
/**
* Another thread has already updated the shard map for this user
*/
hashtable_free(client->shardmap->hash);
MXS_FREE(client->shardmap);
}
spinlock_release(&map->lock);
client->shardmap = map;
}
else
{
hashtable_add(client->router->shard_maps,
client->rses_client_dcb->user,
client->shardmap);
ss_dassert(hashtable_fetch(client->router->shard_maps,
client->rses_client_dcb->user) == client->shardmap);
}
spinlock_release(&client->router->lock);
}
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