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MaxScale/server/modules/routing/dbshard/dbshard.c

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/*
* This file is distributed as part of the MariaDB Corporation MaxScale. It is free
* software: you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation,
* version 2.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright MariaDB Corporation Ab 2013-2014
*/
#include <my_config.h>
#include <stdio.h>
#include <strings.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <router.h>
#include <dbshard.h>
#include <secrets.h>
#include <mysql.h>
#include <skygw_utils.h>
#include <log_manager.h>
#include <query_classifier.h>
#include <dcb.h>
#include <spinlock.h>
#include <modinfo.h>
#include <modutil.h>
#include <mysql_client_server_protocol.h>
MODULE_INFO info = {
MODULE_API_ROUTER,
MODULE_BETA_RELEASE,
ROUTER_VERSION,
"A database sharding router for simple sharding"
};
#if defined(SS_DEBUG)
# include <mysql_client_server_protocol.h>
#endif
/** Defined in log_manager.cc */
extern int lm_enabled_logfiles_bitmask;
extern size_t log_ses_count[];
extern __thread log_info_t tls_log_info;
/**
* @file readwritesplit.c The entry points for the read/write query splitting
* router module.
*
* This file contains the entry points that comprise the API to the read write
* query splitting router.
* @verbatim
* Revision History
*
* Date Who Description
* 01/07/2013 Vilho Raatikka Initial implementation
* 15/07/2013 Massimiliano Pinto Added clientReply
* from master only in case of session change
* 17/07/2013 Massimiliano Pinto clientReply is now used by mysql_backend
* for all reply situations
* 18/07/2013 Massimiliano Pinto routeQuery now handles COM_QUIT
* as QUERY_TYPE_SESSION_WRITE
* 17/07/2014 Massimiliano Pinto Server connection counter is updated in closeSession
*
* @endverbatim
*/
static char *version_str = "V1.0.2";
static ROUTER* createInstance(SERVICE *service, char **options);
static void* newSession(ROUTER *instance, SESSION *session);
static void closeSession(ROUTER *instance, void *session);
static void freeSession(ROUTER *instance, void *session);
static int routeQuery(ROUTER *instance, void *session, GWBUF *queue);
static void diagnostic(ROUTER *instance, DCB *dcb);
static void clientReply(
ROUTER* instance,
void* router_session,
GWBUF* queue,
DCB* backend_dcb);
static void handleError(
ROUTER* instance,
void* router_session,
GWBUF* errmsgbuf,
DCB* backend_dcb,
error_action_t action,
bool* succp);
static void print_error_packet(ROUTER_CLIENT_SES* rses, GWBUF* buf, DCB* dcb);
static int router_get_servercount(ROUTER_INSTANCE* router);
static backend_ref_t* get_bref_from_dcb(ROUTER_CLIENT_SES* rses, DCB* dcb);
static route_target_t get_shard_route_target (
skygw_query_type_t qtype,
bool trx_active,
target_t use_sql_variables_in,
HINT* hint);
#if 0
static backend_ref_t* check_candidate_bref(
backend_ref_t* candidate_bref,
backend_ref_t* new_bref,
select_criteria_t sc);
#endif
static uint8_t getCapabilities (ROUTER* inst, void* router_session);
#if defined(NOT_USED)
static bool router_option_configured(
ROUTER_INSTANCE* router,
const char* optionstr,
void* data);
#endif
#if defined(PREP_STMT_CACHING)
static prep_stmt_t* prep_stmt_init(prep_stmt_type_t type, void* id);
static void prep_stmt_done(prep_stmt_t* pstmt);
#endif /*< PREP_STMT_CACHING */
int bref_cmp_global_conn(
const void* bref1,
const void* bref2);
int bref_cmp_router_conn(
const void* bref1,
const void* bref2);
int bref_cmp_behind_master(
const void* bref1,
const void* bref2);
int bref_cmp_current_load(
const void* bref1,
const void* bref2);
static bool connect_backend_servers(
backend_ref_t* backend_ref,
int router_nservers,
SESSION* session,
ROUTER_INSTANCE* router);
static bool get_shard_dcb(
DCB** dcb,
ROUTER_CLIENT_SES* rses,
char* name);
#if 0
static void rwsplit_process_router_options(
ROUTER_INSTANCE* router,
char** options);
#endif
static ROUTER_OBJECT MyObject = {
createInstance,
newSession,
closeSession,
freeSession,
routeQuery,
diagnostic,
clientReply,
handleError,
getCapabilities
};
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 void dbshard_process_router_options(
ROUTER_INSTANCE* router,
char** options);
static bool route_session_write(
ROUTER_CLIENT_SES* router_client_ses,
GWBUF* querybuf,
ROUTER_INSTANCE* inst,
unsigned char packet_type,
skygw_query_type_t qtype);
static void refreshInstance(
ROUTER_INSTANCE* router,
CONFIG_PARAMETER* param);
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(
SESSION* ses,
ROUTER_CLIENT_SES* rses,
DCB* backend_dcb,
GWBUF* errmsg);
static backend_ref_t* get_root_master_bref(ROUTER_CLIENT_SES* rses);
static BACKEND* get_root_master(
backend_ref_t* servers,
int router_nservers);
static SPINLOCK instlock;
static ROUTER_INSTANCE* instances;
static int hashkeyfun(void* key);
static int hashcmpfun (void *, void *);
static int hashkeyfun(
void* key)
{
if(key == NULL){
return 0;
}
unsigned int hash = 0,c = 0;
char* ptr = (char*)key;
while((c = *ptr++)){
hash = c + (hash << 6) + (hash << 16) - hash;
}
return *(int *)key;
}
static int hashcmpfun(
void* v1,
void* v2)
{
char* i1 = (char*) v1;
char* i2 = (char*) v2;
return strcmp(i1,i2);
}
static void* hstrdup(void* fval)
{
char* str = (char*)fval;
return strdup(str);
}
static void* hfree(void* fval)
{
free (fval);
return NULL;
}
/**
* Updates the hashtable with the database names and where to find them, adding
* new and removing obsolete pairs.
* @param backends Backends to query for database names
* @param hashtable Hashtable to use
* @return True if all database and server names were successfully retrieved
* otherwise false
*/
bool update_dbnames_hash(BACKEND** backends, HASHTABLE* hashtable)
{
const unsigned int connect_timeout = 15;
const unsigned int read_timeout = 10;
bool rval = true;
SERVER* server;
int i, rc, numfields;
for(i = 0;backends[i];i++)
{
MYSQL* handle = mysql_init(NULL);
MYSQL_RES* result = NULL;
MYSQL_ROW row;
char *user,*pwd = NULL;
if(handle == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Failed to initialize "
"MySQL handle.")));
return false;
}
rc = 0;
rc |= mysql_options(handle,
MYSQL_OPT_CONNECT_TIMEOUT,
(void *)&connect_timeout);
rc |= mysql_options(handle,
MYSQL_OPT_READ_TIMEOUT,
(void *)&read_timeout);
if(rc != 0)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Failed to set MySQL connection options.")));
mysql_close(handle);
rval = false;
continue;
}
server = backends[i]->backend_server;
ss_dassert(server != NULL);
if(server->monuser == NULL || server->monpw == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: No username or password "
"defined for server '%s'.",
server->unique_name)));
rval = false;
goto cleanup;
}
/** Plain-text password used for authentication for now */
user = server->monuser;
pwd = server->monpw;
if (mysql_real_connect(handle,
server->name,
user,
pwd,
NULL,
server->port,
NULL,
0) == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Failed to connect to backend "
"server '%s': %d %s",
server->name,
mysql_errno(handle),
mysql_error(handle))));
rval = false;
goto cleanup;
}
/**
* The server was successfully connected to, proceed to query for database names
*/
if((result = mysql_list_dbs(handle,NULL)) == NULL)
{
LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,
"Error: Failed to retrieve databases from backend "
"server '%s': %d %s",
server->name,
mysql_errno(handle),
mysql_error(handle))));
goto cleanup;
}
numfields = mysql_num_fields(result);
if(numfields < 1)
{
LOGIF(LT, (skygw_log_write_flush(
LOGFILE_TRACE,
"Backend '%s' has no databases.",
server->name)));
goto cleanup;
}
/**
* Walk through the list of databases in this backend
* and insert them into the hashtable. If the value is already in the hashtable
* but the backend isn't in the list of backends it is replaced with the first found backend.
*/
while((row = mysql_fetch_row(result)))
{
unsigned long *lengths;
char *dbnm = NULL,*servnm = NULL;
lengths = mysql_fetch_lengths(result);
/**
* Default databases to ignore
*/
if(strncmp(row[0],"information_schema",lengths[0]) == 0 ||
strncmp(row[0],"performance_schema",lengths[0]) == 0 ||
strncmp(row[0],"mysql",lengths[0]) == 0 ||
strncmp(row[0],"mysqlslap",lengths[0]) == 0 ||
strncmp(row[0],"test",lengths[0]) == 0){
continue;
}
dbnm = (char*)calloc(lengths[0] + 1,sizeof(char));
memcpy(dbnm,row[0],lengths[0]);
servnm = strdup(server->unique_name);
if(hashtable_add(hashtable,dbnm,servnm) == 0)
{
char* srvname;
#ifdef SHARD_UPDATES
{
char* old_backend = (char*)hashtable_fetch(hashtable,dbnm);
int j;
bool is_alive = false;
for(j = 0;backends[j];j++)
{
/**
* See if the old backend is still
* alive. If not then update
* the hashtable with the current backend's name.
*/
if(strcmp(server->unique_name,old_backend) == 0 &&
SERVER_IS_RUNNING(server))
{
is_alive = true;
}
}
if(!is_alive)
{
hashtable_delete(hashtable,dbnm);
if(hashtable_add(hashtable,dbnm,servnm))
{
LOGIF(LT, (skygw_log_write_flush(
LOGFILE_TRACE,
"Updated the backend of database '%s' to '%s'.",
dbnm,
servnm)));
}
else
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Failed to insert values into hashtable.")));
}
}
goto cleanup;
}
#endif /*< SHARD_UPDATES */
/*Check if the failure was due to a duplicate value*/
if((srvname = hashtable_fetch(hashtable,dbnm)) == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Failed to insert values into hashtable.")));
}
else
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Conflicting "
"databases found. "
"Both \"%s\" and \"%s\" "
"have a database \"%s\".",
server->unique_name,
srvname,
dbnm)));
}
rval = false;
free(dbnm);
free(servnm);
} /*< hashtable_add failed */
} /*< while */
cleanup:
if(result)
{
mysql_free_result(result);
}
result = NULL;
mysql_close(handle);
} /*< for */
return rval;
}
/**
* Allocates a new hashtable and inserts database names and where to find them
* into it.
* @param backends Backends to query for database names
* @return Pointer to the newly allocated hashtable or NULL if an error occurred
*/
void* dbnames_hash_init(BACKEND** backends)
{
HASHTABLE* htbl = hashtable_alloc(512,hashkeyfun,hashcmpfun);
if(htbl == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Hashtable allocation failed.")));
return NULL;
}
/**Update the new hashtable with the key-value pairs*/
if(!update_dbnames_hash(backends,htbl))
{
/*
LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,"Errors encountered while querying databases.")));
hashtable_free(htbl);
return NULL;
*/
hashtable_free(htbl);
htbl = NULL;
}
return htbl;
}
bool add_shard_info(GWBUF* buffer, char* target)
{
HINT* hint = hint_create_route(NULL,HINT_ROUTE_TO_NAMED_SERVER,target);
return (bool)gwbuf_add_hint(buffer,hint);
}
char* get_shard_target_name(ROUTER_INSTANCE* router, ROUTER_CLIENT_SES* client, GWBUF* buffer){
HASHTABLE* ht = router->dbnames_hash;
int sz = 0,i,j;
char** dbnms = NULL;
char* rval = NULL;
bool has_dbs = false; /**If the query targets any database other than the current one*/
if(!query_is_parsed(buffer)){
parse_query(buffer);
}
dbnms = skygw_get_database_names(buffer,&sz);
if(sz > 0){
has_dbs = true;
for(i = 0; i < sz; i++){
if((rval = (char*)hashtable_fetch(ht,dbnms[i]))){
for(j = i;j < sz;j++) free(dbnms[j]);
break;
}
free(dbnms[i]);
}
free(dbnms);
}
/**
* If the query contains no explicitly stated databases proceed to
* check if the session has an active database and if it is sharded.
*/
if(rval == NULL && !has_dbs && client->rses_mysql_session->db[0] != '\0'){
rval = (char*)hashtable_fetch(ht,client->rses_mysql_session->db);
}
return rval;
}
/**
* Implementation of the mandatory version entry point
*
* @return version string of the module
*/
char *
version()
{
return version_str;
}
/**
* The module initialisation routine, called when the module
* is first loaded.
*/
void
ModuleInit()
{
LOGIF(LM, (skygw_log_write_flush(
LOGFILE_MESSAGE,
"Initializing statemend-based read/write split router module.")));
spinlock_init(&instlock);
instances = NULL;
}
/**
* 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
*/
ROUTER_OBJECT* GetModuleObject()
{
return &MyObject;
}
static void refreshInstance(
ROUTER_INSTANCE* router,
CONFIG_PARAMETER* singleparam)
{
CONFIG_PARAMETER* param;
bool refresh_single;
config_param_type_t paramtype;
if (singleparam != NULL)
{
param = singleparam;
refresh_single = true;
}
else
{
param = router->service->svc_config_param;
refresh_single = false;
}
paramtype = config_get_paramtype(param);
while (param != NULL)
{
/** Catch unused parameter types */
ss_dassert(paramtype == COUNT_TYPE ||
paramtype == PERCENT_TYPE ||
paramtype == SQLVAR_TARGET_TYPE);
if (paramtype == COUNT_TYPE)
{
}
else if (paramtype == PERCENT_TYPE)
{
}
else if (paramtype == SQLVAR_TARGET_TYPE)
{
if (strncmp(param->name,
"use_sql_variables_in",
MAX_PARAM_LEN) == 0)
{
target_t valtarget;
bool succp;
succp = config_get_valtarget(&valtarget, param, NULL, paramtype);
if (succp)
{
router->dbshard_config.rw_use_sql_variables_in = valtarget;
}
}
}
if (refresh_single)
{
break;
}
param = param->next;
}
#if defined(NOT_USED) /*< can't read monitor config parameters */
if ((*router->servers)->backend_server->rlag == -2)
{
rlag_enabled = false;
}
else
{
rlag_enabled = true;
}
/**
* If replication lag detection is not enabled the measure can't be
* used in slave selection.
*/
if (!rlag_enabled)
{
if (rlag_limited)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Warning : Configuration Failed, max_slave_replication_lag "
"is set to %d,\n\t\t but detect_replication_lag "
"is not enabled. Replication lag will not be checked.",
router->dbshard_config.rw_max_slave_replication_lag)));
}
if (router->dbshard_config.rw_slave_select_criteria ==
LEAST_BEHIND_MASTER)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Warning : Configuration Failed, router option "
"\n\t\t slave_selection_criteria=LEAST_BEHIND_MASTER "
"is specified, but detect_replication_lag "
"is not enabled.\n\t\t "
"slave_selection_criteria=%s will be used instead.",
STRCRITERIA(DEFAULT_CRITERIA))));
router->dbshard_config.rw_slave_select_criteria =
DEFAULT_CRITERIA;
}
}
#endif /*< NOT_USED */
}
/**
* Create an instance of dbshard statement 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 ROUTER *
createInstance(SERVICE *service, char **options)
{
ROUTER_INSTANCE* router;
SERVER* server;
int nservers;
int i;
if ((router = calloc(1, sizeof(ROUTER_INSTANCE))) == NULL) {
return NULL;
}
router->service = service;
spinlock_init(&router->lock);
/** Calculate number of servers */
server = service->databases;
nservers = 0;
while (server != NULL)
{
nservers++;
server=server->nextdb;
}
router->servers = (BACKEND **)calloc(nservers + 1, sizeof(BACKEND *));
if (router->servers == NULL)
{
free(router);
return NULL;
}
/**
* Create an array of the backend servers in the router structure to
* maintain a count of the number of connections to each
* backend server.
*/
server = service->databases;
nservers= 0;
while (server != NULL) {
if ((router->servers[nservers] = malloc(sizeof(BACKEND))) == NULL)
{
goto clean_up;
}
router->servers[nservers]->backend_server = server;
router->servers[nservers]->backend_conn_count = 0;
router->servers[nservers]->weight = 1;
router->servers[nservers]->be_valid = false;
if(server->monuser == NULL && service->credentials.name != NULL)
{
router->servers[nservers]->backend_server->monuser =
strdup(service->credentials.name);
}
if(server->monpw == NULL && service->credentials.authdata != NULL)
{
router->servers[nservers]->backend_server->monpw =
strdup(service->credentials.authdata);
}
#if defined(SS_DEBUG)
router->servers[nservers]->be_chk_top = CHK_NUM_BACKEND;
router->servers[nservers]->be_chk_tail = CHK_NUM_BACKEND;
#endif
nservers += 1;
server = server->nextdb;
}
router->servers[nservers] = NULL;
/**
* Process the options
*/
router->bitmask = 0;
router->bitvalue = 0;
/**
* Read config version number from service to inform what configuration
* is used if any.
*/
router->dbshard_version = service->svc_config_version;
/** refreshInstance(router, NULL); */
/**
* Get hashtable which includes dbname,backend pairs
*/
router->dbnames_hash = (HASHTABLE*)dbnames_hash_init(router->servers);
if (router->dbnames_hash == NULL)
{
goto clean_up;
}
/**
* We have completed the creation of the router data, so now
* insert this router into the linked list of routers
* that have been created with this module.
*/
spinlock_acquire(&instlock);
router->next = instances;
instances = router;
spinlock_release(&instlock);
goto retblock;
clean_up:
/** clean up */
for (i = 0; i < nservers; i++)
{
free(router->servers[i]);
}
free(router->servers);
free(router);
router = NULL;
/** Fallthrough */
retblock:
return (ROUTER *)router;
}
/**
* 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 void* newSession(
ROUTER* router_inst,
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 */
int i;
#if 0
/**
* It could be possibe to accept new session if some of the servers are
* not reachable
*/
const int min_nservers = 1; /*< hard-coded for now */
#endif
client_rses = (ROUTER_CLIENT_SES *)calloc(1, sizeof(ROUTER_CLIENT_SES));
if (client_rses == NULL)
{
ss_dassert(false);
goto return_rses;
}
#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->data;
/**
* If service config has been changed, reload config from service to
* router instance first.
*/
spinlock_acquire(&router->lock);
/**
* ??? tarvitaanko - ei vielä
*/
#if 0
if (router->service->svc_config_version > router->dbshard_version)
{
/** re-read all parameters to rwsplit config structure */
refreshInstance(router, NULL); /*< scan through all parameters */
/** increment rwsplit router's config version number */
router->dbshard_version = router->service->svc_config_version;
/** Read options */
dbshard_process_router_options(router, router->service->routerOptions);
}
/** Copy config struct from router instance */
client_rses->rses_config = router->dbshard_config;
#endif
spinlock_release(&router->lock);
/**
* Set defaults to session variables.
* ??? tarvitaanko
*/
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_get_servercount(router);
#if 0
if (!have_enough_servers(&client_rses,
min_nservers,
router_nservers,
router))
{
goto return_rses;
}
#endif
/**
* Create backend reference objects for this session.
*/
backend_ref = (backend_ref_t *)calloc(1, router_nservers*sizeof(backend_ref_t));
if (backend_ref == NULL)
{
/** log this */
free(client_rses);
free(backend_ref);
client_rses = NULL;
goto return_rses;
}
/**
* Initialize backend references with BACKEND ptr.
* Initialize session command cursors for each backend reference.
*/
for (i=0; i< router_nservers; i++)
{
#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].bref_backend = router->servers[i];
/** 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;
}
spinlock_init(&client_rses->rses_lock);
client_rses->rses_backend_ref = backend_ref;
/**
* 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)))
{
free(client_rses->rses_backend_ref);
free(client_rses);
client_rses = NULL;
goto return_rses;
}
/**
* Connect to all backend servers
*/
succp = connect_backend_servers(backend_ref,
router_nservers,
session,
router);
rses_end_locked_router_action(client_rses);
/**
* Master and at least <min_nslaves> slaves must be found
*/
if (!succp) {
free(client_rses->rses_backend_ref);
free(client_rses);
client_rses = NULL;
goto return_rses;
}
/** Copy backend pointers to router session. */
client_rses->rses_capabilities = RCAP_TYPE_STMT_INPUT;
client_rses->rses_backend_ref = backend_ref;
client_rses->rses_nbackends = router_nservers; /*< # of backend servers */
router->stats.n_sessions += 1;
/**
* Version is bigger than zero once initialized.
*/
atomic_add(&client_rses->rses_versno, 2);
ss_dassert(client_rses->rses_versno == 2);
/**
* Add this session to end of the list of active sessions in router.
*/
spinlock_acquire(&router->lock);
client_rses->next = router->connections;
router->connections = client_rses;
spinlock_release(&router->lock);
return_rses:
#if defined(SS_DEBUG)
if (client_rses != NULL)
{
CHK_CLIENT_RSES(client_rses);
}
#endif
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(
ROUTER* instance,
void* router_session)
{
ROUTER_CLIENT_SES* router_cli_ses;
backend_ref_t* backend_ref;
LOGIF(LD, (skygw_log_write(LOGFILE_DEBUG,
"%lu [RWSplit: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);
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->backend_server->stats.n_current, -1);
atomic_add(&bref->bref_backend->backend_conn_count, -1);
}
}
/** Unlock */
rses_end_locked_router_action(router_cli_ses);
}
}
static void freeSession(
ROUTER* router_instance,
void* router_client_session)
{
ROUTER_CLIENT_SES* router_cli_ses;
ROUTER_INSTANCE* router;
int i;
backend_ref_t* backend_ref;
router_cli_ses = (ROUTER_CLIENT_SES *)router_client_session;
router = (ROUTER_INSTANCE *)router_instance;
backend_ref = router_cli_ses->rses_backend_ref;
for (i=0; i<router_cli_ses->rses_nbackends; i++)
{
if (!BREF_IS_IN_USE((&backend_ref[i])))
{
continue;
}
}
spinlock_acquire(&router->lock);
if (router->connections == router_cli_ses) {
router->connections = router_cli_ses->next;
} else {
ROUTER_CLIENT_SES* ptr = router->connections;
while (ptr && ptr->next != router_cli_ses) {
ptr = ptr->next;
}
if (ptr) {
ptr->next = router_cli_ses->next;
}
}
spinlock_release(&router->lock);
/**
* For each property type, walk through the list, finalize properties
* and free the allocated memory.
*/
for (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.
*/
free(router_cli_ses->rses_backend_ref);
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++)
{
BACKEND* 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->backend_server->unique_name,
PATH_MAX) == 0) &&
SERVER_IS_RUNNING(b->backend_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;
}
/**
* ??? Tarvitaanko tätä
*/
#if 0
/**
* Find out which of the two backend servers has smaller value for select
* criteria property.
*
* @param cand previously selected candidate
* @param new challenger
* @param sc select criteria
*
* @return pointer to backend reference of that backend server which has smaller
* value in selection criteria. If either reference pointer is NULL then the
* other reference pointer value is returned.
*/
static backend_ref_t* check_candidate_bref(
backend_ref_t* cand,
backend_ref_t* new,
select_criteria_t sc)
{
int (*p)(const void *, const void *);
/** get compare function */
p = criteria_cmpfun[sc];
if (new == NULL)
{
return cand;
}
else if (cand == NULL || (p((void *)cand,(void *)new) > 0))
{
return new;
}
else
{
return cand;
}
}
#endif
/**
* 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 (
skygw_query_type_t qtype,
bool trx_active, /*< !!! turha ? */
target_t use_sql_variables_in, /*< 'master' == single tässä tapauksessa */
HINT* hint) /*< !!! turha ? */
{
route_target_t target = TARGET_UNDEFINED;
/**
* These queries are not affected by hints
*/
if (QUERY_IS_TYPE(qtype, QUERY_TYPE_SESSION_WRITE) ||
QUERY_IS_TYPE(qtype, QUERY_TYPE_PREPARE_STMT) ||
QUERY_IS_TYPE(qtype, QUERY_TYPE_PREPARE_NAMED_STMT) ||
/** Configured to allow writing variables to all nodes */
(use_sql_variables_in == TYPE_ALL &&
QUERY_IS_TYPE(qtype, QUERY_TYPE_GSYSVAR_WRITE)) ||
/** enable or disable autocommit are always routed to all */
QUERY_IS_TYPE(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT) ||
QUERY_IS_TYPE(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT))
{
/** hints don't affect on routing */
target = TARGET_ALL;
}
else
{
target = TARGET_NAMED_SERVER;
}
#if defined(SS_DEBUG)
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Selected target \"%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(
ROUTER* instance,
void* router_session,
GWBUF* querybuf,
skygw_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->rses_mysql_session->db;
if (is_drop_table_query(querybuf))
{
tbl = skygw_get_table_names(querybuf,&tsize,false);
if(tbl != NULL){
for(i = 0; i<tsize; i++)
{
klen = strlen(dbname) + strlen(tbl[i]) + 2;
hkey = calloc(klen,sizeof(char));
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))
{
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE,
"Temporary table dropped: %s",hkey)));
}
}
free(tbl[i]);
free(hkey);
}
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
*/
skygw_query_type_t is_read_tmp_table(
ROUTER* instance,
void* router_session,
GWBUF* querybuf,
skygw_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;
skygw_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->rses_mysql_session->db;
if (QUERY_IS_TYPE(qtype, QUERY_TYPE_READ) ||
QUERY_IS_TYPE(qtype, QUERY_TYPE_LOCAL_READ) ||
QUERY_IS_TYPE(qtype, QUERY_TYPE_USERVAR_READ) ||
QUERY_IS_TYPE(qtype, QUERY_TYPE_SYSVAR_READ) ||
QUERY_IS_TYPE(qtype, QUERY_TYPE_GSYSVAR_READ))
{
tbl = skygw_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 = calloc(klen,sizeof(char));
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;
LOGIF(LT,
(skygw_log_write(LOGFILE_TRACE,
"Query targets a temporary table: %s",hkey)));
}
}
free(hkey);
}
}
}
if(tbl != NULL){
for(i = 0; i<tsize;i++)
{
free(tbl[i]);
}
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(
ROUTER* instance,
void* router_session,
GWBUF* querybuf,
skygw_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->rses_mysql_session->db;
if (QUERY_IS_TYPE(type, QUERY_TYPE_CREATE_TMP_TABLE))
{
bool is_temp = true;
char* tblname = NULL;
tblname = skygw_get_created_table_name(querybuf);
if (tblname && strlen(tblname) > 0)
{
klen = strlen(dbname) + strlen(tblname) + 2;
hkey = calloc(klen,sizeof(char));
strcpy(hkey,dbname);
strcat(hkey,".");
strcat(hkey,tblname);
}
else
{
hkey = NULL;
}
if(rses_prop_tmp == NULL)
{
if((rses_prop_tmp =
(rses_property_t*)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;
}
else
{
LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,"Error : Call to malloc() failed.")));
}
}
if(rses_prop_tmp){
if (rses_prop_tmp->rses_prop_data.temp_tables == NULL)
{
h = hashtable_alloc(7, hashkeyfun, hashcmpfun);
hashtable_memory_fns(h,hstrdup,NULL,hfree,NULL);
if (h != NULL)
{
rses_prop_tmp->rses_prop_data.temp_tables = h;
}else{
LOGIF(LE, (skygw_log_write_flush(LOGFILE_ERROR,"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 */
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"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)
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Temporary table added: %s",
hkey)));
}
}
#endif
}
free(hkey);
free(tblname);
}
}
/**
* 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.
*
* For now, routeQuery don't tolerate errors, so any error will close
* the session. vraa 14.6.14
*/
static int routeQuery(
ROUTER* instance,
void* router_session,
GWBUF* querybuf)
{
skygw_query_type_t qtype = QUERY_TYPE_UNKNOWN;
mysql_server_cmd_t packet_type;
uint8_t* packet;
int 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;
route_target_t route_target;
bool succp = false;
char* tname = NULL;
CHK_CLIENT_RSES(router_cli_ses);
/** Dirty read for quick check if router is closed. */
if (router_cli_ses->rses_closed)
{
rses_is_closed = true;
}
ss_dassert(!GWBUF_IS_TYPE_UNDEFINED(querybuf));
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);
LOGIF(LE,
(skygw_log_write_flush(
LOGFILE_ERROR,
"Error: Can't route %s:%s:\"%s\" to "
"backend server. Router is closed.",
STRPACKETTYPE(packet_type),
STRQTYPE(qtype),
(query_str == NULL ? "(empty)" : query_str))));
free(query_str);
}
ret = 0;
goto retblock;
}
/** If buffer is not contiguous, make it such */
if (querybuf->next != NULL)
{
querybuf = gwbuf_make_contiguous(querybuf);
}
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 */
if(GWBUF_LENGTH(querybuf) <= MYSQL_DATABASE_MAXLEN - 5)
{
strncpy(router_cli_ses->rses_mysql_session->db,
(char*)(packet + 5),
(int)(GWBUF_LENGTH(querybuf) - 5));
/**
* Update the session's active database only if it's in the hashtable.
* If it isn't found, send a custom error packet to the client.
*/
if(hashtable_fetch(inst->dbnames_hash,
(char*)router_cli_ses->rses_mysql_session->db) == NULL)
{
router_cli_ses->rses_mysql_session->db[0] = '\0';
/**TODO: Add error packet*/
}
}
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 = query_classifier_get_type(querybuf);
break;
case MYSQL_COM_STMT_PREPARE:
qtype = query_classifier_get_type(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 */
/**
* !!! Temporary tablen tutkiminen voi olla turhaa. Poista tarvittaessa.
*/
/**
* Check if the query has anything to do with temporary tables.
*/
qtype = is_read_tmp_table(instance,router_session,querybuf,qtype);
check_create_tmp_table(instance,router_session,querybuf,qtype);
check_drop_tmp_table(instance,router_session,querybuf,qtype);
/**
* !!! Transaktion tutkiminen voi olla turhaa paitsi jos haluataan
* lokittaa. Poista tarvittaessa.
*/
/**
* If autocommit is disabled or transaction is explicitly started
* transaction becomes active and master gets all statements until
* transaction is committed and autocommit is enabled again.
*/
if (router_cli_ses->rses_autocommit_enabled &&
QUERY_IS_TYPE(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT))
{
router_cli_ses->rses_autocommit_enabled = false;
if (!router_cli_ses->rses_transaction_active)
{
router_cli_ses->rses_transaction_active = true;
}
}
else if (!router_cli_ses->rses_transaction_active &&
QUERY_IS_TYPE(qtype, QUERY_TYPE_BEGIN_TRX))
{
router_cli_ses->rses_transaction_active = true;
}
/**
* Explicit COMMIT and ROLLBACK, implicit COMMIT.
*/
if (router_cli_ses->rses_autocommit_enabled &&
router_cli_ses->rses_transaction_active &&
(QUERY_IS_TYPE(qtype,QUERY_TYPE_COMMIT) ||
QUERY_IS_TYPE(qtype,QUERY_TYPE_ROLLBACK)))
{
router_cli_ses->rses_transaction_active = false;
}
else if (!router_cli_ses->rses_autocommit_enabled &&
QUERY_IS_TYPE(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT))
{
router_cli_ses->rses_autocommit_enabled = true;
router_cli_ses->rses_transaction_active = false;
}
if (LOG_IS_ENABLED(LOGFILE_TRACE))
{
uint8_t* packet = GWBUF_DATA(querybuf);
unsigned char ptype = packet[4];
size_t len = MIN(GWBUF_LENGTH(querybuf),
MYSQL_GET_PACKET_LEN((unsigned char *)querybuf->start)-1);
char* data = (char*)&packet[5];
char* contentstr = strndup(data, len);
char* qtypestr = skygw_get_qtype_str(qtype);
skygw_log_write(
LOGFILE_TRACE,
"> Autocommit: %s, trx is %s, cmd: %s, type: %s, "
"stmt: %s%s %s",
(router_cli_ses->rses_autocommit_enabled ? "[enabled]" : "[disabled]"),
(router_cli_ses->rses_transaction_active ? "[open]" : "[not open]"),
STRPACKETTYPE(ptype),
(qtypestr==NULL ? "N/A" : qtypestr),
contentstr,
(querybuf->hint == NULL ? "" : ", Hint:"),
(querybuf->hint == NULL ? "" : STRHINTTYPE(querybuf->hint->type)));
free(contentstr);
free(qtypestr);
}
/**
* Find out whether the query should be routed to single server or to
* all of them.
*/
/**
* Find out where to route the query. Result may not be clear; it is
* possible to have a hint for routing to a named server which can
* be either slave or master.
* If query would otherwise be routed to slave then the hint determines
* actual target server if it exists.
*
* route_target is a bitfield and may include :
* TARGET_ALL
* - route to all connected backend servers
* TARGET_SLAVE[|TARGET_NAMED_SERVER|TARGET_RLAG_MAX]
* - route primarily according to hints, then to slave and if those
* failed, eventually to master
* TARGET_MASTER[|TARGET_NAMED_SERVER|TARGET_RLAG_MAX]
* - route primarily according to the hints and if they failed,
* eventually to master
*/
/**
* Added for simple sharding, using hints for testing.
*/
if((tname = get_shard_target_name(inst,router_cli_ses,querybuf)) != NULL)
{
route_target = TARGET_NAMED_SERVER;
}
else
{
route_target = get_shard_route_target(qtype,
router_cli_ses->rses_transaction_active,
router_cli_ses->rses_config.rw_use_sql_variables_in,
querybuf->hint);
}
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_all, 1);
ret = 1;
}
goto retblock;
}
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Route query aborted! Routing session is closed <")));
ret = 0;
goto retblock;
}
/**
* Query is routed to one of the backends
*/
if (TARGET_IS_NAMED_SERVER(route_target))
{
/**
* 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, tname);
if (!succp)
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Was supposed to route to named server "
"%s but couldn't find the server in a "
"suitable state.",
tname)));
}
}
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;
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Route query to \t%s:%d <",
bref->bref_backend->backend_server->name,
bref->bref_backend->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);
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
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Routing query failed.")));
}
}
rses_end_locked_router_action(router_cli_ses);
retblock:
#if defined(SS_DEBUG2)
{
char* canonical_query_str;
canonical_query_str = skygw_get_canonical(querybuf);
if (canonical_query_str != NULL)
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Canonical version: %s",
canonical_query_str)));
free(canonical_query_str);
}
}
#endif
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(ROUTER *instance, DCB *dcb)
{
ROUTER_CLIENT_SES *router_cli_ses;
ROUTER_INSTANCE *router = (ROUTER_INSTANCE *)instance;
int i = 0;
BACKEND *backend;
char *weightby;
spinlock_acquire(&router->lock);
router_cli_ses = router->connections;
while (router_cli_ses)
{
i++;
router_cli_ses = router_cli_ses->next;
}
spinlock_release(&router->lock);
dcb_printf(dcb,
"\tNumber of router sessions: %d\n",
router->stats.n_sessions);
dcb_printf(dcb,
"\tCurrent no. of router sessions: %d\n",
i);
dcb_printf(dcb,
"\tNumber of queries forwarded: %d\n",
router->stats.n_queries);
dcb_printf(dcb,
"\tNumber of queries forwarded to master: %d\n",
router->stats.n_master);
dcb_printf(dcb,
"\tNumber of queries forwarded to slave: %d\n",
router->stats.n_slave);
dcb_printf(dcb,
"\tNumber of queries forwarded to all: %d\n",
router->stats.n_all);
if ((weightby = serviceGetWeightingParameter(router->service)) != NULL)
{
dcb_printf(dcb,
"\tConnection distribution based on %s "
"server parameter.\n", weightby);
dcb_printf(dcb,
"\t\tServer Target %% Connections "
"Operations\n");
dcb_printf(dcb,
"\t\t Global Router\n");
for (i = 0; router->servers[i]; i++)
{
backend = router->servers[i];
dcb_printf(dcb,
"\t\t%-20s %3.1f%% %-6d %-6d %d\n",
backend->backend_server->unique_name,
(float)backend->weight / 10,
backend->backend_server->stats.n_current,
backend->backend_conn_count,
backend->backend_server->stats.n_current_ops);
}
}
}
/**
* 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 (
ROUTER* instance,
void* router_session,
GWBUF* writebuf,
DCB* backend_dcb)
{
DCB* client_dcb;
ROUTER_CLIENT_SES* router_cli_ses;
sescmd_cursor_t* scur = NULL;
backend_ref_t* bref;
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))
{
print_error_packet(router_cli_ses, writebuf, backend_dcb);
goto lock_failed;
}
/** Holding lock ensures that router session remains open */
ss_dassert(backend_dcb->session != NULL);
client_dcb = backend_dcb->session->client;
/** Unlock */
rses_end_locked_router_action(router_cli_ses);
/**
* 1. Check if backend received reply to sescmd.
* 2. Check sescmd's state whether OK_PACKET has been
* sent to client already and if not, lock property cursor,
* reply to client, and move property cursor forward. Finally
* release the lock.
* 3. If reply for this sescmd is sent, lock property cursor
* and
*/
if (client_dcb == NULL)
{
while ((writebuf = gwbuf_consume(
writebuf,
GWBUF_LENGTH(writebuf))) != NULL);
/** Log that client was closed before reply */
goto lock_failed;
}
/** Lock router session */
if (!rses_begin_locked_router_action(router_cli_ses))
{
/** Log to debug that router was closed */
goto lock_failed;
}
bref = get_bref_from_dcb(router_cli_ses, backend_dcb);
#if !defined(FOR_BUG548_FIX_ONLY)
/** This makes the issue becoming visible in poll.c */
if (bref == NULL)
{
/** Unlock router session */
rses_end_locked_router_action(router_cli_ses);
goto lock_failed;
}
#endif
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 (LOG_IS_ENABLED(LOGFILE_ERROR) &&
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_PACKET_LEN(buf);
size_t replylen = MYSQL_GET_PACKET_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));
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Failed to execute %s in %s:%d. %s %s",
cmdstr,
bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port,
err,
replystr)));
free(cmdstr);
free(err);
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)
{
/** Write reply to client DCB */
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 */
goto lock_failed;
}
/** There is one pending session command to be executed. */
if (sescmd_cursor_is_active(scur))
{
bool succp;
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Backend %s:%d processed reply and starts to execute "
"active cursor.",
bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port)));
succp = execute_sescmd_in_backend(bref);
ss_dassert(succp);
}
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
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Routing query \"%s\" failed.",
bref->bref_pending_cmd)));
}
gwbuf_free(bref->bref_pending_cmd);
bref->bref_pending_cmd = NULL;
}
/** Unlock router session */
rses_end_locked_router_action(router_cli_ses);
lock_failed:
return;
}
/** Compare nunmber of connections from this router in backend servers */
int bref_cmp_router_conn(
const void* bref1,
const void* bref2)
{
BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend;
BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend;
return ((1000 * b1->backend_conn_count) / b1->weight)
- ((1000 * b2->backend_conn_count) / b2->weight);
}
/** Compare nunmber of global connections in backend servers */
int bref_cmp_global_conn(
const void* bref1,
const void* bref2)
{
BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend;
BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend;
return ((1000 * b1->backend_server->stats.n_current) / b1->weight)
- ((1000 * b2->backend_server->stats.n_current) / b2->weight);
}
/** Compare relication lag between backend servers */
int bref_cmp_behind_master(
const void* bref1,
const void* bref2)
{
BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend;
BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend;
return ((b1->backend_server->rlag < b2->backend_server->rlag) ? -1 :
((b1->backend_server->rlag > b2->backend_server->rlag) ? 1 : 0));
}
/** Compare nunmber of current operations in backend servers */
int bref_cmp_current_load(
const void* bref1,
const void* bref2)
{
SERVER* s1 = ((backend_ref_t *)bref1)->bref_backend->backend_server;
SERVER* s2 = ((backend_ref_t *)bref2)->bref_backend->backend_server;
BACKEND* b1 = ((backend_ref_t *)bref1)->bref_backend;
BACKEND* b2 = ((backend_ref_t *)bref2)->bref_backend;
return ((1000 * s1->stats.n_current_ops) - b1->weight)
- ((1000 * s2->stats.n_current_ops) - b2->weight);
}
static void bref_clear_state(
backend_ref_t* bref,
bref_state_t state)
{
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->backend_server->stats.n_current_ops, -1);
ss_dassert(prev2 > 0);
}
}
}
static void bref_set_state(
backend_ref_t* bref,
bref_state_t state)
{
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);
/** Increase global operation count */
prev2 = atomic_add(
&bref->bref_backend->backend_server->stats.n_current_ops, 1);
ss_dassert(prev2 >= 0);
}
}
/**
* @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,
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 0
if (router->bitvalue != 0) /*< 'synced' is the only bitvalue in rwsplit */
{
is_synced_master = true;
}
else
{
is_synced_master = false;
}
#endif
#if defined(EXTRA_SS_DEBUG)
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and conns before ordering:")));
for (i=0; i<router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE,
"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 (LOG_IS_ENABLED(LOGFILE_TRACE))
{
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE,
"Servers and connection counts:")));
for (i=0; i<router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
LOGIF(LT, (skygw_log_write_flush(LOGFILE_TRACE,
"MaxScale connections : %d (%d) in \t%s:%d %s",
b->backend_conn_count,
b->backend_server->stats.n_current,
b->backend_server->name,
b->backend_server->port,
STRSRVSTATUS(b->backend_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++)
{
BACKEND* b = backend_ref[i].bref_backend;
if (SERVER_IS_RUNNING(b->backend_server) &&
((b->backend_server->status & router->bitmask) ==
router->bitvalue))
{
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->backend_server,
session,
b->backend_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.
*/
#if 0
dcb_add_callback(
backend_ref[i].bref_dcb,
DCB_REASON_NOT_RESPONDING,
&router_handle_state_switch,
(void *)&backend_ref[i]);
#endif
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->backend_conn_count, 1);
}
else
{
succp = false;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Unable to establish "
"connection with slave %s:%d",
b->backend_server->name,
b->backend_server->port)));
/* handle connect error */
break;
}
}
}
} /*< for */
#if defined(EXTRA_SS_DEBUG)
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and conns after ordering:")));
for (i=0; i<router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE,
"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 (LOG_IS_ENABLED(LT))
{
for (i=0; i<router_nservers; i++)
{
BACKEND* b = backend_ref[i].bref_backend;
if (BREF_IS_IN_USE((&backend_ref[i])))
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Connected %s in \t%s:%d",
STRSRVSTATUS(b->backend_server),
b->backend_server->name,
b->backend_server->port)));
}
} /* for */
}
}
else
{
LOGIF(LE, (skygw_log_write(
LOGFILE_ERROR,
"Warning : Couldn't connect to all available "
"servers. Session can't be created.")));
/** Clean up connections */
for (i=0; i<router_nservers; i++)
{
if (BREF_IS_IN_USE((&backend_ref[i])))
{
ss_dassert(backend_ref[i].bref_backend->backend_conn_count > 0);
/** disconnect opened connections */
dcb_close(backend_ref[i].bref_dcb);
bref_clear_state(&backend_ref[i], BREF_IN_USE);
/** Decrease backend's connection counter. */
atomic_add(&backend_ref[i].bref_backend->backend_conn_count, -1);
}
}
}
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*)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:
LOGIF(LD, (skygw_log_write(
LOGFILE_DEBUG,
"%lu [rses_property_done] Unknown property type %d "
"in property %p",
pthread_self(),
prop->rses_prop_type,
prop)));
ss_dassert(false);
break;
}
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;
}
/**
static void rses_begin_locked_property_action(
rses_property_t* prop)
{
CHK_RSES_PROP(prop);
spinlock_acquire(&prop->rses_prop_lock);
}
static void rses_end_locked_property_action(
rses_property_t* prop)
{
CHK_RSES_PROP(prop);
spinlock_release(&prop->rses_prop_lock);
}
*/
/**
* 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;
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)
{
/** 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;
LOGIF(LT, (skygw_log_write_flush(
LOGFILE_TRACE,
"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);
}
#if defined(SS_DEBUG)
LOGIF(LT, tracelog_routed_query(scur->scmd_cur_rses,
"execute_sescmd_in_backend",
backend_ref,
sescmd_cursor_clone_querybuf(scur)));
{
GWBUF* tmpbuf = sescmd_cursor_clone_querybuf(scur);
uint8_t* ptr = GWBUF_DATA(tmpbuf);
unsigned char cmd = MYSQL_GET_COMMAND(ptr);
LOGIF(LD, (skygw_log_write(
LOGFILE_DEBUG,
"%lu [execute_sescmd_in_backend] Just before write, fd "
"%d : cmd %s.",
pthread_self(),
dcb->fd,
STRPACKETTYPE(cmd))));
gwbuf_free(tmpbuf);
}
#endif /*< SS_DEBUG */
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_INIT_DB:
{
/**
* Record database name and store to session.
*/
GWBUF* tmpbuf;
MYSQL_session* data;
unsigned int qlen;
data = dcb->session->data;
tmpbuf = scur->scmd_cur_cmd->my_sescmd_buf;
qlen = MYSQL_GET_PACKET_LEN((unsigned char*)tmpbuf->start);
memset(data->db,0,MYSQL_DATABASE_MAXLEN+1);
strncpy(data->db,tmpbuf->start+5,qlen - 1);
}
/** Fallthrough */
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;
}
static void tracelog_routed_query(
ROUTER_CLIENT_SES* rses,
char* funcname,
backend_ref_t* bref,
GWBUF* buf)
{
uint8_t* packet = GWBUF_DATA(buf);
unsigned char packet_type = packet[4];
size_t len;
size_t buflen = GWBUF_LENGTH(buf);
char* querystr;
char* startpos = (char *)&packet[5];
BACKEND* b;
backend_type_t be_type;
DCB* dcb;
CHK_BACKEND_REF(bref);
b = bref->bref_backend;
CHK_BACKEND(b);
dcb = bref->bref_dcb;
CHK_DCB(dcb);
be_type = BACKEND_TYPE(b);
if (GWBUF_IS_TYPE_MYSQL(buf))
{
len = packet[0];
len += 256*packet[1];
len += 256*256*packet[2];
if (packet_type == '\x03')
{
querystr = (char *)malloc(len);
memcpy(querystr, startpos, len-1);
querystr[len-1] = '\0';
LOGIF(LD, (skygw_log_write_flush(
LOGFILE_DEBUG,
"%lu [%s] %d bytes long buf, \"%s\" -> %s:%d %s dcb %p",
pthread_self(),
funcname,
buflen,
querystr,
b->backend_server->name,
b->backend_server->port,
STRBETYPE(be_type),
dcb)));
free(querystr);
}
else if (packet_type == '\x22' ||
packet_type == 0x22 ||
packet_type == '\x26' ||
packet_type == 0x26 ||
true)
{
querystr = (char *)malloc(len);
memcpy(querystr, startpos, len-1);
querystr[len-1] = '\0';
LOGIF(LD, (skygw_log_write_flush(
LOGFILE_DEBUG,
"%lu [%s] %d bytes long buf, \"%s\" -> %s:%d %s dcb %p",
pthread_self(),
funcname,
buflen,
querystr,
b->backend_server->name,
b->backend_server->port,
STRBETYPE(be_type),
dcb)));
free(querystr);
}
}
gwbuf_free(buf);
}
/**
* Return rc, rc < 0 if router session is closed. rc == 0 if there are no
* capabilities specified, rc > 0 when there are capabilities.
*/
static uint8_t getCapabilities (
ROUTER* inst,
void* router_session)
{
ROUTER_CLIENT_SES* rses = (ROUTER_CLIENT_SES *)router_session;
uint8_t rc;
if (!rses_begin_locked_router_action(rses))
{
rc = 0xff;
goto return_rc;
}
rc = rses->rses_capabilities;
rses_end_locked_router_action(rses);
return_rc:
return rc;
}
/**
* 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,
skygw_query_type_t qtype)
{
bool succp;
rses_property_t* prop;
backend_ref_t* backend_ref;
int i;
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"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 (LOG_IS_ENABLED(LOGFILE_TRACE))
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Route query to %s\t%s:%d%s",
(SERVER_IS_MASTER(backend_ref[i].bref_backend->backend_server) ?
"master" : "slave"),
backend_ref[i].bref_backend->backend_server->name,
backend_ref[i].bref_backend->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;
}
/**
* Additional reference is created to querybuf to
* prevent it from being released before properties
* are cleaned up as a part of router sessionclean-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);
for (i=0; i<router_cli_ses->rses_nbackends; i++)
{
if (BREF_IS_IN_USE((&backend_ref[i])))
{
sescmd_cursor_t* scur;
if (LOG_IS_ENABLED(LOGFILE_TRACE))
{
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Route query to %s\t%s:%d%s",
(SERVER_IS_MASTER(backend_ref[i].bref_backend->backend_server) ?
"master" : "slave"),
backend_ref[i].bref_backend->backend_server->name,
backend_ref[i].bref_backend->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;
LOGIF(LT, (skygw_log_write(
LOGFILE_TRACE,
"Backend %s:%d already executing sescmd.",
backend_ref[i].bref_backend->backend_server->name,
backend_ref[i].bref_backend->backend_server->port)));
}
else
{
succp = execute_sescmd_in_backend(&backend_ref[i]);
if (!succp)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Failed to execute session "
"command in %s:%d",
backend_ref[i].bref_backend->backend_server->name,
backend_ref[i].bref_backend->backend_server->port)));
}
}
}
else
{
succp = false;
}
}
/** Unlock router session */
rses_end_locked_router_action(router_cli_ses);
return_succp:
return succp;
}
#if defined(NOT_USED)
static bool router_option_configured(
ROUTER_INSTANCE* router,
const char* optionstr,
void* data)
{
bool succp = false;
char** option;
option = router->service->routerOptions;
while (option != NULL)
{
char* value;
if ((value = strchr(options[i], '=')) == NULL)
{
break;
}
else
{
*value = 0;
value++;
if (strcmp(options[i], "slave_selection_criteria") == 0)
{
if (GET_SELECT_CRITERIA(value) == (select_criteria_t *)*data)
{
succp = true;
break;
}
}
}
}
return succp;
}
#endif /*< NOT_USED */
/**
* 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: REPLY, REPLY_AND_CLOSE, NEW_CONNECTION
* @param succp Result of action.
*
* 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 (
ROUTER* instance,
void* router_session,
GWBUF* errmsgbuf,
DCB* backend_dcb,
error_action_t action,
bool* succp)
{
SESSION* session;
ROUTER_INSTANCE* inst = (ROUTER_INSTANCE *)instance;
ROUTER_CLIENT_SES* rses = (ROUTER_CLIENT_SES *)router_session;
CHK_DCB(backend_dcb);
/** Don't handle same error twice on same DCB */
if (backend_dcb->dcb_errhandle_called)
{
/** we optimistically assume that previous call succeed */
*succp = true;
return;
}
else
{
backend_dcb->dcb_errhandle_called = true;
}
session = backend_dcb->session;
if (session == NULL || rses == NULL)
{
*succp = false;
return;
}
CHK_SESSION(session);
CHK_CLIENT_RSES(rses);
switch (action) {
case ERRACT_NEW_CONNECTION:
{
if (!rses_begin_locked_router_action(rses))
{
*succp = false;
return;
}
/**
* This is called in hope of getting replacement for
* failed slave(s).
*/
*succp = handle_error_new_connection(inst,
rses,
backend_dcb,
errmsgbuf);
rses_end_locked_router_action(rses);
break;
}
case ERRACT_REPLY_CLIENT:
{
handle_error_reply_client(session,
rses,
backend_dcb,
errmsgbuf);
*succp = false; /*< no new backend servers were made available */
break;
}
default:
*succp = false;
break;
}
}
static void handle_error_reply_client(
SESSION* ses,
ROUTER_CLIENT_SES* rses,
DCB* backend_dcb,
GWBUF* errmsg)
{
session_state_t sesstate;
DCB* client_dcb;
backend_ref_t* bref;
spinlock_acquire(&ses->ses_lock);
sesstate = ses->state;
client_dcb = ses->client;
spinlock_release(&ses->ses_lock);
/**
* 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 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)
{
SESSION* ses;
int router_nservers;
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)
{
ss_dassert(bref != 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;
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);
router_nservers = router_get_servercount(inst);
/**
* 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,
router_nservers,
ses,
inst);
return_succp:
return succp;
}
static void print_error_packet(
ROUTER_CLIENT_SES* rses,
GWBUF* buf,
DCB* dcb)
{
#if defined(SS_DEBUG)
if (GWBUF_IS_TYPE_MYSQL(buf))
{
while (gwbuf_length(buf) > 0)
{
/**
* This works with MySQL protocol only !
* Protocol specific packet print functions would be nice.
*/
uint8_t* ptr = GWBUF_DATA(buf);
size_t len = MYSQL_GET_PACKET_LEN(ptr);
if (MYSQL_GET_COMMAND(ptr) == 0xff)
{
SERVER* srv = NULL;
backend_ref_t* bref = rses->rses_backend_ref;
int i;
char* bufstr;
for (i=0; i<rses->rses_nbackends; i++)
{
if (bref[i].bref_dcb == dcb)
{
srv = bref[i].bref_backend->backend_server;
}
}
ss_dassert(srv != NULL);
char* str = (char*)&ptr[7];
bufstr = strndup(str, len-3);
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Backend server %s:%d responded with "
"error : %s",
srv->name,
srv->port,
bufstr)));
free(bufstr);
}
buf = gwbuf_consume(buf, len+4);
}
}
else
{
while ((buf = gwbuf_consume(buf, GWBUF_LENGTH(buf))) != NULL);
}
#endif /*< SS_DEBUG */
}
static int router_get_servercount(
ROUTER_INSTANCE* inst)
{
int router_nservers = 0;
BACKEND** b = inst->servers;
/** count servers */
while (*(b++) != NULL) router_nservers++;
return router_nservers;
}
#if 0
/**
* Find out the number of read backend servers.
* Depending on the configuration value type, either copy direct count
* of slave connections or calculate the count from percentage value.
*/
static int rses_get_max_slavecount(
ROUTER_CLIENT_SES* rses,
int router_nservers)
{
int conf_max_nslaves;
int max_nslaves;
CHK_CLIENT_RSES(rses);
if (rses->rses_config.rw_max_slave_conn_count > 0)
{
conf_max_nslaves = rses->rses_config.rw_max_slave_conn_count;
}
else
{
conf_max_nslaves =
(router_nservers*rses->rses_config.rw_max_slave_conn_percent)/100;
}
max_nslaves = MIN(router_nservers-1, MAX(1, conf_max_nslaves));
return max_nslaves;
}
#endif
/**
* 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.
*/
static int router_handle_state_switch(
DCB* dcb,
DCB_REASON reason,
void* data)
{
backend_ref_t* bref;
int rc = 1;
ROUTER_CLIENT_SES* rses;
SESSION* ses;
SERVER* srv;
CHK_DCB(dcb);
bref = (backend_ref_t *)data;
CHK_BACKEND_REF(bref);
srv = bref->bref_backend->backend_server;
if (SERVER_IS_RUNNING(srv) && SERVER_IS_IN_CLUSTER(srv))
{
goto return_rc;
}
ses = dcb->session;
CHK_SESSION(ses);
rses = (ROUTER_CLIENT_SES *)dcb->session->router_session;
CHK_CLIENT_RSES(rses);
switch (reason) {
case DCB_REASON_NOT_RESPONDING:
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;
}
#if defined(PREP_STMT_CACHING)
#define MAX_STMT_LEN 1024
static prep_stmt_t* prep_stmt_init(
prep_stmt_type_t type,
void* id)
{
prep_stmt_t* pstmt;
pstmt = (prep_stmt_t *)calloc(1, sizeof(prep_stmt_t));
if (pstmt != NULL)
{
#if defined(SS_DEBUG)
pstmt->pstmt_chk_top = CHK_NUM_PREP_STMT;
pstmt->pstmt_chk_tail = CHK_NUM_PREP_STMT;
#endif
pstmt->pstmt_state = PREP_STMT_ALLOC;
pstmt->pstmt_type = type;
if (type == PREP_STMT_NAME)
{
pstmt->pstmt_id.name = strndup((char *)id, MAX_STMT_LEN);
}
else
{
pstmt->pstmt_id.seq = 0;
}
}
CHK_PREP_STMT(pstmt);
return pstmt;
}
static void prep_stmt_done(
prep_stmt_t* pstmt)
{
CHK_PREP_STMT(pstmt);
if (pstmt->pstmt_type == PREP_STMT_NAME)
{
free(pstmt->pstmt_id.name);
}
free(pstmt);
}
static bool prep_stmt_drop(
prep_stmt_t* pstmt)
{
CHK_PREP_STMT(pstmt);
pstmt->pstmt_state = PREP_STMT_DROPPED;
return true;
}
#endif /*< PREP_STMT_CACHING */
/********************************
* This routine returns the root master server from MySQL replication tree
* Get the root Master rule:
*
* find server with the lowest replication depth level
* and the SERVER_MASTER bitval
* Servers are checked even if they are in 'maintenance'
*
* @param servers The list of servers
* @param router_nservers The number of servers
* @return The Master found
*
*/
static BACKEND *get_root_master(
backend_ref_t *servers,
int router_nservers)
{
int i = 0;
BACKEND * master_host = NULL;
for (i = 0; i< router_nservers; i++)
{
BACKEND* b;
if (servers[i].bref_backend == NULL)
{
continue;
}
b = servers[i].bref_backend;
if ((b->backend_server->status &
(SERVER_MASTER|SERVER_MAINT)) == SERVER_MASTER)
{
if (master_host == NULL ||
(b->backend_server->depth < master_host->backend_server->depth))
{
master_host = b;
}
}
}
return master_host;
}
/********************************
* This routine returns the root master server from MySQL replication tree
* Get the root Master rule:
*
* find server with the lowest replication depth level
* and the SERVER_MASTER bitval
* Servers are checked even if they are in 'maintenance'
*
* @param rses pointer to router session
* @return pointer to backend reference of the root master or NULL
*
*/
static backend_ref_t* get_root_master_bref(
ROUTER_CLIENT_SES* rses)
{
backend_ref_t* bref;
backend_ref_t* candidate_bref = NULL;
int i = 0;
bref = rses->rses_backend_ref;
while (i<rses->rses_nbackends)
{
if ((bref->bref_backend->backend_server->status &
(SERVER_MASTER|SERVER_MAINT)) == SERVER_MASTER)
{
if (bref->bref_backend->backend_server->status & SERVER_MASTER)
{
if (candidate_bref == NULL ||
(bref->bref_backend->backend_server->depth <
candidate_bref->bref_backend->backend_server->depth))
{
candidate_bref = bref;
}
}
}
bref++;
i += 1;
}
if (candidate_bref == NULL)
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Could not find master among the backend "
"servers. Previous master's state : %s",
STRSRVSTATUS(BREFSRV(rses->rses_master_ref)))));
}
return candidate_bref;
}
static void dbshard_process_router_options(
ROUTER_INSTANCE* router,
char** options)
{
int i;
char* value;
for (i = 0; options[i]; i++)
{
if ((value = strchr(options[i], '=')) == NULL)
{
LOGIF(LE, (skygw_log_write(
LOGFILE_ERROR, "Warning : Unsupported "
"router option \"%s\" for "
"readwritesplit router.",
options[i])));
}
else
{
*value = 0;
value++;
#if 0
if (strcmp(options[i], "slave_selection_criteria") == 0)
{
c = GET_SELECT_CRITERIA(value);
ss_dassert(
c == LEAST_GLOBAL_CONNECTIONS ||
c == LEAST_ROUTER_CONNECTIONS ||
c == LEAST_BEHIND_MASTER ||
c == LEAST_CURRENT_OPERATIONS ||
c == UNDEFINED_CRITERIA);
if (c == UNDEFINED_CRITERIA)
{
LOGIF(LE, (skygw_log_write(
LOGFILE_ERROR, "Warning : Unknown "
"slave selection criteria \"%s\". "
"Allowed values are LEAST_GLOBAL_CONNECTIONS, "
"LEAST_ROUTER_CONNECTIONS, "
"LEAST_BEHIND_MASTER,"
"and LEAST_CURRENT_OPERATIONS.",
STRCRITERIA(router->dbshard_config.rw_slave_select_criteria))));
}
else
{
router->dbshard_config.rw_slave_select_criteria = c;
}
}
#endif
}
} /*< for */
}
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