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Move MXS-807 refactor read-write split into develop.

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This commit is contained in:
counterpoint 2016-09-20 11:55:02 +01:00
parent 3992135325
commit 923761159f
8 changed files with 4066 additions and 3620 deletions
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142
server/modules/include/rwsplit_internal.h Normal file
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/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
/*
* File: rwsplit_internal.h
* Author: mbrampton
*
* Created on 08 August 2016, 11:54
*/
#ifndef RWSPLIT_INTERNAL_H
#define RWSPLIT_INTERNAL_H
#ifdef __cplusplus
extern "C" {
#endif
#include <query_classifier.h>
/* This needs to be removed along with dependency on it - see the
* rwsplit_tmp_table_multi functions
*/
#include <mysql_client_server_protocol.h>
/*
* The following are implemented in rwsplit_mysql.c
*/
bool route_single_stmt(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf);
void closed_session_reply(GWBUF *querybuf);
void live_session_reply(GWBUF **querybuf, ROUTER_CLIENT_SES *rses);
void print_error_packet(ROUTER_CLIENT_SES *rses, GWBUF *buf, DCB *dcb);
void check_session_command_reply(GWBUF *writebuf, sescmd_cursor_t *scur, backend_ref_t *bref);
bool execute_sescmd_in_backend(backend_ref_t *backend_ref);
bool handle_target_is_all(route_target_t route_target,
ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf, int packet_type, qc_query_type_t qtype);
int determine_packet_type(GWBUF *querybuf, bool *non_empty_packet);
void log_transaction_status(ROUTER_CLIENT_SES *rses, GWBUF *querybuf, qc_query_type_t qtype);
void session_lock_failure_handling(GWBUF *querybuf, int packet_type, qc_query_type_t qtype);
bool is_packet_a_one_way_message(int packet_type);
sescmd_cursor_t *backend_ref_get_sescmd_cursor(backend_ref_t *bref);
bool is_packet_a_query(int packet_type);
bool send_readonly_error(DCB *dcb);
/*
* The following are implemented in readwritesplit.c
*/
bool rses_begin_locked_router_action(ROUTER_CLIENT_SES *rses);
void rses_end_locked_router_action(ROUTER_CLIENT_SES *rses);
void bref_clear_state(backend_ref_t *bref, bref_state_t state);
void bref_set_state(backend_ref_t *bref, bref_state_t state);
int router_handle_state_switch(DCB *dcb, DCB_REASON reason, void *data);
backend_ref_t *get_bref_from_dcb(ROUTER_CLIENT_SES *rses, DCB *dcb);
void rses_property_done(rses_property_t *prop);
int rses_get_max_slavecount(ROUTER_CLIENT_SES *rses, int router_nservers);
int rses_get_max_replication_lag(ROUTER_CLIENT_SES *rses);
/*
* The following are implemented in rwsplit_route_stmt.c
*/
bool route_single_stmt(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf);
int rwsplit_hashkeyfun(const void *key);
int rwsplit_hashcmpfun(const void *v1, const void *v2);
void *rwsplit_hstrdup(const void *fval);
void rwsplit_hfree(void *fval);
bool rwsplit_get_dcb(DCB **p_dcb, ROUTER_CLIENT_SES *rses, backend_type_t btype,
char *name, int max_rlag);
route_target_t get_route_target(ROUTER_CLIENT_SES *rses,
qc_query_type_t qtype, HINT *hint);
rses_property_t *rses_property_init(rses_property_type_t prop_type);
int rses_property_add(ROUTER_CLIENT_SES *rses, rses_property_t *prop);
void handle_multi_temp_and_load(ROUTER_CLIENT_SES *rses, GWBUF *querybuf,
int packet_type, int *qtype);
bool handle_hinted_target(ROUTER_CLIENT_SES *rses, GWBUF *querybuf,
route_target_t route_target, DCB **target_dcb);
bool handle_slave_is_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
DCB **target_dcb);
bool handle_master_is_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
DCB **target_dcb);
bool handle_got_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf, DCB *target_dcb);
bool route_session_write(ROUTER_CLIENT_SES *router_cli_ses,
GWBUF *querybuf, ROUTER_INSTANCE *inst,
int packet_type,
qc_query_type_t qtype);
/*
* The following are implemented in rwsplit_session_cmd.c
*/
mysql_sescmd_t *rses_property_get_sescmd(rses_property_t *prop);
mysql_sescmd_t *mysql_sescmd_init(rses_property_t *rses_prop,
GWBUF *sescmd_buf,
unsigned char packet_type,
ROUTER_CLIENT_SES *rses);
void mysql_sescmd_done(mysql_sescmd_t *sescmd);
mysql_sescmd_t *sescmd_cursor_get_command(sescmd_cursor_t *scur);
bool sescmd_cursor_is_active(sescmd_cursor_t *sescmd_cursor);
void sescmd_cursor_set_active(sescmd_cursor_t *sescmd_cursor,
bool value);
bool execute_sescmd_history(backend_ref_t *bref);
GWBUF *sescmd_cursor_clone_querybuf(sescmd_cursor_t *scur);
GWBUF *sescmd_cursor_process_replies(GWBUF *replybuf,
backend_ref_t *bref,
bool *reconnect);
/*
* The following are implemented in rwsplit_select_backends.c
*/
bool select_connect_backend_servers(backend_ref_t **p_master_ref,
backend_ref_t *backend_ref,
int router_nservers, int max_nslaves,
int max_rlag,
select_criteria_t select_criteria,
SESSION *session,
ROUTER_INSTANCE *router);
/*
* The following are implemented in rwsplit_tmp_table_multi.c
*/
void check_drop_tmp_table(ROUTER_CLIENT_SES *router_cli_ses,
GWBUF *querybuf,
mysql_server_cmd_t packet_type);
qc_query_type_t is_read_tmp_table(ROUTER_CLIENT_SES *router_cli_ses,
GWBUF *querybuf,
qc_query_type_t type);
void check_create_tmp_table(ROUTER_CLIENT_SES *router_cli_ses,
GWBUF *querybuf, qc_query_type_t type);
bool check_for_multi_stmt(GWBUF *buf, void *protocol, mysql_server_cmd_t packet_type);
qc_query_type_t determine_query_type(GWBUF *querybuf, int packet_type, bool non_empty_packet);
#ifdef __cplusplus
}
#endif
#endif /* RWSPLIT_INTERNAL_H */

2
server/modules/routing/readwritesplit/CMakeLists.txt
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add_library(readwritesplit SHARED readwritesplit.c)
add_library(readwritesplit SHARED readwritesplit.c rwsplit_mysql.c rwsplit_route_stmt.c rwsplit_select_backends.c rwsplit_session_cmd.c rwsplit_tmp_table_multi.c)
target_link_libraries(readwritesplit maxscale-common)
set_target_properties(readwritesplit PROPERTIES VERSION "1.0.2")
install_module(readwritesplit core)

4336
server/modules/routing/readwritesplit/readwritesplit.c
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server/modules/routing/readwritesplit/rwsplit_mysql.c Normal file
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/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl.
*
* Change Date: 2019-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include <my_config.h>
#include <stdio.h>
#include <strings.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <router.h>
#include <readwritesplit.h>
#include <rwsplit_internal.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>
#include <mysqld_error.h>
#include <maxscale/alloc.h>
#if defined(SS_DEBUG)
#include <mysql_client_server_protocol.h>
#endif
#define RWSPLIT_TRACE_MSG_LEN 1000
/**
* @file rwsplit_mysql.c Functions within the read-write split router that
* are specific to MySQL. The aim is to either remove these into a separate
* module or to move them into the MySQL protocol modules.
*
* @verbatim
* Revision History
*
* Date Who Description
* 08/08/2016 Martin Brampton Initial implementation
*
* @endverbatim
*/
/*
* The following functions are called from elsewhere in the router and
* are defined in rwsplit_internal.h. They are not intended to be called
* from outside this router.
*/
/* This could be placed in the protocol, with a new API entry point
* It is certainly MySQL specific.
* */
int
determine_packet_type(GWBUF *querybuf, bool *non_empty_packet)
{
mysql_server_cmd_t packet_type;
uint8_t *packet = GWBUF_DATA(querybuf);
if (gw_mysql_get_byte3(packet) == 0)
{
/** Empty packet signals end of LOAD DATA LOCAL INFILE, send it to master*/
*non_empty_packet = false;
packet_type = MYSQL_COM_UNDEFINED;
}
else
{
*non_empty_packet = true;
packet_type = packet[4];
}
return (int)packet_type;
}
/*
* This appears to be MySQL specific
*/
bool
is_packet_a_query(int packet_type)
{
return (packet_type == MYSQL_COM_QUERY);
}
/*
* This looks MySQL specific
*/
bool
is_packet_a_one_way_message(int packet_type)
{
return (packet_type == MYSQL_COM_STMT_SEND_LONG_DATA ||
packet_type == MYSQL_COM_QUIT || packet_type == MYSQL_COM_STMT_CLOSE);
}
/*
* This one is problematic because it is MySQL specific, but also router
* specific.
*/
void
log_transaction_status(ROUTER_CLIENT_SES *rses, GWBUF *querybuf, qc_query_type_t qtype)
{
if (!rses->rses_load_active)
{
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, MIN(len, RWSPLIT_TRACE_MSG_LEN));
char *qtypestr = qc_get_qtype_str(qtype);
MXS_INFO("> Autocommit: %s, trx is %s, cmd: %s, type: %s, stmt: %s%s %s",
(rses->rses_autocommit_enabled ? "[enabled]" : "[disabled]"),
(rses->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)));
MXS_FREE(contentstr);
MXS_FREE(qtypestr);
}
else
{
MXS_INFO("> Processing LOAD DATA LOCAL INFILE: %lu bytes sent.",
rses->rses_load_data_sent);
}
}
/*
* This is mostly router code, but it contains MySQL specific operations that
* maybe could be moved to the protocol module. The modutil functions are mostly
* MySQL specific and could migrate to the MySQL protocol; likewise the
* utility to convert packet type to a string. The aim is for most of this
* code to remain as part of the router.
*/
bool
handle_target_is_all(route_target_t route_target,
ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf, int packet_type, qc_query_type_t qtype)
{
bool result;
/** Multiple, conflicting routing target. Return error */
if (TARGET_IS_MASTER(route_target) || TARGET_IS_SLAVE(route_target))
{
backend_ref_t *bref = rses->rses_backend_ref;
/* NOTE: modutil_get_query is MySQL specific */
char *query_str = modutil_get_query(querybuf);
char *qtype_str = qc_get_qtype_str(qtype);
/* NOTE: packet_type is MySQL specific */
MXS_ERROR("Can't route %s:%s:\"%s\". SELECT with session data "
"modification is not supported if configuration parameter "
"use_sql_variables_in=all .", STRPACKETTYPE(packet_type),
qtype_str, (query_str == NULL ? "(empty)" : query_str));
MXS_INFO("Unable to route the query without losing session data "
"modification from other servers. <");
while (bref != NULL && !BREF_IS_IN_USE(bref))
{
bref++;
}
if (bref != NULL && BREF_IS_IN_USE(bref))
{
/** Create and add MySQL error to eventqueue */
modutil_reply_parse_error(bref->bref_dcb,
MXS_STRDUP_A("Routing query to backend failed. "
"See the error log for further "
"details."), 0);
result = true;
}
else
{
/**
* If there were no available backend references
* available return false - session will be closed
*/
MXS_ERROR("Sending error message to client "
"failed. Router doesn't have any "
"available backends. Session will be "
"closed.");
result = false;
}
/* Test shouldn't be needed */
if (query_str)
{
MXS_FREE(query_str);
}
if (qtype_str)
{
MXS_FREE(qtype_str);
}
return result;
}
/**
* 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.
*/
result = route_session_write(rses, gwbuf_clone(querybuf), inst,
packet_type, qtype);
if (result)
{
atomic_add(&inst->stats.n_all, 1);
}
return result;
}
/* This is MySQL specific */
void
session_lock_failure_handling(GWBUF *querybuf, int packet_type, qc_query_type_t qtype)
{
if (packet_type != MYSQL_COM_QUIT)
{
/* NOTE: modutil_get_query is MySQL specific */
char *query_str = modutil_get_query(querybuf);
MXS_ERROR("Can't route %s:%s:\"%s\" to "
"backend server. Router is closed.",
STRPACKETTYPE(packet_type), STRQTYPE(qtype),
(query_str == NULL ? "(empty)" : query_str));
MXS_FREE(query_str);
}
}
/*
* Probably MySQL specific because of modutil function
*/
void closed_session_reply(GWBUF *querybuf)
{
uint8_t* data = GWBUF_DATA(querybuf);
if (GWBUF_LENGTH(querybuf) >= 5 && !MYSQL_IS_COM_QUIT(data))
{
/* Note that most modutil functions are MySQL specific */
char *query_str = modutil_get_query(querybuf);
MXS_ERROR("Can't route %s:\"%s\" to backend server. Router is closed.",
STRPACKETTYPE(data[4]), query_str ? query_str : "(empty)");
MXS_FREE(query_str);
}
}
/*
* Probably MySQL specific because of modutil function
*/
void live_session_reply(GWBUF **querybuf, ROUTER_CLIENT_SES *rses)
{
GWBUF *tmpbuf = *querybuf;
if (GWBUF_IS_TYPE_UNDEFINED(tmpbuf))
{
/* Note that many modutil functions are MySQL specific */
*querybuf = modutil_get_complete_packets(&tmpbuf);
if (tmpbuf)
{
rses->client_dcb->dcb_readqueue = gwbuf_append(rses->client_dcb->dcb_readqueue, tmpbuf);
}
*querybuf = gwbuf_make_contiguous(*querybuf);
/** Mark buffer to as MySQL type */
gwbuf_set_type(*querybuf, GWBUF_TYPE_MYSQL);
gwbuf_set_type(*querybuf, GWBUF_TYPE_SINGLE_STMT);
}
}
/*
* Uses MySQL specific mechanisms
*/
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);
MXS_ERROR("Backend server %s:%d responded with "
"error : %s",
srv->name, srv->port, bufstr);
MXS_FREE(bufstr);
}
buf = gwbuf_consume(buf, len + 4);
}
}
else
{
gwbuf_free(buf);
}
#endif /*< SS_DEBUG */
}
/*
* Uses MySQL specific mechanisms
*/
void check_session_command_reply(GWBUF *writebuf, sescmd_cursor_t *scur, backend_ref_t *bref)
{
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_ERR) &&
MYSQL_IS_ERROR_PACKET(((uint8_t *)GWBUF_DATA(writebuf))))
{
uint8_t *buf = (uint8_t *)GWBUF_DATA((scur->scmd_cur_cmd->my_sescmd_buf));
uint8_t *replybuf = (uint8_t *)GWBUF_DATA(writebuf);
size_t len = MYSQL_GET_PACKET_LEN(buf);
size_t replylen = MYSQL_GET_PACKET_LEN(replybuf);
char *err = strndup(&((char *)replybuf)[8], 5);
char *replystr = strndup(&((char *)replybuf)[13], replylen - 4 - 5);
ss_dassert(len + 4 == GWBUF_LENGTH(scur->scmd_cur_cmd->my_sescmd_buf));
MXS_ERROR("Failed to execute session command in %s:%d. Error was: %s %s",
bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port, err, replystr);
MXS_FREE(err);
MXS_FREE(replystr);
}
}
/**
* 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.
*/
/*
* Uses MySQL specific values in the large switch statement, although it
* may be possible to generalize them.
*/
bool execute_sescmd_in_backend(backend_ref_t *backend_ref)
{
DCB *dcb;
bool succp;
int rc = 0;
sescmd_cursor_t *scur;
GWBUF *buf;
if (backend_ref == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return false;
}
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 = true;
MXS_INFO("Cursor had no pending session commands.");
goto return_succp;
}
if (!sescmd_cursor_is_active(scur))
{
/** Cursor is left active when function returns. */
sescmd_cursor_set_active(scur, true);
}
switch (scur->scmd_cur_cmd->my_sescmd_packet_type)
{
case MYSQL_COM_CHANGE_USER:
/** This makes it possible to handle replies correctly */
gwbuf_set_type(scur->scmd_cur_cmd->my_sescmd_buf, GWBUF_TYPE_SESCMD);
buf = sescmd_cursor_clone_querybuf(scur);
rc = dcb->func.auth(dcb, NULL, dcb->session, buf);
break;
case MYSQL_COM_INIT_DB:
{
/**
* Record database name and store to session.
*/
GWBUF *tmpbuf;
MYSQL_session *data;
unsigned int qlen;
data = dcb->session->client_dcb->data;
*data->db = 0;
tmpbuf = scur->scmd_cur_cmd->my_sescmd_buf;
qlen = MYSQL_GET_PACKET_LEN((unsigned char *) GWBUF_DATA(tmpbuf));
if (qlen)
{
--qlen; // The COM_INIT_DB byte
if (qlen > MYSQL_DATABASE_MAXLEN)
{
MXS_ERROR("Too long a database name received in COM_INIT_DB, "
"trailing data will be cut.");
qlen = MYSQL_DATABASE_MAXLEN;
}
memcpy(data->db, (char*)GWBUF_DATA(tmpbuf) + 5, qlen);
data->db[qlen] = 0;
}
}
/** 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);
buf = sescmd_cursor_clone_querybuf(scur);
rc = dcb->func.write(dcb, buf);
break;
}
if (rc == 1)
{
succp = true;
}
else
{
succp = false;
}
return_succp:
return succp;
}
/*
* End of functions called from other router modules; start of functions that
* are internal to this module
*/
/**
* Get client DCB pointer of the router client session.
* This routine must be protected by Router client session lock.
*
* APPEARS TO NEVER BE USED!!
*
* @param rses Router client session pointer
*
* @return Pointer to client DCB
*/
static DCB *rses_get_client_dcb(ROUTER_CLIENT_SES *rses)
{
DCB *dcb = NULL;
int i;
for (i = 0; i < rses->rses_nbackends; i++)
{
if ((dcb = rses->rses_backend_ref[i].bref_dcb) != NULL &&
BREF_IS_IN_USE(&rses->rses_backend_ref[i]) && dcb->session != NULL &&
dcb->session->client_dcb != NULL)
{
return dcb->session->client_dcb;
}
}
return NULL;
}
/*
* The following are internal (directly or indirectly) to routing a statement
* and should be moved to rwsplit_route_cmd.c if the MySQL specific code can
* be removed.
*/
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;
}
/**
* Send an error message to the client telling that the server is in read only mode
* @param dcb Client DCB
* @return True if sending the message was successful, false if an error occurred
*/
bool send_readonly_error(DCB *dcb)
{
bool succp = false;
const char* errmsg = "The MariaDB server is running with the --read-only"
" option so it cannot execute this statement";
GWBUF* err = modutil_create_mysql_err_msg(1, 0, ER_OPTION_PREVENTS_STATEMENT,
"HY000", errmsg);
if (err)
{
succp = dcb->func.write(dcb, err);
}
else
{
MXS_ERROR("Memory allocation failed when creating client error message.");
}
return succp;
}

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server/modules/routing/readwritesplit/rwsplit_route_stmt.c Normal file
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/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl.
*
* Change Date: 2019-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include <stdio.h>
#include <strings.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <router.h>
#include <readwritesplit.h>
#include <rwsplit_internal.h>
/**
* @file rwsplit_select_backends.c The functions that implement back end
* selection for the read write split router. All of these functions are
* internal to that router and not intended to be called from elsewhere.
*
* @verbatim
* Revision History
*
* Date Who Description
* 08/08/2016 Martin Brampton Initial implementation
*
* @endverbatim
*/
static bool connect_server(backend_ref_t *bref, SESSION *session, bool execute_history);
static void log_server_connections(select_criteria_t select_criteria,
backend_ref_t *backend_ref, int router_nservers);
static BACKEND *get_root_master(backend_ref_t *servers, int router_nservers);
static int bref_cmp_global_conn(const void *bref1, const void *bref2);
static int bref_cmp_router_conn(const void *bref1, const void *bref2);
static int bref_cmp_behind_master(const void *bref1, const void *bref2);
static int bref_cmp_current_load(const void *bref1, const void *bref2);
/**
* The order of functions _must_ match with the order the select criteria are
* listed in select_criteria_t definition in readwritesplit.h
*/
int (*criteria_cmpfun[LAST_CRITERIA])(const void *, const void *) =
{
NULL,
bref_cmp_global_conn,
bref_cmp_router_conn,
bref_cmp_behind_master,
bref_cmp_current_load
};
/*
* The following function is the only one that is called from elsewhere in
* the read write split router. It is not intended for use from outside this
* router. Other functions in this module are internal and are called
* directly or indirectly by this function.
*/
/**
* @brief Search suitable backend servers from those of router instance
*
* It is assumed that there is only one master among servers of a router instance.
* As a result, the first master found is chosen. There will possibly be more
* backend references than connected backends because only those in correct state
* are connected to.
*
* @param p_master_ref Pointer to location where master's backend reference is to be stored
* @param backend_ref Pointer to backend server reference object array
* @param router_nservers Number of backend server pointers pointed to by @p backend_ref
* @param max_nslaves Upper limit for the number of slaves
* @param max_slave_rlag Maximum allowed replication lag for any slave
* @param select_criteria Slave selection criteria
* @param session Client session
* @param router Router instance
* @return true, if at least one master and one slave was found.
*/
bool select_connect_backend_servers(backend_ref_t **p_master_ref,
backend_ref_t *backend_ref,
int router_nservers, int max_nslaves,
int max_slave_rlag,
select_criteria_t select_criteria,
SESSION *session,
ROUTER_INSTANCE *router)
{
if (p_master_ref == NULL || backend_ref == NULL)
{
MXS_ERROR("Master reference (%p) or backend reference (%p) is NULL.",
p_master_ref, backend_ref);
ss_dassert(false);
return false;
}
/* get the root Master */
BACKEND *master_host = get_root_master(backend_ref, router_nservers);
if (router->rwsplit_config.rw_master_failure_mode == RW_FAIL_INSTANTLY &&
(master_host == NULL || SERVER_IS_DOWN(master_host->backend_server)))
{
MXS_ERROR("Couldn't find suitable Master from %d candidates.", router_nservers);
return false;
}
/**
* Existing session : master is already chosen and connected.
* The function was called because new slave must be selected to replace
* failed one.
*/
bool master_connected = *p_master_ref != NULL;
/** Check slave selection criteria and set compare function */
int (*p)(const void *, const void *) = criteria_cmpfun[select_criteria];
ss_dassert(p);
/** Sort the pointer list to servers according to slave selection criteria.
* The servers that match the criteria the best are at the beginning of
* the list. */
qsort(backend_ref, (size_t) router_nservers, sizeof(backend_ref_t), p);
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))
{
log_server_connections(select_criteria, backend_ref, router_nservers);
}
int slaves_found = 0;
int slaves_connected = 0;
const int min_nslaves = 0; /*< not configurable at the time */
bool succp = false;
/**
* Choose at least 1+min_nslaves (master and slave) and at most 1+max_nslaves
* servers from the sorted list. First master found is selected.
*/
for (int i = 0; i < router_nservers &&
(slaves_connected < max_nslaves || !master_connected); i++)
{
SERVER *serv = backend_ref[i].bref_backend->backend_server;
if (!BREF_HAS_FAILED(&backend_ref[i]) && SERVER_IS_RUNNING(serv))
{
/* check also for relay servers and don't take the master_host */
if (slaves_found < max_nslaves &&
(max_slave_rlag == MAX_RLAG_UNDEFINED ||
(serv->rlag != MAX_RLAG_NOT_AVAILABLE &&
serv->rlag <= max_slave_rlag)) &&
(SERVER_IS_SLAVE(serv) || SERVER_IS_RELAY_SERVER(serv)) &&
(master_host == NULL || (serv != master_host->backend_server)))
{
slaves_found += 1;
if (BREF_IS_IN_USE((&backend_ref[i])) ||
connect_server(&backend_ref[i], session, true))
{
slaves_connected += 1;
}
}
/* take the master_host for master */
else if (master_host && (serv == master_host->backend_server))
{
/** p_master_ref must be assigned with this backend_ref pointer
* because its original value may have been lost when backend
* references were sorted with qsort. */
*p_master_ref = &backend_ref[i];
if (!master_connected)
{
if (connect_server(&backend_ref[i], session, false))
{
master_connected = true;
}
}
}
}
} /*< for */
/**
* Successful cases
*/
if (slaves_connected >= min_nslaves && slaves_connected <= max_nslaves)
{
succp = true;
if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))
{
if (slaves_connected < max_nslaves)
{
MXS_INFO("Couldn't connect to maximum number of "
"slaves. Connected successfully to %d slaves "
"of %d of them.", slaves_connected, slaves_found);
}
for (int i = 0; i < router_nservers; i++)
{
if (BREF_IS_IN_USE((&backend_ref[i])))
{
MXS_INFO("Selected %s in \t%s:%d",
STRSRVSTATUS(backend_ref[i].bref_backend->backend_server),
backend_ref[i].bref_backend->backend_server->name,
backend_ref[i].bref_backend->backend_server->port);
}
} /* for */
}
}
/** Failure cases */
else
{
if (slaves_connected < min_nslaves)
{
MXS_ERROR("Couldn't establish required amount of "
"slave connections for router session.");
}
/** Clean up connections */
for (int 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 */
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);
dcb_close(backend_ref[i].bref_dcb);
}
}
}
return succp;
}
/** Compare number of connections from this router in backend servers */
static 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;
if (b1->weight == 0 && b2->weight == 0)
{
return b1->backend_server->stats.n_current -
b2->backend_server->stats.n_current;
}
else if (b1->weight == 0)
{
return 1;
}
else if (b2->weight == 0)
{
return -1;
}
return ((1000 + 1000 * b1->backend_conn_count) / b1->weight) -
((1000 + 1000 * b2->backend_conn_count) / b2->weight);
}
/** Compare number of global connections in backend servers */
static 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;
if (b1->weight == 0 && b2->weight == 0)
{
return b1->backend_server->stats.n_current -
b2->backend_server->stats.n_current;
}
else if (b1->weight == 0)
{
return 1;
}
else if (b2->weight == 0)
{
return -1;
}
return ((1000 + 1000 * b1->backend_server->stats.n_current) / b1->weight) -
((1000 + 1000 * b2->backend_server->stats.n_current) / b2->weight);
}
/** Compare replication lag between backend servers */
static 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 number of current operations in backend servers */
static 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;
if (b1->weight == 0 && b2->weight == 0)
{
return b1->backend_server->stats.n_current -
b2->backend_server->stats.n_current;
}
else if (b1->weight == 0)
{
return 1;
}
else if (b2->weight == 0)
{
return -1;
}
return ((1000 * s1->stats.n_current_ops) - b1->weight) -
((1000 * s2->stats.n_current_ops) - b2->weight);
}
/**
* @brief Connect a server
*
* Connects to a server, adds callbacks to the created DCB and updates
* router statistics. If @p execute_history is true, the session command
* history will be executed on this server.
*
* @param b Router's backend structure for the server
* @param session Client's session object
* @param execute_history Execute session command history
* @return True if successful, false if an error occurred
*/
static bool connect_server(backend_ref_t *bref, SESSION *session, bool execute_history)
{
SERVER *serv = bref->bref_backend->backend_server;
bool rval = false;
bref->bref_dcb = dcb_connect(serv, session, serv->protocol);
if (bref->bref_dcb != NULL)
{
if (!execute_history || execute_sescmd_history(bref))
{
/** Add a callback for unresponsive server */
dcb_add_callback(bref->bref_dcb, DCB_REASON_NOT_RESPONDING,
&router_handle_state_switch, (void *) bref);
bref->bref_state = 0;
bref_set_state(bref, BREF_IN_USE);
atomic_add(&bref->bref_backend->backend_conn_count, 1);
rval = true;
}
else
{
MXS_ERROR("Failed to execute session command in %s (%s:%d). See earlier "
"errors for more details.",
bref->bref_backend->backend_server->unique_name,
bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port);
dcb_close(bref->bref_dcb);
bref->bref_dcb = NULL;
}
}
else
{
MXS_ERROR("Unable to establish connection with server %s:%d",
serv->name, serv->port);
}
return rval;
}
/**
* @brief Log server connections
*
* @param select_criteria Slave selection criteria
* @param backend_ref Backend reference array
* @param router_nservers Number of backends in @p backend_ref
*/
static void log_server_connections(select_criteria_t select_criteria,
backend_ref_t *backend_ref, int router_nservers)
{
if (select_criteria == LEAST_GLOBAL_CONNECTIONS ||
select_criteria == LEAST_ROUTER_CONNECTIONS ||
select_criteria == LEAST_BEHIND_MASTER ||
select_criteria == LEAST_CURRENT_OPERATIONS)
{
MXS_INFO("Servers and %s connection counts:",
select_criteria == LEAST_GLOBAL_CONNECTIONS ? "all MaxScale"
: "router");
for (int i = 0; i < router_nservers; i++)
{
BACKEND *b = backend_ref[i].bref_backend;
switch (select_criteria)
{
case LEAST_GLOBAL_CONNECTIONS:
MXS_INFO("MaxScale connections : %d in \t%s:%d %s",
b->backend_server->stats.n_current, b->backend_server->name,
b->backend_server->port, STRSRVSTATUS(b->backend_server));
break;
case LEAST_ROUTER_CONNECTIONS:
MXS_INFO("RWSplit connections : %d in \t%s:%d %s",
b->backend_conn_count, b->backend_server->name,
b->backend_server->port, STRSRVSTATUS(b->backend_server));
break;
case LEAST_CURRENT_OPERATIONS:
MXS_INFO("current operations : %d in \t%s:%d %s",
b->backend_server->stats.n_current_ops,
b->backend_server->name, b->backend_server->port,
STRSRVSTATUS(b->backend_server));
break;
case LEAST_BEHIND_MASTER:
MXS_INFO("replication lag : %d in \t%s:%d %s",
b->backend_server->rlag, b->backend_server->name,
b->backend_server->port, STRSRVSTATUS(b->backend_server));
default:
break;
}
}
}
}
/********************************
* 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;
}

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@ -0,0 +1,480 @@
/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl.
*
* Change Date: 2019-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include <stdio.h>
#include <strings.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <router.h>
#include <readwritesplit.h>
#include <rwsplit_internal.h>
/**
* @file rwsplit_session_cmd.c The functions that provide session command
* handling for the read write split router.
*
* @verbatim
* Revision History
*
* Date Who Description
* 08/08/2016 Martin Brampton Initial implementation
*
* @endverbatim
*/
static bool sescmd_cursor_history_empty(sescmd_cursor_t *scur);
static void sescmd_cursor_reset(sescmd_cursor_t *scur);
static bool sescmd_cursor_next(sescmd_cursor_t *scur);
static rses_property_t *mysql_sescmd_get_property(mysql_sescmd_t *scmd);
/*
* The following functions, all to do with the handling of session commands,
* are called from other modules of the read write split router:
*/
/**
* Router session must be locked.
* Return session command pointer if succeed, NULL if failed.
*/
mysql_sescmd_t *rses_property_get_sescmd(rses_property_t *prop)
{
mysql_sescmd_t *sescmd;
if (prop == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return NULL;
}
CHK_RSES_PROP(prop);
ss_dassert(prop->rses_prop_rsession == NULL ||
SPINLOCK_IS_LOCKED(&prop->rses_prop_rsession->rses_lock));
sescmd = &prop->rses_prop_data.sescmd;
if (sescmd != NULL)
{
CHK_MYSQL_SESCMD(sescmd);
}
return sescmd;
}
/**
* Create session command property.
*/
mysql_sescmd_t *mysql_sescmd_init(rses_property_t *rses_prop,
GWBUF *sescmd_buf,
unsigned char packet_type,
ROUTER_CLIENT_SES *rses)
{
mysql_sescmd_t *sescmd;
CHK_RSES_PROP(rses_prop);
/** Can't call rses_property_get_sescmd with uninitialized sescmd */
sescmd = &rses_prop->rses_prop_data.sescmd;
sescmd->my_sescmd_prop = rses_prop; /*< reference to owning property */
#if defined(SS_DEBUG)
sescmd->my_sescmd_chk_top = CHK_NUM_MY_SESCMD;
sescmd->my_sescmd_chk_tail = CHK_NUM_MY_SESCMD;
#endif
/** Set session command buffer */
sescmd->my_sescmd_buf = sescmd_buf;
sescmd->my_sescmd_packet_type = packet_type;
sescmd->position = atomic_add(&rses->pos_generator, 1);
return sescmd;
}
void mysql_sescmd_done(mysql_sescmd_t *sescmd)
{
if (sescmd == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return;
}
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+
*/
GWBUF *sescmd_cursor_process_replies(GWBUF *replybuf,
backend_ref_t *bref,
bool *reconnect)
{
mysql_sescmd_t *scmd;
sescmd_cursor_t *scur;
ROUTER_CLIENT_SES *ses;
scur = &bref->bref_sescmd_cur;
ss_dassert(SPINLOCK_IS_LOCKED(&(scur->scmd_cur_rses->rses_lock)));
scmd = sescmd_cursor_get_command(scur);
ses = (*scur->scmd_cur_ptr_property)->rses_prop_rsession;
CHK_GWBUF(replybuf);
/**
* Walk through packets in the message and the list of session
* commands.
*/
while (scmd != NULL && replybuf != NULL)
{
bref->reply_cmd = *((unsigned char *)replybuf->start + 4);
scur->position = scmd->position;
/** Faster backend has already responded to client : discard */
if (scmd->my_sescmd_is_replied)
{
bool last_packet = false;
CHK_GWBUF(replybuf);
while (!last_packet)
{
int buflen;
buflen = GWBUF_LENGTH(replybuf);
last_packet = GWBUF_IS_TYPE_RESPONSE_END(replybuf);
/** discard packet */
replybuf = gwbuf_consume(replybuf, buflen);
}
/** Set response status received */
bref_clear_state(bref, BREF_WAITING_RESULT);
if (bref->reply_cmd != scmd->reply_cmd)
{
MXS_ERROR("Slave server '%s': response differs from master's response. "
"Closing connection due to inconsistent session state.",
bref->bref_backend->backend_server->unique_name);
sescmd_cursor_set_active(scur, false);
bref_clear_state(bref, BREF_QUERY_ACTIVE);
bref_clear_state(bref, BREF_IN_USE);
bref_set_state(bref, BREF_CLOSED);
bref_set_state(bref, BREF_SESCMD_FAILED);
if (bref->bref_dcb)
{
dcb_close(bref->bref_dcb);
}
*reconnect = true;
gwbuf_free(replybuf);
replybuf = NULL;
}
}
/** This is a response from the master and it is the "right" one.
* A slave server's response will be compared to this and if
* their response differs from the master server's response, they
* are dropped from the valid list of backend servers.
* Response is in the buffer and it will be sent to client.
*
* If we have no master server, the first slave's response is considered
* the "right" one. */
else if (ses->rses_master_ref == NULL ||
!BREF_IS_IN_USE(ses->rses_master_ref) ||
ses->rses_master_ref->bref_dcb == bref->bref_dcb)
{
/** Mark the rest session commands as replied */
scmd->my_sescmd_is_replied = true;
scmd->reply_cmd = *((unsigned char *)replybuf->start + 4);
MXS_INFO("Server '%s' responded to a session command, sending the response "
"to the client.", bref->bref_backend->backend_server->unique_name);
for (int i = 0; i < ses->rses_nbackends; i++)
{
if (!BREF_IS_WAITING_RESULT(&ses->rses_backend_ref[i]))
{
/** This backend has already received a response */
if (ses->rses_backend_ref[i].reply_cmd != scmd->reply_cmd &&
!BREF_IS_CLOSED(&ses->rses_backend_ref[i]))
{
bref_clear_state(&ses->rses_backend_ref[i], BREF_QUERY_ACTIVE);
bref_clear_state(&ses->rses_backend_ref[i], BREF_IN_USE);
bref_set_state(&ses->rses_backend_ref[i], BREF_CLOSED);
bref_set_state(bref, BREF_SESCMD_FAILED);
if (ses->rses_backend_ref[i].bref_dcb)
{
dcb_close(ses->rses_backend_ref[i].bref_dcb);
}
*reconnect = true;
MXS_INFO("Disabling slave %s:%d, result differs from "
"master's result. Master: %d Slave: %d",
ses->rses_backend_ref[i].bref_backend->backend_server->name,
ses->rses_backend_ref[i].bref_backend->backend_server->port,
bref->reply_cmd, ses->rses_backend_ref[i].reply_cmd);
}
}
}
}
else
{
MXS_INFO("Slave '%s' responded before master to a session command. Result: %d",
bref->bref_backend->backend_server->unique_name,
(int)bref->reply_cmd);
if (bref->reply_cmd == 0xff)
{
SERVER *serv = bref->bref_backend->backend_server;
MXS_ERROR("Slave '%s' (%s:%u) failed to execute session command.",
serv->unique_name, serv->name, serv->port);
}
gwbuf_free(replybuf);
replybuf = NULL;
}
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 */
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 */
bool sescmd_cursor_is_active(sescmd_cursor_t *sescmd_cursor)
{
bool succp;
if (sescmd_cursor == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return false;
}
ss_dassert(SPINLOCK_IS_LOCKED(&sescmd_cursor->scmd_cur_rses->rses_lock));
succp = sescmd_cursor->scmd_cur_active;
return succp;
}
/** router must be locked */
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
*/
GWBUF *sescmd_cursor_clone_querybuf(sescmd_cursor_t *scur)
{
GWBUF *buf;
if (scur == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return NULL;
}
ss_dassert(scur->scmd_cur_cmd != NULL);
buf = gwbuf_clone_all(scur->scmd_cur_cmd->my_sescmd_buf);
CHK_GWBUF(buf);
return buf;
}
bool execute_sescmd_history(backend_ref_t *bref)
{
bool succp = true;
sescmd_cursor_t *scur;
if (bref == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return false;
}
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);
}
return succp;
}
static bool sescmd_cursor_history_empty(sescmd_cursor_t *scur)
{
bool succp;
if (scur == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return true;
}
CHK_SESCMD_CUR(scur);
if (scur->scmd_cur_rses->rses_properties[RSES_PROP_TYPE_SESCMD] == NULL)
{
succp = true;
}
else
{
succp = false;
}
return succp;
}
/*
* End of functions called from other modules of the read write split router;
* start of functions that are internal to this module.
*/
static void sescmd_cursor_reset(sescmd_cursor_t *scur)
{
ROUTER_CLIENT_SES *rses;
if (scur == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return;
}
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;
}
/**
* 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;
if (scur == NULL)
{
MXS_ERROR("[%s] Error: NULL parameter.", __FUNCTION__);
return false;
}
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;
}

408
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@ -0,0 +1,408 @@
/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl.
*
* Change Date: 2019-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include <stdio.h>
#include <strings.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <maxscale/alloc.h>
/* Note that modutil contains much MySQL specific code */
#include <modutil.h>
#include <router.h>
#include <readwritesplit.h>
#include <rwsplit_internal.h>
/**
* @file rwsplit_tmp_table.c The functions that carry out checks on
* statements to see if they involve various operations involving temporary
* tables or multi-statement queries.
*
* @verbatim
* Revision History
*
* Date Who Description
* 08/08/2016 Martin Brampton Initial implementation
*
* @endverbatim
*/
/*
* The following are to do with checking whether the statement refers to
* temporary tables, or is a multi-statement request. Maybe they belong
* somewhere else, outside this router. Perhaps in the query classifier?
*/
/**
* Check if the query is a DROP TABLE... query and
* if it targets a temporary table, remove it from the hashtable.
* @param router_cli_ses 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_CLIENT_SES *router_cli_ses, GWBUF *querybuf,
mysql_server_cmd_t packet_type)
{
if (packet_type != MYSQL_COM_QUERY && packet_type != MYSQL_COM_DROP_DB)
{
return;
}
int tsize = 0, klen = 0, i;
char **tbl = NULL;
char *hkey, *dbname;
MYSQL_session *my_data;
rses_property_t *rses_prop_tmp;
MYSQL_session *data = (MYSQL_session *)router_cli_ses->client_dcb->data;
rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES];
dbname = (char *)data->db;
if (qc_is_drop_table_query(querybuf))
{
tbl = qc_get_table_names(querybuf, &tsize, false);
if (tbl != NULL)
{
for (i = 0; i < tsize; i++)
{
/* Not clear why the next six lines are outside the if block */
klen = strlen(dbname) + strlen(tbl[i]) + 2;
hkey = MXS_CALLOC(klen, sizeof(char));
MXS_ABORT_IF_NULL(hkey);
strcpy(hkey, dbname);
strcat(hkey, ".");
strcat(hkey, tbl[i]);
if (rses_prop_tmp && rses_prop_tmp->rses_prop_data.temp_tables)
{
if (hashtable_delete(rses_prop_tmp->rses_prop_data.temp_tables,
(void *)hkey))
{
MXS_INFO("Temporary table dropped: %s", hkey);
}
}
MXS_FREE(tbl[i]);
MXS_FREE(hkey);
}
MXS_FREE(tbl);
}
}
}
/**
* Check if the query targets a temporary table.
* @param router_cli_ses Router client session
* @param querybuf GWBUF containing the query
* @param type The type of the query resolved so far
* @return The type of the query
*/
qc_query_type_t is_read_tmp_table(ROUTER_CLIENT_SES *router_cli_ses,
GWBUF *querybuf,
qc_query_type_t type)
{
bool target_tmp_table = false;
int tsize = 0, klen = 0, i;
char **tbl = NULL;
char *dbname;
char hkey[MYSQL_DATABASE_MAXLEN + MYSQL_TABLE_MAXLEN + 2];
MYSQL_session *data;
qc_query_type_t qtype = type;
rses_property_t *rses_prop_tmp;
if (router_cli_ses == NULL || querybuf == NULL)
{
MXS_ERROR("[%s] Error: NULL parameters passed: %p %p", __FUNCTION__,
router_cli_ses, querybuf);
return type;
}
if (router_cli_ses->client_dcb == NULL)
{
MXS_ERROR("[%s] Error: Client DCB is NULL.", __FUNCTION__);
return type;
}
rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES];
data = (MYSQL_session *)router_cli_ses->client_dcb->data;
if (data == NULL)
{
MXS_ERROR("[%s] Error: User data in client DBC is NULL.", __FUNCTION__);
return qtype;
}
dbname = (char *)data->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 = qc_get_table_names(querybuf, &tsize, false);
if (tbl != NULL && tsize > 0)
{
/** Query targets at least one table */
for (i = 0; i < tsize && !target_tmp_table && tbl[i]; i++)
{
sprintf(hkey, "%s.%s", dbname, tbl[i]);
if (rses_prop_tmp && rses_prop_tmp->rses_prop_data.temp_tables)
{
if (hashtable_fetch(rses_prop_tmp->rses_prop_data.temp_tables, hkey))
{
/**Query target is a temporary table*/
qtype = QUERY_TYPE_READ_TMP_TABLE;
MXS_INFO("Query targets a temporary table: %s", hkey);
break;
}
}
}
}
}
if (tbl != NULL)
{
for (i = 0; i < tsize; i++)
{
MXS_FREE(tbl[i]);
}
MXS_FREE(tbl);
}
return qtype;
}
/**
* If query is of type QUERY_TYPE_CREATE_TMP_TABLE then find out
* the database and table name, create a hashvalue and
* add it to the router client session's property. If property
* doesn't exist then create it first.
* @param router_cli_ses 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_CLIENT_SES *router_cli_ses,
GWBUF *querybuf, qc_query_type_t type)
{
if (!QUERY_IS_TYPE(type, QUERY_TYPE_CREATE_TMP_TABLE))
{
return;
}
int klen = 0;
char *hkey, *dbname;
MYSQL_session *data;
rses_property_t *rses_prop_tmp;
HASHTABLE *h;
if (router_cli_ses == NULL || querybuf == NULL)
{
MXS_ERROR("[%s] Error: NULL parameters passed: %p %p", __FUNCTION__,
router_cli_ses, querybuf);
return;
}
if (router_cli_ses->client_dcb == NULL)
{
MXS_ERROR("[%s] Error: Client DCB is NULL.", __FUNCTION__);
return;
}
router_cli_ses->have_tmp_tables = true;
rses_prop_tmp = router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES];
data = (MYSQL_session *)router_cli_ses->client_dcb->data;
if (data == NULL)
{
MXS_ERROR("[%s] Error: User data in master server DBC is NULL.",
__FUNCTION__);
return;
}
dbname = (char *)data->db;
bool is_temp = true;
char *tblname = NULL;
tblname = qc_get_created_table_name(querybuf);
if (tblname && strlen(tblname) > 0)
{
klen = strlen(dbname) + strlen(tblname) + 2;
hkey = MXS_CALLOC(klen, sizeof(char));
MXS_ABORT_IF_NULL(hkey);
strcpy(hkey, dbname);
strcat(hkey, ".");
strcat(hkey, tblname);
}
else
{
hkey = NULL;
}
if (rses_prop_tmp == NULL)
{
if ((rses_prop_tmp = (rses_property_t *)MXS_CALLOC(1, sizeof(rses_property_t))))
{
#if defined(SS_DEBUG)
rses_prop_tmp->rses_prop_chk_top = CHK_NUM_ROUTER_PROPERTY;
rses_prop_tmp->rses_prop_chk_tail = CHK_NUM_ROUTER_PROPERTY;
#endif
rses_prop_tmp->rses_prop_rsession = router_cli_ses;
rses_prop_tmp->rses_prop_refcount = 1;
rses_prop_tmp->rses_prop_next = NULL;
rses_prop_tmp->rses_prop_type = RSES_PROP_TYPE_TMPTABLES;
router_cli_ses->rses_properties[RSES_PROP_TYPE_TMPTABLES] = rses_prop_tmp;
}
}
if (rses_prop_tmp)
{
if (rses_prop_tmp->rses_prop_data.temp_tables == NULL)
{
h = hashtable_alloc(7, rwsplit_hashkeyfun, rwsplit_hashcmpfun);
hashtable_memory_fns(h, rwsplit_hstrdup, NULL, rwsplit_hfree, NULL);
if (h != NULL)
{
rses_prop_tmp->rses_prop_data.temp_tables = h;
}
else
{
MXS_ERROR("Failed to allocate a new hashtable.");
}
}
if (hkey && rses_prop_tmp->rses_prop_data.temp_tables &&
hashtable_add(rses_prop_tmp->rses_prop_data.temp_tables, (void *)hkey,
(void *)is_temp) == 0) /*< Conflict in hash table */
{
MXS_INFO("Temporary table conflict in hashtable: %s", hkey);
}
#if defined(SS_DEBUG)
{
bool retkey = hashtable_fetch(rses_prop_tmp->rses_prop_data.temp_tables, hkey);
if (retkey)
{
MXS_INFO("Temporary table added: %s", hkey);
}
}
#endif
}
MXS_FREE(hkey);
MXS_FREE(tblname);
}
/**
* @brief Detect multi-statement queries
*
* It is possible that the session state is modified inside a multi-statement
* query which would leave any slave sessions in an inconsistent state. Due to
* this, for the duration of this session, all queries will be sent to the
* master
* if the current query contains a multi-statement query.
* @param rses Router client session
* @param buf Buffer containing the full query
* @return True if the query contains multiple statements
*/
bool check_for_multi_stmt(GWBUF *buf, void *protocol, mysql_server_cmd_t packet_type)
{
MySQLProtocol *proto = (MySQLProtocol *)protocol;
bool rval = false;
if (proto->client_capabilities & GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS &&
packet_type == MYSQL_COM_QUERY)
{
char *ptr, *data = GWBUF_DATA(buf) + 5;
/** Payload size without command byte */
int buflen = gw_mysql_get_byte3((uint8_t *)GWBUF_DATA(buf)) - 1;
if ((ptr = strnchr_esc_mysql(data, ';', buflen)))
{
/** Skip stored procedures etc. */
while (ptr && is_mysql_sp_end(ptr, buflen - (ptr - data)))
{
ptr = strnchr_esc_mysql(ptr + 1, ';', buflen - (ptr - data) - 1);
}
if (ptr)
{
if (ptr < data + buflen &&
!is_mysql_statement_end(ptr, buflen - (ptr - data)))
{
rval = true;
}
}
}
}
return rval;
}
qc_query_type_t
determine_query_type(GWBUF *querybuf, int packet_type, bool non_empty_packet)
{
qc_query_type_t qtype = QUERY_TYPE_UNKNOWN;
if (non_empty_packet)
{
mysql_server_cmd_t my_packet_type = (mysql_server_cmd_t)packet_type;
switch (my_packet_type)
{
case MYSQL_COM_QUIT: /*< 1 QUIT will close all sessions */
case MYSQL_COM_INIT_DB: /*< 2 DDL must go to the master */
case MYSQL_COM_REFRESH: /*< 7 - I guess this is session but not sure */
case MYSQL_COM_DEBUG: /*< 0d all servers dump debug info to stdout */
case MYSQL_COM_PING: /*< 0e all servers are pinged */
case MYSQL_COM_CHANGE_USER: /*< 11 all servers change it accordingly */
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 */
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_WRITE;
break;
case MYSQL_COM_QUERY:
qtype = qc_get_type(querybuf);
break;
case MYSQL_COM_STMT_PREPARE:
qtype = qc_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 */
}
return qtype;
}