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Improved multi-statement detection in readwritesplit

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Now comment blocks and identifiers quoted with backticks are taken into
consideration when multi-statements are processed.
This commit is contained in:
Markus Makela
2016-03-02 09:55:24 +02:00
parent 9b2748f50c
commit 9bfef5c7c1
3 changed files with 146 additions and 24 deletions
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57
server/modules/routing/readwritesplit/readwritesplit.c
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@ -308,6 +308,8 @@ static ROUTER_INSTANCE* instances;
static int hashkeyfun(void* key);
static int hashcmpfun (void *, void *);
static void check_for_multi_stmt(ROUTER_CLIENT_SES* rses, GWBUF *buf,
mysql_server_cmd_t packet_type);
static int hashkeyfun(
void* key)
@ -2156,23 +2158,7 @@ static bool route_single_stmt(
/** Check for multi-statement queries. We assume here that the client
* protocol is MySQLClient.
* TODO: add warnings when incompatible protocols are used */
MySQLProtocol *proto = (MySQLProtocol*)rses->client_dcb->protocol;
if (proto->client_capabilities & GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS &&
packet_type == MYSQL_COM_QUERY && rses->forced_node != rses->rses_master_ref)
{
for (GWBUF *buf = querybuf; buf != NULL; buf = buf->next)
{
if (strnchr_esc(GWBUF_DATA(buf), ';', GWBUF_LENGTH(buf)))
{
/** It is possible that the session state is modified inside
* the 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. */
rses->forced_node = rses->rses_master_ref;
MXS_INFO("Multi-statement query, routing all future queries to master.");
}
}
}
check_for_multi_stmt(rses, querybuf, packet_type);
/**
* Check if the query has anything to do with temporary tables.
@ -5357,12 +5343,35 @@ static backend_ref_t* get_root_master_bref(
return candidate_bref;
}
/**
* @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
*/
static void check_for_multi_stmt(ROUTER_CLIENT_SES* rses, GWBUF *buf,
mysql_server_cmd_t packet_type)
{
MySQLProtocol *proto = (MySQLProtocol*) rses->client_dcb->protocol;
if (proto->client_capabilities & GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS &&
packet_type == MYSQL_COM_QUERY && rses->forced_node != rses->rses_master_ref)
{
char *ptr, *data = GWBUF_DATA(buf) + 5;
int buflen = GWBUF_LENGTH(buf) - 5;
if ((ptr = strnchr_esc_mysql(data, ';', buflen)))
{
ptr++;
if (ptr - data < buflen && !is_mysql_comment_start(ptr, ptr - data))
{
rses->forced_node = rses->rses_master_ref;
MXS_INFO("Multi-statement query, routing all future queries to master.");
}
}
}
}