Commit 8a71fde0 authored by Daniele Sciascia's avatar Daniele Sciascia Committed by Nirbhay Choubey

refs codership/mysql-wsrep#201

- Fixes query cache so that it is aware of wsrep_sync_wait.
  Query cache would return (possibly stale) results to the
  client, regardless of the value of wsrep_sync_wait.
- Includes the test case that reproduced the issue.
parent 70113ee1
CREATE TABLE t1 (id INT PRIMARY KEY AUTO_INCREMENT) ENGINE=InnoDB;
INSERT INTO t1 VALUES (DEFAULT);
SET GLOBAL query_cache_size=1355776;
SET SESSION wsrep_sync_wait = 7;
--source include/galera_cluster.inc
--source include/have_innodb.inc
--source include/have_query_cache.inc
CREATE TABLE t1 (id INT PRIMARY KEY AUTO_INCREMENT) ENGINE=InnoDB;
INSERT INTO t1 VALUES (DEFAULT);
--connection node_2
--let $qcache_size_orig = `SELECT @@GLOBAL.query_cache_size`
SET GLOBAL query_cache_size=1355776;
SET SESSION wsrep_sync_wait = 7;
--disable_query_log
--let $count = 10000
while ($count)
{
--connection node_1
INSERT INTO t1 VALUES (DEFAULT);
--let $val1 = `SELECT LAST_INSERT_ID()`
--connection node_2
--let $val2 = `SELECT MAX(id) FROM t1`
--let $val3 = `SELECT $val1 != $val2`
if ($val3)
{
--echo $val1 $val2
--die wsrep_sync_wait failed
}
--dec $count
}
--eval SET GLOBAL query_cache_size = $qcache_size_orig
DROP TABLE t1;
......@@ -1804,6 +1804,7 @@ Query_cache::send_result_to_client(THD *thd, char *org_sql, uint query_length)
goto err;
}
}
/*
Try to obtain an exclusive lock on the query cache. If the cache is
disabled or if a full cache flush is in progress, the attempt to
......@@ -1915,6 +1916,25 @@ def_week_frmt: %lu, in_trans: %d, autocommit: %d",
}
DBUG_PRINT("qcache", ("Query in query hash 0x%lx", (ulong)query_block));
#ifdef WITH_WSREP
if (WSREP_CLIENT(thd) && wsrep_must_sync_wait(thd)) {
unlock();
if (wsrep_sync_wait(thd))
goto err;
if (try_lock(TRUE))
goto err;
query_block = (Query_cache_block *) my_hash_search(&queries,
(uchar*) sql,
tot_length);
if (query_block == 0 ||
query_block->query()->result() == 0 ||
query_block->query()->result()->type != Query_cache_block::RESULT)
{
goto err_unlock;
}
}
#endif /* WITH_WSREP */
/* Now lock and test that nothing changed while blocks was unlocked */
BLOCK_LOCK_RD(query_block);
......
......@@ -1118,6 +1118,7 @@ THD::THD()
wsrep_bf_thd = NULL;
wsrep_TOI_pre_query = NULL;
wsrep_TOI_pre_query_len = 0;
wsrep_sync_wait_gtid= WSREP_GTID_UNDEFINED;
#endif
/* Call to init() below requires fully initialized Open_tables_state. */
reset_open_tables_state(this);
......@@ -1487,6 +1488,7 @@ void THD::init(void)
wsrep_bf_thd = NULL;
wsrep_TOI_pre_query = NULL;
wsrep_TOI_pre_query_len = 0;
wsrep_sync_wait_gtid= WSREP_GTID_UNDEFINED;
/*
@@wsrep_causal_reads is now being handled via wsrep_sync_wait, update it
......@@ -2137,6 +2139,10 @@ void THD::cleanup_after_query()
rli_slave->cleanup_after_query();
#endif
#ifdef WITH_WSREP
wsrep_sync_wait_gtid= WSREP_GTID_UNDEFINED;
#endif /* WITH_WSREP */
DBUG_VOID_RETURN;
}
......
......@@ -2395,6 +2395,7 @@ public:
size_t wsrep_TOI_pre_query_len;
void* wsrep_apply_format;
bool wsrep_apply_toi; /* applier processing in TOI */
wsrep_gtid_t wsrep_sync_wait_gtid;
#endif /* WITH_WSREP */
/**
Internal parser state.
......
......@@ -866,19 +866,24 @@ bool wsrep_start_replication()
return true;
}
bool wsrep_sync_wait (THD* thd, uint mask)
bool wsrep_must_sync_wait (THD* thd, uint mask)
{
if ((thd->variables.wsrep_sync_wait & mask) &&
return (thd->variables.wsrep_sync_wait & mask) &&
thd->variables.wsrep_on &&
!thd->in_active_multi_stmt_transaction() &&
thd->wsrep_conflict_state != REPLAYING)
thd->wsrep_conflict_state != REPLAYING &&
thd->wsrep_sync_wait_gtid.seqno == WSREP_SEQNO_UNDEFINED;
}
bool wsrep_sync_wait (THD* thd, uint mask)
{
if (wsrep_must_sync_wait(thd, mask))
{
WSREP_DEBUG("wsrep_sync_wait: thd->variables.wsrep_sync_wait = %u, mask = %u",
thd->variables.wsrep_sync_wait, mask);
// This allows autocommit SELECTs and a first SELECT after SET AUTOCOMMIT=0
// TODO: modify to check if thd has locked any rows.
wsrep_gtid_t gtid;
wsrep_status_t ret= wsrep->causal_read (wsrep, &gtid);
wsrep_status_t ret= wsrep->causal_read (wsrep, &thd->wsrep_sync_wait_gtid);
if (unlikely(WSREP_OK != ret))
{
......
......@@ -183,6 +183,7 @@ extern void wsrep_kill_mysql(THD *thd);
/* new defines */
extern void wsrep_stop_replication(THD *thd);
extern bool wsrep_start_replication();
extern bool wsrep_must_sync_wait (THD* thd, uint mask = WSREP_SYNC_WAIT_BEFORE_READ);
extern bool wsrep_sync_wait (THD* thd, uint mask = WSREP_SYNC_WAIT_BEFORE_READ);
extern int wsrep_check_opts (int argc, char* const* argv);
extern void wsrep_prepend_PATH (const char* path);
......
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