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For Galera cluster, detect MySQL backend version
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Because MySQL 5.7 deprecates INFORMATION_SCHEMA.GLOBAL_STATUS and returns
errors unless show_compatibility_56=ON, the new Galera check determines the
version of the backend and uses either INFORMATION_SCHEMA.GLOBAL_STATUS or
performance_schema.global_status
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@renecannao
renecannao committed Sep 2, 2018
1 parent c00e6ef commit 42a0e7c
Showing 1 changed file with 10 additions and 4 deletions.
14 changes: 10 additions & 4 deletions lib/MySQL_Monitor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1141,11 +1141,17 @@ void * monitor_galera_thread(void *arg) {
}

mmsd->t1=monotonic_time();
//mmsd->async_exit_status=mysql_query_start(&mmsd->interr,mmsd->mysql,"SELECT (SELECT IF(VARIABLE_VALUE=4,'YES','NO') FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_LOCAL_STATE') wsrep_local_state, (SELECT IF(VARIABLE_VALUE=0 OR VARIABLE_VALUE='OFF','NO','YES') FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME='READ_ONLY') read_only, (SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_LOCAL_RECV_QUEUE') wsrep_local_recv_queue");
// FIXME : INFORMATION_SCHEMA.GLOBAL_STATUS is deprecated
// FIXME : future versions should be able to detect backend version and use PERFORMANCE SCHEMA instead
mmsd->interr=0; // reset the value
mmsd->async_exit_status=mysql_query_start(&mmsd->interr,mmsd->mysql,"SELECT (SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_LOCAL_STATE') wsrep_local_state, @@read_only read_only, (SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_LOCAL_RECV_QUEUE') wsrep_local_recv_queue , @@wsrep_desync wsrep_desync, @@wsrep_reject_queries wsrep_reject_queries, @@wsrep_sst_donor_rejects_queries wsrep_sst_donor_rejects_queries, (SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_CLUSTER_STATUS') wsrep_cluster_status");
{
char *sv = mmsd->mysql->server_version;
if (strncmp(sv,(char *)"5.7",3)==0 || strncmp(sv,(char *)"8",1)==0) {
// the backend is either MySQL 5.7 or MySQL 8 : INFORMATION_SCHEMA.GLOBAL_STATUS is deprecated
mmsd->async_exit_status=mysql_query_start(&mmsd->interr,mmsd->mysql,"SELECT (SELECT VARIABLE_VALUE FROM performance_schema.global_status WHERE VARIABLE_NAME='WSREP_LOCAL_STATE') wsrep_local_state, @@read_only read_only, (SELECT VARIABLE_VALUE FROM performance_schema.global_status WHERE VARIABLE_NAME='WSREP_LOCAL_RECV_QUEUE') wsrep_local_recv_queue , @@wsrep_desync wsrep_desync, @@wsrep_reject_queries wsrep_reject_queries, @@wsrep_sst_donor_rejects_queries wsrep_sst_donor_rejects_queries, (SELECT VARIABLE_VALUE FROM performance_schema.global_status WHERE VARIABLE_NAME='WSREP_CLUSTER_STATUS') wsrep_cluster_status");
} else {
// any other version
mmsd->async_exit_status=mysql_query_start(&mmsd->interr,mmsd->mysql,"SELECT (SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_LOCAL_STATE') wsrep_local_state, @@read_only read_only, (SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_LOCAL_RECV_QUEUE') wsrep_local_recv_queue , @@wsrep_desync wsrep_desync, @@wsrep_reject_queries wsrep_reject_queries, @@wsrep_sst_donor_rejects_queries wsrep_sst_donor_rejects_queries, (SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME='WSREP_CLUSTER_STATUS') wsrep_cluster_status");
}
}
while (mmsd->async_exit_status) {
mmsd->async_exit_status=wait_for_mysql(mmsd->mysql, mmsd->async_exit_status);
unsigned long long now=monotonic_time();
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