we have 12GB 8core percona 5.5.25a server.
at random interval it start to pile up the queries and freeze.
all our db tables are using innodb.
when i do innodb status it showed
TRANSACTION 1A932BE, ACTIVE 55 sec starting index read
the full innodb during this freeze is attached.
what can cause such sudden freeze.
thread waited on buf0buf at those lines:
for (i = 0; i < srv_buf_pool_instances; i++) { buf_pool_t* buf_pool; buf_pool = buf_pool_from_array(i); buf_flush_list_mutex_enter(buf_pool); bpage = UT_LIST_GET_LAST(buf_pool->flush_list); if (bpage != NULL) { ut_ad(bpage->in_flush_list); lsn = bpage->oldest_modification; } buf_flush_list_mutex_exit(buf_pool);