FLUSH INDEX_STATISTICS / FLUSH CHANGED_PAGE_BITMAPS and FLUSH USER_STATISTICS / RESET CHANGE_PAGE_BITMAPS pairs of commands are joined

[Raghavendra D Prabhu]

From mysql_com.h in 5.6
=====

#define REFRESH_INDEX_STATS 0x400000L /* Refresh index stats my_hash
                                             table */
#define REFRESH_USER_STATS 0x800000L /* Refresh user stats my_hash
                                             table */

#define REFRESH_FLUSH_PAGE_BITMAPS 0x400000L
#define REFRESH_RESET_PAGE_BITMAPS 0x800000L

This can cause one operation to affect or cause another and vice-versa.

[Raghavendra D Prabhu (raghavendra-prabhu)]

Also in 5.5:

#define REFRESH_TABLE_STATS 0x200000L /* Refresh table stats my_hash table */
#define REFRESH_INDEX_STATS 0x400000L /* Refresh index stats my_hash table */
#define REFRESH_USER_STATS 0x800000L /* Refresh user stats my_hash table */
#define REFRESH_CLIENT_STATS 0x1000000L /* Refresh client stats my_hash table */
#define REFRESH_THREAD_STATS 0x2000000L /* Refresh thread stats my_hash table */
#define REFRESH_FLUSH_PAGE_BITMAPS 0x400000L
#define REFRESH_RESET_PAGE_BITMAPS 0x800000L

[Raghavendra D Prabhu (raghavendra-prabhu)]

5.1 looks good:

#define REFRESH_TABLE_STATS 256 /* Refresh table stats hash table */
#define REFRESH_INDEX_STATS 512 /* Refresh index stats hash table */
#define REFRESH_USER_STATS 1024 /* Refresh user stats hash table */
#define REFRESH_SLOW_QUERY_LOG 2048 /* Flush slow query log and rotate*/
#define REFRESH_CLIENT_STATS 4096 /* Refresh client stats hash table */
#define REFRESH_THREAD_STATS 8192 /* Refresh thread stats hash table */

/* The following can't be set with mysql_refresh() */
#define REFRESH_READ_LOCK 16384 /* Lock tables for read */
#define REFRESH_FAST 32768 /* Intern flag */

/* RESET (remove all queries) from query cache */
#define REFRESH_QUERY_CACHE 65536
#define REFRESH_QUERY_CACHE_FREE 0x20000L /* pack query cache */
#define REFRESH_DES_KEY_FILE 0x40000L
#define REFRESH_USER_RESOURCES 0x80000L
#define REFRESH_QUERY_RESPONSE_TIME 0x100000L /* response time distibution */
#define REFRESH_FLUSH_PAGE_BITMAPS 0x200000L
#define REFRESH_RESET_PAGE_BITMAPS 0x400000L

[Laurynas Biveinis (laurynas-biveinis)]

Effectively this makes the pairs of FLUSH INDEX_STATISTICS / FLUSH CHANGED_PAGE_BITMAPS and FLUSH USER_STATISTICS / RESET CHANGE_PAGE_BITMAPS joined, issuing either command has the effect of both. The first is relatively benign but has a bug that FLUSH INDEX_STATISTICS starts requiring SUPER instead of RELOAD privilege. The second pair destroys bitmaps if one issues FLUSH USER_STATISTICS, which is more serious.

[Laurynas Biveinis (laurynas-biveinis)]

https://github.com/percona/percona-server/pull/111
https://github.com/percona/percona-server/pull/112

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-913