Following the IRC discussion, I've made a patch that make ANALYZE timing hooks not to be invoked for non-ANALYZE statements.

However, it made no difference in execution on my system. svoj, could you please check if the patch fixes the problem?

(Note to self: before this patch is pushed, sort out how it works with UNIONs)

The patch seem to be incomplete: ANALYZE_START_TRACKING /ANALYZE_STOP_TRACKING in sql_delete.cc and sql_update.cc were not updated. I'll call those with do_tracking= 1.

I can see little improvement, almost as good as if it was when I commented it out.

perf proof (event: cycles):

ha_index_next() 0.38% -> 0.25%

my_timer_cycles() - 0.36% -> out of radar

So we freed up 0.49% CPU cycles.

When tracker functionality is removed from TABLE_IO_WAIT perf says:

ha_index_next() 0.38% -> 0.18%

my_timer_cycles() - 0.36% -> out of radar

That is 0.56%.

Ideally we should have different method with out-of-loop condition check. But that may be complex. Reducing number of conditions from 2 to 1 is trivial and should be worthy:

#define TABLE_IO_WAIT(TRACKER, PSI, OP, INDEX, FLAGS, PAYLOAD) \

  { \

    if (unlikely(tracker)) \

    { \

      tracker->start_tracking(); \

      MYSQL_TABLE_IO_WAIT(PSI, OP, INDEX, FLAGS, PAYLOAD); \

      tracker->stop_tracking(); \

    } \

    else \

      MYSQL_TABLE_IO_WAIT(PSI, OP, INDEX, FLAGS, PAYLOAD); \      

  }