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Bug 12356373 - PERFORMANCE REGRESSION FROM 5.1 TO 5.5 : GROUP BY:

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The title of the bug is a little confusing. The actual fix is to
reintroduce random readahead inside InnoDB with a dynamic, global
switch innodb_random_read_ahead [default = off].

Approved by: Sunny Bains
rb://696
This commit is contained in:
Inaam Rana
2011-07-19 10:37:37 -04:00
parent afd6f46b7b
commit 41258f8e6c
8 changed files with 232 additions and 7 deletions
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6
storage/innodb_plugin/buf/buf0buf.c
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@@ -3590,12 +3590,16 @@ buf_print_io(
/* Statistics about read ahead algorithm */
fprintf(file, "Pages read ahead %.2f/s,"
" evicted without access %.2f/s\n",
" evicted without access %.2f/s,"
" Random read ahead %.2f/s\n",
(buf_pool->stat.n_ra_pages_read
- buf_pool->old_stat.n_ra_pages_read)
/ time_elapsed,
(buf_pool->stat.n_ra_pages_evicted
- buf_pool->old_stat.n_ra_pages_evicted)
/ time_elapsed,
(buf_pool->stat.n_ra_pages_read_rnd
- buf_pool->old_stat.n_ra_pages_read_rnd)
/ time_elapsed);
/* Print some values to help us with visualizing what is