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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
commit 41258f8e6c
8 changed files with 232 additions and 7 deletions
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28
storage/innodb_plugin/include/buf0buf.ic
View file

@ -61,6 +61,27 @@ buf_block_get_freed_page_clock(
return(buf_page_get_freed_page_clock(&block->page));
}
/********************************************************************//**
Tells if a block is still close enough to the MRU end of the LRU list
meaning that it is not in danger of getting evicted and also implying
that it has been accessed recently.
Note that this is for heuristics only and does not reserve buffer pool
mutex.
@return TRUE if block is close to MRU end of LRU */
UNIV_INLINE
ibool
buf_page_peek_if_young(
/*===================*/
const buf_page_t* bpage) /*!< in: block */
{
/* FIXME: bpage->freed_page_clock is 31 bits */
return((buf_pool->freed_page_clock & ((1UL << 31) - 1))
< ((ulint) bpage->freed_page_clock
+ (buf_pool->curr_size
* (BUF_LRU_OLD_RATIO_DIV - buf_LRU_old_ratio)
/ (BUF_LRU_OLD_RATIO_DIV * 4))));
}
/********************************************************************//**
Recommends a move of a block to the start of the LRU list if there is danger
of dropping from the buffer pool. NOTE: does not reserve the buffer pool
@ -89,12 +110,7 @@ buf_page_peek_if_too_old(
buf_pool->stat.n_pages_not_made_young++;
return(FALSE);
} else {
/* FIXME: bpage->freed_page_clock is 31 bits */
return((buf_pool->freed_page_clock & ((1UL << 31) - 1))
> ((ulint) bpage->freed_page_clock
+ (buf_pool->curr_size
* (BUF_LRU_OLD_RATIO_DIV - buf_LRU_old_ratio)
/ (BUF_LRU_OLD_RATIO_DIV * 4))));
return(!buf_page_peek_if_young(bpage));
}
}