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Applying InnoDB snashot 5.0-ss4007, part 1. Fixes

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Bug #39939: DROP TABLE/DISCARD TABLESPACE takes long time in buf_LRU_invalidate_tablespace()

This was already fixed in 5.1+; this is a backport to 5.0.

Detailed revision comments:

r2743 | inaam | 2008-10-08 22:18:12 +0300 (Wed, 08 Oct 2008) | 13 lines
branches/5.0:

Backport of r2742 from branches/5.1:

Fix Bug#39939 DROP TABLE/DISCARD TABLESPACE takes long time in
buf_LRU_invalidate_tablespace()

Improve implementation of buf_LRU_invalidate_tablespace by attempting
hash index drop in batches instead of doing it one by one.

Reviewed by: Heikki, Sunny, Marko
Approved by: Heikki
This commit is contained in:
Timothy Smith 2009-03-02 17:24:23 -07:00
parent 82c21e46f6
commit 901b29860d
1 changed files with 127 additions and 0 deletions
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127
innobase/buf/buf0lru.c
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@ -42,6 +42,11 @@ initial segment in buf_LRU_get_recent_limit */
#define BUF_LRU_INITIAL_RATIO 8
/* When dropping the search hash index entries before deleting an ibd
file, we build a local array of pages belonging to that tablespace
in the buffer pool. Following is the size of that array. */
#define BUF_LRU_DROP_SEARCH_HASH_SIZE 1024
/* If we switch on the InnoDB monitor because there are too few available
frames in the buffer pool, we set this to TRUE */
ibool buf_lru_switched_on_innodb_mon = FALSE;
@ -65,6 +70,120 @@ buf_LRU_block_free_hashed_page(
buf_block_t* block); /* in: block, must contain a file page and
be in a state where it can be freed */
/**********************************************************************
Attempts to drop page hash index on a batch of pages belonging to a
particular space id. */
static
void
buf_LRU_drop_page_hash_batch(
/*=========================*/
ulint id, /* in: space id */
const ulint* arr, /* in: array of page_no */
ulint count) /* in: number of entries in array */
{
ulint i;
ut_ad(arr != NULL);
ut_ad(count <= BUF_LRU_DROP_SEARCH_HASH_SIZE);
for (i = 0; i < count; ++i) {
btr_search_drop_page_hash_when_freed(id, arr[i]);
}
}
/**********************************************************************
When doing a DROP TABLE/DISCARD TABLESPACE we have to drop all page
hash index entries belonging to that table. This function tries to
do that in batch. Note that this is a 'best effort' attempt and does
not guarantee that ALL hash entries will be removed. */
static
void
buf_LRU_drop_page_hash_for_tablespace(
/*==================================*/
ulint id) /* in: space id */
{
buf_block_t* block;
ulint* page_arr;
ulint num_entries;
page_arr = ut_malloc(sizeof(ulint)
* BUF_LRU_DROP_SEARCH_HASH_SIZE);
mutex_enter(&buf_pool->mutex);
scan_again:
num_entries = 0;
block = UT_LIST_GET_LAST(buf_pool->LRU);
while (block != NULL) {
buf_block_t* prev_block;
mutex_enter(&block->mutex);
prev_block = UT_LIST_GET_PREV(LRU, block);
ut_a(block->state == BUF_BLOCK_FILE_PAGE);
if (block->space != id
|| block->buf_fix_count > 0
|| block->io_fix != 0) {
/* We leave the fixed pages as is in this scan.
To be dealt with later in the final scan. */
mutex_exit(&block->mutex);
goto next_page;
}
ut_ad(block->space == id);
if (block->is_hashed) {
/* Store the offset(i.e.: page_no) in the array
so that we can drop hash index in a batch
later. */
page_arr[num_entries] = block->offset;
mutex_exit(&block->mutex);
ut_a(num_entries < BUF_LRU_DROP_SEARCH_HASH_SIZE);
++num_entries;
if (num_entries < BUF_LRU_DROP_SEARCH_HASH_SIZE) {
goto next_page;
}
/* Array full. We release the buf_pool->mutex to
obey the latching order. */
mutex_exit(&buf_pool->mutex);
buf_LRU_drop_page_hash_batch(id, page_arr,
num_entries);
num_entries = 0;
mutex_enter(&buf_pool->mutex);
} else {
mutex_exit(&block->mutex);
}
next_page:
/* Note that we may have released the buf_pool->mutex
above after reading the prev_block during processing
of a page_hash_batch (i.e.: when the array was full).
This means that prev_block can change in LRU list.
This is OK because this function is a 'best effort'
to drop as many search hash entries as possible and
it does not guarantee that ALL such entries will be
dropped. */
block = prev_block;
/* If, however, block has been removed from LRU list
to the free list then we should restart the scan.
block->state is protected by buf_pool->mutex. */
if (block && block->state != BUF_BLOCK_FILE_PAGE) {
ut_a(num_entries == 0);
goto scan_again;
}
}
mutex_exit(&buf_pool->mutex);
/* Drop any remaining batch of search hashed pages. */
buf_LRU_drop_page_hash_batch(id, page_arr, num_entries);
ut_free(page_arr);
}
/**********************************************************************
Invalidates all pages belonging to a given tablespace when we are deleting
the data file(s) of that tablespace. */
@ -78,6 +197,14 @@ buf_LRU_invalidate_tablespace(
ulint page_no;
ibool all_freed;
/* Before we attempt to drop pages one by one we first
attempt to drop page hash index entries in batches to make
it more efficient. The batching attempt is a best effort
attempt and does not guarantee that all pages hash entries
will be dropped. We get rid of remaining page hash entries
one by one below. */
buf_LRU_drop_page_hash_for_tablespace(id);
scan_again:
mutex_enter(&(buf_pool->mutex));