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Bug#12560151 61132: infinite loop in buf_page_get_gen() when handling

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compressed pages

After loading a compressed-only page in buf_page_get_gen() we allocate a new
block for decompression. The problem is that the compressed page is neither
buffer-fixed nor I/O-fixed by the time we call buf_LRU_get_free_block(),
so it may end up being evicted and returned back as a new block.

buf_page_get_gen(): Temporarily buffer-fix the compressed-only block
while allocating memory for an uncompressed page frame.
This should prevent this form of the infinite loop, which is more likely
with a small innodb_buffer_pool_size.

rb#2511 approved by Jimmy Yang, Sunny Bains
This commit is contained in:
Marko Mäkelä 2013-08-21 08:22:05 +03:00
parent 55129f676a
commit 6a3bb3c07c
2 changed files with 22 additions and 27 deletions
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6
storage/innodb_plugin/ChangeLog
View File

@ -1,3 +1,9 @@
2013-08-21 The InnoDB Team
* buf/buf0buf.c:
Fix Bug#12560151 61132: infinite loop in buf_page_get_gen()
when handling compressed pages
2013-08-16 The InnoDB Team 2013-08-16 The InnoDB Team
* row/row0sel.c: * row/row0sel.c:

43
storage/innodb_plugin/buf/buf0buf.c
View File

@ -1615,7 +1615,6 @@ loop:
block = (buf_block_t*) buf_page_hash_get(space, offset); block = (buf_block_t*) buf_page_hash_get(space, offset);
} }
loop2:
if (block == NULL) { if (block == NULL) {
/* Page not in buf_pool: needs to be read from file */ /* Page not in buf_pool: needs to be read from file */
@ -1706,6 +1705,11 @@ wait_until_unfixed:
goto loop; goto loop;
} }
/* Buffer-fix the block so that it cannot be evicted
or relocated while we are attempting to allocate an
uncompressed page. */
bpage->buf_fix_count++;
/* Allocate an uncompressed page. */ /* Allocate an uncompressed page. */
buf_pool_mutex_exit(); buf_pool_mutex_exit();
mutex_exit(&buf_pool_zip_mutex); mutex_exit(&buf_pool_zip_mutex);
@ -1715,32 +1719,19 @@ wait_until_unfixed:
buf_pool_mutex_enter(); buf_pool_mutex_enter();
mutex_enter(&block->mutex); mutex_enter(&block->mutex);
mutex_enter(&buf_pool_zip_mutex);
/* Buffer-fixing prevents the page_hash from changing. */
ut_ad(bpage == buf_page_hash_get(space, offset));
{ if (--bpage->buf_fix_count
buf_page_t* hash_bpage || buf_page_get_io_fix(bpage) != BUF_IO_NONE) {
= buf_page_hash_get(space, offset);
if (UNIV_UNLIKELY(bpage != hash_bpage)) { mutex_exit(&buf_pool_zip_mutex);
/* The buf_pool->page_hash was modified /* The block was buffer-fixed or I/O-fixed while
while buf_pool_mutex was released. buf_pool_mutex was not held by this thread.
Free the block that was allocated. */ Free the block that was allocated and retry.
This should be extremely unlikely, for example,
buf_LRU_block_free_non_file_page(block); if buf_page_get_zip() was invoked. */
mutex_exit(&block->mutex);
block = (buf_block_t*) hash_bpage;
goto loop2;
}
}
if (UNIV_UNLIKELY
(bpage->buf_fix_count
|| buf_page_get_io_fix(bpage) != BUF_IO_NONE)) {
/* The block was buffer-fixed or I/O-fixed
while buf_pool_mutex was not held by this thread.
Free the block that was allocated and try again.
This should be extremely unlikely. */
buf_LRU_block_free_non_file_page(block); buf_LRU_block_free_non_file_page(block);
mutex_exit(&block->mutex); mutex_exit(&block->mutex);
@ -1751,8 +1742,6 @@ wait_until_unfixed:
/* Move the compressed page from bpage to block, /* Move the compressed page from bpage to block,
and uncompress it. */ and uncompress it. */
mutex_enter(&buf_pool_zip_mutex);
buf_relocate(bpage, &block->page); buf_relocate(bpage, &block->page);
buf_block_init_low(block); buf_block_init_low(block);
block->lock_hash_val = lock_rec_hash(space, offset); block->lock_hash_val = lock_rec_hash(space, offset);