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polardbxengine/storage/innobase/buf/buf0lru.cc

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/*****************************************************************************
Copyright (c) 1995, 2018, Oracle and/or its affiliates. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License, version 2.0, as published by the
Free Software Foundation.
This program is also distributed with certain software (including but not
limited to OpenSSL) that is licensed under separate terms, as designated in a
particular file or component or in included license documentation. The authors
of MySQL hereby grant you an additional permission to link the program and
your derivative works with the separately licensed software that they have
included with MySQL.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*****************************************************************************/
/** @file buf/buf0lru.cc
The database buffer replacement algorithm
Created 11/5/1995 Heikki Tuuri
*******************************************************/
#include "buf0lru.h"
#include "btr0btr.h"
#include "btr0sea.h"
#include "buf0buddy.h"
#include "buf0buf.h"
#include "buf0dblwr.h"
#include "buf0flu.h"
#include "buf0rea.h"
#include "buf0stats.h"
#include "fil0fil.h"
#include "hash0hash.h"
#include "ibuf0ibuf.h"
#include "log0recv.h"
#include "my_dbug.h"
#include "os0event.h"
#include "os0file.h"
#include "page0zip.h"
#include "srv0mon.h"
#include "srv0srv.h"
#include "sync0rw.h"
#include "trx0trx.h"
#include "ut0byte.h"
#include "ut0rnd.h"
#include "lizard0tcn.h"
/** The number of blocks from the LRU_old pointer onward, including
the block pointed to, must be buf_pool->LRU_old_ratio/BUF_LRU_OLD_RATIO_DIV
of the whole LRU list length, except that the tolerance defined below
is allowed. Note that the tolerance must be small enough such that for
even the BUF_LRU_OLD_MIN_LEN long LRU list, the LRU_old pointer is not
allowed to point to either end of the LRU list. */
#define BUF_LRU_OLD_TOLERANCE 20 // #define since it is used in #if below
/** The minimum amount of non-old blocks when the LRU_old list exists
(that is, when there are more than BUF_LRU_OLD_MIN_LEN blocks).
@see buf_LRU_old_adjust_len */
#define BUF_LRU_NON_OLD_MIN_LEN 5
#if BUF_LRU_NON_OLD_MIN_LEN >= BUF_LRU_OLD_MIN_LEN
#error "BUF_LRU_NON_OLD_MIN_LEN >= BUF_LRU_OLD_MIN_LEN"
#endif
/** 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.
We also release buf_pool->LRU_list_mutex after scanning this many pages of the
flush_list when dropping a table. This is to ensure that other threads
are not blocked for extended period of time when using very large
buffer pools. */
static const ulint BUF_LRU_DROP_SEARCH_SIZE = 1024;
/** We scan these many blocks when looking for a clean page to evict
during LRU eviction. */
static const ulint BUF_LRU_SEARCH_SCAN_THRESHOLD = 100;
/** If we switch on the InnoDB monitor because there are too few available
frames in the buffer pool, we set this to TRUE */
static bool buf_lru_switched_on_innodb_mon = false;
/** These statistics are not 'of' LRU but 'for' LRU. We keep count of I/O
and page_zip_decompress() operations. Based on the statistics,
buf_LRU_evict_from_unzip_LRU() decides if we want to evict from
unzip_LRU or the regular LRU. From unzip_LRU, we will only evict the
uncompressed frame (meaning we can evict dirty blocks as well). From
the regular LRU, we will evict the entire block (i.e.: both the
uncompressed and compressed data), which must be clean. */
/* @{ */
/** Number of intervals for which we keep the history of these stats.
Each interval is 1 second, defined by the rate at which
srv_error_monitor_thread() calls buf_LRU_stat_update(). */
static const ulint BUF_LRU_STAT_N_INTERVAL = 50;
/** Co-efficient with which we multiply I/O operations to equate them
with page_zip_decompress() operations. */
static const ulint BUF_LRU_IO_TO_UNZIP_FACTOR = 50;
/** Sampled values buf_LRU_stat_cur.
Not protected by any mutex. Updated by buf_LRU_stat_update(). */
static buf_LRU_stat_t buf_LRU_stat_arr[BUF_LRU_STAT_N_INTERVAL];
/** Cursor to buf_LRU_stat_arr[] that is updated in a round-robin fashion. */
static ulint buf_LRU_stat_arr_ind;
/** Current operation counters. Not protected by any mutex. Cleared
by buf_LRU_stat_update(). */
buf_LRU_stat_t buf_LRU_stat_cur;
/** Running sum of past values of buf_LRU_stat_cur.
Updated by buf_LRU_stat_update(). Not Protected by any mutex. */
buf_LRU_stat_t buf_LRU_stat_sum;
/* @} */
/** @name Heuristics for detecting index scan @{ */
/** Move blocks to "new" LRU list only if the first access was at
least this many milliseconds ago. Not protected by any mutex or latch. */
uint buf_LRU_old_threshold_ms;
/* @} */
/** Takes a block out of the LRU list and page hash table.
If the block is compressed-only (BUF_BLOCK_ZIP_PAGE),
the object will be freed.
The caller must hold buf_pool->LRU_list_mutex, the buf_page_get_mutex() mutex
and the appropriate hash_lock. This function will release the
buf_page_get_mutex() and the hash_lock.
If a compressed page is freed other compressed pages may be relocated.
@param[in] bpage block, must contain a file page and
be in a state where it can be freed; there
may or may not be a hash index to the page
@param[in] zip true if should remove also the
compressed page of an uncompressed page
@param[in] ignore_content true if should ignore page content, since it
could be not initialized
@retval true if BUF_BLOCK_FILE_PAGE was removed from page_hash. The
caller needs to free the page to the free list
@retval false if BUF_BLOCK_ZIP_PAGE was removed from page_hash. In
this case the block is already returned to the buddy allocator. */
static MY_ATTRIBUTE((warn_unused_result)) bool buf_LRU_block_remove_hashed(
buf_page_t *bpage, bool zip, bool ignore_content);
/** Puts a file page whose has no hash index to the free list. */
static void 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 */
/** Increases LRU size in bytes with page size inline function
@param[in] bpage control block
@param[in] buf_pool buffer pool instance */
static inline void incr_LRU_size_in_bytes(buf_page_t *bpage,
buf_pool_t *buf_pool) {
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
buf_pool->stat.LRU_bytes += bpage->size.physical();
ut_ad(buf_pool->stat.LRU_bytes <= buf_pool->curr_pool_size);
}
/** Determines if the unzip_LRU list should be used for evicting a victim
instead of the general LRU list.
@param[in,out] buf_pool buffer pool instance
@return true if should use unzip_LRU */
ibool buf_LRU_evict_from_unzip_LRU(buf_pool_t *buf_pool) {
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
/* If the unzip_LRU list is empty, we can only use the LRU. */
if (UT_LIST_GET_LEN(buf_pool->unzip_LRU) == 0) {
return (FALSE);
}
/* If unzip_LRU is at most 10% of the size of the LRU list,
then use the LRU. This slack allows us to keep hot
decompressed pages in the buffer pool. */
if (UT_LIST_GET_LEN(buf_pool->unzip_LRU) <=
UT_LIST_GET_LEN(buf_pool->LRU) / 10) {
return (FALSE);
}
/* If eviction hasn't started yet, we assume by default
that a workload is disk bound. */
if (buf_pool->freed_page_clock == 0) {
return (TRUE);
}
/* Calculate the average over past intervals, and add the values
of the current interval. */
ulint io_avg =
buf_LRU_stat_sum.io / BUF_LRU_STAT_N_INTERVAL + buf_LRU_stat_cur.io;
ulint unzip_avg =
buf_LRU_stat_sum.unzip / BUF_LRU_STAT_N_INTERVAL + buf_LRU_stat_cur.unzip;
/* Decide based on our formula. If the load is I/O bound
(unzip_avg is smaller than the weighted io_avg), evict an
uncompressed frame from unzip_LRU. Otherwise we assume that
the load is CPU bound and evict from the regular LRU. */
return (unzip_avg <= io_avg * BUF_LRU_IO_TO_UNZIP_FACTOR);
}
/** Attempts to drop page hash index on a batch of pages belonging to a
particular space id.
@param[in] space_id space id
@param[in] page_size page size
@param[in] arr array of page_no
@param[in] count number of entries in array */
static void buf_LRU_drop_page_hash_batch(space_id_t space_id,
const page_size_t &page_size,
const page_no_t *arr, ulint count) {
ut_ad(count <= BUF_LRU_DROP_SEARCH_SIZE);
for (ulint i = 0; i < count; ++i, ++arr) {
/* While our only caller
buf_LRU_drop_page_hash_for_tablespace()
is being executed for DROP TABLE or similar,
the table cannot be evicted from the buffer pool.
Note: this should not be executed for DROP TABLESPACE,
because DROP TABLESPACE would be refused if tables existed
in the tablespace, and a previous DROP TABLE would have
already removed the AHI entries. */
btr_search_drop_page_hash_when_freed(page_id_t(space_id, *arr), page_size);
}
}
/** 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.
@param[in] buf_pool buffer pool instance
@param[in] space_id space id */
static void buf_LRU_drop_page_hash_for_tablespace(buf_pool_t *buf_pool,
space_id_t space_id) {
bool found;
const page_size_t page_size(fil_space_get_page_size(space_id, &found));
if (!found) {
/* Somehow, the tablespace does not exist. Nothing to drop. */
ut_ad(0);
return;
}
page_no_t *page_arr = static_cast<page_no_t *>(
ut_malloc_nokey(sizeof(page_no_t) * BUF_LRU_DROP_SEARCH_SIZE));
ulint num_entries = 0;
mutex_enter(&buf_pool->LRU_list_mutex);
scan_again:
for (buf_page_t *bpage = UT_LIST_GET_LAST(buf_pool->LRU); bpage != NULL;
/* No op */) {
buf_page_t *prev_bpage = UT_LIST_GET_PREV(LRU, bpage);
ut_a(buf_page_in_file(bpage));
if (buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE ||
bpage->id.space() != space_id || bpage->io_fix != BUF_IO_NONE) {
/* Compressed pages are never hashed.
Skip blocks of other tablespaces.
Skip I/O-fixed blocks (to be dealt with later). */
next_page:
bpage = prev_bpage;
continue;
}
buf_block_t *block = reinterpret_cast<buf_block_t *>(bpage);
mutex_enter(&block->mutex);
/* This debug check uses a dirty read that could
theoretically cause false positives while
buf_pool_clear_hash_index() is executing.
(Other conflicting access paths to the adaptive hash
index should not be possible, because when a
tablespace is being discarded or dropped, there must
be no concurrect access to the contained tables.) */
assert_block_ahi_valid(block);
bool skip = bpage->buf_fix_count > 0 || !block->index;
mutex_exit(&block->mutex);
if (skip) {
/* Skip this block, because there are
no adaptive hash index entries
pointing to it, or because we cannot
drop them due to the buffer-fix. */
goto next_page;
}
/* Store the page number so that we can drop the hash
index in a batch later. */
page_arr[num_entries] = bpage->id.page_no();
ut_a(num_entries < BUF_LRU_DROP_SEARCH_SIZE);
++num_entries;
if (num_entries < BUF_LRU_DROP_SEARCH_SIZE) {
goto next_page;
}
/* Array full. We release the LRU list mutex to obey
the latching order. */
mutex_exit(&buf_pool->LRU_list_mutex);
buf_LRU_drop_page_hash_batch(space_id, page_size, page_arr, num_entries);
num_entries = 0;
mutex_enter(&buf_pool->LRU_list_mutex);
/* Note that we released the buf_pool->LRU_list_mutex above
after reading the prev_bpage during processing of a
page_hash_batch (i.e.: when the array was full).
Because prev_bpage could belong to a compressed-only
block, it may have been relocated, and thus the
pointer cannot be trusted. Because bpage is of type
buf_block_t, it is safe to dereference.
bpage can change in the 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. */
/* If, however, bpage has been removed from LRU list
to the free list then we should restart the scan. */
if (bpage != NULL && buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) {
goto scan_again;
}
}
mutex_exit(&buf_pool->LRU_list_mutex);
/* Drop any remaining batch of search hashed pages. */
buf_LRU_drop_page_hash_batch(space_id, page_size, page_arr, num_entries);
ut_free(page_arr);
}
/** While flushing (or removing dirty) pages from a tablespace we don't
want to hog the CPU and resources. Release the LRU list and block
mutexes and try to force a context switch. Then reacquire the same mutexes.
The current page is "fixed" before the release of the mutexes and then
"unfixed" again once we have reacquired the mutexes.
@param[in,out] buf_pool buffer pool instance
@param[in,out] bpage current page */
static void buf_flush_yield(buf_pool_t *buf_pool, buf_page_t *bpage) {
BPageMutex *block_mutex = buf_page_get_mutex(bpage);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_ad(mutex_own(block_mutex));
ut_ad(buf_page_in_file(bpage));
/* "Fix" the block so that the position cannot be
changed after we release the buffer pool and
block mutexes. */
buf_page_set_sticky(bpage);
/* Now it is safe to release the LRU list mutex. */
mutex_exit(&buf_pool->LRU_list_mutex);
mutex_exit(block_mutex);
/* Try and force a context switch. */
os_thread_yield();
mutex_enter(&buf_pool->LRU_list_mutex);
mutex_enter(block_mutex);
/* "Unfix" the block now that we have both the
LRU list and block mutexes again. */
buf_page_unset_sticky(bpage);
mutex_exit(block_mutex);
}
/** If we have hogged the resources for too long then release the LRU list and
flush list mutexes and do a thread yield. Set the current page
to "sticky" so that it is not relocated during the yield.
@return true if yielded */
static MY_ATTRIBUTE((warn_unused_result)) bool buf_flush_try_yield(
buf_pool_t *buf_pool, /*!< in/out: buffer pool instance */
buf_page_t *bpage, /*!< in/out: bpage to remove */
ulint processed, /*!< in: number of pages processed */
bool *must_restart) /*!< in/out: if true, we have to
restart the flush list scan */
{
/* Every BUF_LRU_DROP_SEARCH_SIZE iterations in the
loop we release buf_pool->LRU_list_mutex to let other threads
do their job but only if the block is not IO fixed. This
ensures that the block stays in its position in the
flush_list. */
if (bpage != NULL && processed >= BUF_LRU_DROP_SEARCH_SIZE &&
buf_page_get_io_fix_unlocked(bpage) == BUF_IO_NONE) {
BPageMutex *block_mutex = buf_page_get_mutex(bpage);
buf_flush_list_mutex_exit(buf_pool);
/* We don't have to worry about bpage becoming a dangling
pointer by a compressed page flush list relocation because
buf_page_get_gen() won't be called for pages from this
tablespace. */
mutex_enter(block_mutex);
/* Recheck the I/O fix and the flush list presence now that we
hold the right mutex */
if (buf_page_get_io_fix(bpage) != BUF_IO_NONE ||
bpage->oldest_modification == 0) {
mutex_exit(block_mutex);
*must_restart = true;
buf_flush_list_mutex_enter(buf_pool);
return false;
}
*must_restart = false;
/* Release the LRU list and buf_page_get_mutex() mutex
to give the other threads a go. */
buf_flush_yield(buf_pool, bpage);
buf_flush_list_mutex_enter(buf_pool);
/* Should not have been removed from the flush
list during the yield. However, this check is
not sufficient to catch a remove -> add. */
ut_ad(bpage->in_flush_list);
return (true);
}
return (false);
}
/** Removes a single page from a given tablespace inside a specific
buffer pool instance.
@param[in,out] buf_pool buffer pool instance
@param[in,out] bpage bpage to remove
@param[in] flush flush to disk if true but don't remove
else remove without flushing to disk
@param[in,out] must_restart flag if must restart the flush list scan
@return true if page was removed. */
static MY_ATTRIBUTE((warn_unused_result)) bool buf_flush_or_remove_page(
buf_pool_t *buf_pool, buf_page_t *bpage, bool flush, bool *must_restart) {
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_ad(buf_flush_list_mutex_own(buf_pool));
/* It is safe to check bpage->space and bpage->io_fix while holding
buf_pool->LRU_list_mutex only. */
if (buf_page_get_io_fix_unlocked(bpage) != BUF_IO_NONE) {
/* We cannot remove this page during this scan
yet; maybe the system is currently reading it
in, or flushing the modifications to the file */
return (false);
}
BPageMutex *block_mutex = buf_page_get_mutex(bpage);
bool processed = false;
/* We don't have to worry about bpage becoming a dangling
pointer by a compressed page flush list relocation because
buf_page_get_gen() won't be called for pages from this
tablespace. */
buf_flush_list_mutex_exit(buf_pool);
mutex_enter(block_mutex);
/* Recheck the page I/O fix and the flush list presence now
that we hold the right mutex. */
if (buf_page_get_io_fix(bpage) != BUF_IO_NONE ||
bpage->oldest_modification == 0) {
/* The page became I/O-fixed or is not on the flush
list anymore, this invalidates any flush-list-page
pointers we have. */
mutex_exit(block_mutex);
*must_restart = true;
processed = false;
} else if (!flush) {
buf_flush_remove(bpage);
mutex_exit(block_mutex);
processed = true;
} else if (buf_flush_ready_for_flush(bpage, BUF_FLUSH_SINGLE_PAGE)) {
/* The following call will release the LRU list
and block mutexes. */
processed = buf_flush_page(buf_pool, bpage, BUF_FLUSH_SINGLE_PAGE, false);
if (processed) {
/* Wake possible simulated aio thread to actually
post the writes to the operating system */
os_aio_simulated_wake_handler_threads();
mutex_enter(&buf_pool->LRU_list_mutex);
} else {
mutex_exit(block_mutex);
}
} else {
mutex_exit(block_mutex);
}
buf_flush_list_mutex_enter(buf_pool);
ut_ad(!mutex_own(block_mutex));
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
return (processed);
}
/** Remove all dirty pages belonging to a given tablespace inside a specific
buffer pool instance when we are deleting the data file(s) of that
tablespace. The pages still remain a part of LRU and are evicted from
the list as they age towards the tail of the LRU.
@param[in,out] buf_pool buffer pool instance
@param[in] id space id for which to remove or flush pages
@param[in] observer flush observer
@param[in] flush flush to disk if true but don't remove,
otherwise remove without flushing to disk
@param[in] trx transaction to check if the operation must be
interrupted, can be NULL
@retval DB_SUCCESS if all freed
@retval DB_FAIL if not all freed
@retval DB_INTERRUPTED if the transaction was interrupted */
static MY_ATTRIBUTE((warn_unused_result)) dberr_t
buf_flush_or_remove_pages(buf_pool_t *buf_pool, space_id_t id,
FlushObserver *observer, bool flush,
const trx_t *trx) {
buf_page_t *prev;
buf_page_t *bpage;
ulint processed = 0;
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
buf_flush_list_mutex_enter(buf_pool);
rescan:
bool must_restart = false;
bool all_freed = true;
for (bpage = UT_LIST_GET_LAST(buf_pool->flush_list); bpage != NULL;
bpage = prev) {
ut_a(buf_page_in_file(bpage));
/* Save the previous link because once we free the
page we can't rely on the links. */
prev = UT_LIST_GET_PREV(list, bpage);
/* If flush observer is NULL, flush page for space id,
or flush page for flush observer. */
if ((observer != NULL && observer != bpage->flush_observer) ||
(observer == NULL && id != bpage->id.space())) {
/* Skip this block, as it does not belong to
the target space. */
} else if (!buf_flush_or_remove_page(buf_pool, bpage, flush,
&must_restart)) {
/* Remove was unsuccessful, we have to try again
by scanning the entire list from the end.
This also means that we never released the
flust list mutex. Therefore we can trust the prev
pointer.
buf_flush_or_remove_page() released the
flush list mutex but not the LRU list mutex.
Therefore it is possible that a new page was
added to the flush list. For example, in case
where we are at the head of the flush list and
prev == NULL. That is OK because we have the
tablespace quiesced and no new pages for this
space-id should enter flush_list. This is
because the only callers of this function are
DROP TABLE and FLUSH TABLE FOR EXPORT.
We know that we'll have to do at least one more
scan but we don't break out of loop here and
try to do as much work as we can in this
iteration. */
all_freed = false;
} else if (flush) {
/* The processing was successful. And during the
processing we have released all the buf_pool mutexes
when calling buf_page_flush(). We cannot trust
prev pointer. */
goto rescan;
} else if (must_restart) {
ut_ad(!all_freed);
break;
}
++processed;
/* Yield if we have hogged the CPU and mutexes for too long. */
if (buf_flush_try_yield(buf_pool, prev, processed, &must_restart)) {
ut_ad(!must_restart);
/* Reset the batch size counter if we had to yield. */
processed = 0;
}
/* The check for trx is interrupted is expensive, we want
to check every N iterations. */
if (!processed && trx && trx_is_interrupted(trx)) {
if (trx->flush_observer != NULL) {
if (flush) {
trx->flush_observer->interrupted();
} else {
/* We should remove all pages with the
the flush observer. */
continue;
}
}
buf_flush_list_mutex_exit(buf_pool);
return (DB_INTERRUPTED);
}
}
buf_flush_list_mutex_exit(buf_pool);
return (all_freed ? DB_SUCCESS : DB_FAIL);
}
/** Remove or flush all the dirty pages that belong to a given tablespace
inside a specific buffer pool instance. The pages will remain in the LRU
list and will be evicted from the LRU list as they age and move towards
the tail of the LRU list.
@param[in,out] buf_pool buffer pool instance
@param[in] id space id
@param[in] observer flush observer
@param[in] flush flush to disk if true, otherwise remove
the pages without flushing
@param[in] trx transaction to check if the operation
must be interrupted
@param[in] strict true, if no page from tablespace
can be in buffer pool just after flush */
static void buf_flush_dirty_pages(buf_pool_t *buf_pool, space_id_t id,
FlushObserver *observer, bool flush,
const trx_t *trx, bool strict) {
dberr_t err;
do {
/* TODO: it should be possible to avoid locking the LRU list
mutex here. */
mutex_enter(&buf_pool->LRU_list_mutex);
err = buf_flush_or_remove_pages(buf_pool, id, observer, flush, trx);
mutex_exit(&buf_pool->LRU_list_mutex);
ut_ad(buf_flush_validate(buf_pool));
if (err == DB_FAIL) {
os_thread_sleep(2000);
}
if (err == DB_INTERRUPTED && observer != NULL) {
ut_a(flush);
flush = false;
err = DB_FAIL;
}
/* DB_FAIL is a soft error, it means that the task wasn't
completed, needs to be retried. */
ut_ad(buf_flush_validate(buf_pool));
} while (err == DB_FAIL);
ut_ad(err == DB_INTERRUPTED || !strict ||
buf_pool_get_dirty_pages_count(buf_pool, id, observer) == 0);
}
/** Remove all pages that belong to a given tablespace inside a specific
buffer pool instance when we are DISCARDing the tablespace.
@param[in,out] buf_pool buffer pool instance
@param[in] id space id */
static void buf_LRU_remove_all_pages(buf_pool_t *buf_pool, ulint id) {
buf_page_t *bpage;
ibool all_freed;
scan_again:
mutex_enter(&buf_pool->LRU_list_mutex);
all_freed = TRUE;
for (bpage = UT_LIST_GET_LAST(buf_pool->LRU); bpage != NULL;
/* No op */) {
rw_lock_t *hash_lock;
buf_page_t *prev_bpage;
BPageMutex *block_mutex;
ut_a(buf_page_in_file(bpage));
ut_ad(bpage->in_LRU_list);
prev_bpage = UT_LIST_GET_PREV(LRU, bpage);
/* It is safe to check bpage->id.space() and bpage->io_fix
while holding buf_pool->LRU_list_mutex only and later recheck
while holding the buf_page_get_mutex() mutex. */
if (bpage->id.space() != id) {
/* Skip this block, as it does not belong to
the space that is being invalidated. */
goto next_page;
} else if (buf_page_get_io_fix_unlocked(bpage) != BUF_IO_NONE) {
/* We cannot remove this page during this scan
yet; maybe the system is currently reading it
in, or flushing the modifications to the file */
all_freed = FALSE;
goto next_page;
} else {
hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id);
rw_lock_x_lock(hash_lock);
block_mutex = buf_page_get_mutex(bpage);
mutex_enter(block_mutex);
if (bpage->id.space() != id || bpage->buf_fix_count > 0 ||
(buf_page_get_io_fix(bpage) != BUF_IO_NONE)) {
mutex_exit(block_mutex);
rw_lock_x_unlock(hash_lock);
/* We cannot remove this page during
this scan yet; maybe the system is
currently reading it in, or flushing
the modifications to the file */
all_freed = FALSE;
goto next_page;
}
}
ut_ad(mutex_own(block_mutex));
DBUG_PRINT("ib_buf",
("evict page " UINT32PF ":" UINT32PF " state %u",
bpage->id.space(), bpage->id.page_no(), bpage->state));
if (buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) {
/* Do nothing, because the adaptive hash index
covers uncompressed pages only. */
} else if (((buf_block_t *)bpage)->index) {
mutex_exit(&buf_pool->LRU_list_mutex);
rw_lock_x_unlock(hash_lock);
mutex_exit(block_mutex);
/* Note that the following call will acquire
and release block->lock X-latch.
Note that the table cannot be evicted during
the execution of ALTER TABLE...DISCARD TABLESPACE
because MySQL is keeping the table handle open. */
btr_search_drop_page_hash_when_freed(bpage->id, bpage->size);
goto scan_again;
} else {
/* This debug check uses a dirty read that could
theoretically cause false positives while
buf_pool_clear_hash_index() is executing,
if the writes to block->index=NULL and
block->n_pointers=0 are reordered.
(Other conflicting access paths to the adaptive hash
index should not be possible, because when a
tablespace is being discarded or dropped, there must
be no concurrect access to the contained tables.) */
assert_block_ahi_empty((buf_block_t *)bpage);
}
if (bpage->oldest_modification != 0) {
buf_flush_remove(bpage);
}
ut_ad(!bpage->in_flush_list);
/* Remove from the LRU list. */
if (buf_LRU_block_remove_hashed(bpage, true, false)) {
buf_LRU_block_free_hashed_page((buf_block_t *)bpage);
} else {
ut_ad(block_mutex == &buf_pool->zip_mutex);
}
ut_ad(!mutex_own(block_mutex));
/* buf_LRU_block_remove_hashed() releases the hash_lock */
ut_ad(!rw_lock_own(hash_lock, RW_LOCK_X));
ut_ad(!rw_lock_own(hash_lock, RW_LOCK_S));
next_page:
bpage = prev_bpage;
}
mutex_exit(&buf_pool->LRU_list_mutex);
if (!all_freed) {
os_thread_sleep(20000);
goto scan_again;
}
}
/** Remove pages belonging to a given tablespace inside a specific
buffer pool instance when we are deleting the data file(s) of that
tablespace. The pages still remain a part of LRU and are evicted from
the list as they age towards the tail of the LRU only if buf_remove
is BUF_REMOVE_FLUSH_NO_WRITE. */
static void buf_LRU_remove_pages(
buf_pool_t *buf_pool, /*!< buffer pool instance */
space_id_t id, /*!< in: space id */
buf_remove_t buf_remove, /*!< in: remove or flush strategy */
const trx_t *trx, /*!< to check if the operation must
be interrupted */
bool strict) /*!< in: true if no page from tablespace
can be in buffer pool just after flush */
{
FlushObserver *observer = (trx == NULL) ? NULL : trx->flush_observer;
switch (buf_remove) {
case BUF_REMOVE_ALL_NO_WRITE:
buf_LRU_remove_all_pages(buf_pool, id);
break;
case BUF_REMOVE_FLUSH_NO_WRITE:
/* Pass trx as NULL to avoid interruption check. */
buf_flush_dirty_pages(buf_pool, id, observer, false, NULL, strict);
break;
case BUF_REMOVE_FLUSH_WRITE:
buf_flush_dirty_pages(buf_pool, id, observer, true, trx, strict);
if (observer == NULL) {
/* Ensure that all asynchronous IO is completed. */
os_aio_wait_until_no_pending_writes();
fil_flush(id);
}
break;
}
}
/** Flushes all dirty pages or removes all pages belonging
to a given tablespace. A PROBLEM: if readahead is being started, what
guarantees that it will not try to read in pages after this operation
has completed? */
void buf_LRU_flush_or_remove_pages(
space_id_t id, /*!< in: space id */
buf_remove_t buf_remove, /*!< in: remove or flush strategy */
const trx_t *trx, /*!< to check if the operation must
be interrupted */
bool strict) /*!< in: true if no page from tablespace
can be in buffer pool just after flush */
{
ulint i;
/* 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. */
for (i = 0; i < srv_buf_pool_instances; i++) {
buf_pool_t *buf_pool;
buf_pool = buf_pool_from_array(i);
switch (buf_remove) {
case BUF_REMOVE_ALL_NO_WRITE:
buf_LRU_drop_page_hash_for_tablespace(buf_pool, id);
break;
case BUF_REMOVE_FLUSH_NO_WRITE:
/* It is a DROP TABLE for a single table
tablespace. No AHI entries exist because
we already dealt with them when freeing up
extents. */
case BUF_REMOVE_FLUSH_WRITE:
/* We allow read-only queries against the
table, there is no need to drop the AHI entries. */
break;
}
buf_LRU_remove_pages(buf_pool, id, buf_remove, trx, strict);
}
}
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/** Insert a compressed block into buf_pool->zip_clean in the LRU order.
@param[in] bpage pointer to the block in question */
void buf_LRU_insert_zip_clean(buf_page_t *bpage) {
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_ad(mutex_own(&buf_pool->zip_mutex));
ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_PAGE);
/* Find the first successor of bpage in the LRU list
that is in the zip_clean list. */
buf_page_t *b = bpage;
do {
b = UT_LIST_GET_NEXT(LRU, b);
} while (b && buf_page_get_state(b) != BUF_BLOCK_ZIP_PAGE);
/* Insert bpage before b, i.e., after the predecessor of b. */
if (b != NULL) {
b = UT_LIST_GET_PREV(list, b);
}
if (b != NULL) {
UT_LIST_INSERT_AFTER(buf_pool->zip_clean, b, bpage);
} else {
UT_LIST_ADD_FIRST(buf_pool->zip_clean, bpage);
}
}
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
/** Try to free an uncompressed page of a compressed block from the unzip
LRU list. The compressed page is preserved, and it need not be clean.
@param[in] buf_pool buffer pool instance
@param[in] scan_all scan whole LRU list if true, otherwise
scan only srv_LRU_scan_depth / 2 blocks
@return true if freed */
static bool buf_LRU_free_from_unzip_LRU_list(buf_pool_t *buf_pool,
bool scan_all) {
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
if (!buf_LRU_evict_from_unzip_LRU(buf_pool)) {
return (false);
}
ulint scanned = 0;
bool freed = false;
for (buf_block_t *block = UT_LIST_GET_LAST(buf_pool->unzip_LRU);
block != NULL && !freed && (scan_all || scanned < srv_LRU_scan_depth);
++scanned) {
buf_block_t *prev_block;
prev_block = UT_LIST_GET_PREV(unzip_LRU, block);
mutex_enter(&block->mutex);
ut_ad(buf_block_get_state(block) == BUF_BLOCK_FILE_PAGE);
ut_ad(block->in_unzip_LRU_list);
ut_ad(block->page.in_LRU_list);
freed = buf_LRU_free_page(&block->page, false);
if (!freed) mutex_exit(&block->mutex);
block = prev_block;
}
if (scanned) {
MONITOR_INC_VALUE_CUMULATIVE(MONITOR_LRU_UNZIP_SEARCH_SCANNED,
MONITOR_LRU_UNZIP_SEARCH_SCANNED_NUM_CALL,
MONITOR_LRU_UNZIP_SEARCH_SCANNED_PER_CALL,
scanned);
}
return (freed);
}
/** Try to free a clean page from the common LRU list.
@param[in,out] buf_pool buffer pool instance
@param[in] scan_all scan whole LRU list if true, otherwise scan
only up to BUF_LRU_SEARCH_SCAN_THRESHOLD
@return true if freed */
static bool buf_LRU_free_from_common_LRU_list(buf_pool_t *buf_pool,
bool scan_all) {
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ulint scanned = 0;
bool freed = false;
for (buf_page_t *bpage = buf_pool->lru_scan_itr.start();
bpage != NULL && !freed &&
(scan_all || scanned < BUF_LRU_SEARCH_SCAN_THRESHOLD);
++scanned, bpage = buf_pool->lru_scan_itr.get()) {
buf_page_t *prev = UT_LIST_GET_PREV(LRU, bpage);
BPageMutex *mutex = buf_page_get_mutex(bpage);
buf_pool->lru_scan_itr.set(prev);
ut_ad(buf_page_in_file(bpage));
ut_ad(bpage->in_LRU_list);
unsigned accessed = buf_page_is_accessed(bpage);
mutex_enter(mutex);
if (buf_flush_ready_for_replace(bpage)) {
freed = buf_LRU_free_page(bpage, true);
}
if (!freed) mutex_exit(mutex);
if (freed && !accessed) {
/* Keep track of pages that are evicted without
ever being accessed. This gives us a measure of
the effectiveness of readahead */
++buf_pool->stat.n_ra_pages_evicted;
}
ut_ad(!mutex_own(mutex));
if (freed) break;
}
if (scanned) {
MONITOR_INC_VALUE_CUMULATIVE(MONITOR_LRU_SEARCH_SCANNED,
MONITOR_LRU_SEARCH_SCANNED_NUM_CALL,
MONITOR_LRU_SEARCH_SCANNED_PER_CALL, scanned);
}
return (freed);
}
/** Try to free a replaceable block.
@param[in,out] buf_pool buffer pool instance
@param[in] scan_all scan whole LRU list if ture, otherwise scan
only BUF_LRU_SEARCH_SCAN_THRESHOLD blocks
@return true if found and freed */
bool buf_LRU_scan_and_free_block(buf_pool_t *buf_pool, bool scan_all) {
bool freed = false;
bool use_unzip_list = UT_LIST_GET_LEN(buf_pool->unzip_LRU) > 0;
mutex_enter(&buf_pool->LRU_list_mutex);
if (use_unzip_list) {
freed = buf_LRU_free_from_unzip_LRU_list(buf_pool, scan_all);
}
if (!freed) {
freed = buf_LRU_free_from_common_LRU_list(buf_pool, scan_all);
}
if (!freed) {
mutex_exit(&buf_pool->LRU_list_mutex);
}
return (freed);
}
/** Returns TRUE if less than 25 % of the buffer pool in any instance is
available. This can be used in heuristics to prevent huge transactions
eating up the whole buffer pool for their locks.
@return true if less than 25 % of buffer pool left */
ibool buf_LRU_buf_pool_running_out(void) {
ibool ret = FALSE;
for (ulint i = 0; i < srv_buf_pool_instances && !ret; i++) {
buf_pool_t *buf_pool;
buf_pool = buf_pool_from_array(i);
if (!recv_recovery_is_on() &&
UT_LIST_GET_LEN(buf_pool->free) + UT_LIST_GET_LEN(buf_pool->LRU) <
ut_min(buf_pool->curr_size, buf_pool->old_size) / 4) {
ret = TRUE;
}
}
return (ret);
}
/** Returns a free block from the buf_pool.
The block is taken off the free list. If it is empty, returns NULL.
@param[in] buf_pool buffer pool instance
@return a free control block, or NULL if the buf_block->free list is empty */
buf_block_t *buf_LRU_get_free_only(buf_pool_t *buf_pool) {
buf_block_t *block;
mutex_enter(&buf_pool->free_list_mutex);
block = reinterpret_cast<buf_block_t *>(UT_LIST_GET_FIRST(buf_pool->free));
while (block != NULL) {
ut_ad(block->page.in_free_list);
ut_d(block->page.in_free_list = FALSE);
ut_ad(!block->page.in_flush_list);
ut_ad(!block->page.in_LRU_list);
ut_a(!buf_page_in_file(&block->page));
UT_LIST_REMOVE(buf_pool->free, &block->page);
mutex_exit(&buf_pool->free_list_mutex);
if (!buf_get_withdraw_depth(buf_pool) ||
!buf_block_will_withdrawn(buf_pool, block)) {
/* found valid free block */
/* No adaptive hash index entries may point to
a free block. */
assert_block_ahi_empty(block);
buf_block_set_state(block, BUF_BLOCK_READY_FOR_USE);
UNIV_MEM_ALLOC(block->frame, UNIV_PAGE_SIZE);
ut_ad(buf_pool_from_block(block) == buf_pool);
return (block);
}
/* This should be withdrawn */
mutex_enter(&buf_pool->free_list_mutex);
UT_LIST_ADD_LAST(buf_pool->withdraw, &block->page);
ut_d(block->in_withdraw_list = TRUE);
block = reinterpret_cast<buf_block_t *>(UT_LIST_GET_FIRST(buf_pool->free));
}
mutex_exit(&buf_pool->free_list_mutex);
return (block);
}
/** Checks how much of buf_pool is occupied by non-data objects like
AHI, lock heaps etc. Depending on the size of non-data objects this
function will either assert or issue a warning and switch on the
status monitor. */
static void buf_LRU_check_size_of_non_data_objects(
const buf_pool_t *buf_pool) /*!< in: buffer pool instance */
{
if (!recv_recovery_is_on() && buf_pool->curr_size == buf_pool->old_size &&
UT_LIST_GET_LEN(buf_pool->free) + UT_LIST_GET_LEN(buf_pool->LRU) <
buf_pool->curr_size / 20) {
ib::fatal(ER_IB_MSG_132)
<< "Over 95 percent of the buffer pool is"
" occupied by lock heaps or the adaptive hash index!"
" Check that your transactions do not set too many"
" row locks. Your buffer pool size is "
<< (buf_pool->curr_size / (1024 * 1024 / UNIV_PAGE_SIZE))
<< " MB."
" Maybe you should make the buffer pool bigger?"
" We intentionally generate a seg fault to print"
" a stack trace on Linux!";
} else if (!recv_recovery_is_on() &&
buf_pool->curr_size == buf_pool->old_size &&
(UT_LIST_GET_LEN(buf_pool->free) +
UT_LIST_GET_LEN(buf_pool->LRU)) < buf_pool->curr_size / 3) {
if (!buf_lru_switched_on_innodb_mon) {
/* Over 67 % of the buffer pool is occupied by lock
heaps or the adaptive hash index. This may be a memory
leak! */
ib::warn(ER_IB_MSG_133)
<< "Over 67 percent of the buffer pool is"
" occupied by lock heaps or the adaptive hash"
" index! Check that your transactions do not"
" set too many row locks. Your buffer pool"
" size is "
<< (buf_pool->curr_size / (1024 * 1024 / UNIV_PAGE_SIZE))
<< " MB. Maybe you should make the buffer pool"
" bigger?. Starting the InnoDB Monitor to print"
" diagnostics, including lock heap and hash"
" index sizes.";
buf_lru_switched_on_innodb_mon = true;
srv_print_innodb_monitor = TRUE;
os_event_set(srv_monitor_event);
}
} else if (buf_lru_switched_on_innodb_mon) {
/* Switch off the InnoDB Monitor; this is a simple way
to stop the monitor if the situation becomes less urgent,
but may also surprise users if the user also switched on the
monitor! */
buf_lru_switched_on_innodb_mon = false;
srv_print_innodb_monitor = FALSE;
}
}
/** Returns a free block from the buf_pool. The block is taken off the
free list. If free list is empty, blocks are moved from the end of the
LRU list to the free list.
This function is called from a user thread when it needs a clean
block to read in a page. Note that we only ever get a block from
the free list. Even when we flush a page or find a page in LRU scan
we put it to free list to be used.
* iteration 0:
* get a block from free list, success:done
* if buf_pool->try_LRU_scan is set
* scan LRU up to srv_LRU_scan_depth to find a clean block
* the above will put the block on free list
* success:retry the free list
* flush one dirty page from tail of LRU to disk
* the above will put the block on free list
* success: retry the free list
* iteration 1:
* same as iteration 0 except:
* scan whole LRU list
* scan LRU list even if buf_pool->try_LRU_scan is not set
* iteration > 1:
* same as iteration 1 but sleep 10ms
@param[in,out] buf_pool buffer pool instance
@return the free control block, in state BUF_BLOCK_READY_FOR_USE */
buf_block_t *buf_LRU_get_free_block(buf_pool_t *buf_pool) {
buf_block_t *block = NULL;
bool freed = false;
ulint n_iterations = 0;
ulint flush_failures = 0;
bool mon_value_was = false;
bool started_monitor = false;
ut_ad(!mutex_own(&buf_pool->LRU_list_mutex));
MONITOR_INC(MONITOR_LRU_GET_FREE_SEARCH);
loop:
buf_LRU_check_size_of_non_data_objects(buf_pool);
/* If there is a block in the free list, take it */
block = buf_LRU_get_free_only(buf_pool);
if (block != NULL) {
ut_ad(buf_pool_from_block(block) == buf_pool);
memset(&block->page.zip, 0, sizeof block->page.zip);
if (started_monitor) {
srv_print_innodb_monitor = static_cast<bool>(mon_value_was);
}
block->page.flush_observer = NULL;
return (block);
}
MONITOR_INC(MONITOR_LRU_GET_FREE_LOOPS);
freed = false;
os_rmb;
if (buf_pool->try_LRU_scan || n_iterations > 0) {
/* If no block was in the free list, search from the
end of the LRU list and try to free a block there.
If we are doing for the first time we'll scan only
tail of the LRU list otherwise we scan the whole LRU
list. */
freed = buf_LRU_scan_and_free_block(buf_pool, n_iterations > 0);
if (!freed && n_iterations == 0) {
/* Tell other threads that there is no point
in scanning the LRU list. This flag is set to
TRUE again when we flush a batch from this
buffer pool. */
buf_pool->try_LRU_scan = FALSE;
os_wmb;
}
}
if (freed) {
goto loop;
}
if (n_iterations > 20 && srv_buf_pool_old_size == srv_buf_pool_size) {
ib::warn(ER_IB_MSG_134)
<< "Difficult to find free blocks in the buffer pool"
" ("
<< n_iterations << " search iterations)! " << flush_failures
<< " failed attempts to"
" flush a page! Consider increasing the buffer pool"
" size. It is also possible that in your Unix version"
" fsync is very slow, or completely frozen inside"
" the OS kernel. Then upgrading to a newer version"
" of your operating system may help. Look at the"
" number of fsyncs in diagnostic info below."
" Pending flushes (fsync) log: "
<< fil_n_pending_log_flushes
<< "; buffer pool: " << fil_n_pending_tablespace_flushes << ". "
<< os_n_file_reads << " OS file reads, " << os_n_file_writes
<< " OS file writes, " << os_n_fsyncs
<< " OS fsyncs. Starting InnoDB Monitor to print"
" further diagnostics to the standard output.";
mon_value_was = srv_print_innodb_monitor;
started_monitor = true;
srv_print_innodb_monitor = true;
os_event_set(srv_monitor_event);
}
/* If we have scanned the whole LRU and still are unable to
find a free block then we should sleep here to let the
page_cleaner do an LRU batch for us. */
if (!srv_read_only_mode) {
os_event_set(buf_flush_event);
}
if (n_iterations > 1) {
MONITOR_INC(MONITOR_LRU_GET_FREE_WAITS);
os_thread_sleep(10000);
}
/* No free block was found: try to flush the LRU list.
This call will flush one page from the LRU and put it on the
free list. That means that the free block is up for grabs for
all user threads.
TODO: A more elegant way would have been to return the freed
up block to the caller here but the code that deals with
removing the block from page_hash and LRU_list is fairly
involved (particularly in case of compressed pages). We
can do that in a separate patch sometime in future. */
if (!buf_flush_single_page_from_LRU(buf_pool)) {
MONITOR_INC(MONITOR_LRU_SINGLE_FLUSH_FAILURE_COUNT);
++flush_failures;
}
srv_stats.buf_pool_wait_free.add(n_iterations, 1);
n_iterations++;
goto loop;
}
/** Moves the LRU_old pointer so that the length of the old blocks list
is inside the allowed limits.
@param[in] buf_pool buffer pool instance */
UNIV_INLINE
void buf_LRU_old_adjust_len(buf_pool_t *buf_pool) {
ulint old_len;
ulint new_len;
ut_a(buf_pool->LRU_old);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_ad(buf_pool->LRU_old_ratio >= BUF_LRU_OLD_RATIO_MIN);
ut_ad(buf_pool->LRU_old_ratio <= BUF_LRU_OLD_RATIO_MAX);
#if BUF_LRU_OLD_RATIO_MIN * BUF_LRU_OLD_MIN_LEN <= \
BUF_LRU_OLD_RATIO_DIV * (BUF_LRU_OLD_TOLERANCE + 5)
#error \
"BUF_LRU_OLD_RATIO_MIN * BUF_LRU_OLD_MIN_LEN <= BUF_LRU_OLD_RATIO_DIV * (BUF_LRU_OLD_TOLERANCE + 5)"
#endif
#ifdef UNIV_LRU_DEBUG
/* buf_pool->LRU_old must be the first item in the LRU list
whose "old" flag is set. */
ut_a(buf_pool->LRU_old->old);
ut_a(!UT_LIST_GET_PREV(LRU, buf_pool->LRU_old) ||
!UT_LIST_GET_PREV(LRU, buf_pool->LRU_old)->old);
ut_a(!UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old) ||
UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old)->old);
#endif /* UNIV_LRU_DEBUG */
old_len = buf_pool->LRU_old_len;
new_len = ut_min(UT_LIST_GET_LEN(buf_pool->LRU) * buf_pool->LRU_old_ratio /
BUF_LRU_OLD_RATIO_DIV,
UT_LIST_GET_LEN(buf_pool->LRU) -
(BUF_LRU_OLD_TOLERANCE + BUF_LRU_NON_OLD_MIN_LEN));
for (;;) {
buf_page_t *LRU_old = buf_pool->LRU_old;
ut_a(LRU_old);
ut_ad(LRU_old->in_LRU_list);
#ifdef UNIV_LRU_DEBUG
ut_a(LRU_old->old);
#endif /* UNIV_LRU_DEBUG */
/* Update the LRU_old pointer if necessary */
if (old_len + BUF_LRU_OLD_TOLERANCE < new_len) {
buf_pool->LRU_old = LRU_old = UT_LIST_GET_PREV(LRU, LRU_old);
#ifdef UNIV_LRU_DEBUG
ut_a(!LRU_old->old);
#endif /* UNIV_LRU_DEBUG */
old_len = ++buf_pool->LRU_old_len;
buf_page_set_old(LRU_old, TRUE);
} else if (old_len > new_len + BUF_LRU_OLD_TOLERANCE) {
buf_pool->LRU_old = UT_LIST_GET_NEXT(LRU, LRU_old);
old_len = --buf_pool->LRU_old_len;
buf_page_set_old(LRU_old, FALSE);
} else {
return;
}
}
}
/** Initializes the old blocks pointer in the LRU list. This function should be
called when the LRU list grows to BUF_LRU_OLD_MIN_LEN length.
@param[in,out] buf_pool buffer pool instance */
static void buf_LRU_old_init(buf_pool_t *buf_pool) {
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_a(UT_LIST_GET_LEN(buf_pool->LRU) == BUF_LRU_OLD_MIN_LEN);
/* We first initialize all blocks in the LRU list as old and then use
the adjust function to move the LRU_old pointer to the right
position */
for (buf_page_t *bpage = UT_LIST_GET_LAST(buf_pool->LRU); bpage != NULL;
bpage = UT_LIST_GET_PREV(LRU, bpage)) {
ut_ad(bpage->in_LRU_list);
ut_ad(buf_page_in_file(bpage));
/* This loop temporarily violates the
assertions of buf_page_set_old(). */
bpage->old = TRUE;
}
buf_pool->LRU_old = UT_LIST_GET_FIRST(buf_pool->LRU);
buf_pool->LRU_old_len = UT_LIST_GET_LEN(buf_pool->LRU);
buf_LRU_old_adjust_len(buf_pool);
}
/** Remove a block from the unzip_LRU list if it belonged to the list.
@param[in] bpage control block */
static void buf_unzip_LRU_remove_block_if_needed(buf_page_t *bpage) {
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
ut_ad(buf_page_in_file(bpage));
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
if (buf_page_belongs_to_unzip_LRU(bpage)) {
buf_block_t *block = reinterpret_cast<buf_block_t *>(bpage);
ut_ad(block->in_unzip_LRU_list);
ut_d(block->in_unzip_LRU_list = FALSE);
UT_LIST_REMOVE(buf_pool->unzip_LRU, block);
}
}
/** Adjust LRU hazard pointers if needed. */
void buf_LRU_adjust_hp(buf_pool_t *buf_pool, /*!< in: buffer pool instance */
const buf_page_t *bpage) /*!< in: control block */
{
buf_pool->lru_hp.adjust(bpage);
buf_pool->lru_scan_itr.adjust(bpage);
buf_pool->single_scan_itr.adjust(bpage);
}
/** Removes a block from the LRU list.
@param[in] bpage control block */
UNIV_INLINE
void buf_LRU_remove_block(buf_page_t *bpage) {
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_a(buf_page_in_file(bpage));
ut_ad(bpage->in_LRU_list);
/* Important that we adjust the hazard pointers before removing
bpage from the LRU list. */
buf_LRU_adjust_hp(buf_pool, bpage);
/* If the LRU_old pointer is defined and points to just this block,
move it backward one step */
if (bpage == buf_pool->LRU_old) {
/* Below: the previous block is guaranteed to exist,
because the LRU_old pointer is only allowed to differ
by BUF_LRU_OLD_TOLERANCE from strict
buf_pool->LRU_old_ratio/BUF_LRU_OLD_RATIO_DIV of the LRU
list length. */
buf_page_t *prev_bpage = UT_LIST_GET_PREV(LRU, bpage);
ut_a(prev_bpage);
#ifdef UNIV_LRU_DEBUG
ut_a(!prev_bpage->old);
#endif /* UNIV_LRU_DEBUG */
buf_pool->LRU_old = prev_bpage;
buf_page_set_old(prev_bpage, TRUE);
buf_pool->LRU_old_len++;
}
/* Remove the block from the LRU list */
UT_LIST_REMOVE(buf_pool->LRU, bpage);
ut_d(bpage->in_LRU_list = FALSE);
buf_pool->stat.LRU_bytes -= bpage->size.physical();
buf_unzip_LRU_remove_block_if_needed(bpage);
/* If the LRU list is so short that LRU_old is not defined,
clear the "old" flags and return */
if (UT_LIST_GET_LEN(buf_pool->LRU) < BUF_LRU_OLD_MIN_LEN) {
for (buf_page_t *bpage = UT_LIST_GET_FIRST(buf_pool->LRU); bpage != NULL;
bpage = UT_LIST_GET_NEXT(LRU, bpage)) {
/* This loop temporarily violates the
assertions of buf_page_set_old(). */
bpage->old = FALSE;
}
buf_pool->LRU_old = NULL;
buf_pool->LRU_old_len = 0;
return;
}
ut_ad(buf_pool->LRU_old);
/* Update the LRU_old_len field if necessary */
if (buf_page_is_old(bpage)) {
buf_pool->LRU_old_len--;
}
/* Adjust the length of the old block list if necessary */
buf_LRU_old_adjust_len(buf_pool);
}
/** Adds a block to the LRU list of decompressed zip pages.
@param[in] block control block
@param[in] old TRUE if should be put to the end of the list,
else put to the start */
void buf_unzip_LRU_add_block(buf_block_t *block, ibool old) {
buf_pool_t *buf_pool = buf_pool_from_block(block);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_a(buf_page_belongs_to_unzip_LRU(&block->page));
ut_ad(!block->in_unzip_LRU_list);
ut_d(block->in_unzip_LRU_list = TRUE);
if (old) {
UT_LIST_ADD_LAST(buf_pool->unzip_LRU, block);
} else {
UT_LIST_ADD_FIRST(buf_pool->unzip_LRU, block);
}
}
/** Adds a block to the LRU list. Please make sure that the page_size is
already set when invoking the function, so that we can get correct
page_size from the buffer page when adding a block into LRU
@param[in] bpage control block
@param[in] old TRUE if should be put to the old blocks in the LRU list,
else put to the start; if the LRU list is very short,
the block is added to the start, regardless of this
parameter */
UNIV_INLINE
void buf_LRU_add_block_low(buf_page_t *bpage, ibool old) {
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_a(buf_page_in_file(bpage));
ut_ad(!bpage->in_LRU_list);
if (!old || (UT_LIST_GET_LEN(buf_pool->LRU) < BUF_LRU_OLD_MIN_LEN)) {
UT_LIST_ADD_FIRST(buf_pool->LRU, bpage);
bpage->freed_page_clock = buf_pool->freed_page_clock;
} else {
#ifdef UNIV_LRU_DEBUG
/* buf_pool->LRU_old must be the first item in the LRU list
whose "old" flag is set. */
ut_a(buf_pool->LRU_old->old);
ut_a(!UT_LIST_GET_PREV(LRU, buf_pool->LRU_old) ||
!UT_LIST_GET_PREV(LRU, buf_pool->LRU_old)->old);
ut_a(!UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old) ||
UT_LIST_GET_NEXT(LRU, buf_pool->LRU_old)->old);
#endif /* UNIV_LRU_DEBUG */
UT_LIST_INSERT_AFTER(buf_pool->LRU, buf_pool->LRU_old, bpage);
buf_pool->LRU_old_len++;
}
ut_d(bpage->in_LRU_list = TRUE);
incr_LRU_size_in_bytes(bpage, buf_pool);
if (UT_LIST_GET_LEN(buf_pool->LRU) > BUF_LRU_OLD_MIN_LEN) {
ut_ad(buf_pool->LRU_old);
/* Adjust the length of the old block list if necessary */
buf_page_set_old(bpage, old);
buf_LRU_old_adjust_len(buf_pool);
} else if (UT_LIST_GET_LEN(buf_pool->LRU) == BUF_LRU_OLD_MIN_LEN) {
/* The LRU list is now long enough for LRU_old to become
defined: init it */
buf_LRU_old_init(buf_pool);
} else {
buf_page_set_old(bpage, buf_pool->LRU_old != NULL);
}
/* If this is a zipped block with decompressed frame as well
then put it on the unzip_LRU list */
if (buf_page_belongs_to_unzip_LRU(bpage)) {
buf_unzip_LRU_add_block((buf_block_t *)bpage, old);
}
}
/** Adds a block to the LRU list. Please make sure that the page_size is
already set when invoking the function, so that we can get correct
page_size from the buffer page when adding a block into LRU */
void buf_LRU_add_block(buf_page_t *bpage, /*!< in: control block */
ibool old) /*!< in: TRUE if should be put to the old
blocks in the LRU list, else put to the start;
if the LRU list is very short, the block is
added to the start, regardless of this
parameter */
{
buf_LRU_add_block_low(bpage, old);
}
/** Moves a block to the start of the LRU list.
@param[in] bpage control block */
void buf_LRU_make_block_young(buf_page_t *bpage) {
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
if (bpage->old) {
buf_pool->stat.n_pages_made_young++;
}
buf_LRU_remove_block(bpage);
buf_LRU_add_block_low(bpage, FALSE);
}
/** Try to free a block. If bpage is a descriptor of a compressed-only
page, the descriptor object will be freed as well.
NOTE: this function may temporarily release and relock the
buf_page_get_get_mutex(). Furthermore, the page frame will no longer be
accessible via bpage. If this function returns true, it will also release
the LRU list mutex.
The caller must hold the LRU list and buf_page_get_mutex() mutexes.
@param[in] bpage block to be freed
@param[in] zip true if should remove also the compressed page of
an uncompressed page
@return true if freed, false otherwise. */
bool buf_LRU_free_page(buf_page_t *bpage, bool zip) {
buf_page_t *b = NULL;
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
rw_lock_t *hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id);
BPageMutex *block_mutex = buf_page_get_mutex(bpage);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_ad(mutex_own(block_mutex));
ut_ad(buf_page_in_file(bpage));
ut_ad(bpage->in_LRU_list);
if (!buf_page_can_relocate(bpage)) {
/* Do not free buffer fixed and I/O-fixed blocks. */
return (false);
}
#ifdef UNIV_IBUF_COUNT_DEBUG
ut_a(ibuf_count_get(bpage->id) == 0);
#endif /* UNIV_IBUF_COUNT_DEBUG */
if (zip || !bpage->zip.data) {
/* This would completely free the block. */
/* Do not completely free dirty blocks. */
if (bpage->oldest_modification) {
return (false);
}
} else if (bpage->oldest_modification > 0 &&
buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) {
ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_DIRTY);
return (false);
} else if (buf_page_get_state(bpage) == BUF_BLOCK_FILE_PAGE) {
b = buf_page_alloc_descriptor();
ut_a(b);
}
ut_ad(buf_page_in_file(bpage));
ut_ad(bpage->in_LRU_list);
ut_ad(!bpage->in_flush_list == !bpage->oldest_modification);
DBUG_PRINT("ib_buf", ("free page " UINT32PF ":" UINT32PF, bpage->id.space(),
bpage->id.page_no()));
mutex_exit(block_mutex);
rw_lock_x_lock(hash_lock);
mutex_enter(block_mutex);
if (!buf_page_can_relocate(bpage) ||
((zip || bpage->zip.data == NULL) && bpage->oldest_modification > 0)) {
not_freed:
rw_lock_x_unlock(hash_lock);
if (b != NULL) {
buf_page_free_descriptor(b);
}
return (false);
} else if (bpage->oldest_modification > 0 &&
buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) {
ut_ad(buf_page_get_state(bpage) == BUF_BLOCK_ZIP_DIRTY);
goto not_freed;
} else if (b != NULL) {
new (b) buf_page_t(*bpage);
}
ut_ad(rw_lock_own(hash_lock, RW_LOCK_X));
ut_ad(buf_page_can_relocate(bpage));
lizard::page_evit_stat(bpage);
if (!buf_LRU_block_remove_hashed(bpage, zip, false)) {
mutex_exit(&buf_pool->LRU_list_mutex);
if (b != NULL) {
buf_page_free_descriptor(b);
}
return (true);
}
/* buf_LRU_block_remove_hashed() releases the hash_lock */
ut_ad(!rw_lock_own(hash_lock, RW_LOCK_X) &&
!rw_lock_own(hash_lock, RW_LOCK_S));
/* We have just freed a BUF_BLOCK_FILE_PAGE. If b != NULL
then it was a compressed page with an uncompressed frame and
we are interested in freeing only the uncompressed frame.
Therefore we have to reinsert the compressed page descriptor
into the LRU and page_hash (and possibly flush_list).
if b == NULL then it was a regular page that has been freed */
if (b != NULL) {
buf_page_t *prev_b = UT_LIST_GET_PREV(LRU, b);
rw_lock_x_lock(hash_lock);
mutex_enter(block_mutex);
ut_a(!buf_page_hash_get_low(buf_pool, b->id));
b->state =
b->oldest_modification ? BUF_BLOCK_ZIP_DIRTY : BUF_BLOCK_ZIP_PAGE;
ut_ad(b->size.is_compressed());
UNIV_MEM_DESC(b->zip.data, b->size.physical());
/* The fields in_page_hash and in_LRU_list of
the to-be-freed block descriptor should have
been cleared in
buf_LRU_block_remove_hashed(), which
invokes buf_LRU_remove_block(). */
ut_ad(!bpage->in_page_hash);
ut_ad(!bpage->in_LRU_list);
/* bpage->state was BUF_BLOCK_FILE_PAGE because
b != NULL. The type cast below is thus valid. */
ut_ad(!((buf_block_t *)bpage)->in_unzip_LRU_list);
/* The fields of bpage were copied to b before
buf_LRU_block_remove_hashed() was invoked. */
ut_ad(!b->in_zip_hash);
ut_ad(b->in_page_hash);
ut_ad(b->in_LRU_list);
HASH_INSERT(buf_page_t, hash, buf_pool->page_hash, b->id.fold(), b);
/* Insert b where bpage was in the LRU list. */
if (prev_b != NULL) {
ulint lru_len;
ut_ad(prev_b->in_LRU_list);
ut_ad(buf_page_in_file(prev_b));
UT_LIST_INSERT_AFTER(buf_pool->LRU, prev_b, b);
incr_LRU_size_in_bytes(b, buf_pool);
if (buf_page_is_old(b)) {
buf_pool->LRU_old_len++;
if (buf_pool->LRU_old == UT_LIST_GET_NEXT(LRU, b)) {
buf_pool->LRU_old = b;
}
}
lru_len = UT_LIST_GET_LEN(buf_pool->LRU);
if (lru_len > BUF_LRU_OLD_MIN_LEN) {
ut_ad(buf_pool->LRU_old);
/* Adjust the length of the
old block list if necessary */
buf_LRU_old_adjust_len(buf_pool);
} else if (lru_len == BUF_LRU_OLD_MIN_LEN) {
/* The LRU list is now long
enough for LRU_old to become
defined: init it */
buf_LRU_old_init(buf_pool);
}
#ifdef UNIV_LRU_DEBUG
/* Check that the "old" flag is consistent
in the block and its neighbours. */
buf_page_set_old(b, buf_page_is_old(b));
#endif /* UNIV_LRU_DEBUG */
} else {
ut_d(b->in_LRU_list = FALSE);
buf_LRU_add_block_low(b, buf_page_is_old(b));
}
mutex_enter(&buf_pool->zip_mutex);
rw_lock_x_unlock(hash_lock);
if (b->state == BUF_BLOCK_ZIP_PAGE) {
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
buf_LRU_insert_zip_clean(b);
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
} else {
/* Relocate on buf_pool->flush_list. */
buf_flush_relocate_on_flush_list(bpage, b);
}
bpage->zip.data = NULL;
page_zip_set_size(&bpage->zip, 0);
bpage->size.copy_from(
page_size_t(bpage->size.logical(), bpage->size.logical(), false));
/* Prevent buf_page_get_gen() from
decompressing the block while we release block_mutex. */
buf_page_set_sticky(b);
mutex_exit(&buf_pool->zip_mutex);
mutex_exit(block_mutex);
}
mutex_exit(&buf_pool->LRU_list_mutex);
/* Remove possible adaptive hash index on the page.
The page was declared uninitialized by
buf_LRU_block_remove_hashed(). We need to flag
the contents of the page valid (which it still is) in
order to avoid bogus Valgrind warnings.*/
UNIV_MEM_VALID(((buf_block_t *)bpage)->frame, UNIV_PAGE_SIZE);
btr_search_drop_page_hash_index((buf_block_t *)bpage);
UNIV_MEM_INVALID(((buf_block_t *)bpage)->frame, UNIV_PAGE_SIZE);
if (b != NULL) {
/* Compute and stamp the compressed page
checksum while not holding any mutex. The
block is already half-freed
(BUF_BLOCK_REMOVE_HASH) and removed from
buf_pool->page_hash, thus inaccessible by any
other thread. */
ut_ad(b->size.is_compressed());
BlockReporter reporter = BlockReporter(false, b->zip.data, b->size, false);
const uint32_t checksum = reporter.calc_zip_checksum(
static_cast<srv_checksum_algorithm_t>(srv_checksum_algorithm));
mach_write_to_4(b->zip.data + FIL_PAGE_SPACE_OR_CHKSUM, checksum);
}
if (b != NULL) {
mutex_enter(&buf_pool->zip_mutex);
buf_page_unset_sticky(b);
mutex_exit(&buf_pool->zip_mutex);
}
buf_LRU_block_free_hashed_page((buf_block_t *)bpage);
return (true);
}
/** Puts a block back to the free list.
@param[in] block block must not contain a file page */
void buf_LRU_block_free_non_file_page(buf_block_t *block) {
void *data;
buf_pool_t *buf_pool = buf_pool_from_block(block);
switch (buf_block_get_state(block)) {
case BUF_BLOCK_MEMORY:
case BUF_BLOCK_READY_FOR_USE:
break;
default:
ut_error;
}
assert_block_ahi_empty(block);
ut_ad(!block->page.in_free_list);
ut_ad(!block->page.in_flush_list);
ut_ad(!block->page.in_LRU_list);
#ifdef UNIV_DEBUG
/* Wipe contents of page to reveal possible stale pointers to it */
memset(block->frame, '\0', UNIV_PAGE_SIZE);
#else
/* Wipe page_no and space_id */
memset(block->frame + FIL_PAGE_OFFSET, 0xfe, 4);
memset(block->frame + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID, 0xfe, 4);
#endif /* UNIV_DEBUG */
UNIV_MEM_ASSERT_AND_FREE(block->frame, UNIV_PAGE_SIZE);
data = block->page.zip.data;
if (data != NULL) {
block->page.zip.data = NULL;
ut_ad(block->page.size.is_compressed());
buf_buddy_free(buf_pool, data, block->page.size.physical());
page_zip_set_size(&block->page.zip, 0);
block->page.size.copy_from(page_size_t(block->page.size.logical(),
block->page.size.logical(), false));
}
lizard::deallocate_block_tcn(block);
if (buf_get_withdraw_depth(buf_pool) &&
buf_block_will_withdrawn(buf_pool, block)) {
/* This should be withdrawn */
buf_block_set_state(block, BUF_BLOCK_NOT_USED);
mutex_enter(&buf_pool->free_list_mutex);
UT_LIST_ADD_LAST(buf_pool->withdraw, &block->page);
ut_d(block->in_withdraw_list = TRUE);
mutex_exit(&buf_pool->free_list_mutex);
} else {
buf_block_set_state(block, BUF_BLOCK_NOT_USED);
mutex_enter(&buf_pool->free_list_mutex);
UT_LIST_ADD_FIRST(buf_pool->free, &block->page);
ut_d(block->page.in_free_list = TRUE);
mutex_exit(&buf_pool->free_list_mutex);
}
}
/** Takes a block out of the LRU list and page hash table.
If the block is compressed-only (BUF_BLOCK_ZIP_PAGE),
the object will be freed.
The caller must hold buf_pool->LRU_list_mutex, the buf_page_get_mutex() mutex
and the appropriate hash_lock. This function will release the
buf_page_get_mutex() and the hash_lock.
If a compressed page is freed other compressed pages may be relocated.
@param[in] bpage block, must contain a file page and
be in a state where it can be freed; there
may or may not be a hash index to the page
@param[in] zip true if should remove also the
compressed page of an uncompressed page
@param[in] ignore_content true if should ignore page content, since it
could be not initialized
@retval true if BUF_BLOCK_FILE_PAGE was removed from page_hash. The
caller needs to free the page to the free list
@retval false if BUF_BLOCK_ZIP_PAGE was removed from page_hash. In
this case the block is already returned to the buddy allocator. */
static bool buf_LRU_block_remove_hashed(buf_page_t *bpage, bool zip,
bool ignore_content) {
const buf_page_t *hashed_bpage;
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
rw_lock_t *hash_lock;
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_ad(mutex_own(buf_page_get_mutex(bpage)));
hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id);
ut_ad(rw_lock_own(hash_lock, RW_LOCK_X));
ut_a(buf_page_get_io_fix(bpage) == BUF_IO_NONE);
ut_a(bpage->buf_fix_count == 0);
buf_LRU_remove_block(bpage);
buf_pool->freed_page_clock += 1;
switch (buf_page_get_state(bpage)) {
case BUF_BLOCK_FILE_PAGE: {
UNIV_MEM_ASSERT_W(bpage, sizeof(buf_block_t));
UNIV_MEM_ASSERT_W(((buf_block_t *)bpage)->frame, UNIV_PAGE_SIZE);
buf_block_modify_clock_inc((buf_block_t *)bpage);
if (bpage->zip.data != NULL) {
const page_t *page = ((buf_block_t *)bpage)->frame;
ut_a(!zip || bpage->oldest_modification == 0);
ut_ad(bpage->size.is_compressed());
if (ignore_content) {
break;
}
switch (fil_page_get_type(page)) {
case FIL_PAGE_TYPE_ALLOCATED:
case FIL_PAGE_INODE:
case FIL_PAGE_IBUF_BITMAP:
case FIL_PAGE_TYPE_FSP_HDR:
case FIL_PAGE_TYPE_XDES:
case FIL_PAGE_TYPE_ZLOB_FIRST:
case FIL_PAGE_TYPE_ZLOB_DATA:
case FIL_PAGE_TYPE_ZLOB_INDEX:
case FIL_PAGE_TYPE_ZLOB_FRAG:
case FIL_PAGE_TYPE_ZLOB_FRAG_ENTRY:
/* These are essentially uncompressed pages. */
if (!zip) {
/* InnoDB writes the data to the
uncompressed page frame. Copy it
to the compressed page, which will
be preserved. */
memcpy(bpage->zip.data, page, bpage->size.physical());
}
break;
case FIL_PAGE_TYPE_ZBLOB:
case FIL_PAGE_TYPE_ZBLOB2:
case FIL_PAGE_SDI_ZBLOB:
break;
case FIL_PAGE_INDEX:
case FIL_PAGE_SDI:
case FIL_PAGE_RTREE:
#ifdef UNIV_ZIP_DEBUG
ut_a(page_zip_validate(&bpage->zip, page,
((buf_block_t *)bpage)->index));
#endif /* UNIV_ZIP_DEBUG */
break;
default:
ib::error(ER_IB_MSG_135) << "The compressed page to be"
" evicted seems corrupt:";
ut_print_buf(stderr, page, bpage->size.logical());
ib::error(ER_IB_MSG_136) << "Possibly older version of"
" the page:";
ut_print_buf(stderr, bpage->zip.data, bpage->size.physical());
putc('\n', stderr);
ut_error;
}
break;
}
if (!ignore_content) {
/* Account the eviction of index leaf pages from
the buffer pool(s). */
const byte *frame = bpage->zip.data != NULL
? bpage->zip.data
: reinterpret_cast<buf_block_t *>(bpage)->frame;
const ulint type = fil_page_get_type(frame);
if ((type == FIL_PAGE_INDEX || type == FIL_PAGE_RTREE) &&
page_is_leaf(frame)) {
uint32_t space_id = bpage->id.space();
space_index_t idx_id = btr_page_get_index_id(frame);
buf_stat_per_index->dec(index_id_t(space_id, idx_id));
}
}
}
/* fall through */
case BUF_BLOCK_ZIP_PAGE:
ut_a(bpage->oldest_modification == 0);
if (bpage->size.is_compressed()) {
UNIV_MEM_ASSERT_W(bpage->zip.data, bpage->size.physical());
}
break;
case BUF_BLOCK_POOL_WATCH:
case BUF_BLOCK_ZIP_DIRTY:
case BUF_BLOCK_NOT_USED:
case BUF_BLOCK_READY_FOR_USE:
case BUF_BLOCK_MEMORY:
case BUF_BLOCK_REMOVE_HASH:
ut_error;
break;
}
hashed_bpage = buf_page_hash_get_low(buf_pool, bpage->id);
if (bpage != hashed_bpage) {
ib::error(ER_IB_MSG_137)
<< "Page " << bpage->id << " not found in the hash table";
if (hashed_bpage) {
ib::error(ER_IB_MSG_138)
<< "In hash table we find block " << hashed_bpage << " of "
<< hashed_bpage->id << " which is not " << bpage;
}
ut_d(mutex_exit(buf_page_get_mutex(bpage)));
ut_d(rw_lock_x_unlock(hash_lock));
ut_d(mutex_exit(&buf_pool->LRU_list_mutex));
ut_d(buf_print());
ut_d(buf_LRU_print());
ut_d(buf_validate());
ut_d(buf_LRU_validate());
ut_ad(0);
}
ut_ad(!bpage->in_zip_hash);
ut_ad(bpage->in_page_hash);
ut_d(bpage->in_page_hash = FALSE);
HASH_DELETE(buf_page_t, hash, buf_pool->page_hash, bpage->id.fold(), bpage);
switch (buf_page_get_state(bpage)) {
case BUF_BLOCK_ZIP_PAGE:
ut_ad(!bpage->in_free_list);
ut_ad(!bpage->in_flush_list);
ut_ad(!bpage->in_LRU_list);
ut_a(bpage->zip.data);
ut_a(bpage->size.is_compressed());
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
UT_LIST_REMOVE(buf_pool->zip_clean, bpage);
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
mutex_exit(&buf_pool->zip_mutex);
rw_lock_x_unlock(hash_lock);
buf_buddy_free(buf_pool, bpage->zip.data, bpage->size.physical());
buf_page_free_descriptor(bpage);
return (false);
case BUF_BLOCK_FILE_PAGE:
memset(((buf_block_t *)bpage)->frame + FIL_PAGE_OFFSET, 0xff, 4);
memset(((buf_block_t *)bpage)->frame + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID,
0xff, 4);
UNIV_MEM_INVALID(((buf_block_t *)bpage)->frame, UNIV_PAGE_SIZE);
buf_page_set_state(bpage, BUF_BLOCK_REMOVE_HASH);
/* Question: If we release bpage and hash mutex here
then what protects us against:
1) Some other thread buffer fixing this page
2) Some other thread trying to read this page and
not finding it in buffer pool attempting to read it
from the disk.
Answer:
1) Cannot happen because the page is no longer in the
page_hash. Only possibility is when while invalidating
a tablespace we buffer fix the prev_page in LRU to
avoid relocation during the scan. But that is not
possible because we are holding LRU list mutex.
2) Not possible because in buf_page_init_for_read()
we do a look up of page_hash while holding LRU list
mutex and since we are holding LRU list mutex here
and by the time we'll release it in the caller we'd
have inserted the compressed only descriptor in the
page_hash. */
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
rw_lock_x_unlock(hash_lock);
mutex_exit(&((buf_block_t *)bpage)->mutex);
if (zip && bpage->zip.data) {
/* Free the compressed page. */
void *data = bpage->zip.data;
bpage->zip.data = NULL;
ut_ad(!bpage->in_free_list);
ut_ad(!bpage->in_flush_list);
ut_ad(!bpage->in_LRU_list);
buf_buddy_free(buf_pool, data, bpage->size.physical());
page_zip_set_size(&bpage->zip, 0);
bpage->size.copy_from(
page_size_t(bpage->size.logical(), bpage->size.logical(), false));
}
return (true);
case BUF_BLOCK_POOL_WATCH:
case BUF_BLOCK_ZIP_DIRTY:
case BUF_BLOCK_NOT_USED:
case BUF_BLOCK_READY_FOR_USE:
case BUF_BLOCK_MEMORY:
case BUF_BLOCK_REMOVE_HASH:
break;
}
ut_error;
}
/** Puts a file page whose has no hash index to the free list. */
static void 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 */
{
buf_pool_t *buf_pool = buf_pool_from_block(block);
if (buf_pool->flush_rbt == NULL) {
block->page.id.reset(UINT32_UNDEFINED, UINT32_UNDEFINED);
}
buf_block_set_state(block, BUF_BLOCK_MEMORY);
buf_LRU_block_free_non_file_page(block);
}
/** Remove one page from LRU list and put it to free list. The caller must hold
the LRU list and block mutexes and have page hash latched in X. The latch and
the block mutexes will be released.
@param[in,out] bpage block, must contain a file page and
be in a state where it can be freed; there
may or may not be a hash index to the page
@param[in] zip true if should remove also the compressed page
of an uncompressed page
@param[in] ignore_content true if should ignore page content, since it
could be not initialized */
void buf_LRU_free_one_page(buf_page_t *bpage, bool zip, bool ignore_content) {
#ifdef UNIV_DEBUG
buf_pool_t *buf_pool = buf_pool_from_bpage(bpage);
BPageMutex *block_mutex = buf_page_get_mutex(bpage);
rw_lock_t *hash_lock = buf_page_hash_lock_get(buf_pool, bpage->id);
ut_ad(mutex_own(&buf_pool->LRU_list_mutex));
ut_ad(mutex_own(block_mutex));
ut_ad(rw_lock_own(hash_lock, RW_LOCK_X));
#endif /* UNIV_DEBUG */
if (buf_LRU_block_remove_hashed(bpage, true, ignore_content)) {
buf_LRU_block_free_hashed_page((buf_block_t *)bpage);
}
/* buf_LRU_block_remove_hashed() releases hash_lock and block_mutex */
ut_ad(!rw_lock_own(hash_lock, RW_LOCK_X) &&
!rw_lock_own(hash_lock, RW_LOCK_S));
ut_ad(!mutex_own(block_mutex));
}
/** Updates buf_pool->LRU_old_ratio for one buffer pool instance.
@param[in] buf_pool buffer pool instance
@param[in] old_pct Reserve this percentage of
the buffer pool for "old" blocks
@param[in] adjust TRUE=adjust the LRU list;
FALSE=just assign buf_pool->LRU_old_ratio
during the initialization of InnoDB
@return updated old_pct */
static uint buf_LRU_old_ratio_update_instance(buf_pool_t *buf_pool,
uint old_pct, ibool adjust) {
uint ratio;
ratio = old_pct * BUF_LRU_OLD_RATIO_DIV / 100;
if (ratio < BUF_LRU_OLD_RATIO_MIN) {
ratio = BUF_LRU_OLD_RATIO_MIN;
} else if (ratio > BUF_LRU_OLD_RATIO_MAX) {
ratio = BUF_LRU_OLD_RATIO_MAX;
}
if (adjust) {
mutex_enter(&buf_pool->LRU_list_mutex);
if (ratio != buf_pool->LRU_old_ratio) {
buf_pool->LRU_old_ratio = ratio;
if (UT_LIST_GET_LEN(buf_pool->LRU) >= BUF_LRU_OLD_MIN_LEN) {
buf_LRU_old_adjust_len(buf_pool);
}
}
mutex_exit(&buf_pool->LRU_list_mutex);
} else {
buf_pool->LRU_old_ratio = ratio;
}
/* the reverse of
ratio = old_pct * BUF_LRU_OLD_RATIO_DIV / 100 */
return ((uint)(ratio * 100 / (double)BUF_LRU_OLD_RATIO_DIV + 0.5));
}
/** Updates buf_pool->LRU_old_ratio.
@return updated old_pct */
uint buf_LRU_old_ratio_update(
uint old_pct, /*!< in: Reserve this percentage of
the buffer pool for "old" blocks. */
ibool adjust) /*!< in: TRUE=adjust the LRU list;
FALSE=just assign buf_pool->LRU_old_ratio
during the initialization of InnoDB */
{
uint new_ratio = 0;
for (ulint i = 0; i < srv_buf_pool_instances; i++) {
buf_pool_t *buf_pool;
buf_pool = buf_pool_from_array(i);
new_ratio = buf_LRU_old_ratio_update_instance(buf_pool, old_pct, adjust);
}
return (new_ratio);
}
/** Update the historical stats that we are collecting for LRU eviction
policy at the end of each interval. */
void buf_LRU_stat_update(void) {
buf_LRU_stat_t *item;
buf_pool_t *buf_pool;
bool evict_started = FALSE;
buf_LRU_stat_t cur_stat;
/* If we haven't started eviction yet then don't update stats. */
os_rmb;
for (ulint i = 0; i < srv_buf_pool_instances; i++) {
buf_pool = buf_pool_from_array(i);
if (buf_pool->freed_page_clock != 0) {
evict_started = true;
break;
}
}
if (!evict_started) {
goto func_exit;
}
/* Update the index. */
item = &buf_LRU_stat_arr[buf_LRU_stat_arr_ind];
buf_LRU_stat_arr_ind++;
buf_LRU_stat_arr_ind %= BUF_LRU_STAT_N_INTERVAL;
/* Add the current value and subtract the obsolete entry.
Since buf_LRU_stat_cur is not protected by any mutex,
it can be changing between adding to buf_LRU_stat_sum
and copying to item. Assign it to local variables to make
sure the same value assign to the buf_LRU_stat_sum
and item */
cur_stat = buf_LRU_stat_cur;
buf_LRU_stat_sum.io += cur_stat.io - item->io;
buf_LRU_stat_sum.unzip += cur_stat.unzip - item->unzip;
/* Put current entry in the array. */
memcpy(item, &cur_stat, sizeof *item);
func_exit:
/* Clear the current entry. */
memset(&buf_LRU_stat_cur, 0, sizeof buf_LRU_stat_cur);
os_wmb;
}
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/** Validates the LRU list for one buffer pool instance.
@param[in] buf_pool buffer pool instance */
static void buf_LRU_validate_instance(buf_pool_t *buf_pool) {
ulint old_len;
ulint new_len;
mutex_enter(&buf_pool->LRU_list_mutex);
if (UT_LIST_GET_LEN(buf_pool->LRU) >= BUF_LRU_OLD_MIN_LEN) {
ut_a(buf_pool->LRU_old);
old_len = buf_pool->LRU_old_len;
new_len = ut_min(UT_LIST_GET_LEN(buf_pool->LRU) * buf_pool->LRU_old_ratio /
BUF_LRU_OLD_RATIO_DIV,
UT_LIST_GET_LEN(buf_pool->LRU) -
(BUF_LRU_OLD_TOLERANCE + BUF_LRU_NON_OLD_MIN_LEN));
ut_a(old_len >= new_len - BUF_LRU_OLD_TOLERANCE);
ut_a(old_len <= new_len + BUF_LRU_OLD_TOLERANCE);
}
CheckInLRUList::validate(buf_pool);
old_len = 0;
for (buf_page_t *bpage = UT_LIST_GET_FIRST(buf_pool->LRU); bpage != NULL;
bpage = UT_LIST_GET_NEXT(LRU, bpage)) {
switch (buf_page_get_state(bpage)) {
case BUF_BLOCK_POOL_WATCH:
case BUF_BLOCK_NOT_USED:
case BUF_BLOCK_READY_FOR_USE:
case BUF_BLOCK_MEMORY:
case BUF_BLOCK_REMOVE_HASH:
ut_error;
break;
case BUF_BLOCK_FILE_PAGE:
ut_ad(((buf_block_t *)bpage)->in_unzip_LRU_list ==
buf_page_belongs_to_unzip_LRU(bpage));
case BUF_BLOCK_ZIP_PAGE:
case BUF_BLOCK_ZIP_DIRTY:
break;
}
if (buf_page_is_old(bpage)) {
const buf_page_t *prev = UT_LIST_GET_PREV(LRU, bpage);
const buf_page_t *next = UT_LIST_GET_NEXT(LRU, bpage);
if (!old_len++) {
ut_a(buf_pool->LRU_old == bpage);
} else {
ut_a(!prev || buf_page_is_old(prev));
}
ut_a(!next || buf_page_is_old(next));
}
}
ut_a(buf_pool->LRU_old_len == old_len);
mutex_exit(&buf_pool->LRU_list_mutex);
mutex_enter(&buf_pool->free_list_mutex);
CheckInFreeList::validate(buf_pool);
for (buf_page_t *bpage = UT_LIST_GET_FIRST(buf_pool->free); bpage != NULL;
bpage = UT_LIST_GET_NEXT(list, bpage)) {
ut_a(buf_page_get_state(bpage) == BUF_BLOCK_NOT_USED);
}
mutex_exit(&buf_pool->free_list_mutex);
mutex_enter(&buf_pool->LRU_list_mutex);
CheckUnzipLRUAndLRUList::validate(buf_pool);
for (buf_block_t *block = UT_LIST_GET_FIRST(buf_pool->unzip_LRU);
block != NULL; block = UT_LIST_GET_NEXT(unzip_LRU, block)) {
ut_ad(block->in_unzip_LRU_list);
ut_ad(block->page.in_LRU_list);
ut_a(buf_page_belongs_to_unzip_LRU(&block->page));
}
mutex_exit(&buf_pool->LRU_list_mutex);
}
/** Validates the LRU list.
@return true */
ibool buf_LRU_validate(void) {
for (ulint i = 0; i < srv_buf_pool_instances; i++) {
buf_pool_t *buf_pool;
buf_pool = buf_pool_from_array(i);
buf_LRU_validate_instance(buf_pool);
}
return (TRUE);
}
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
#if defined UNIV_DEBUG_PRINT || defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/** Prints the LRU list for one buffer pool instance.
@param[in] buf_pool buffer pool instance */
static void buf_LRU_print_instance(buf_pool_t *buf_pool) {
mutex_enter(&buf_pool->LRU_list_mutex);
for (const buf_page_t *bpage = UT_LIST_GET_FIRST(buf_pool->LRU);
bpage != NULL; bpage = UT_LIST_GET_NEXT(LRU, bpage)) {
mutex_enter(buf_page_get_mutex(bpage));
fprintf(stderr, "BLOCK space " UINT32PF " page " UINT32PF " ",
bpage->id.space(), bpage->id.page_no());
if (buf_page_is_old(bpage)) {
fputs("old ", stderr);
}
if (bpage->buf_fix_count) {
fprintf(stderr, "buffix count %lu ", (ulong)bpage->buf_fix_count);
}
if (buf_page_get_io_fix(bpage)) {
fprintf(stderr, "io_fix %lu ", (ulong)buf_page_get_io_fix(bpage));
}
if (bpage->oldest_modification) {
fputs("modif. ", stderr);
}
switch (buf_page_get_state(bpage)) {
const byte *frame;
case BUF_BLOCK_FILE_PAGE:
frame = buf_block_get_frame((buf_block_t *)bpage);
fprintf(stderr,
"\ntype %lu"
" index id " IB_ID_FMT "\n",
(ulong)fil_page_get_type(frame), btr_page_get_index_id(frame));
break;
case BUF_BLOCK_ZIP_PAGE:
frame = bpage->zip.data;
fprintf(stderr,
"\ntype %lu size %lu"
" index id " IB_ID_FMT "\n",
(ulong)fil_page_get_type(frame), (ulong)bpage->size.physical(),
btr_page_get_index_id(frame));
break;
default:
fprintf(stderr, "\n!state %lu!\n", (ulong)buf_page_get_state(bpage));
break;
}
mutex_exit(buf_page_get_mutex(bpage));
}
mutex_exit(&buf_pool->LRU_list_mutex);
}
/** Prints the LRU list. */
void buf_LRU_print(void) {
for (ulint i = 0; i < srv_buf_pool_instances; i++) {
buf_pool_t *buf_pool;
buf_pool = buf_pool_from_array(i);
buf_LRU_print_instance(buf_pool);
}
}
#endif /* UNIV_DEBUG_PRINT || UNIV_DEBUG || UNIV_BUF_DEBUG */
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