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mariadb/storage/innobase/buf/buf0lru.cc
Oleksandr Byelkin 4a3d51c76c Merge branch '10.2' into 10.3
2019-06-14 07:36:47 +02:00

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/*****************************************************************************
Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2017, 2019, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
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 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 Street, Fifth Floor, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file buf/buf0lru.cc
The database buffer replacement algorithm
Created 11/5/1995 Heikki Tuuri
*******************************************************/
#include "buf0lru.h"
#include "ut0byte.h"
#include "ut0rnd.h"
#include "sync0rw.h"
#include "hash0hash.h"
#include "os0event.h"
#include "fil0fil.h"
#include "btr0btr.h"
#include "buf0buddy.h"
#include "buf0buf.h"
#include "buf0dblwr.h"
#include "buf0flu.h"
#include "buf0rea.h"
#include "btr0sea.h"
#include "ibuf0ibuf.h"
#include "os0file.h"
#include "page0zip.h"
#include "log0recv.h"
#include "srv0srv.h"
#include "srv0mon.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. */
static const ulint BUF_LRU_OLD_TOLERANCE = 20;
/** 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
/** 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->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;
/** True if diagnostic message about difficult to find free blocks
in the buffer bool has already printed. */
static bool buf_lru_free_blocks_error_printed;
/******************************************************************//**
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->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.
@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, /*!< in: 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 */
bool zip); /*!< in: true if should remove also the
compressed page of an uncompressed page */
/******************************************************************//**
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 */
static inline
void
incr_LRU_size_in_bytes(
/*===================*/
buf_page_t* bpage, /*!< in: control block */
buf_pool_t* buf_pool) /*!< in: buffer pool instance */
{
ut_ad(buf_pool_mutex_own(buf_pool));
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.
@return TRUE if should use unzip_LRU */
ibool
buf_LRU_evict_from_unzip_LRU(
/*=========================*/
buf_pool_t* buf_pool)
{
ut_ad(buf_pool_mutex_own(buf_pool));
/* 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);
}
#ifdef BTR_CUR_HASH_ADAPT
/** 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] arr array of page_no
@param[in] count number of entries in array */
static
void
buf_LRU_drop_page_hash_batch(ulint space_id, const ulint* arr, ulint count)
{
ut_ad(count <= BUF_LRU_DROP_SEARCH_SIZE);
for (const ulint* const end = arr + count; arr != end; ) {
/* 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. */
btr_search_drop_page_hash_when_freed(
page_id_t(space_id, *arr++));
}
}
/******************************************************************//**
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(
/*==================================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
ulint id) /*!< in: space id */
{
ulint* page_arr = static_cast<ulint*>(ut_malloc_nokey(
sizeof(ulint) * BUF_LRU_DROP_SEARCH_SIZE));
ulint num_entries = 0;
buf_pool_mutex_enter(buf_pool);
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() != 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 buf_pool->mutex to obey
the latching order. */
buf_pool_mutex_exit(buf_pool);
buf_LRU_drop_page_hash_batch(id, page_arr, num_entries);
num_entries = 0;
buf_pool_mutex_enter(buf_pool);
/* Note that we released the buf_pool 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.
bpage->state is protected by buf_pool mutex. */
if (bpage != NULL
&& buf_page_get_state(bpage) != BUF_BLOCK_FILE_PAGE) {
goto scan_again;
}
}
buf_pool_mutex_exit(buf_pool);
/* Drop any remaining batch of search hashed pages. */
buf_LRU_drop_page_hash_batch(id, page_arr, num_entries);
ut_free(page_arr);
}
/** Try to drop the adaptive hash index for a tablespace.
@param[in,out] table table
@return whether anything was dropped */
bool buf_LRU_drop_page_hash_for_tablespace(dict_table_t* table)
{
for (dict_index_t* index = dict_table_get_first_index(table);
index != NULL;
index = dict_table_get_next_index(index)) {
if (btr_search_info_get_ref_count(btr_search_get_info(index),
index)) {
goto drop_ahi;
}
}
return false;
drop_ahi:
ulint id = table->space_id;
for (ulint i = 0; i < srv_buf_pool_instances; i++) {
buf_LRU_drop_page_hash_for_tablespace(buf_pool_from_array(i),
id);
}
return true;
}
#endif /* BTR_CUR_HASH_ADAPT */
/******************************************************************//**
While flushing (or removing dirty) pages from a tablespace we don't
want to hog the CPU and resources. Release the buffer pool and block
mutex 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. */
static
void
buf_flush_yield(
/*============*/
buf_pool_t* buf_pool, /*!< in/out: buffer pool instance */
buf_page_t* bpage) /*!< in/out: current page */
{
BPageMutex* block_mutex;
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(buf_page_in_file(bpage));
block_mutex = buf_page_get_mutex(bpage);
mutex_enter(block_mutex);
/* "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 buf_pool->mutex. */
buf_pool_mutex_exit(buf_pool);
mutex_exit(block_mutex);
/* Try and force a context switch. */
os_thread_yield();
buf_pool_mutex_enter(buf_pool);
mutex_enter(block_mutex);
/* "Unfix" the block now that we have both the
buffer pool and block mutex again. */
buf_page_unset_sticky(bpage);
mutex_exit(block_mutex);
}
/******************************************************************//**
If we have hogged the resources for too long then release the buffer
pool and flush list mutex 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 */
{
/* Every BUF_LRU_DROP_SEARCH_SIZE iterations in the
loop we release buf_pool->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(bpage) == BUF_IO_NONE) {
buf_flush_list_mutex_exit(buf_pool);
/* Release the buffer pool and block 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.
@return true if page was removed. */
static MY_ATTRIBUTE((warn_unused_result))
bool
buf_flush_or_remove_page(
/*=====================*/
buf_pool_t* buf_pool, /*!< in/out: buffer pool instance */
buf_page_t* bpage, /*!< in/out: bpage to remove */
bool flush) /*!< in: flush to disk if true but
don't remove else remove without
flushing to disk */
{
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(buf_flush_list_mutex_own(buf_pool));
/* bpage->space and bpage->io_fix are protected by
buf_pool->mutex and block_mutex. It is safe to check
them while holding buf_pool->mutex only. */
if (buf_page_get_io_fix(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;
bool processed = false;
block_mutex = buf_page_get_mutex(bpage);
/* We have to release the flush_list_mutex to obey the
latching order. We are however guaranteed that the page
will stay in the flush_list and won't be relocated because
buf_flush_remove() and buf_flush_relocate_on_flush_list()
need buf_pool->mutex as well. */
buf_flush_list_mutex_exit(buf_pool);
mutex_enter(block_mutex);
ut_ad(bpage->oldest_modification != 0);
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 buffer pool
and block mutex. */
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();
buf_pool_mutex_enter(buf_pool);
} 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(buf_pool_mutex_own(buf_pool));
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
@param[in] id tablespace identifier
@param[in] observer flush observer (to check for interrupt),
or NULL if the files should not be written to
@param[in] first first page to be flushed or evicted
@return whether all matching dirty pages were removed */
static MY_ATTRIBUTE((warn_unused_result))
bool
buf_flush_or_remove_pages(
buf_pool_t* buf_pool,
ulint id,
FlushObserver* observer,
ulint first)
{
buf_page_t* prev;
buf_page_t* bpage;
ulint processed = 0;
buf_flush_list_mutex_enter(buf_pool);
rescan:
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);
/* Flush the pages matching space id,
or pages matching the flush observer. */
if (observer && observer->is_partial_flush()) {
if (observer != bpage->flush_observer) {
/* Skip this block. */
} else if (!buf_flush_or_remove_page(
buf_pool, bpage,
!observer->is_interrupted())) {
all_freed = false;
} else if (!observer->is_interrupted()) {
/* The processing was successful. And during the
processing we have released the buf_pool mutex
when calling buf_page_flush(). We cannot trust
prev pointer. */
goto rescan;
}
} else if (id != bpage->id.space()) {
/* Skip this block, because it is for a
different tablespace. */
} else if (bpage->id.page_no() < first) {
/* Skip this block, because it is below the limit. */
} else if (!buf_flush_or_remove_page(
buf_pool, bpage, observer != NULL)) {
/* Remove was unsuccessful, we have to try again
by scanning the entire list from the end.
This also means that we never released the
buf_pool mutex. Therefore we can trust the prev
pointer.
buf_flush_or_remove_page() released the
flush list mutex but not the buf_pool 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 (observer) {
/* The processing was successful. And during the
processing we have released the buf_pool mutex
when calling buf_page_flush(). We cannot trust
prev pointer. */
goto rescan;
}
++processed;
/* Yield if we have hogged the CPU and mutexes for too long. */
if (buf_flush_try_yield(buf_pool, prev, processed)) {
/* 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 && observer) {
observer->check_interrupted();
}
}
buf_flush_list_mutex_exit(buf_pool);
return(all_freed);
}
/** 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
@param[in] id tablespace identifier
@param[in] observer flush observer,
or NULL if the files should not be written to
@param[in] first first page to be flushed or evicted */
static
void
buf_flush_dirty_pages(
buf_pool_t* buf_pool,
ulint id,
FlushObserver* observer,
ulint first)
{
for (;;) {
buf_pool_mutex_enter(buf_pool);
bool freed = buf_flush_or_remove_pages(buf_pool, id, observer,
first);
buf_pool_mutex_exit(buf_pool);
ut_ad(buf_flush_validate(buf_pool));
if (freed) {
break;
}
os_thread_sleep(2000);
ut_ad(buf_flush_validate(buf_pool));
}
ut_ad((observer && observer->is_interrupted())
|| first
|| buf_pool_get_dirty_pages_count(buf_pool, id, observer) == 0);
}
/** Empty the flush list for all pages belonging to a tablespace.
@param[in] id tablespace identifier
@param[in] observer flush observer,
or NULL if nothing is to be written
@param[in] first first page to be flushed or evicted */
void buf_LRU_flush_or_remove_pages(ulint id, FlushObserver* observer,
ulint first)
{
/* Pages in the system tablespace must never be discarded. */
ut_ad(id || observer);
for (ulint i = 0; i < srv_buf_pool_instances; i++) {
buf_flush_dirty_pages(buf_pool_from_array(i), id, observer,
first);
}
if (observer && !observer->is_interrupted()) {
/* Ensure that all asynchronous IO is completed. */
os_aio_wait_until_no_pending_writes();
fil_flush(id);
}
}
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/********************************************************************//**
Insert a compressed block into buf_pool->zip_clean in the LRU order. */
void
buf_LRU_insert_zip_clean(
/*=====================*/
buf_page_t* bpage) /*!< in: pointer to the block in question */
{
buf_pool_t* buf_pool = buf_pool_from_bpage(bpage);
ut_ad(buf_pool_mutex_own(buf_pool));
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.
@return true if freed */
static
bool
buf_LRU_free_from_unzip_LRU_list(
/*=============================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
bool scan_all) /*!< in: scan whole LRU list
if true, otherwise scan only
srv_LRU_scan_depth / 2 blocks. */
{
ut_ad(buf_pool_mutex_own(buf_pool));
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);
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);
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.
@return true if freed */
static
bool
buf_LRU_free_from_common_LRU_list(
/*==============================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
bool scan_all) /*!< in: scan whole LRU list
if true, otherwise scan only
up to BUF_LRU_SEARCH_SCAN_THRESHOLD */
{
ut_ad(buf_pool_mutex_own(buf_pool));
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);
mutex_enter(mutex);
ut_ad(buf_page_in_file(bpage));
ut_ad(bpage->in_LRU_list);
unsigned accessed = buf_page_is_accessed(bpage);
if (buf_flush_ready_for_replace(bpage)) {
mutex_exit(mutex);
freed = buf_LRU_free_page(bpage, true);
} else {
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(buf_pool_mutex_own(buf_pool));
ut_ad(!mutex_own(mutex));
}
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.
@return true if found and freed */
bool
buf_LRU_scan_and_free_block(
/*========================*/
buf_pool_t* buf_pool, /*!< in: buffer pool instance */
bool scan_all) /*!< in: scan whole LRU list
if true, otherwise scan only
BUF_LRU_SEARCH_SCAN_THRESHOLD
blocks. */
{
ut_ad(buf_pool_mutex_own(buf_pool));
return(buf_LRU_free_from_unzip_LRU_list(buf_pool, scan_all)
|| buf_LRU_free_from_common_LRU_list(buf_pool, scan_all));
}
/******************************************************************//**
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);
buf_pool_mutex_enter(buf_pool);
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;
}
buf_pool_mutex_exit(buf_pool);
}
return(ret);
}
/******************************************************************//**
Returns a free block from the buf_pool. The block is taken off the
free list. If it is empty, returns NULL.
@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;
ut_ad(buf_pool_mutex_own(buf_pool));
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);
if (buf_pool->curr_size >= buf_pool->old_size
|| UT_LIST_GET_LEN(buf_pool->withdraw)
>= buf_pool->withdraw_target
|| !buf_block_will_withdrawn(buf_pool, block)) {
/* found valid free block */
buf_page_mutex_enter(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, srv_page_size);
ut_ad(buf_pool_from_block(block) == buf_pool);
buf_page_mutex_exit(block);
break;
}
/* This should be withdrawn */
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));
}
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 */
{
ut_ad(buf_pool_mutex_own(buf_pool));
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() << "Over 95 percent of the buffer pool is"
" occupied by lock heaps"
#ifdef BTR_CUR_HASH_ADAPT
" or the adaptive hash index!"
#endif /* BTR_CUR_HASH_ADAPT */
" Check that your transactions do not set too many"
" row locks, or review if"
" innodb_buffer_pool_size="
<< (buf_pool->curr_size >> (20U - srv_page_size_shift))
<< "M could be bigger.";
} 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() << "Over 67 percent of the buffer pool is"
" occupied by lock heaps"
#ifdef BTR_CUR_HASH_ADAPT
" or the adaptive hash index!"
#endif /* BTR_CUR_HASH_ADAPT */
" Check that your transactions do not"
" set too many row locks."
" innodb_buffer_pool_size="
<< (buf_pool->curr_size >>
(20U - srv_page_size_shift)) << "M."
" Starting the InnoDB Monitor to print"
" diagnostics.";
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
@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) /*!< in/out: buffer pool instance */
{
buf_block_t* block = NULL;
bool freed = false;
ulint n_iterations = 0;
ulint flush_failures = 0;
MONITOR_INC(MONITOR_LRU_GET_FREE_SEARCH);
loop:
buf_pool_mutex_enter(buf_pool);
buf_LRU_check_size_of_non_data_objects(buf_pool);
DBUG_EXECUTE_IF("ib_lru_force_no_free_page",
if (!buf_lru_free_blocks_error_printed) {
n_iterations = 21;
goto not_found;});
/* If there is a block in the free list, take it */
block = buf_LRU_get_free_only(buf_pool);
if (block != NULL) {
buf_pool_mutex_exit(buf_pool);
ut_ad(buf_pool_from_block(block) == buf_pool);
memset(&block->page.zip, 0, sizeof block->page.zip);
block->skip_flush_check = false;
block->page.flush_observer = NULL;
return(block);
}
MONITOR_INC( MONITOR_LRU_GET_FREE_LOOPS );
freed = false;
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;
/* Also tell the page_cleaner thread that
there is work for it to do. */
os_event_set(buf_flush_event);
}
}
#ifndef DBUG_OFF
not_found:
#endif
buf_pool_mutex_exit(buf_pool);
if (freed) {
goto loop;
}
if (n_iterations > 20 && !buf_lru_free_blocks_error_printed
&& srv_buf_pool_old_size == srv_buf_pool_size) {
ib::warn() << "Difficult to find free blocks in the buffer pool"
" (" << n_iterations << " search iterations)! "
<< flush_failures << " failed attempts to"
" flush a page!"
" Consider increasing innodb_buffer_pool_size."
" 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.";
buf_lru_free_blocks_error_printed = true;
}
/* 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.inc();
n_iterations++;
goto loop;
}
/*******************************************************************//**
Moves the LRU_old pointer so that the length of the old blocks list
is inside the allowed limits. */
UNIV_INLINE
void
buf_LRU_old_adjust_len(
/*===================*/
buf_pool_t* buf_pool) /*!< in: buffer pool instance */
{
ulint old_len;
ulint new_len;
ut_a(buf_pool->LRU_old);
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(buf_pool->LRU_old_ratio >= BUF_LRU_OLD_RATIO_MIN);
ut_ad(buf_pool->LRU_old_ratio <= BUF_LRU_OLD_RATIO_MAX);
compile_time_assert(BUF_LRU_OLD_RATIO_MIN * BUF_LRU_OLD_MIN_LEN
> BUF_LRU_OLD_RATIO_DIV
* (BUF_LRU_OLD_TOLERANCE + 5));
compile_time_assert(BUF_LRU_NON_OLD_MIN_LEN < BUF_LRU_OLD_MIN_LEN);
#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. */
static
void
buf_LRU_old_init(
/*=============*/
buf_pool_t* buf_pool)
{
ut_ad(buf_pool_mutex_own(buf_pool));
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. */
static
void
buf_unzip_LRU_remove_block_if_needed(
/*=================================*/
buf_page_t* bpage) /*!< in/out: control block */
{
buf_pool_t* buf_pool = buf_pool_from_bpage(bpage);
ut_ad(buf_page_in_file(bpage));
ut_ad(buf_pool_mutex_own(buf_pool));
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. */
UNIV_INLINE
void
buf_LRU_remove_block(
/*=================*/
buf_page_t* bpage) /*!< in: control block */
{
buf_pool_t* buf_pool = buf_pool_from_bpage(bpage);
ut_ad(buf_pool_mutex_own(buf_pool));
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. */
void
buf_unzip_LRU_add_block(
/*====================*/
buf_block_t* block, /*!< in: control block */
ibool old) /*!< in: TRUE if should be put to the end
of the list, else put to the start */
{
buf_pool_t* buf_pool = buf_pool_from_block(block);
ut_ad(buf_pool_mutex_own(buf_pool));
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 */
UNIV_INLINE
void
buf_LRU_add_block_low(
/*==================*/
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_pool_t* buf_pool = buf_pool_from_bpage(bpage);
ut_ad(buf_pool_mutex_own(buf_pool));
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. */
void
buf_LRU_make_block_young(
/*=====================*/
buf_page_t* bpage) /*!< in: control block */
{
buf_pool_t* buf_pool = buf_pool_from_bpage(bpage);
ut_ad(buf_pool_mutex_own(buf_pool));
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: If this function returns true, it will temporarily
release buf_pool->mutex. Furthermore, the page frame will no longer be
accessible via bpage.
The caller must hold buf_pool->mutex and must not hold any
buf_page_get_mutex() when calling this function.
@return true if freed, false otherwise. */
bool
buf_LRU_free_page(
/*===============*/
buf_page_t* bpage, /*!< in: block to be freed */
bool zip) /*!< in: true if should remove also the
compressed page of an uncompressed page */
{
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(buf_pool_mutex_own(buf_pool));
ut_ad(buf_page_in_file(bpage));
ut_ad(bpage->in_LRU_list);
rw_lock_x_lock(hash_lock);
mutex_enter(block_mutex);
if (!buf_page_can_relocate(bpage)) {
/* Do not free buffer fixed and I/O-fixed blocks. */
goto func_exit;
}
if (zip || !bpage->zip.data) {
/* This would completely free the block. */
/* Do not completely free dirty blocks. */
if (bpage->oldest_modification) {
goto func_exit;
}
} 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);
func_exit:
rw_lock_x_unlock(hash_lock);
mutex_exit(block_mutex);
return(false);
} else if (buf_page_get_state(bpage) == BUF_BLOCK_FILE_PAGE) {
b = buf_page_alloc_descriptor();
ut_a(b);
new (b) buf_page_t(*bpage);
}
ut_ad(buf_pool_mutex_own(buf_pool));
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 %u:%u",
bpage->id.space(), bpage->id.page_no()));
ut_ad(rw_lock_own(hash_lock, RW_LOCK_X));
ut_ad(buf_page_can_relocate(bpage));
if (!buf_LRU_block_remove_hashed(bpage, zip)) {
return(true);
}
/* buf_LRU_block_remove_hashed() releases the hash_lock */
ut_ad(!rw_lock_own_flagged(hash_lock,
RW_LOCK_FLAG_X | RW_LOCK_FLAG_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));
}
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));
mutex_exit(block_mutex);
/* Prevent buf_page_get_gen() from
decompressing the block while we release
buf_pool->mutex and block_mutex. */
block_mutex = buf_page_get_mutex(b);
mutex_enter(block_mutex);
buf_page_set_sticky(b);
mutex_exit(block_mutex);
rw_lock_x_unlock(hash_lock);
}
buf_pool_mutex_exit(buf_pool);
/* 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,
srv_page_size);
btr_search_drop_page_hash_index((buf_block_t*) bpage);
UNIV_MEM_INVALID(((buf_block_t*) bpage)->frame,
srv_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());
const uint32_t checksum = page_zip_calc_checksum(
b->zip.data,
b->size.physical(),
static_cast<srv_checksum_algorithm_t>(
srv_checksum_algorithm));
mach_write_to_4(b->zip.data + FIL_PAGE_SPACE_OR_CHKSUM,
checksum);
}
buf_pool_mutex_enter(buf_pool);
if (b != NULL) {
mutex_enter(block_mutex);
buf_page_unset_sticky(b);
mutex_exit(block_mutex);
}
buf_LRU_block_free_hashed_page((buf_block_t*) bpage);
return(true);
}
/******************************************************************//**
Puts a block back to the free list. */
void
buf_LRU_block_free_non_file_page(
/*=============================*/
buf_block_t* block) /*!< in: block, must not contain a file page */
{
void* data;
buf_pool_t* buf_pool = buf_pool_from_block(block);
ut_ad(buf_pool_mutex_own(buf_pool));
ut_ad(buf_page_mutex_own(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);
buf_block_set_state(block, BUF_BLOCK_NOT_USED);
UNIV_MEM_ALLOC(block->frame, srv_page_size);
#ifdef UNIV_DEBUG
/* Wipe contents of page to reveal possible stale pointers to it */
memset(block->frame, '\0', srv_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 */
data = block->page.zip.data;
if (data != NULL) {
block->page.zip.data = NULL;
buf_page_mutex_exit(block);
buf_pool_mutex_exit_forbid(buf_pool);
ut_ad(block->page.size.is_compressed());
buf_buddy_free(buf_pool, data, block->page.size.physical());
buf_pool_mutex_exit_allow(buf_pool);
buf_page_mutex_enter(block);
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));
}
if (buf_pool->curr_size < buf_pool->old_size
&& UT_LIST_GET_LEN(buf_pool->withdraw) < buf_pool->withdraw_target
&& buf_block_will_withdrawn(buf_pool, block)) {
/* This should be withdrawn */
UT_LIST_ADD_LAST(
buf_pool->withdraw,
&block->page);
ut_d(block->in_withdraw_list = TRUE);
} else {
UT_LIST_ADD_FIRST(buf_pool->free, &block->page);
ut_d(block->page.in_free_list = TRUE);
}
UNIV_MEM_FREE(block->frame, srv_page_size);
}
/******************************************************************//**
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->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.
@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, /*!< in: 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 */
bool zip) /*!< in: true if should remove also the
compressed page of an uncompressed page */
{
const buf_page_t* hashed_bpage;
buf_pool_t* buf_pool = buf_pool_from_bpage(bpage);
rw_lock_t* hash_lock;
ut_ad(buf_pool_mutex_own(buf_pool));
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,
srv_page_size);
buf_block_modify_clock_inc((buf_block_t*) bpage);
if (bpage->zip.data) {
const page_t* page = ((buf_block_t*) bpage)->frame;
ut_a(!zip || bpage->oldest_modification == 0);
ut_ad(bpage->size.is_compressed());
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:
/* 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:
break;
case FIL_PAGE_INDEX:
case FIL_PAGE_RTREE:
#if defined UNIV_ZIP_DEBUG && defined BTR_CUR_HASH_ADAPT
ut_a(page_zip_validate(
&bpage->zip, page,
((buf_block_t*) bpage)->index));
#endif /* UNIV_ZIP_DEBUG && BTR_CUR_HASH_ADAPT */
break;
default:
ib::error() << "The compressed page to be"
" evicted seems corrupt:";
ut_print_buf(stderr, page,
bpage->size.logical());
ib::error() << "Possibly older version of"
" the page:";
ut_print_buf(stderr, bpage->zip.data,
bpage->size.physical());
putc('\n', stderr);
ut_error;
}
break;
}
/* 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() << "Page " << bpage->id
<< " not found in the hash table";
#ifdef UNIV_DEBUG
ib::error()
<< "in_page_hash:" << bpage->in_page_hash
<< " in_zip_hash:" << bpage->in_zip_hash
// << " in_free_list:"<< bpage->in_fee_list
<< " in_flush_list:" << bpage->in_flush_list
<< " in_LRU_list:" << bpage->in_LRU_list
<< " zip.data:" << bpage->zip.data
<< " zip_size:" << bpage->size.logical()
<< " page_state:" << buf_page_get_state(bpage);
#else
ib::error()
<< " zip.data:" << bpage->zip.data
<< " zip_size:" << bpage->size.logical()
<< " page_state:" << buf_page_get_state(bpage);
#endif
if (hashed_bpage) {
ib::error() << "In hash table we find block "
<< hashed_bpage << " of " << hashed_bpage->id
<< " which is not " << bpage;
}
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
mutex_exit(buf_page_get_mutex(bpage));
rw_lock_x_unlock(hash_lock);
buf_pool_mutex_exit(buf_pool);
buf_print();
buf_LRU_print();
buf_validate();
buf_LRU_validate();
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
ut_error;
}
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_pool_mutex_exit_forbid(buf_pool);
buf_buddy_free(buf_pool, bpage->zip.data,
bpage->size.physical());
buf_pool_mutex_exit_allow(buf_pool);
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,
srv_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 buf_pool mutex.
2) Not possible because in buf_page_init_for_read()
we do a look up of page_hash while holding buf_pool
mutex and since we are holding buf_pool 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. */
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_pool_mutex_exit_forbid(buf_pool);
buf_buddy_free(buf_pool, data, bpage->size.physical());
buf_pool_mutex_exit_allow(buf_pool);
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;
return(false);
}
/******************************************************************//**
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);
ut_ad(buf_pool_mutex_own(buf_pool));
buf_page_mutex_enter(block);
if (buf_pool->flush_rbt == NULL) {
block->page.id
= page_id_t(ULINT32_UNDEFINED, ULINT32_UNDEFINED);
}
buf_block_set_state(block, BUF_BLOCK_MEMORY);
buf_LRU_block_free_non_file_page(block);
buf_page_mutex_exit(block);
}
/** Remove one page from LRU list and put it to free list.
@param[in,out] bpage block, must contain a file page and be in
a freeable state; there may or may not be a
hash index to the page
@param[in] old_page_id page number before bpage->id was invalidated */
void buf_LRU_free_one_page(buf_page_t* bpage, page_id_t old_page_id)
{
buf_pool_t* buf_pool = buf_pool_from_bpage(bpage);
rw_lock_t* hash_lock = buf_page_hash_lock_get(buf_pool,
old_page_id);
BPageMutex* block_mutex = buf_page_get_mutex(bpage);
ut_ad(buf_pool_mutex_own(buf_pool));
rw_lock_x_lock(hash_lock);
while (buf_block_get_fix(bpage) > 0) {
/* Wait for other threads to release the fix count
before releasing the bpage from LRU list. */
}
mutex_enter(block_mutex);
bpage->id = old_page_id;
if (buf_LRU_block_remove_hashed(bpage, true)) {
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_flagged(hash_lock,
RW_LOCK_FLAG_X | RW_LOCK_FLAG_S));
ut_ad(!mutex_own(block_mutex));
}
/**********************************************************************//**
Updates buf_pool->LRU_old_ratio for one buffer pool instance.
@return updated old_pct */
static
uint
buf_LRU_old_ratio_update_instance(
/*==============================*/
buf_pool_t* buf_pool,/*!< in: buffer pool instance */
uint old_pct,/*!< in: Reserve this percentage of
the buffer pool for "old" blocks. */
bool adjust) /*!< in: true=adjust the LRU list;
false=just assign buf_pool->LRU_old_ratio
during the initialization of InnoDB */
{
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) {
buf_pool_mutex_enter(buf_pool);
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);
}
}
buf_pool_mutex_exit(buf_pool);
} 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. */
bool 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. */
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);
}
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/**********************************************************************//**
Validates the LRU list for one buffer pool instance. */
static
void
buf_LRU_validate_instance(
/*======================*/
buf_pool_t* buf_pool)
{
ulint old_len;
ulint new_len;
buf_pool_mutex_enter(buf_pool);
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);
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);
}
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));
}
buf_pool_mutex_exit(buf_pool);
}
/**********************************************************************//**
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. */
static
void
buf_LRU_print_instance(
/*===================*/
buf_pool_t* buf_pool)
{
buf_pool_mutex_enter(buf_pool);
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 %u page %u ",
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 %u ",
bpage->buf_fix_count);
}
if (buf_page_get_io_fix(bpage)) {
fprintf(stderr, "io_fix %d ",
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 %u index id " IB_ID_FMT "\n",
fil_page_get_type(frame),
btr_page_get_index_id(frame));
break;
case BUF_BLOCK_ZIP_PAGE:
frame = bpage->zip.data;
fprintf(stderr, "\ntype %u size " ULINTPF
" index id " IB_ID_FMT "\n",
fil_page_get_type(frame),
bpage->size.physical(),
btr_page_get_index_id(frame));
break;
default:
fprintf(stderr, "\n!state %d!\n",
buf_page_get_state(bpage));
break;
}
mutex_exit(buf_page_get_mutex(bpage));
}
buf_pool_mutex_exit(buf_pool);
}
/**********************************************************************//**
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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