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mariadb/storage/innobase/buf/buf0flu.cc
Marko Mäkelä 0d6d63e150 MDEV-22027 Assertion oldest_lsn >= log_sys.last_checkpoint_lsn failed 
log_buf_pool_get_oldest_modification(): Acquire
log_sys_t::flush_order_mutex in order to prevent a race condition
that was introduced in
commit 1a6f708ec5 (MDEV-15058).

Before that change, log_buf_pool_get_oldest_modification()
was protected by both log_sys.mutex and log_sys.flush_order_mutex
like it was supposed to be ever since
commit a52c4820a3 (MySQL 5.5.10).

buf_pool_t::get_oldest_modification(): Replaces
buf_pool_get_oldest_modification(), to emphasize that
log_sys.flush_order_mutex must be acquired by the caller if needed.

log_close(): Invoke log_buf_pool_get_oldest_modification()
in order to ensure a clean shutdown.

The scenario of the race condition is as follows:

1. The buffer pool is clean (no writes are pending).
2. mtr_add_dirtied_pages_to_flush_list() releases log_sys.mutex.
3. log_buf_pool_get_oldest_modification() observes that the
buffer pool is clean and returns log_sys.lsn.
4. log_checkpoint() completes, writing a wrong checkpoint header
according to which everything up to log_sys.lsn was clean.
5. mtr_add_dirtied_pages_to_flush_list() completes the execution
of mtr_memo_note_modifications(), releases the page latches and
the flush_order_mutex.
6. On a subsequent log_checkpoint(), the assertion could fail
if the page modifications had not been flushed yet.

The failing assertion (which is valid) was added in MySQL 5.7
mysql/mysql-server@5c6c6ec693
and merged to MariaDB Server 10.2.2 in
commit fec844aca8.
2020-06-02 08:17:10 +03:00

3230 lines
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/*****************************************************************************
Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2013, 2020, MariaDB Corporation.
Copyright (c) 2013, 2014, Fusion-io
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/buf0flu.cc
The database buffer buf_pool flush algorithm
Created 11/11/1995 Heikki Tuuri
*******************************************************/
#include "univ.i"
#include <mysql/service_thd_wait.h>
#include <sql_class.h>
#include "buf0flu.h"
#include "buf0buf.h"
#include "buf0checksum.h"
#include "buf0dblwr.h"
#include "srv0start.h"
#include "srv0srv.h"
#include "page0zip.h"
#include "ut0byte.h"
#include "page0page.h"
#include "fil0fil.h"
#include "buf0lru.h"
#include "buf0rea.h"
#include "ibuf0ibuf.h"
#include "log0log.h"
#include "log0crypt.h"
#include "os0file.h"
#include "trx0sys.h"
#include "srv0mon.h"
#include "ut0stage.h"
#include "fil0pagecompress.h"
#ifdef UNIV_LINUX
/* include defs for CPU time priority settings */
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/resource.h>
static const int buf_flush_page_cleaner_priority = -20;
#endif /* UNIV_LINUX */
#ifdef HAVE_LZO
#include "lzo/lzo1x.h"
#endif
#ifdef HAVE_SNAPPY
#include "snappy-c.h"
#endif
/** Sleep time in microseconds for loop waiting for the oldest
modification lsn */
static const ulint buf_flush_wait_flushed_sleep_time = 10000;
#include <my_service_manager.h>
/** Number of pages flushed through non flush_list flushes. */
ulint buf_lru_flush_page_count;
/** Flag indicating if the page_cleaner is in active state. This flag
is set to TRUE by the page_cleaner thread when it is spawned and is set
back to FALSE at shutdown by the page_cleaner as well. Therefore no
need to protect it by a mutex. It is only ever read by the thread
doing the shutdown */
bool buf_page_cleaner_is_active;
/** Factor for scan length to determine n_pages for intended oldest LSN
progress */
static ulint buf_flush_lsn_scan_factor = 3;
/** Average redo generation rate */
static lsn_t lsn_avg_rate = 0;
/** Target oldest LSN for the requested flush_sync */
static lsn_t buf_flush_sync_lsn = 0;
#ifdef UNIV_PFS_THREAD
mysql_pfs_key_t page_cleaner_thread_key;
#endif /* UNIV_PFS_THREAD */
/** Event to synchronise with the flushing. */
os_event_t buf_flush_event;
static void pc_flush_slot_func(void *);
static tpool::task_group page_cleaner_task_group(1);
static tpool::waitable_task pc_flush_slot_task(
pc_flush_slot_func, 0, &page_cleaner_task_group);
/** State for page cleaner array slot */
enum page_cleaner_state_t {
/** Not requested any yet. Moved from FINISHED. */
PAGE_CLEANER_STATE_NONE = 0,
/** Requested but not started flushing. Moved from NONE. */
PAGE_CLEANER_STATE_REQUESTED,
/** Flushing is on going. Moved from REQUESTED. */
PAGE_CLEANER_STATE_FLUSHING,
/** Flushing was finished. Moved from FLUSHING. */
PAGE_CLEANER_STATE_FINISHED
};
/** Page cleaner request state for buf_pool */
struct page_cleaner_slot_t {
page_cleaner_state_t state; /*!< state of the request.
protected by page_cleaner_t::mutex
if the worker thread got the slot and
set to PAGE_CLEANER_STATE_FLUSHING,
n_flushed_lru and n_flushed_list can be
updated only by the worker thread */
/* This value is set during state==PAGE_CLEANER_STATE_NONE */
ulint n_pages_requested;
/*!< number of requested pages
for the slot */
/* These values are updated during state==PAGE_CLEANER_STATE_FLUSHING,
and commited with state==PAGE_CLEANER_STATE_FINISHED.
The consistency is protected by the 'state' */
ulint n_flushed_lru;
/*!< number of flushed pages
by LRU scan flushing */
ulint n_flushed_list;
/*!< number of flushed pages
by flush_list flushing */
bool succeeded_list;
/*!< true if flush_list flushing
succeeded. */
ulint flush_lru_time;
/*!< elapsed time for LRU flushing */
ulint flush_list_time;
/*!< elapsed time for flush_list
flushing */
ulint flush_lru_pass;
/*!< count to attempt LRU flushing */
ulint flush_list_pass;
/*!< count to attempt flush_list
flushing */
};
/** Page cleaner structure */
struct page_cleaner_t {
/* FIXME: do we need mutex? use atomics? */
ib_mutex_t mutex; /*!< mutex to protect whole of
page_cleaner_t struct and
page_cleaner_slot_t slots. */
os_event_t is_finished; /*!< event to signal that all
slots were finished. */
bool requested; /*!< true if requested pages
to flush */
lsn_t lsn_limit; /*!< upper limit of LSN to be
flushed */
#if 1 /* FIXME: use bool for these, or remove some of these */
ulint n_slots_requested;
/*!< number of slots
in the state
PAGE_CLEANER_STATE_REQUESTED */
ulint n_slots_flushing;
/*!< number of slots
in the state
PAGE_CLEANER_STATE_FLUSHING */
ulint n_slots_finished;
/*!< number of slots
in the state
PAGE_CLEANER_STATE_FINISHED */
#endif
ulint flush_time; /*!< elapsed time to flush
requests for all slots */
ulint flush_pass; /*!< count to finish to flush
requests for all slots */
page_cleaner_slot_t slot;
bool is_running; /*!< false if attempt
to shutdown */
};
static page_cleaner_t page_cleaner;
#ifdef UNIV_DEBUG
my_bool innodb_page_cleaner_disabled_debug;
#endif /* UNIV_DEBUG */
/** If LRU list of a buf_pool is less than this size then LRU eviction
should not happen. This is because when we do LRU flushing we also put
the blocks on free list. If LRU list is very small then we can end up
in thrashing. */
#define BUF_LRU_MIN_LEN 256
/* @} */
/** Increases flush_list size in bytes with the page size */
static inline void incr_flush_list_size_in_bytes(const buf_block_t* block)
{
/* FIXME: use std::atomic! */
ut_ad(mutex_own(&buf_pool.flush_list_mutex));
buf_pool.stat.flush_list_bytes += block->physical_size();
ut_ad(buf_pool.stat.flush_list_bytes <= buf_pool.curr_pool_size);
}
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/** Validate the flush list. */
static void buf_flush_validate_low();
/** Validates the flush list some of the time. */
static void buf_flush_validate_skip()
{
/** Try buf_flush_validate_low() every this many times */
# define BUF_FLUSH_VALIDATE_SKIP 23
/** The buf_flush_validate_low() call skip counter.
Use a signed type because of the race condition below. */
static int buf_flush_validate_count = BUF_FLUSH_VALIDATE_SKIP;
/* There is a race condition below, but it does not matter,
because this call is only for heuristic purposes. We want to
reduce the call frequency of the costly buf_flush_validate_low()
check in debug builds. */
if (--buf_flush_validate_count > 0) {
return;
}
buf_flush_validate_count = BUF_FLUSH_VALIDATE_SKIP;
buf_flush_validate_low();
}
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
/******************************************************************//**
Insert a block in the flush_rbt and returns a pointer to its
predecessor or NULL if no predecessor. The ordering is maintained
on the basis of the <oldest_modification, space, offset> key.
@return pointer to the predecessor or NULL if no predecessor. */
static
buf_page_t*
buf_flush_insert_in_flush_rbt(
/*==========================*/
buf_page_t* bpage) /*!< in: bpage to be inserted. */
{
const ib_rbt_node_t* c_node;
const ib_rbt_node_t* p_node;
buf_page_t* prev = NULL;
ut_ad(srv_shutdown_state != SRV_SHUTDOWN_FLUSH_PHASE);
ut_ad(mutex_own(&buf_pool.flush_list_mutex));
/* Insert this buffer into the rbt. */
c_node = rbt_insert(buf_pool.flush_rbt, &bpage, &bpage);
ut_a(c_node != NULL);
/* Get the predecessor. */
p_node = rbt_prev(buf_pool.flush_rbt, c_node);
if (p_node != NULL) {
buf_page_t** value;
value = rbt_value(buf_page_t*, p_node);
prev = *value;
ut_a(prev != NULL);
}
return(prev);
}
/*********************************************************//**
Delete a bpage from the flush_rbt. */
static
void
buf_flush_delete_from_flush_rbt(
/*============================*/
buf_page_t* bpage) /*!< in: bpage to be removed. */
{
ut_ad(mutex_own(&buf_pool.flush_list_mutex));
#ifdef UNIV_DEBUG
ibool ret =
#endif /* UNIV_DEBUG */
rbt_delete(buf_pool.flush_rbt, &bpage);
ut_ad(ret);
}
/*****************************************************************//**
Compare two modified blocks in the buffer pool. The key for comparison
is:
key = <oldest_modification, space, offset>
This comparison is used to maintian ordering of blocks in the
buf_pool.flush_rbt.
Note that for the purpose of flush_rbt, we only need to order blocks
on the oldest_modification. The other two fields are used to uniquely
identify the blocks.
@return < 0 if b2 < b1, 0 if b2 == b1, > 0 if b2 > b1 */
static
int
buf_flush_block_cmp(
/*================*/
const void* p1, /*!< in: block1 */
const void* p2) /*!< in: block2 */
{
int ret;
const buf_page_t* b1 = *(const buf_page_t**) p1;
const buf_page_t* b2 = *(const buf_page_t**) p2;
ut_ad(b1 != NULL);
ut_ad(b2 != NULL);
ut_ad(mutex_own(&buf_pool.flush_list_mutex));
ut_ad(b1->in_flush_list);
ut_ad(b2->in_flush_list);
if (b2->oldest_modification > b1->oldest_modification) {
return(1);
} else if (b2->oldest_modification < b1->oldest_modification) {
return(-1);
}
/* If oldest_modification is same then decide on the space. */
ret = (int)(b2->id.space() - b1->id.space());
/* Or else decide ordering on the page number. */
return(ret ? ret : (int) (b2->id.page_no() - b1->id.page_no()));
}
/********************************************************************//**
Initialize the red-black tree to speed up insertions into the flush_list
during recovery process. Should be called at the start of recovery
process before any page has been read/written. */
void
buf_flush_init_flush_rbt(void)
/*==========================*/
{
mutex_enter(&buf_pool.flush_list_mutex);
ut_ad(buf_pool.flush_rbt == NULL);
/* Create red black tree for speedy insertions in flush list. */
buf_pool.flush_rbt = rbt_create(
sizeof(buf_page_t*), buf_flush_block_cmp);
mutex_exit(&buf_pool.flush_list_mutex);
}
/********************************************************************//**
Frees up the red-black tree. */
void
buf_flush_free_flush_rbt(void)
/*==========================*/
{
mutex_enter(&buf_pool.flush_list_mutex);
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
buf_flush_validate_low();
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
rbt_free(buf_pool.flush_rbt);
buf_pool.flush_rbt = NULL;
mutex_exit(&buf_pool.flush_list_mutex);
}
/** Insert a modified block into the flush list.
@param[in,out] block modified block
@param[in] lsn oldest modification */
void buf_flush_insert_into_flush_list(buf_block_t* block, lsn_t lsn)
{
ut_ad(!mutex_own(&buf_pool.mutex));
ut_ad(log_flush_order_mutex_own());
ut_ad(buf_page_mutex_own(block));
ut_ad(lsn);
mutex_enter(&buf_pool.flush_list_mutex);
ut_ad(!block->page.in_flush_list);
ut_d(block->page.in_flush_list = TRUE);
ut_ad(!block->page.oldest_modification);
block->page.oldest_modification = lsn;
UNIV_MEM_ASSERT_RW(block->page.zip.data
? block->page.zip.data : block->frame,
block->physical_size());
incr_flush_list_size_in_bytes(block);
if (UNIV_LIKELY_NULL(buf_pool.flush_rbt)) {
ut_ad(srv_shutdown_state != SRV_SHUTDOWN_FLUSH_PHASE);
/* The field in_LRU_list is protected by buf_pool.mutex, which
we are not holding. However, while a block is in the flush
list, it is dirty and cannot be discarded, not from the
page_hash or from the LRU list. At most, the uncompressed
page frame of a compressed block may be discarded or created
(copying the block->page to or from a buf_page_t that is
dynamically allocated from buf_buddy_alloc()). Because those
transitions hold block->mutex and the flush list mutex (via
buf_flush_relocate_on_flush_list()), there is no possibility
of a race condition in the assertions below. */
ut_ad(block->page.in_LRU_list);
ut_ad(block->page.in_page_hash);
/* buf_buddy_block_register() will take a block in the
BUF_BLOCK_MEMORY state, not a file page. */
ut_ad(!block->page.in_zip_hash);
if (buf_page_t* prev_b =
buf_flush_insert_in_flush_rbt(&block->page)) {
UT_LIST_INSERT_AFTER(buf_pool.flush_list, prev_b, &block->page);
goto func_exit;
}
}
UT_LIST_ADD_FIRST(buf_pool.flush_list, &block->page);
func_exit:
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
buf_flush_validate_skip();
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
mutex_exit(&buf_pool.flush_list_mutex);
}
/********************************************************************//**
Returns TRUE if the file page block is immediately suitable for replacement,
i.e., the transition FILE_PAGE => NOT_USED allowed.
@return TRUE if can replace immediately */
ibool
buf_flush_ready_for_replace(
/*========================*/
buf_page_t* bpage) /*!< in: buffer control block, must be
buf_page_in_file(bpage) and in the LRU list */
{
ut_ad(mutex_own(&buf_pool.mutex));
ut_ad(mutex_own(buf_page_get_mutex(bpage)));
ut_ad(bpage->in_LRU_list);
if (buf_page_in_file(bpage)) {
return(bpage->oldest_modification == 0
&& bpage->buf_fix_count == 0
&& buf_page_get_io_fix(bpage) == BUF_IO_NONE);
}
ib::fatal() << "Buffer block " << bpage << " state " << bpage->state
<< " in the LRU list!";
return(FALSE);
}
/********************************************************************//**
Returns true if the block is modified and ready for flushing.
@return true if can flush immediately */
bool
buf_flush_ready_for_flush(
/*======================*/
buf_page_t* bpage, /*!< in: buffer control block, must be
buf_page_in_file(bpage) */
buf_flush_t flush_type)/*!< in: type of flush */
{
ut_ad(mutex_own(&buf_pool.mutex));
ut_a(buf_page_in_file(bpage));
ut_ad(mutex_own(buf_page_get_mutex(bpage)));
ut_ad(flush_type < BUF_FLUSH_N_TYPES);
if (bpage->oldest_modification == 0
|| buf_page_get_io_fix(bpage) != BUF_IO_NONE) {
return(false);
}
ut_ad(bpage->in_flush_list);
switch (flush_type) {
case BUF_FLUSH_LIST:
case BUF_FLUSH_LRU:
case BUF_FLUSH_SINGLE_PAGE:
return(true);
case BUF_FLUSH_N_TYPES:
break;
}
ut_error;
return(false);
}
/** Remove a block from the flush list of modified blocks.
@param[in] bpage block to be removed from the flush list */
void buf_flush_remove(buf_page_t* bpage)
{
#if 0 // FIXME: Rate-limit the output. Move this to the page cleaner?
if (UNIV_UNLIKELY(srv_shutdown_state == SRV_SHUTDOWN_FLUSH_PHASE)) {
service_manager_extend_timeout(
INNODB_EXTEND_TIMEOUT_INTERVAL,
"Flush and remove page with tablespace id %u"
", flush list length " ULINTPF,
bpage->space, UT_LIST_GET_LEN(buf_pool.flush_list));
}
#endif
ut_ad(mutex_own(&buf_pool.mutex));
ut_ad(mutex_own(buf_page_get_mutex(bpage)));
ut_ad(bpage->in_flush_list);
mutex_enter(&buf_pool.flush_list_mutex);
/* Important that we adjust the hazard pointer before removing
the bpage from flush list. */
buf_pool.flush_hp.adjust(bpage);
switch (buf_page_get_state(bpage)) {
case BUF_BLOCK_POOL_WATCH:
case BUF_BLOCK_ZIP_PAGE:
/* Clean compressed pages should not be on the flush list */
case BUF_BLOCK_NOT_USED:
case BUF_BLOCK_READY_FOR_USE:
case BUF_BLOCK_MEMORY:
case BUF_BLOCK_REMOVE_HASH:
ut_error;
return;
case BUF_BLOCK_ZIP_DIRTY:
buf_page_set_state(bpage, BUF_BLOCK_ZIP_PAGE);
UT_LIST_REMOVE(buf_pool.flush_list, bpage);
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
buf_LRU_insert_zip_clean(bpage);
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
break;
case BUF_BLOCK_FILE_PAGE:
UT_LIST_REMOVE(buf_pool.flush_list, bpage);
break;
}
/* If the flush_rbt is active then delete from there as well. */
if (UNIV_LIKELY_NULL(buf_pool.flush_rbt)) {
buf_flush_delete_from_flush_rbt(bpage);
}
/* Must be done after we have removed it from the flush_rbt
because we assert on in_flush_list in comparison function. */
ut_d(bpage->in_flush_list = FALSE);
buf_pool.stat.flush_list_bytes -= bpage->physical_size();
bpage->oldest_modification = 0;
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
buf_flush_validate_skip();
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
mutex_exit(&buf_pool.flush_list_mutex);
}
/*******************************************************************//**
Relocates a buffer control block on the flush_list.
Note that it is assumed that the contents of bpage have already been
copied to dpage.
IMPORTANT: When this function is called bpage and dpage are not
exact copies of each other. For example, they both will have different
::state. Also the ::list pointers in dpage may be stale. We need to
use the current list node (bpage) to do the list manipulation because
the list pointers could have changed between the time that we copied
the contents of bpage to the dpage and the flush list manipulation
below. */
void
buf_flush_relocate_on_flush_list(
/*=============================*/
buf_page_t* bpage, /*!< in/out: control block being moved */
buf_page_t* dpage) /*!< in/out: destination block */
{
buf_page_t* prev;
buf_page_t* prev_b = NULL;
ut_ad(mutex_own(&buf_pool.mutex));
ut_ad(mutex_own(buf_page_get_mutex(bpage)));
mutex_enter(&buf_pool.flush_list_mutex);
/* FIXME: At this point we have both buf_pool and flush_list
mutexes. Theoretically removal of a block from flush list is
only covered by flush_list mutex but currently we do
have buf_pool mutex in buf_flush_remove() therefore this block
is guaranteed to be in the flush list. We need to check if
this will work without the assumption of block removing code
having the buf_pool mutex. */
ut_ad(bpage->in_flush_list);
ut_ad(dpage->in_flush_list);
/* If recovery is active we must swap the control blocks in
the flush_rbt as well. */
if (UNIV_LIKELY_NULL(buf_pool.flush_rbt)) {
buf_flush_delete_from_flush_rbt(bpage);
prev_b = buf_flush_insert_in_flush_rbt(dpage);
}
/* Important that we adjust the hazard pointer before removing
the bpage from the flush list. */
buf_pool.flush_hp.adjust(bpage);
/* Must be done after we have removed it from the flush_rbt
because we assert on in_flush_list in comparison function. */
ut_d(bpage->in_flush_list = FALSE);
prev = UT_LIST_GET_PREV(list, bpage);
UT_LIST_REMOVE(buf_pool.flush_list, bpage);
if (prev) {
ut_ad(prev->in_flush_list);
UT_LIST_INSERT_AFTER( buf_pool.flush_list, prev, dpage);
} else {
UT_LIST_ADD_FIRST(buf_pool.flush_list, dpage);
}
/* Just an extra check. Previous in flush_list
should be the same control block as in flush_rbt. */
ut_a(buf_pool.flush_rbt == NULL || prev_b == prev);
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
buf_flush_validate_low();
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
mutex_exit(&buf_pool.flush_list_mutex);
}
/** Update the flush system data structures when a write is completed.
@param[in,out] bpage flushed page
@param[in] dblwr whether the doublewrite buffer was used */
void buf_flush_write_complete(buf_page_t* bpage, bool dblwr)
{
ut_ad(bpage);
buf_flush_remove(bpage);
const buf_flush_t flush_type = buf_page_get_flush_type(bpage);
buf_pool.n_flush[flush_type]--;
ut_ad(buf_pool.n_flush[flush_type] != ULINT_MAX);
ut_ad(mutex_own(&buf_pool.mutex));
if (buf_pool.n_flush[flush_type] == 0
&& buf_pool.init_flush[flush_type] == FALSE) {
/* The running flush batch has ended */
os_event_set(buf_pool.no_flush[flush_type]);
}
if (dblwr) {
buf_dblwr_update(bpage, flush_type);
}
}
/** Calculate a ROW_FORMAT=COMPRESSED page checksum and update the page.
@param[in,out] page page to update
@param[in] size compressed page size */
void buf_flush_update_zip_checksum(buf_frame_t *page, ulint size)
{
ut_ad(size > 0);
mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM,
page_zip_calc_checksum(page, size,
static_cast<srv_checksum_algorithm_t>
(srv_checksum_algorithm)));
}
/** Assign the full crc32 checksum for non-compressed page.
@param[in,out] page page to be updated */
void buf_flush_assign_full_crc32_checksum(byte* page)
{
ut_d(bool compressed = false);
ut_d(bool corrupted = false);
ut_d(const uint size = buf_page_full_crc32_size(page, &compressed,
&corrupted));
ut_ad(!compressed);
ut_ad(!corrupted);
ut_ad(size == uint(srv_page_size));
const ulint payload = srv_page_size - FIL_PAGE_FCRC32_CHECKSUM;
mach_write_to_4(page + payload, ut_crc32(page, payload));
}
/** Initialize a page for writing to the tablespace.
@param[in] block buffer block; NULL if bypassing
the buffer pool
@param[in,out] page page frame
@param[in,out] page_zip_ compressed page, or NULL if
uncompressed
@param[in] use_full_checksum whether tablespace uses full checksum */
void
buf_flush_init_for_writing(
const buf_block_t* block,
byte* page,
void* page_zip_,
bool use_full_checksum)
{
if (block != NULL && block->frame != page) {
/* If page is encrypted in full crc32 format then
checksum stored already as a part of fil_encrypt_buf() */
ut_ad(use_full_checksum);
return;
}
ut_ad(block == NULL || block->frame == page);
ut_ad(block == NULL || page_zip_ == NULL
|| &block->page.zip == page_zip_);
ut_ad(page);
if (page_zip_) {
page_zip_des_t* page_zip;
ulint size;
page_zip = static_cast<page_zip_des_t*>(page_zip_);
size = page_zip_get_size(page_zip);
ut_ad(size);
ut_ad(ut_is_2pow(size));
ut_ad(size <= UNIV_ZIP_SIZE_MAX);
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. */
memcpy(page_zip->data, page, size);
/* fall through */
case FIL_PAGE_TYPE_ZBLOB:
case FIL_PAGE_TYPE_ZBLOB2:
case FIL_PAGE_INDEX:
case FIL_PAGE_RTREE:
buf_flush_update_zip_checksum(page_zip->data, size);
return;
}
ib::error() << "The compressed page to be written"
" seems corrupt:";
ut_print_buf(stderr, page, size);
fputs("\nInnoDB: Possibly older version of the page:", stderr);
ut_print_buf(stderr, page_zip->data, size);
putc('\n', stderr);
ut_error;
}
if (use_full_checksum) {
static_assert(FIL_PAGE_FCRC32_END_LSN % 4 == 0, "aligned");
static_assert(FIL_PAGE_LSN % 4 == 0, "aligned");
memcpy_aligned<4>(page + srv_page_size
- FIL_PAGE_FCRC32_END_LSN,
FIL_PAGE_LSN + 4 + page, 4);
return buf_flush_assign_full_crc32_checksum(page);
}
static_assert(FIL_PAGE_END_LSN_OLD_CHKSUM % 8 == 0, "aligned");
static_assert(FIL_PAGE_LSN % 8 == 0, "aligned");
memcpy_aligned<8>(page + srv_page_size - FIL_PAGE_END_LSN_OLD_CHKSUM,
FIL_PAGE_LSN + page, 8);
if (block && srv_page_size == 16384) {
/* The page type could be garbage in old files
created before MySQL 5.5. Such files always
had a page size of 16 kilobytes. */
ulint page_type = fil_page_get_type(page);
ulint reset_type = page_type;
switch (block->page.id.page_no() % 16384) {
case 0:
reset_type = block->page.id.page_no() == 0
? FIL_PAGE_TYPE_FSP_HDR
: FIL_PAGE_TYPE_XDES;
break;
case 1:
reset_type = FIL_PAGE_IBUF_BITMAP;
break;
case FSP_TRX_SYS_PAGE_NO:
if (block->page.id.page_no()
== TRX_SYS_PAGE_NO
&& block->page.id.space()
== TRX_SYS_SPACE) {
reset_type = FIL_PAGE_TYPE_TRX_SYS;
break;
}
/* fall through */
default:
switch (page_type) {
case FIL_PAGE_INDEX:
case FIL_PAGE_TYPE_INSTANT:
case FIL_PAGE_RTREE:
case FIL_PAGE_UNDO_LOG:
case FIL_PAGE_INODE:
case FIL_PAGE_IBUF_FREE_LIST:
case FIL_PAGE_TYPE_ALLOCATED:
case FIL_PAGE_TYPE_SYS:
case FIL_PAGE_TYPE_TRX_SYS:
case FIL_PAGE_TYPE_BLOB:
case FIL_PAGE_TYPE_ZBLOB:
case FIL_PAGE_TYPE_ZBLOB2:
break;
case FIL_PAGE_TYPE_FSP_HDR:
case FIL_PAGE_TYPE_XDES:
case FIL_PAGE_IBUF_BITMAP:
/* These pages should have
predetermined page numbers
(see above). */
default:
reset_type = FIL_PAGE_TYPE_UNKNOWN;
break;
}
}
if (UNIV_UNLIKELY(page_type != reset_type)) {
ib::info()
<< "Resetting invalid page "
<< block->page.id << " type "
<< page_type << " to "
<< reset_type << " when flushing.";
fil_page_set_type(page, reset_type);
}
}
uint32_t checksum = BUF_NO_CHECKSUM_MAGIC;
switch (srv_checksum_algorithm_t(srv_checksum_algorithm)) {
case SRV_CHECKSUM_ALGORITHM_INNODB:
case SRV_CHECKSUM_ALGORITHM_STRICT_INNODB:
checksum = buf_calc_page_new_checksum(page);
mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM,
checksum);
/* With the InnoDB checksum, we overwrite the first 4 bytes of
the end lsn field to store the old formula checksum. Since it
depends also on the field FIL_PAGE_SPACE_OR_CHKSUM, it has to
be calculated after storing the new formula checksum. */
checksum = buf_calc_page_old_checksum(page);
break;
case SRV_CHECKSUM_ALGORITHM_FULL_CRC32:
case SRV_CHECKSUM_ALGORITHM_STRICT_FULL_CRC32:
case SRV_CHECKSUM_ALGORITHM_CRC32:
case SRV_CHECKSUM_ALGORITHM_STRICT_CRC32:
/* In other cases we write the same checksum to both fields. */
checksum = buf_calc_page_crc32(page);
mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM,
checksum);
break;
case SRV_CHECKSUM_ALGORITHM_NONE:
case SRV_CHECKSUM_ALGORITHM_STRICT_NONE:
mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM,
checksum);
break;
/* no default so the compiler will emit a warning if
new enum is added and not handled here */
}
mach_write_to_4(page + srv_page_size - FIL_PAGE_END_LSN_OLD_CHKSUM,
checksum);
}
/** Reserve a buffer for compression.
@param[in,out] slot reserved slot */
static void buf_tmp_reserve_compression_buf(buf_tmp_buffer_t* slot)
{
if (slot->comp_buf)
return;
/* Both Snappy and LZO compression methods require that the output
buffer be bigger than input buffer. Adjust the allocated size. */
ulint size= srv_page_size;
#ifdef HAVE_LZO
size+= LZO1X_1_15_MEM_COMPRESS;
#elif defined HAVE_SNAPPY
size= snappy_max_compressed_length(size);
#endif
slot->comp_buf= static_cast<byte*>(aligned_malloc(size, srv_page_size));
}
/** Encrypt a buffer of temporary tablespace
@param[in] offset Page offset
@param[in] s Page to encrypt
@param[in,out] d Output buffer
@return encrypted buffer or NULL */
static byte* buf_tmp_page_encrypt(ulint offset, const byte* s, byte* d)
{
/* Calculate the start offset in a page */
uint srclen= static_cast<uint>(srv_page_size) -
(FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION +
FIL_PAGE_FCRC32_CHECKSUM);
const byte* src= s + FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION;
byte* dst= d + FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION;
memcpy(d, s, FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION);
if (!log_tmp_block_encrypt(src, srclen, dst, (offset * srv_page_size), true))
return NULL;
const ulint payload= srv_page_size - FIL_PAGE_FCRC32_CHECKSUM;
mach_write_to_4(d + payload, ut_crc32(d, payload));
srv_stats.pages_encrypted.inc();
srv_stats.n_temp_blocks_encrypted.inc();
return d;
}
/** Encryption and page_compression hook that is called just before
a page is written to disk.
@param[in,out] space tablespace
@param[in,out] bpage buffer page
@param[in] s physical page frame that is being encrypted
@return page frame to be written to file
(may be src_frame or an encrypted/compressed copy of it) */
static byte* buf_page_encrypt(fil_space_t* space, buf_page_t* bpage, byte* s)
{
if (bpage->status == buf_page_t::FREED) {
return s;
}
ut_ad(space->id == bpage->id.space());
bpage->real_size = srv_page_size;
ut_d(fil_page_type_validate(space, s));
switch (bpage->id.page_no()) {
case TRX_SYS_PAGE_NO:
if (bpage->id.space() != TRX_SYS_SPACE)
break;
/* The TRX_SYS page is neither encrypted nor compressed, because
it contains the address of the doublewrite buffer. */
/* fall through */
case 0:
/* Page 0 of a tablespace is not encrypted/compressed */
return s;
}
fil_space_crypt_t *crypt_data= space->crypt_data;
bool encrypted, page_compressed;
if (space->purpose == FIL_TYPE_TEMPORARY)
{
ut_ad(!crypt_data);
encrypted= innodb_encrypt_temporary_tables;
page_compressed= false;
}
else
{
encrypted= crypt_data && !crypt_data->not_encrypted() &&
crypt_data->type != CRYPT_SCHEME_UNENCRYPTED &&
(!crypt_data->is_default_encryption() || srv_encrypt_tables);
page_compressed= space->is_compressed();
}
const bool full_crc32= space->full_crc32();
if (!encrypted && !page_compressed)
{
/* No need to encrypt or compress. Clear key-version & crypt-checksum. */
static_assert(FIL_PAGE_FCRC32_KEY_VERSION % 4 == 0, "alignment");
static_assert(FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION % 4 == 2,
"not perfect alignment");
if (full_crc32)
memset_aligned<4>(s + FIL_PAGE_FCRC32_KEY_VERSION, 0, 4);
else
memset_aligned<2>(s + FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION, 0, 8);
return s;
}
static_assert(FIL_PAGE_FCRC32_END_LSN % 4 == 0, "alignment");
static_assert(FIL_PAGE_LSN % 8 == 0, "alignment");
if (full_crc32)
memcpy_aligned<4>(s + srv_page_size - FIL_PAGE_FCRC32_END_LSN,
FIL_PAGE_LSN + 4 + s, 4);
ut_ad(!bpage->zip_size() || !page_compressed);
/* Find free slot from temporary memory array */
buf_tmp_buffer_t *slot= buf_pool.io_buf_reserve();
ut_a(slot);
slot->allocate();
slot->out_buf= NULL;
bpage->slot= slot;
byte *d= slot->crypt_buf;
if (!page_compressed)
{
not_compressed:
byte *tmp= space->purpose == FIL_TYPE_TEMPORARY
? buf_tmp_page_encrypt(bpage->id.page_no(), s, d)
: fil_space_encrypt(space, bpage->id.page_no(), s, d);
slot->out_buf= d= tmp;
ut_d(fil_page_type_validate(space, tmp));
}
else
{
ut_ad(space->purpose != FIL_TYPE_TEMPORARY);
/* First we compress the page content */
buf_tmp_reserve_compression_buf(slot);
byte *tmp= slot->comp_buf;
ulint len= fil_page_compress(s, tmp, space->flags,
fil_space_get_block_size(space,
bpage->id.page_no()),
encrypted);
if (!len)
goto not_compressed;
bpage->real_size= len;
if (full_crc32)
{
ut_d(bool compressed = false);
len= buf_page_full_crc32_size(tmp,
#ifdef UNIV_DEBUG
&compressed,
#else
NULL,
#endif
NULL);
ut_ad(compressed);
}
/* Workaround for MDEV-15527. */
memset(tmp + len, 0 , srv_page_size - len);
ut_d(fil_page_type_validate(space, tmp));
if (encrypted)
tmp = fil_space_encrypt(space, bpage->id.page_no(), tmp, d);
if (full_crc32)
{
static_assert(FIL_PAGE_FCRC32_CHECKSUM == 4, "alignment");
mach_write_to_4(tmp + len - 4, ut_crc32(tmp, len - 4));
ut_ad(!buf_page_is_corrupted(true, tmp, space->flags));
}
slot->out_buf= d= tmp;
}
ut_d(fil_page_type_validate(space, d));
return d;
}
/** The following function deals with freed page during flushing.
i) Writing zeros to the file asynchronously if scrubbing is enabled
ii) Punch the hole to the file synchoronously if page_compressed is
enabled for the tablespace
This function also resets the IO_FIX to IO_NONE and making the
page status as NORMAL. It initiates the write to the file only after
releasing the page from flush list and its associated mutex.
@param[in,out] bpage freed buffer page
@param[in] space tablespace object of the freed page */
static void buf_flush_freed_page(buf_page_t *bpage, fil_space_t *space)
{
ut_ad(buf_page_in_file(bpage));
const bool uncompressed= buf_page_get_state(bpage) == BUF_BLOCK_FILE_PAGE;
BPageMutex *block_mutex= uncompressed
? &reinterpret_cast<buf_block_t*>(bpage)->mutex
: &buf_pool.zip_mutex;
mutex_enter(&buf_pool.mutex);
mutex_enter(block_mutex);
buf_page_set_io_fix(bpage, BUF_IO_NONE);
bpage->status= buf_page_t::NORMAL;
buf_flush_write_complete(bpage, false);
if (uncompressed)
rw_lock_sx_unlock_gen(&reinterpret_cast<buf_block_t*>(bpage)->lock,
BUF_IO_WRITE);
buf_pool.stat.n_pages_written++;
mutex_exit(&buf_pool.mutex);
const page_id_t page_id(bpage->id);
const auto zip_size= bpage->zip_size();
mutex_exit(block_mutex);
const bool punch_hole=
#if defined(HAVE_FALLOC_PUNCH_HOLE_AND_KEEP_SIZE) || defined(_WIN32)
space->is_compressed() ||
#endif
false;
ut_ad(space->id == page_id.space());
ut_ad(space->zip_size() == zip_size);
if (punch_hole || srv_immediate_scrub_data_uncompressed)
fil_io(IORequestWrite, punch_hole, page_id, zip_size, 0,
zip_size ? zip_size : srv_page_size,
const_cast<byte*>(field_ref_zero), nullptr, false, punch_hole);
space->release_for_io();
}
/********************************************************************//**
Does an asynchronous write of a buffer page. NOTE: when the
doublewrite buffer is used, we must call
buf_dblwr_flush_buffered_writes after we have posted a batch of
writes! */
static
void
buf_flush_write_block_low(
/*======================*/
buf_page_t* bpage, /*!< in: buffer block to write */
buf_flush_t flush_type, /*!< in: type of flush */
bool sync) /*!< in: true if sync IO request */
{
fil_space_t* space = fil_space_acquire_for_io(bpage->id.space());
if (!space) {
return;
}
ut_ad(space->purpose == FIL_TYPE_TEMPORARY
|| space->purpose == FIL_TYPE_IMPORT
|| space->purpose == FIL_TYPE_TABLESPACE);
ut_ad((space->purpose == FIL_TYPE_TEMPORARY)
== (space == fil_system.temp_space));
page_t* frame = NULL;
const bool full_crc32 = space->full_crc32();
DBUG_PRINT("ib_buf", ("flush %s %u page %u:%u",
sync ? "sync" : "async", (unsigned) flush_type,
bpage->id.space(), bpage->id.page_no()));
ut_ad(buf_page_in_file(bpage));
/* We are not holding buf_pool.mutex or block_mutex here.
Nevertheless, it is safe to access bpage, because it is
io_fixed and oldest_modification != 0. Thus, it cannot be
relocated in the buffer pool or removed from flush_list or
LRU_list. */
ut_ad(!mutex_own(&buf_pool.mutex));
ut_ad(!mutex_own(&buf_pool.flush_list_mutex));
ut_ad(!buf_page_get_mutex(bpage)->is_owned());
ut_ad(buf_page_get_io_fix(bpage) == BUF_IO_WRITE);
ut_ad(bpage->oldest_modification != 0);
switch (buf_page_get_state(bpage)) {
case BUF_BLOCK_POOL_WATCH:
case BUF_BLOCK_ZIP_PAGE: /* The page should be dirty. */
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_ZIP_DIRTY:
frame = bpage->zip.data;
ut_a(page_zip_verify_checksum(frame, bpage->zip_size()));
break;
case BUF_BLOCK_FILE_PAGE:
frame = bpage->zip.data;
if (!frame) {
frame = ((buf_block_t*) bpage)->frame;
}
/* Skip the encryption and compression for the
freed page */
if (bpage->status == buf_page_t::FREED) {
break;
}
byte* page = reinterpret_cast<const buf_block_t*>(bpage)->frame;
if (full_crc32) {
page = buf_page_encrypt(space, bpage, page);
frame = page;
}
buf_flush_init_for_writing(
reinterpret_cast<const buf_block_t*>(bpage), page,
bpage->zip.data ? &bpage->zip : NULL, full_crc32);
break;
}
if (!full_crc32) {
frame = buf_page_encrypt(space, bpage, frame);
}
if (UNIV_LIKELY(space->purpose == FIL_TYPE_TABLESPACE)) {
const lsn_t lsn = mach_read_from_8(frame + FIL_PAGE_LSN);
ut_ad(lsn);
ut_ad(lsn >= bpage->oldest_modification);
ut_ad(!srv_read_only_mode);
log_write_up_to(lsn, true);
} else {
ut_ad(space->atomic_write_supported);
}
if (bpage->status == buf_page_t::FREED) {
buf_flush_freed_page(bpage, space);
return;
}
const bool use_doublewrite = bpage->status != buf_page_t::INIT_ON_FLUSH
&& space->use_doublewrite();
if (!use_doublewrite) {
ulint type = IORequest::WRITE;
IORequest request(type, bpage);
/* TODO: pass the tablespace to fil_io() */
fil_io(request,
sync, bpage->id, bpage->zip_size(), 0,
bpage->physical_size(),
frame, bpage);
} else {
ut_ad(!srv_read_only_mode);
if (flush_type == BUF_FLUSH_SINGLE_PAGE) {
buf_dblwr_write_single_page(bpage, sync);
} else {
ut_ad(!sync);
buf_dblwr_add_to_batch(bpage);
}
}
/* When doing single page flushing the IO is done synchronously
and we flush the changes to disk only for the tablespace we
are working on. */
if (sync) {
ut_ad(flush_type == BUF_FLUSH_SINGLE_PAGE);
if (space->purpose != FIL_TYPE_TEMPORARY) {
fil_flush(space);
}
/* The tablespace could already have been dropped,
because fil_io(request, sync) would already have
decremented the node->n_pending. However,
buf_page_io_complete() only needs to look up the
tablespace during read requests, not during writes. */
ut_ad(buf_page_get_io_fix(bpage) == BUF_IO_WRITE);
#ifdef UNIV_DEBUG
dberr_t err =
#endif
/* true means we want to evict this page from the
LRU list as well. */
buf_page_io_complete(bpage, use_doublewrite, true);
ut_ad(err == DB_SUCCESS);
}
space->release_for_io();
/* Increment the counter of I/O operations used
for selecting LRU policy. */
buf_LRU_stat_inc_io();
}
/** Write a flushable page asynchronously from the buffer pool to a file.
NOTE: 1. in simulated aio we must call os_aio_simulated_wake_handler_threads
after we have posted a batch of writes! 2. buf_page_get_mutex(bpage) must be
held upon entering this function. The LRU list mutex must be held if flush_type
== BUF_FLUSH_SINGLE_PAGE. Both mutexes will be released by this function if it
returns true.
@param[in] bpage buffer control block
@param[in] flush_type type of flush
@param[in] sync true if sync IO request
@return whether the page was flushed */
bool buf_flush_page(buf_page_t* bpage, buf_flush_t flush_type, bool sync)
{
BPageMutex* block_mutex;
ut_ad(flush_type < BUF_FLUSH_N_TYPES);
ut_ad(mutex_own(&buf_pool.mutex));
ut_ad(buf_page_in_file(bpage));
ut_ad(!sync || flush_type == BUF_FLUSH_SINGLE_PAGE);
block_mutex = buf_page_get_mutex(bpage);
ut_ad(mutex_own(block_mutex));
ut_ad(buf_flush_ready_for_flush(bpage, flush_type));
bool is_uncompressed = (buf_page_get_state(bpage)
== BUF_BLOCK_FILE_PAGE);
ut_ad(is_uncompressed == (block_mutex != &buf_pool.zip_mutex));
rw_lock_t* rw_lock;
bool no_fix_count = bpage->buf_fix_count == 0;
if (!is_uncompressed) {
rw_lock = NULL;
} else if (!(no_fix_count || flush_type == BUF_FLUSH_LIST)
|| (!no_fix_count
&& srv_shutdown_state <= SRV_SHUTDOWN_CLEANUP
&& fsp_is_system_temporary(bpage->id.space()))) {
/* This is a heuristic, to avoid expensive SX attempts. */
/* For table residing in temporary tablespace sync is done
using IO_FIX and so before scheduling for flush ensure that
page is not fixed. */
return false;
} else {
rw_lock = &reinterpret_cast<buf_block_t*>(bpage)->lock;
if (flush_type != BUF_FLUSH_LIST
&& !rw_lock_sx_lock_nowait(rw_lock, BUF_IO_WRITE)) {
return false;
}
}
/* We are committed to flushing by the time we get here */
buf_page_set_io_fix(bpage, BUF_IO_WRITE);
buf_page_set_flush_type(bpage, flush_type);
if (buf_pool.n_flush[flush_type] == 0) {
os_event_reset(buf_pool.no_flush[flush_type]);
}
++buf_pool.n_flush[flush_type];
ut_ad(buf_pool.n_flush[flush_type] != 0);
mutex_exit(block_mutex);
mutex_exit(&buf_pool.mutex);
if (flush_type == BUF_FLUSH_LIST
&& is_uncompressed
&& !rw_lock_sx_lock_nowait(rw_lock, BUF_IO_WRITE)) {
if (!fsp_is_system_temporary(bpage->id.space())) {
/* avoiding deadlock possibility involves
doublewrite buffer, should flush it, because
it might hold the another block->lock. */
buf_dblwr_flush_buffered_writes();
} else {
buf_dblwr_sync_datafiles();
}
rw_lock_sx_lock_gen(rw_lock, BUF_IO_WRITE);
}
/* Even though bpage is not protected by any mutex at this
point, it is safe to access bpage, because it is io_fixed and
oldest_modification != 0. Thus, it cannot be relocated in the
buffer pool or removed from flush_list or LRU_list. */
buf_flush_write_block_low(bpage, flush_type, sync);
return true;
}
# if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
/** Writes a flushable page asynchronously from the buffer pool to a file.
NOTE: block and LRU list mutexes must be held upon entering this function, and
they will be released by this function after flushing. This is loosely based on
buf_flush_batch() and buf_flush_page().
@param[in,out] block buffer control block
@return whether the page was flushed and the mutex released */
bool buf_flush_page_try(buf_block_t* block)
{
ut_ad(mutex_own(&buf_pool.mutex));
ut_ad(buf_block_get_state(block) == BUF_BLOCK_FILE_PAGE);
ut_ad(buf_page_mutex_own(block));
if (!buf_flush_ready_for_flush(&block->page, BUF_FLUSH_SINGLE_PAGE)) {
return false;
}
/* The following call will release the buf_pool and block mutex. */
return buf_flush_page(&block->page, BUF_FLUSH_SINGLE_PAGE, true);
}
# endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
/** Check the page is in buffer pool and can be flushed.
@param[in] page_id page id
@param[in] flush_type BUF_FLUSH_LRU or BUF_FLUSH_LIST
@return true if the page can be flushed. */
static
bool
buf_flush_check_neighbor(
const page_id_t page_id,
buf_flush_t flush_type)
{
buf_page_t* bpage;
bool ret;
ut_ad(flush_type == BUF_FLUSH_LRU
|| flush_type == BUF_FLUSH_LIST);
mutex_enter(&buf_pool.mutex);
bpage = buf_page_hash_get(page_id);
if (!bpage) {
mutex_exit(&buf_pool.mutex);
return(false);
}
ut_a(buf_page_in_file(bpage));
/* We avoid flushing 'non-old' blocks in an LRU flush,
because the flushed blocks are soon freed */
ret = false;
if (flush_type != BUF_FLUSH_LRU || buf_page_is_old(bpage)) {
BPageMutex* block_mutex = buf_page_get_mutex(bpage);
mutex_enter(block_mutex);
if (buf_flush_ready_for_flush(bpage, flush_type)) {
ret = true;
}
mutex_exit(block_mutex);
}
mutex_exit(&buf_pool.mutex);
return(ret);
}
/** Flushes to disk all flushable pages within the flush area.
@param[in] page_id page id
@param[in] flush_type BUF_FLUSH_LRU or BUF_FLUSH_LIST
@param[in] n_flushed number of pages flushed so far in this batch
@param[in] n_to_flush maximum number of pages we are allowed to flush
@return number of pages flushed */
static
ulint
buf_flush_try_neighbors(
const page_id_t page_id,
buf_flush_t flush_type,
ulint n_flushed,
ulint n_to_flush)
{
ulint i;
ulint low;
ulint high;
ulint count = 0;
ut_ad(flush_type == BUF_FLUSH_LRU || flush_type == BUF_FLUSH_LIST);
fil_space_t* space = fil_space_acquire_for_io(page_id.space());
if (!space) {
return 0;
}
if (UT_LIST_GET_LEN(buf_pool.LRU) < BUF_LRU_OLD_MIN_LEN
|| !srv_flush_neighbors || !space->is_rotational()) {
/* If there is little space or neighbor flushing is
not enabled then just flush the victim. */
low = page_id.page_no();
high = page_id.page_no() + 1;
} else {
/* When flushed, dirty blocks are searched in
neighborhoods of this size, and flushed along with the
original page. */
ulint buf_flush_area;
buf_flush_area = ut_min(
buf_pool.read_ahead_area,
buf_pool.curr_size / 16);
low = (page_id.page_no() / buf_flush_area) * buf_flush_area;
high = (page_id.page_no() / buf_flush_area + 1) * buf_flush_area;
if (srv_flush_neighbors == 1) {
/* adjust 'low' and 'high' to limit
for contiguous dirty area */
if (page_id.page_no() > low) {
for (i = page_id.page_no() - 1; i >= low; i--) {
if (!buf_flush_check_neighbor(
page_id_t(page_id.space(), i),
flush_type)) {
break;
}
if (i == low) {
/* Avoid overwrap when low == 0
and calling
buf_flush_check_neighbor() with
i == (ulint) -1 */
i--;
break;
}
}
low = i + 1;
}
for (i = page_id.page_no() + 1;
i < high
&& buf_flush_check_neighbor(
page_id_t(page_id.space(), i),
flush_type);
i++) {
/* do nothing */
}
high = i;
}
}
if (high > space->size) {
high = space->size;
}
DBUG_PRINT("ib_buf", ("flush %u:%u..%u",
page_id.space(),
(unsigned) low, (unsigned) high));
for (ulint i = low; i < high; i++) {
buf_page_t* bpage;
if ((count + n_flushed) >= n_to_flush) {
/* We have already flushed enough pages and
should call it a day. There is, however, one
exception. If the page whose neighbors we
are flushing has not been flushed yet then
we'll try to flush the victim that we
selected originally. */
if (i <= page_id.page_no()) {
i = page_id.page_no();
} else {
break;
}
}
const page_id_t cur_page_id(page_id.space(), i);
mutex_enter(&buf_pool.mutex);
bpage = buf_page_hash_get(cur_page_id);
if (bpage == NULL) {
mutex_exit(&buf_pool.mutex);
continue;
}
ut_a(buf_page_in_file(bpage));
/* We avoid flushing 'non-old' blocks in an LRU flush,
because the flushed blocks are soon freed */
if (flush_type != BUF_FLUSH_LRU
|| i == page_id.page_no()
|| buf_page_is_old(bpage)) {
BPageMutex* block_mutex = buf_page_get_mutex(bpage);
mutex_enter(block_mutex);
if (buf_flush_ready_for_flush(bpage, flush_type)
&& (i == page_id.page_no()
|| bpage->buf_fix_count == 0)) {
/* We also try to flush those
neighbors != offset */
if (buf_flush_page(bpage, flush_type, false)) {
++count;
} else {
mutex_exit(block_mutex);
mutex_exit(&buf_pool.mutex);
}
continue;
} else {
mutex_exit(block_mutex);
}
}
mutex_exit(&buf_pool.mutex);
}
space->release_for_io();
if (count > 1) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_FLUSH_NEIGHBOR_TOTAL_PAGE,
MONITOR_FLUSH_NEIGHBOR_COUNT,
MONITOR_FLUSH_NEIGHBOR_PAGES,
(count - 1));
}
return(count);
}
/** Check if the block is modified and ready for flushing.
If the the block is ready to flush then flush the page and try o flush
its neighbors.
@param[in] bpage buffer control block,
must be buf_page_in_file(bpage)
@param[in] flush_type BUF_FLUSH_LRU or BUF_FLUSH_LIST
@param[in] n_to_flush number of pages to flush
@param[in,out] count number of pages flushed
@return TRUE if buf_pool mutex was released during this function.
This does not guarantee that some pages were written as well.
Number of pages written are incremented to the count. */
static
bool
buf_flush_page_and_try_neighbors(
buf_page_t* bpage,
buf_flush_t flush_type,
ulint n_to_flush,
ulint* count)
{
ut_ad(mutex_own(&buf_pool.mutex));
bool flushed;
BPageMutex* block_mutex = buf_page_get_mutex(bpage);
mutex_enter(block_mutex);
ut_a(buf_page_in_file(bpage));
if (buf_flush_ready_for_flush(bpage, flush_type)) {
const page_id_t page_id = bpage->id;
mutex_exit(block_mutex);
mutex_exit(&buf_pool.mutex);
/* Try to flush also all the neighbors */
*count += buf_flush_try_neighbors(
page_id, flush_type, *count, n_to_flush);
mutex_enter(&buf_pool.mutex);
flushed = true;
} else {
mutex_exit(block_mutex);
flushed = false;
}
ut_ad(mutex_own(&buf_pool.mutex));
return(flushed);
}
/*******************************************************************//**
This utility moves the uncompressed frames of pages to the free list.
Note that this function does not actually flush any data to disk. It
just detaches the uncompressed frames from the compressed pages at the
tail of the unzip_LRU and puts those freed frames in the free list.
Note that it is a best effort attempt and it is not guaranteed that
after a call to this function there will be 'max' blocks in the free
list.
@param[in] max desired number of blocks in the free_list
@return number of blocks moved to the free list. */
static ulint buf_free_from_unzip_LRU_list_batch(ulint max)
{
ulint scanned = 0;
ulint count = 0;
ulint free_len = UT_LIST_GET_LEN(buf_pool.free);
ulint lru_len = UT_LIST_GET_LEN(buf_pool.unzip_LRU);
ut_ad(mutex_own(&buf_pool.mutex));
buf_block_t* block = UT_LIST_GET_LAST(buf_pool.unzip_LRU);
while (block != NULL
&& count < max
&& free_len < srv_LRU_scan_depth
&& lru_len > UT_LIST_GET_LEN(buf_pool.LRU) / 10) {
++scanned;
if (buf_LRU_free_page(&block->page, false)) {
/* Block was freed. buf_pool.mutex potentially
released and reacquired */
++count;
block = UT_LIST_GET_LAST(buf_pool.unzip_LRU);
} else {
block = UT_LIST_GET_PREV(unzip_LRU, block);
}
free_len = UT_LIST_GET_LEN(buf_pool.free);
lru_len = UT_LIST_GET_LEN(buf_pool.unzip_LRU);
}
ut_ad(mutex_own(&buf_pool.mutex));
if (scanned) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_LRU_BATCH_SCANNED,
MONITOR_LRU_BATCH_SCANNED_NUM_CALL,
MONITOR_LRU_BATCH_SCANNED_PER_CALL,
scanned);
}
return(count);
}
/** Flush dirty blocks from the end of the LRU list.
The calling thread is not allowed to own any latches on pages!
@param[in] max desired number of blocks to make available
in the free list (best effort; not guaranteed)
@param[out] n counts of flushed and evicted pages */
static void buf_flush_LRU_list_batch(ulint max, flush_counters_t* n)
{
buf_page_t* bpage;
ulint scanned = 0;
ulint free_len = UT_LIST_GET_LEN(buf_pool.free);
ulint lru_len = UT_LIST_GET_LEN(buf_pool.LRU);
ulint withdraw_depth = 0;
n->flushed = 0;
n->evicted = 0;
n->unzip_LRU_evicted = 0;
ut_ad(mutex_own(&buf_pool.mutex));
if (buf_pool.curr_size < buf_pool.old_size
&& buf_pool.withdraw_target > 0) {
withdraw_depth = buf_pool.withdraw_target
- UT_LIST_GET_LEN(buf_pool.withdraw);
}
for (bpage = UT_LIST_GET_LAST(buf_pool.LRU);
bpage != NULL && n->flushed + n->evicted < max
&& free_len < srv_LRU_scan_depth + withdraw_depth
&& lru_len > BUF_LRU_MIN_LEN;
++scanned,
bpage = buf_pool.lru_hp.get()) {
buf_page_t* prev = UT_LIST_GET_PREV(LRU, bpage);
buf_pool.lru_hp.set(prev);
BPageMutex* block_mutex = buf_page_get_mutex(bpage);
mutex_enter(block_mutex);
if (buf_flush_ready_for_replace(bpage)) {
/* block is ready for eviction i.e., it is
clean and is not IO-fixed or buffer fixed. */
mutex_exit(block_mutex);
if (buf_LRU_free_page(bpage, true)) {
++n->evicted;
}
} else if (buf_flush_ready_for_flush(bpage, BUF_FLUSH_LRU)) {
/* Block is ready for flush. Dispatch an IO
request. The IO helper thread will put it on
free list in IO completion routine. */
mutex_exit(block_mutex);
buf_flush_page_and_try_neighbors(
bpage, BUF_FLUSH_LRU, max, &n->flushed);
} else {
/* Can't evict or dispatch this block. Go to
previous. */
ut_ad(buf_pool.lru_hp.is_hp(prev));
mutex_exit(block_mutex);
}
ut_ad(!mutex_own(block_mutex));
ut_ad(mutex_own(&buf_pool.mutex));
free_len = UT_LIST_GET_LEN(buf_pool.free);
lru_len = UT_LIST_GET_LEN(buf_pool.LRU);
}
buf_pool.lru_hp.set(NULL);
/* We keep track of all flushes happening as part of LRU
flush. When estimating the desired rate at which flush_list
should be flushed, we factor in this value. */
buf_lru_flush_page_count += n->flushed;
ut_ad(mutex_own(&buf_pool.mutex));
if (n->evicted) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_LRU_BATCH_EVICT_TOTAL_PAGE,
MONITOR_LRU_BATCH_EVICT_COUNT,
MONITOR_LRU_BATCH_EVICT_PAGES,
n->evicted);
}
if (scanned) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_LRU_BATCH_SCANNED,
MONITOR_LRU_BATCH_SCANNED_NUM_CALL,
MONITOR_LRU_BATCH_SCANNED_PER_CALL,
scanned);
}
}
/** Flush and move pages from LRU or unzip_LRU list to the free list.
Whether LRU or unzip_LRU is used depends on the state of the system.
@param[in] max desired number of blocks to make available
in the free list (best effort; not guaranteed)
@param[out] n counts of flushed and evicted pages */
static void buf_do_LRU_batch(ulint max, flush_counters_t* n)
{
n->unzip_LRU_evicted = buf_LRU_evict_from_unzip_LRU()
? buf_free_from_unzip_LRU_list_batch(max) : 0;
if (max > n->unzip_LRU_evicted) {
buf_flush_LRU_list_batch(max - n->unzip_LRU_evicted, n);
} else {
n->evicted = 0;
n->flushed = 0;
}
/* Add evicted pages from unzip_LRU to the evicted pages from
the simple LRU. */
n->evicted += n->unzip_LRU_evicted;
}
/** This utility flushes dirty blocks from the end of the flush_list.
The calling thread is not allowed to own any latches on pages!
@param[in] min_n wished minimum mumber of blocks flushed (it is
not guaranteed that the actual number is that big, though)
@param[in] lsn_limit all blocks whose oldest_modification is smaller
than this should be flushed (if their number does not exceed min_n)
@return number of blocks for which the write request was queued;
ULINT_UNDEFINED if there was a flush of the same type already
running */
static ulint buf_do_flush_list_batch(ulint min_n, lsn_t lsn_limit)
{
ulint count = 0;
ulint scanned = 0;
ut_ad(mutex_own(&buf_pool.mutex));
/* Start from the end of the list looking for a suitable
block to be flushed. */
mutex_enter(&buf_pool.flush_list_mutex);
ulint len = UT_LIST_GET_LEN(buf_pool.flush_list);
/* In order not to degenerate this scan to O(n*n) we attempt
to preserve pointer of previous block in the flush list. To do
so we declare it a hazard pointer. Any thread working on the
flush list must check the hazard pointer and if it is removing
the same block then it must reset it. */
for (buf_page_t* bpage = UT_LIST_GET_LAST(buf_pool.flush_list);
count < min_n && bpage != NULL && len > 0
&& bpage->oldest_modification < lsn_limit;
bpage = buf_pool.flush_hp.get(),
++scanned) {
buf_page_t* prev;
ut_a(bpage->oldest_modification > 0);
ut_ad(bpage->in_flush_list);
prev = UT_LIST_GET_PREV(list, bpage);
buf_pool.flush_hp.set(prev);
mutex_exit(&buf_pool.flush_list_mutex);
#ifdef UNIV_DEBUG
bool flushed =
#endif /* UNIV_DEBUG */
buf_flush_page_and_try_neighbors(
bpage, BUF_FLUSH_LIST, min_n, &count);
mutex_enter(&buf_pool.flush_list_mutex);
ut_ad(flushed || buf_pool.flush_hp.is_hp(prev));
--len;
}
buf_pool.flush_hp.set(NULL);
mutex_exit(&buf_pool.flush_list_mutex);
if (scanned) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_FLUSH_BATCH_SCANNED,
MONITOR_FLUSH_BATCH_SCANNED_NUM_CALL,
MONITOR_FLUSH_BATCH_SCANNED_PER_CALL,
scanned);
}
if (count) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_FLUSH_BATCH_TOTAL_PAGE,
MONITOR_FLUSH_BATCH_COUNT,
MONITOR_FLUSH_BATCH_PAGES,
count);
}
ut_ad(mutex_own(&buf_pool.mutex));
return(count);
}
/** This utility flushes dirty blocks from the end of the LRU list or
flush_list.
NOTE 1: in the case of an LRU flush the calling thread may own latches to
pages: to avoid deadlocks, this function must be written so that it cannot
end up waiting for these latches! NOTE 2: in the case of a flush list flush,
the calling thread is not allowed to own any latches on pages!
@param[in] flush_type BUF_FLUSH_LRU or BUF_FLUSH_LIST; if
BUF_FLUSH_LIST, then the caller must not own any latches on pages
@param[in] min_n wished minimum mumber of blocks flushed (it is
not guaranteed that the actual number is that big, though)
@param[in] lsn_limit in the case of BUF_FLUSH_LIST all blocks whose
@param[out] n counts of flushed and evicted pages
oldest_modification is smaller than this should be flushed (if their number
does not exceed min_n), otherwise ignored */
static
void
buf_flush_batch(
buf_flush_t flush_type,
ulint min_n,
lsn_t lsn_limit,
flush_counters_t* n)
{
ut_ad(flush_type == BUF_FLUSH_LRU || flush_type == BUF_FLUSH_LIST);
ut_ad(flush_type == BUF_FLUSH_LRU
|| !sync_check_iterate(dict_sync_check()));
mutex_enter(&buf_pool.mutex);
/* Note: The buffer pool mutex is released and reacquired within
the flush functions. */
switch (flush_type) {
case BUF_FLUSH_LRU:
buf_do_LRU_batch(min_n, n);
break;
case BUF_FLUSH_LIST:
n->flushed = buf_do_flush_list_batch(min_n, lsn_limit);
n->evicted = 0;
break;
default:
ut_error;
}
mutex_exit(&buf_pool.mutex);
DBUG_LOG("ib_buf", "flush " << flush_type << " completed");
}
/******************************************************************//**
Gather the aggregated stats for both flush list and LRU list flushing.
@param page_count_flush number of pages flushed from the end of the flush_list
@param page_count_LRU number of pages flushed from the end of the LRU list
*/
static
void
buf_flush_stats(
/*============*/
ulint page_count_flush,
ulint page_count_LRU)
{
DBUG_PRINT("ib_buf", ("flush completed, from flush_list %u pages, "
"from LRU_list %u pages",
unsigned(page_count_flush),
unsigned(page_count_LRU)));
srv_stats.buf_pool_flushed.add(page_count_flush + page_count_LRU);
}
/** Start a buffer flush batch for LRU or flush list
@param[in] flush_type BUF_FLUSH_LRU or BUF_FLUSH_LIST
@return whether the flush batch was started (was not already running) */
static bool buf_flush_start(buf_flush_t flush_type)
{
ut_ad(flush_type == BUF_FLUSH_LRU || flush_type == BUF_FLUSH_LIST);
mutex_enter(&buf_pool.mutex);
if (buf_pool.n_flush[flush_type] > 0
|| buf_pool.init_flush[flush_type] == TRUE) {
/* There is already a flush batch of the same type running */
mutex_exit(&buf_pool.mutex);
return(false);
}
buf_pool.init_flush[flush_type] = TRUE;
os_event_reset(buf_pool.no_flush[flush_type]);
mutex_exit(&buf_pool.mutex);
return(true);
}
/** End a buffer flush batch.
@param[in] flush_type BUF_FLUSH_LRU or BUF_FLUSH_LIST */
static void buf_flush_end(buf_flush_t flush_type)
{
mutex_enter(&buf_pool.mutex);
buf_pool.init_flush[flush_type] = FALSE;
buf_pool.try_LRU_scan = TRUE;
if (buf_pool.n_flush[flush_type] == 0) {
/* The running flush batch has ended */
os_event_set(buf_pool.no_flush[flush_type]);
}
mutex_exit(&buf_pool.mutex);
if (!srv_read_only_mode) {
buf_dblwr_flush_buffered_writes();
}
}
/** Wait until a flush batch ends.
@param[in] type BUF_FLUSH_LRU or BUF_FLUSH_LIST */
void buf_flush_wait_batch_end(buf_flush_t type)
{
ut_ad(type == BUF_FLUSH_LRU || type == BUF_FLUSH_LIST);
thd_wait_begin(NULL, THD_WAIT_DISKIO);
os_event_wait(buf_pool.no_flush[type]);
thd_wait_end(NULL);
}
/** Do flushing batch of a given type.
NOTE: The calling thread is not allowed to own any latches on pages!
@param[in] type flush type
@param[in] min_n wished minimum mumber of blocks flushed
(it is not guaranteed that the actual number is that big, though)
@param[in] lsn_limit in the case BUF_FLUSH_LIST all blocks whose
oldest_modification is smaller than this should be flushed (if their number
does not exceed min_n), otherwise ignored
@param[out] n_processed the number of pages which were processed is
passed back to caller. Ignored if NULL
@retval true if a batch was queued successfully.
@retval false if another batch of same type was already running. */
bool
buf_flush_do_batch(
buf_flush_t type,
ulint min_n,
lsn_t lsn_limit,
flush_counters_t* n)
{
ut_ad(type == BUF_FLUSH_LRU || type == BUF_FLUSH_LIST);
if (n != NULL) {
n->flushed = 0;
}
if (!buf_flush_start(type)) {
return(false);
}
buf_flush_batch(type, min_n, lsn_limit, n);
buf_flush_end(type);
return(true);
}
/** Wait until a flush batch of the given lsn ends
@param[in] new_oldest target oldest_modified_lsn to wait for */
void buf_flush_wait_flushed(lsn_t new_oldest)
{
for (;;) {
/* We don't need to wait for fsync of the flushed
blocks, because anyway we need fsync to make chekpoint.
So, we don't need to wait for the batch end here. */
mutex_enter(&buf_pool.flush_list_mutex);
buf_page_t* bpage;
/* FIXME: Keep temporary tablespace pages in a separate flush
list. We would only need to write out temporary pages if the
page is about to be evicted from the buffer pool, and the page
contents is still needed (the page has not been freed). */
for (bpage = UT_LIST_GET_LAST(buf_pool.flush_list);
bpage && fsp_is_system_temporary(bpage->id.space());
bpage = UT_LIST_GET_PREV(list, bpage)) {
ut_ad(bpage->in_flush_list);
}
lsn_t oldest = bpage ? bpage->oldest_modification : 0;
mutex_exit(&buf_pool.flush_list_mutex);
if (oldest == 0 || oldest >= new_oldest) {
break;
}
/* sleep and retry */
os_thread_sleep(buf_flush_wait_flushed_sleep_time);
MONITOR_INC(MONITOR_FLUSH_SYNC_WAITS);
}
}
/** This utility flushes dirty blocks from the end of the flush list.
NOTE: The calling thread is not allowed to own any latches on pages!
@param[in] min_n wished minimum mumber of blocks flushed (it is
not guaranteed that the actual number is that big, though)
@param[in] lsn_limit in the case BUF_FLUSH_LIST all blocks whose
oldest_modification is smaller than this should be flushed (if their number
does not exceed min_n), otherwise ignored
@param[out] n_processed the number of pages which were processed is
passed back to caller. Ignored if NULL.
@retval true if a batch was queued successfully
@retval false if another batch of same type was already running */
bool buf_flush_lists(ulint min_n, lsn_t lsn_limit, ulint *n_processed)
{
flush_counters_t n;
bool success = buf_flush_do_batch(
BUF_FLUSH_LIST, min_n, lsn_limit, &n);
if (n.flushed) {
buf_flush_stats(n.flushed, 0);
}
if (n_processed) {
*n_processed = n.flushed;
}
return success;
}
/******************************************************************//**
This function picks up a single page from the tail of the LRU
list, flushes it (if it is dirty), removes it from page_hash and LRU
list and puts it on the free list. It is called from user threads when
they are unable to find a replaceable page at the tail of the LRU
list i.e.: when the background LRU flushing in the page_cleaner thread
is not fast enough to keep pace with the workload.
@return true if success. */
bool buf_flush_single_page_from_LRU()
{
ulint scanned;
buf_page_t* bpage;
ibool freed;
mutex_enter(&buf_pool.mutex);
for (bpage = buf_pool.single_scan_itr.start(), scanned = 0,
freed = false;
bpage != NULL;
++scanned, bpage = buf_pool.single_scan_itr.get()) {
ut_ad(mutex_own(&buf_pool.mutex));
buf_page_t* prev = UT_LIST_GET_PREV(LRU, bpage);
buf_pool.single_scan_itr.set(prev);
BPageMutex* block_mutex;
block_mutex = buf_page_get_mutex(bpage);
mutex_enter(block_mutex);
if (buf_flush_ready_for_replace(bpage)) {
/* block is ready for eviction i.e., it is
clean and is not IO-fixed or buffer fixed. */
mutex_exit(block_mutex);
if (buf_LRU_free_page(bpage, true)) {
mutex_exit(&buf_pool.mutex);
freed = true;
break;
}
} else if (buf_flush_ready_for_flush(
bpage, BUF_FLUSH_SINGLE_PAGE)) {
/* Block is ready for flush. Try and dispatch an IO
request. We'll put it on free list in IO completion
routine if it is not buffer fixed. The following call
will release the buffer pool and block mutex.
Note: There is no guarantee that this page has actually
been freed, only that it has been flushed to disk */
freed = buf_flush_page(bpage, BUF_FLUSH_SINGLE_PAGE,
true);
if (freed) {
break;
}
mutex_exit(block_mutex);
} else {
mutex_exit(block_mutex);
}
ut_ad(!mutex_own(block_mutex));
}
if (!freed) {
/* Can't find a single flushable page. */
ut_ad(!bpage);
mutex_exit(&buf_pool.mutex);
}
if (scanned) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_LRU_SINGLE_FLUSH_SCANNED,
MONITOR_LRU_SINGLE_FLUSH_SCANNED_NUM_CALL,
MONITOR_LRU_SINGLE_FLUSH_SCANNED_PER_CALL,
scanned);
}
ut_ad(!mutex_own(&buf_pool.mutex));
return(freed);
}
/**
Clear up the tail of the LRU list.
Put replaceable pages at the tail of LRU to the free list.
Flush dirty pages at the tail of LRU to the disk.
The depth to which we scan each buffer pool is controlled by dynamic
config parameter innodb_LRU_scan_depth.
@return total pages flushed */
static ulint buf_flush_LRU_list()
{
ulint scan_depth, withdraw_depth;
flush_counters_t n;
memset(&n, 0, sizeof(flush_counters_t));
/* srv_LRU_scan_depth can be arbitrarily large value.
We cap it with current LRU size. */
mutex_enter(&buf_pool.mutex);
scan_depth = UT_LIST_GET_LEN(buf_pool.LRU);
if (buf_pool.curr_size < buf_pool.old_size
&& buf_pool.withdraw_target > 0) {
withdraw_depth = buf_pool.withdraw_target
- UT_LIST_GET_LEN(buf_pool.withdraw);
} else {
withdraw_depth = 0;
}
mutex_exit(&buf_pool.mutex);
if (withdraw_depth > srv_LRU_scan_depth) {
scan_depth = ut_min(withdraw_depth, scan_depth);
} else {
scan_depth = ut_min(static_cast<ulint>(srv_LRU_scan_depth),
scan_depth);
}
/* Currently one of page_cleaners is the only thread
that can trigger an LRU flush at the same time.
So, it is not possible that a batch triggered during
last iteration is still running, */
buf_flush_do_batch(BUF_FLUSH_LRU, scan_depth, 0, &n);
return(n.flushed);
}
/** Wait for any possible LRU flushes to complete. */
void buf_flush_wait_LRU_batch_end()
{
mutex_enter(&buf_pool.mutex);
bool wait = buf_pool.n_flush[BUF_FLUSH_LRU]
|| buf_pool.init_flush[BUF_FLUSH_LRU];
mutex_exit(&buf_pool.mutex);
if (wait) {
buf_flush_wait_batch_end(BUF_FLUSH_LRU);
}
}
/*********************************************************************//**
Calculates if flushing is required based on number of dirty pages in
the buffer pool.
@return percent of io_capacity to flush to manage dirty page ratio */
static
ulint
af_get_pct_for_dirty()
{
const ulint dirty = UT_LIST_GET_LEN(buf_pool.flush_list);
if (!dirty) {
/* No pages modified */
return 0;
}
/* 1 + is there to avoid division by zero (in case the buffer
pool (including the flush_list) was emptied while we are
looking at it) */
double dirty_pct = 100 * static_cast<double>(dirty)
/ static_cast<double>(1 + UT_LIST_GET_LEN(buf_pool.LRU)
+ UT_LIST_GET_LEN(buf_pool.free));
ut_a(srv_max_dirty_pages_pct_lwm
<= srv_max_buf_pool_modified_pct);
if (srv_max_dirty_pages_pct_lwm == 0) {
/* The user has not set the option to preflush dirty
pages as we approach the high water mark. */
if (dirty_pct >= srv_max_buf_pool_modified_pct) {
/* We have crossed the high water mark of dirty
pages In this case we start flushing at 100% of
innodb_io_capacity. */
return(100);
}
} else if (dirty_pct >= srv_max_dirty_pages_pct_lwm) {
/* We should start flushing pages gradually. */
return(static_cast<ulint>((dirty_pct * 100)
/ (srv_max_buf_pool_modified_pct + 1)));
}
return(0);
}
/*********************************************************************//**
Calculates if flushing is required based on redo generation rate.
@return percent of io_capacity to flush to manage redo space */
static
ulint
af_get_pct_for_lsn(
/*===============*/
lsn_t age) /*!< in: current age of LSN. */
{
lsn_t max_async_age;
lsn_t lsn_age_factor;
lsn_t af_lwm = static_cast<lsn_t>(
srv_adaptive_flushing_lwm
* static_cast<double>(log_get_capacity()) / 100);
if (age < af_lwm) {
/* No adaptive flushing. */
return(0);
}
max_async_age = log_get_max_modified_age_async();
if (age < max_async_age && !srv_adaptive_flushing) {
/* We have still not reached the max_async point and
the user has disabled adaptive flushing. */
return(0);
}
/* If we are here then we know that either:
1) User has enabled adaptive flushing
2) User may have disabled adaptive flushing but we have reached
max_async_age. */
lsn_age_factor = (age * 100) / max_async_age;
ut_ad(srv_max_io_capacity >= srv_io_capacity);
return static_cast<ulint>(
(static_cast<double>(srv_max_io_capacity / srv_io_capacity
* lsn_age_factor)
* sqrt(static_cast<double>(lsn_age_factor))
/ 7.5));
}
/*********************************************************************//**
This function is called approximately once every second by the
page_cleaner thread. Based on various factors it decides if there is a
need to do flushing.
@return number of pages recommended to be flushed
@param last_pages_in the number of pages flushed by the last flush_list
flushing. */
static
ulint
page_cleaner_flush_pages_recommendation(ulint last_pages_in)
{
static lsn_t prev_lsn = 0;
static ulint sum_pages = 0;
static ulint avg_page_rate = 0;
static ulint n_iterations = 0;
static time_t prev_time;
lsn_t oldest_lsn;
lsn_t cur_lsn;
lsn_t age;
lsn_t lsn_rate;
ulint n_pages = 0;
ulint pct_for_dirty = 0;
ulint pct_for_lsn = 0;
ulint pct_total = 0;
cur_lsn = log_sys.get_lsn();
if (prev_lsn == 0) {
/* First time around. */
prev_lsn = cur_lsn;
prev_time = time(NULL);
return(0);
}
if (prev_lsn == cur_lsn) {
return(0);
}
sum_pages += last_pages_in;
time_t curr_time = time(NULL);
double time_elapsed = difftime(curr_time, prev_time);
/* We update our variables every srv_flushing_avg_loops
iterations to smooth out transition in workload. */
if (++n_iterations >= srv_flushing_avg_loops
|| time_elapsed >= static_cast<double>(srv_flushing_avg_loops)) {
if (time_elapsed < 1) {
time_elapsed = 1;
}
avg_page_rate = static_cast<ulint>(
((static_cast<double>(sum_pages)
/ time_elapsed)
+ static_cast<double>(avg_page_rate)) / 2);
/* How much LSN we have generated since last call. */
lsn_rate = static_cast<lsn_t>(
static_cast<double>(cur_lsn - prev_lsn)
/ time_elapsed);
lsn_avg_rate = (lsn_avg_rate + lsn_rate) / 2;
/* aggregate stats of all slots */
mutex_enter(&page_cleaner.mutex);
ulint flush_tm = page_cleaner.flush_time;
ulint flush_pass = page_cleaner.flush_pass;
page_cleaner.flush_time = 0;
page_cleaner.flush_pass = 0;
ulint lru_tm = page_cleaner.slot.flush_lru_time;
ulint list_tm = page_cleaner.slot.flush_list_time;
ulint lru_pass = page_cleaner.slot.flush_lru_pass;
ulint list_pass = page_cleaner.slot.flush_list_pass;
page_cleaner.slot.flush_lru_time = 0;
page_cleaner.slot.flush_lru_pass = 0;
page_cleaner.slot.flush_list_time = 0;
page_cleaner.slot.flush_list_pass = 0;
mutex_exit(&page_cleaner.mutex);
/* minimum values are 1, to avoid dividing by zero. */
if (lru_tm < 1) {
lru_tm = 1;
}
if (list_tm < 1) {
list_tm = 1;
}
if (flush_tm < 1) {
flush_tm = 1;
}
if (lru_pass < 1) {
lru_pass = 1;
}
if (list_pass < 1) {
list_pass = 1;
}
if (flush_pass < 1) {
flush_pass = 1;
}
MONITOR_SET(MONITOR_FLUSH_ADAPTIVE_AVG_TIME_SLOT,
list_tm / list_pass);
MONITOR_SET(MONITOR_LRU_BATCH_FLUSH_AVG_TIME_SLOT,
lru_tm / lru_pass);
MONITOR_SET(MONITOR_FLUSH_ADAPTIVE_AVG_TIME_THREAD,
list_tm / flush_pass);
MONITOR_SET(MONITOR_LRU_BATCH_FLUSH_AVG_TIME_THREAD,
lru_tm / flush_pass);
MONITOR_SET(MONITOR_FLUSH_ADAPTIVE_AVG_TIME_EST,
flush_tm * list_tm / flush_pass
/ (list_tm + lru_tm));
MONITOR_SET(MONITOR_LRU_BATCH_FLUSH_AVG_TIME_EST,
flush_tm * lru_tm / flush_pass
/ (list_tm + lru_tm));
MONITOR_SET(MONITOR_FLUSH_AVG_TIME, flush_tm / flush_pass);
MONITOR_SET(MONITOR_FLUSH_ADAPTIVE_AVG_PASS, list_pass);
MONITOR_SET(MONITOR_LRU_BATCH_FLUSH_AVG_PASS, lru_pass);
MONITOR_SET(MONITOR_FLUSH_AVG_PASS, flush_pass);
prev_lsn = cur_lsn;
prev_time = curr_time;
n_iterations = 0;
sum_pages = 0;
}
oldest_lsn = buf_pool.get_oldest_modification();
ut_ad(oldest_lsn <= log_get_lsn());
age = cur_lsn > oldest_lsn ? cur_lsn - oldest_lsn : 0;
pct_for_dirty = af_get_pct_for_dirty();
pct_for_lsn = af_get_pct_for_lsn(age);
pct_total = ut_max(pct_for_dirty, pct_for_lsn);
/* Estimate pages to be flushed for the lsn progress */
lsn_t target_lsn = oldest_lsn
+ lsn_avg_rate * buf_flush_lsn_scan_factor;
ulint pages_for_lsn = 0;
mutex_enter(&buf_pool.flush_list_mutex);
for (buf_page_t* b = UT_LIST_GET_LAST(buf_pool.flush_list);
b != NULL;
b = UT_LIST_GET_PREV(list, b)) {
if (b->oldest_modification > target_lsn) {
break;
}
++pages_for_lsn;
}
mutex_exit(&buf_pool.flush_list_mutex);
mutex_enter(&page_cleaner.mutex);
ut_ad(page_cleaner.slot.state == PAGE_CLEANER_STATE_NONE);
page_cleaner.slot.n_pages_requested
= pages_for_lsn / buf_flush_lsn_scan_factor + 1;
mutex_exit(&page_cleaner.mutex);
pages_for_lsn /= buf_flush_lsn_scan_factor;
if (pages_for_lsn < 1) {
pages_for_lsn = 1;
}
/* Cap the maximum IO capacity that we are going to use by
max_io_capacity. Limit the value to avoid too quick increase */
pages_for_lsn = std::min<ulint>(
pages_for_lsn, srv_max_io_capacity * 2);
n_pages = (ulint(double(srv_io_capacity) * double(pct_total) / 100.0)
+ avg_page_rate + pages_for_lsn) / 3;
if (n_pages > srv_max_io_capacity) {
n_pages = srv_max_io_capacity;
}
mutex_enter(&page_cleaner.mutex);
ut_ad(page_cleaner.n_slots_requested == 0);
ut_ad(page_cleaner.n_slots_flushing == 0);
ut_ad(page_cleaner.n_slots_finished == 0);
/* if REDO has enough of free space,
don't care about age distribution of pages */
if (pct_for_lsn > 30) {
page_cleaner.slot.n_pages_requested *= n_pages
/ pages_for_lsn + 1;
} else {
page_cleaner.slot.n_pages_requested = n_pages;
}
mutex_exit(&page_cleaner.mutex);
MONITOR_SET(MONITOR_FLUSH_N_TO_FLUSH_REQUESTED, n_pages);
MONITOR_SET(MONITOR_FLUSH_N_TO_FLUSH_BY_AGE, pages_for_lsn);
MONITOR_SET(MONITOR_FLUSH_AVG_PAGE_RATE, avg_page_rate);
MONITOR_SET(MONITOR_FLUSH_LSN_AVG_RATE, lsn_avg_rate);
MONITOR_SET(MONITOR_FLUSH_PCT_FOR_DIRTY, pct_for_dirty);
MONITOR_SET(MONITOR_FLUSH_PCT_FOR_LSN, pct_for_lsn);
return(n_pages);
}
/*********************************************************************//**
Puts the page_cleaner thread to sleep if it has finished work in less
than a second
@retval 0 wake up by event set,
@retval OS_SYNC_TIME_EXCEEDED if timeout was exceeded
@param next_loop_time time when next loop iteration should start
@param sig_count zero or the value returned by previous call of
os_event_reset()
@param cur_time current time as in ut_time_ms() */
static
ulint
pc_sleep_if_needed(
/*===============*/
ulint next_loop_time,
int64_t sig_count,
ulint cur_time)
{
/* No sleep if we are cleaning the buffer pool during the shutdown
with everything else finished */
if (srv_shutdown_state == SRV_SHUTDOWN_FLUSH_PHASE)
return OS_SYNC_TIME_EXCEEDED;
if (next_loop_time > cur_time) {
/* Get sleep interval in micro seconds. We use
ut_min() to avoid long sleep in case of wrap around. */
ulint sleep_us;
sleep_us = ut_min(static_cast<ulint>(1000000),
(next_loop_time - cur_time) * 1000);
return(os_event_wait_time_low(buf_flush_event,
sleep_us, sig_count));
}
return(OS_SYNC_TIME_EXCEEDED);
}
/**
Requests for all slots to flush.
@param min_n wished minimum mumber of blocks flushed
(it is not guaranteed that the actual number is that big)
@param lsn_limit in the case BUF_FLUSH_LIST all blocks whose
oldest_modification is smaller than this should be flushed
(if their number does not exceed min_n), otherwise ignored
*/
static void pc_request(ulint min_n, lsn_t lsn_limit)
{
mutex_enter(&page_cleaner.mutex);
ut_ad(page_cleaner.n_slots_requested == 0);
ut_ad(page_cleaner.n_slots_flushing == 0);
ut_ad(page_cleaner.n_slots_finished == 0);
page_cleaner.requested = (min_n > 0);
page_cleaner.lsn_limit = lsn_limit;
ut_ad(page_cleaner.slot.state == PAGE_CLEANER_STATE_NONE);
if (min_n == 0 || min_n == ULINT_MAX) {
page_cleaner.slot.n_pages_requested = min_n;
}
/* page_cleaner.slot.n_pages_requested was already set by
page_cleaner_flush_pages_recommendation() */
page_cleaner.slot.state = PAGE_CLEANER_STATE_REQUESTED;
page_cleaner.n_slots_requested = 1;
page_cleaner.n_slots_flushing = 0;
page_cleaner.n_slots_finished = 0;
mutex_exit(&page_cleaner.mutex);
}
/**
Do flush for one slot.
@return the number of the slots which has not been treated yet. */
static ulint pc_flush_slot()
{
ulint lru_tm = 0;
ulint list_tm = 0;
ulint lru_pass = 0;
ulint list_pass = 0;
mutex_enter(&page_cleaner.mutex);
if (page_cleaner.n_slots_requested) {
ut_ad(page_cleaner.slot.state == PAGE_CLEANER_STATE_REQUESTED);
page_cleaner.n_slots_requested--;
page_cleaner.n_slots_flushing++;
page_cleaner.slot.state = PAGE_CLEANER_STATE_FLUSHING;
if (UNIV_UNLIKELY(!page_cleaner.is_running)) {
page_cleaner.slot.n_flushed_lru = 0;
page_cleaner.slot.n_flushed_list = 0;
goto finish_mutex;
}
mutex_exit(&page_cleaner.mutex);
lru_tm = ut_time_ms();
/* Flush pages from end of LRU if required */
page_cleaner.slot.n_flushed_lru = buf_flush_LRU_list();
lru_tm = ut_time_ms() - lru_tm;
lru_pass++;
if (UNIV_UNLIKELY(!page_cleaner.is_running)) {
page_cleaner.slot.n_flushed_list = 0;
goto finish;
}
/* Flush pages from flush_list if required */
if (page_cleaner.requested) {
flush_counters_t n;
memset(&n, 0, sizeof(flush_counters_t));
list_tm = ut_time_ms();
page_cleaner.slot.succeeded_list = buf_flush_do_batch(
BUF_FLUSH_LIST,
page_cleaner.slot.n_pages_requested,
page_cleaner.lsn_limit,
&n);
page_cleaner.slot.n_flushed_list = n.flushed;
list_tm = ut_time_ms() - list_tm;
list_pass++;
} else {
page_cleaner.slot.n_flushed_list = 0;
page_cleaner.slot.succeeded_list = true;
}
finish:
mutex_enter(&page_cleaner.mutex);
finish_mutex:
page_cleaner.n_slots_flushing--;
page_cleaner.n_slots_finished++;
page_cleaner.slot.state = PAGE_CLEANER_STATE_FINISHED;
page_cleaner.slot.flush_lru_time += lru_tm;
page_cleaner.slot.flush_list_time += list_tm;
page_cleaner.slot.flush_lru_pass += lru_pass;
page_cleaner.slot.flush_list_pass += list_pass;
if (page_cleaner.n_slots_requested == 0
&& page_cleaner.n_slots_flushing == 0) {
os_event_set(page_cleaner.is_finished);
}
}
ulint ret = page_cleaner.n_slots_requested;
mutex_exit(&page_cleaner.mutex);
return(ret);
}
/**
Wait until all flush requests are finished.
@param n_flushed_lru number of pages flushed from the end of the LRU list.
@param n_flushed_list number of pages flushed from the end of the
flush_list.
@return true if all flush_list flushing batch were success. */
static
bool
pc_wait_finished(
ulint* n_flushed_lru,
ulint* n_flushed_list)
{
bool all_succeeded = true;
*n_flushed_lru = 0;
*n_flushed_list = 0;
os_event_wait(page_cleaner.is_finished);
mutex_enter(&page_cleaner.mutex);
ut_ad(page_cleaner.n_slots_requested == 0);
ut_ad(page_cleaner.n_slots_flushing == 0);
ut_ad(page_cleaner.n_slots_finished == 1);
ut_ad(page_cleaner.slot.state == PAGE_CLEANER_STATE_FINISHED);
page_cleaner.slot.state = PAGE_CLEANER_STATE_NONE;
*n_flushed_lru = page_cleaner.slot.n_flushed_lru;
*n_flushed_list = page_cleaner.slot.n_flushed_list;
all_succeeded = page_cleaner.slot.succeeded_list;
page_cleaner.slot.n_pages_requested = 0;
page_cleaner.n_slots_finished = 0;
os_event_reset(page_cleaner.is_finished);
mutex_exit(&page_cleaner.mutex);
return(all_succeeded);
}
#ifdef UNIV_LINUX
/**
Set priority for page_cleaner threads.
@param[in] priority priority intended to set
@return true if set as intended */
static
bool
buf_flush_page_cleaner_set_priority(
int priority)
{
setpriority(PRIO_PROCESS, (pid_t)syscall(SYS_gettid),
priority);
return(getpriority(PRIO_PROCESS, (pid_t)syscall(SYS_gettid))
== priority);
}
#endif /* UNIV_LINUX */
#ifdef UNIV_DEBUG
/** Loop used to disable the page cleaner thread. */
static void buf_flush_page_cleaner_disabled_loop()
{
while (innodb_page_cleaner_disabled_debug
&& srv_shutdown_state == SRV_SHUTDOWN_NONE
&& page_cleaner.is_running) {
os_thread_sleep(100000);
}
}
#endif /* UNIV_DEBUG */
/******************************************************************//**
page_cleaner thread tasked with flushing dirty pages from the buffer
pools. As of now we'll have only one coordinator.
@return a dummy parameter */
static os_thread_ret_t DECLARE_THREAD(buf_flush_page_cleaner)(void*)
{
my_thread_init();
#ifdef UNIV_PFS_THREAD
pfs_register_thread(page_cleaner_thread_key);
#endif /* UNIV_PFS_THREAD */
ut_ad(!srv_read_only_mode);
#ifdef UNIV_DEBUG_THREAD_CREATION
ib::info() << "page_cleaner thread running, id "
<< os_thread_pf(os_thread_get_curr_id());
#endif /* UNIV_DEBUG_THREAD_CREATION */
#ifdef UNIV_LINUX
/* linux might be able to set different setting for each thread.
worth to try to set high priority for page cleaner threads */
if (buf_flush_page_cleaner_set_priority(
buf_flush_page_cleaner_priority)) {
ib::info() << "page_cleaner coordinator priority: "
<< buf_flush_page_cleaner_priority;
} else {
ib::info() << "If the mysqld execution user is authorized,"
" page cleaner thread priority can be changed."
" See the man page of setpriority().";
}
/* Signal that setpriority() has been attempted. */
os_event_set(recv_sys.flush_end);
#endif /* UNIV_LINUX */
do {
/* treat flushing requests during recovery. */
ulint n_flushed_lru = 0;
ulint n_flushed_list = 0;
os_event_wait(recv_sys.flush_start);
if (!recv_writer_thread_active) {
break;
}
switch (recv_sys.flush_type) {
case BUF_FLUSH_LRU:
/* Flush pages from end of LRU if required */
pc_request(0, LSN_MAX);
while (pc_flush_slot() > 0) {}
pc_wait_finished(&n_flushed_lru, &n_flushed_list);
break;
case BUF_FLUSH_LIST:
/* Flush all pages */
do {
pc_request(ULINT_MAX, LSN_MAX);
while (pc_flush_slot() > 0) {}
} while (!pc_wait_finished(&n_flushed_lru,
&n_flushed_list));
break;
default:
ut_ad(0);
}
os_event_reset(recv_sys.flush_start);
os_event_set(recv_sys.flush_end);
} while (recv_writer_thread_active);
os_event_wait(buf_flush_event);
ulint ret_sleep = 0;
ulint n_evicted = 0;
ulint n_flushed_last = 0;
ulint warn_interval = 1;
ulint warn_count = 0;
int64_t sig_count = os_event_reset(buf_flush_event);
ulint next_loop_time = ut_time_ms() + 1000;
ulint n_flushed = 0;
ulint last_activity = srv_get_activity_count();
ulint last_pages = 0;
while (srv_shutdown_state == SRV_SHUTDOWN_NONE) {
ulint curr_time = ut_time_ms();
/* The page_cleaner skips sleep if the server is
idle and there are no pending IOs in the buffer pool
and there is work to do. */
if (!n_flushed || !buf_pool.n_pend_reads
|| srv_check_activity(last_activity)) {
ret_sleep = pc_sleep_if_needed(
next_loop_time, sig_count, curr_time);
} else if (curr_time > next_loop_time) {
ret_sleep = OS_SYNC_TIME_EXCEEDED;
} else {
ret_sleep = 0;
}
if (srv_shutdown_state != SRV_SHUTDOWN_NONE) {
break;
}
sig_count = os_event_reset(buf_flush_event);
if (ret_sleep == OS_SYNC_TIME_EXCEEDED) {
if (global_system_variables.log_warnings > 2
&& curr_time > next_loop_time + 3000
&& !(test_flags & TEST_SIGINT)) {
if (warn_count == 0) {
ib::info() << "page_cleaner: 1000ms"
" intended loop took "
<< 1000 + curr_time
- next_loop_time
<< "ms. The settings might not"
" be optimal. (flushed="
<< n_flushed_last
<< " and evicted="
<< n_evicted
<< ", during the time.)";
if (warn_interval > 300) {
warn_interval = 600;
} else {
warn_interval *= 2;
}
warn_count = warn_interval;
} else {
--warn_count;
}
} else {
/* reset counter */
warn_interval = 1;
warn_count = 0;
}
next_loop_time = curr_time + 1000;
n_flushed_last = n_evicted = 0;
}
if (ret_sleep != OS_SYNC_TIME_EXCEEDED
&& srv_flush_sync
&& buf_flush_sync_lsn > 0) {
/* woke up for flush_sync */
mutex_enter(&page_cleaner.mutex);
lsn_t lsn_limit = buf_flush_sync_lsn;
buf_flush_sync_lsn = 0;
mutex_exit(&page_cleaner.mutex);
/* Request flushing for threads */
pc_request(ULINT_MAX, lsn_limit);
ulint tm = ut_time_ms();
/* Coordinator also treats requests */
while (pc_flush_slot() > 0) {}
/* only coordinator is using these counters,
so no need to protect by lock. */
page_cleaner.flush_time += ut_time_ms() - tm;
page_cleaner.flush_pass++;
/* Wait for all slots to be finished */
ulint n_flushed_lru = 0;
ulint n_flushed_list = 0;
pc_wait_finished(&n_flushed_lru, &n_flushed_list);
if (n_flushed_list > 0 || n_flushed_lru > 0) {
buf_flush_stats(n_flushed_list, n_flushed_lru);
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_FLUSH_SYNC_TOTAL_PAGE,
MONITOR_FLUSH_SYNC_COUNT,
MONITOR_FLUSH_SYNC_PAGES,
n_flushed_lru + n_flushed_list);
}
n_flushed = n_flushed_lru + n_flushed_list;
} else if (srv_check_activity(last_activity)) {
ulint n_to_flush;
lsn_t lsn_limit;
/* Estimate pages from flush_list to be flushed */
if (ret_sleep == OS_SYNC_TIME_EXCEEDED) {
last_activity = srv_get_activity_count();
n_to_flush =
page_cleaner_flush_pages_recommendation(
last_pages);
lsn_limit = LSN_MAX;
} else {
n_to_flush = 0;
lsn_limit = 0;
}
/* Request flushing for threads */
pc_request(n_to_flush, lsn_limit);
ulint tm = ut_time_ms();
/* Coordinator also treats requests */
while (pc_flush_slot() > 0) {
/* No op */
}
/* only coordinator is using these counters,
so no need to protect by lock. */
page_cleaner.flush_time += ut_time_ms() - tm;
page_cleaner.flush_pass++ ;
/* Wait for all slots to be finished */
ulint n_flushed_lru = 0;
ulint n_flushed_list = 0;
pc_wait_finished(&n_flushed_lru, &n_flushed_list);
if (n_flushed_list > 0 || n_flushed_lru > 0) {
buf_flush_stats(n_flushed_list, n_flushed_lru);
}
if (ret_sleep == OS_SYNC_TIME_EXCEEDED) {
last_pages = n_flushed_list;
}
n_evicted += n_flushed_lru;
n_flushed_last += n_flushed_list;
n_flushed = n_flushed_lru + n_flushed_list;
if (n_flushed_lru) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_LRU_BATCH_FLUSH_TOTAL_PAGE,
MONITOR_LRU_BATCH_FLUSH_COUNT,
MONITOR_LRU_BATCH_FLUSH_PAGES,
n_flushed_lru);
}
if (n_flushed_list) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_FLUSH_ADAPTIVE_TOTAL_PAGE,
MONITOR_FLUSH_ADAPTIVE_COUNT,
MONITOR_FLUSH_ADAPTIVE_PAGES,
n_flushed_list);
}
} else if (ret_sleep == OS_SYNC_TIME_EXCEEDED) {
/* no activity, slept enough */
buf_flush_lists(srv_io_capacity, LSN_MAX, &n_flushed);
n_flushed_last += n_flushed;
if (n_flushed) {
MONITOR_INC_VALUE_CUMULATIVE(
MONITOR_FLUSH_BACKGROUND_TOTAL_PAGE,
MONITOR_FLUSH_BACKGROUND_COUNT,
MONITOR_FLUSH_BACKGROUND_PAGES,
n_flushed);
}
} else {
/* no activity, but woken up by event */
n_flushed = 0;
}
ut_d(buf_flush_page_cleaner_disabled_loop());
}
ut_ad(srv_shutdown_state > 0);
if (srv_fast_shutdown == 2
|| srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS) {
/* In very fast shutdown or when innodb failed to start, we
simulate a crash of the buffer pool. We are not required to do
any flushing. */
goto thread_exit;
}
/* In case of normal and slow shutdown the page_cleaner thread
must wait for all other activity in the server to die down.
Note that we can start flushing the buffer pool as soon as the
server enters shutdown phase but we must stay alive long enough
to ensure that any work done by the master or purge threads is
also flushed.
During shutdown we pass through two stages. In the first stage,
when SRV_SHUTDOWN_CLEANUP is set other threads like the master
and the purge threads may be working as well. We start flushing
the buffer pool but can't be sure that no new pages are being
dirtied until we enter SRV_SHUTDOWN_FLUSH_PHASE phase. */
do {
pc_request(ULINT_MAX, LSN_MAX);
while (pc_flush_slot() > 0) {}
ulint n_flushed_lru = 0;
ulint n_flushed_list = 0;
pc_wait_finished(&n_flushed_lru, &n_flushed_list);
n_flushed = n_flushed_lru + n_flushed_list;
/* We sleep only if there are no pages to flush */
if (n_flushed == 0) {
os_thread_sleep(100000);
}
} while (srv_shutdown_state == SRV_SHUTDOWN_CLEANUP);
/* At this point all threads including the master and the purge
thread must have been suspended. */
ut_ad(!srv_any_background_activity());
ut_ad(srv_shutdown_state == SRV_SHUTDOWN_FLUSH_PHASE);
/* We can now make a final sweep on flushing the buffer pool
and exit after we have cleaned the whole buffer pool.
It is important that we wait for any running batch that has
been triggered by us to finish. Otherwise we can end up
considering end of that batch as a finish of our final
sweep and we'll come out of the loop leaving behind dirty pages
in the flush_list */
buf_flush_wait_batch_end(BUF_FLUSH_LIST);
buf_flush_wait_LRU_batch_end();
bool success;
do {
pc_request(ULINT_MAX, LSN_MAX);
while (pc_flush_slot() > 0) {}
ulint n_flushed_lru = 0;
ulint n_flushed_list = 0;
success = pc_wait_finished(&n_flushed_lru, &n_flushed_list);
n_flushed = n_flushed_lru + n_flushed_list;
buf_flush_wait_batch_end(BUF_FLUSH_LIST);
buf_flush_wait_LRU_batch_end();
} while (!success || n_flushed > 0);
/* Some sanity checks */
ut_ad(!srv_any_background_activity());
ut_ad(srv_shutdown_state == SRV_SHUTDOWN_FLUSH_PHASE);
ut_a(UT_LIST_GET_LEN(buf_pool.flush_list) == 0);
/* We have lived our life. Time to die. */
thread_exit:
page_cleaner.is_running = false;
mutex_destroy(&page_cleaner.mutex);
os_event_destroy(page_cleaner.is_finished);
buf_page_cleaner_is_active = false;
my_thread_end();
/* We count the number of threads in os_thread_exit(). A created
thread should always use that to exit and not use return() to exit. */
os_thread_exit();
OS_THREAD_DUMMY_RETURN;
}
static void pc_flush_slot_func(void*)
{
while (pc_flush_slot() > 0) {};
}
/** Initialize page_cleaner. */
void buf_flush_page_cleaner_init()
{
ut_ad(!page_cleaner.is_running);
mutex_create(LATCH_ID_PAGE_CLEANER, &page_cleaner.mutex);
page_cleaner.is_finished = os_event_create("pc_is_finished");
page_cleaner.is_running = true;
buf_page_cleaner_is_active = true;
os_thread_create(buf_flush_page_cleaner, NULL, NULL);
}
/** Synchronously flush dirty blocks.
NOTE: The calling thread is not allowed to hold any buffer page latches! */
void buf_flush_sync()
{
bool success;
do {
success = buf_flush_lists(ULINT_MAX, LSN_MAX, NULL);
buf_flush_wait_batch_end(BUF_FLUSH_LIST);
} while (!success);
}
/** Request IO burst and wake page_cleaner up.
@param[in] lsn_limit upper limit of LSN to be flushed */
void buf_flush_request_force(lsn_t lsn_limit)
{
/* adjust based on lsn_avg_rate not to get old */
lsn_t lsn_target = lsn_limit + lsn_avg_rate * 3;
mutex_enter(&page_cleaner.mutex);
if (lsn_target > buf_flush_sync_lsn) {
buf_flush_sync_lsn = lsn_target;
}
mutex_exit(&page_cleaner.mutex);
os_event_set(buf_flush_event);
}
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/** Functor to validate the flush list. */
struct Check {
void operator()(const buf_page_t* elem) const
{
ut_a(elem->in_flush_list);
}
};
/** Validate the flush list. */
static void buf_flush_validate_low()
{
buf_page_t* bpage;
const ib_rbt_node_t* rnode = NULL;
ut_ad(mutex_own(&buf_pool.flush_list_mutex));
ut_list_validate(buf_pool.flush_list, Check());
bpage = UT_LIST_GET_FIRST(buf_pool.flush_list);
/* If we are in recovery mode i.e.: flush_rbt != NULL
then each block in the flush_list must also be present
in the flush_rbt. */
if (UNIV_LIKELY_NULL(buf_pool.flush_rbt)) {
rnode = rbt_first(buf_pool.flush_rbt);
}
while (bpage != NULL) {
const lsn_t om = bpage->oldest_modification;
ut_ad(bpage->in_flush_list);
/* A page in buf_pool.flush_list can be in
BUF_BLOCK_REMOVE_HASH state. This happens when a page
is in the middle of being relocated. In that case the
original descriptor can have this state and still be
in the flush list waiting to acquire the
buf_pool.flush_list_mutex to complete the relocation. */
ut_a(buf_page_in_file(bpage)
|| buf_page_get_state(bpage) == BUF_BLOCK_REMOVE_HASH);
ut_a(om > 0);
if (UNIV_LIKELY_NULL(buf_pool.flush_rbt)) {
buf_page_t** prpage;
ut_a(rnode != NULL);
prpage = rbt_value(buf_page_t*, rnode);
ut_a(*prpage != NULL);
ut_a(*prpage == bpage);
rnode = rbt_next(buf_pool.flush_rbt, rnode);
}
bpage = UT_LIST_GET_NEXT(list, bpage);
ut_a(bpage == NULL || om >= bpage->oldest_modification);
}
/* By this time we must have exhausted the traversal of
flush_rbt (if active) as well. */
ut_a(rnode == NULL);
}
/** Validate the flush list. */
void buf_flush_validate()
{
mutex_enter(&buf_pool.flush_list_mutex);
buf_flush_validate_low();
mutex_exit(&buf_pool.flush_list_mutex);
}
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
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