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MDEV-24537 innodb_max_dirty_pages_pct_lwm=0 lost its special meaning

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In commit 3a9a3be1c64b14c05648e87ebe0f1dd96457de41 (MDEV-23855)
some previous logic was replaced with the condition
dirty_pct < srv_max_dirty_pages_pct_lwm, which caused
the default value of the parameter innodb_max_dirty_pages_pct_lwm=0
to lose its special meaning: 'refer to innodb_max_dirty_pages_pct instead'.

This implicit special meaning was visible in the function
af_get_pct_for_dirty(), which was removed in
commit f0c295e2de8c074c2ca72e19ff06e1d0e3ee6d2b (MDEV-24369).

page_cleaner_flush_pages_recommendation(): Restore the special
meaning that was removed in MDEV-24369.

buf_flush_page_cleaner(): If srv_max_dirty_pages_pct_lwm==0.0,
refer to srv_max_buf_pool_modified_pct. This fixes the observed
performance regression due to excessive page flushing.

buf_pool_t::page_cleaner_wakeup(): Revise the wakeup condition.

innodb_init(): Do initialize srv_max_io_capacity in Mariabackup.
It was previously constantly 0, which caused mariadb-backup --prepare
to hang in buf_flush_sync(), making no progress.
This commit is contained in:
Marko Mäkelä 2021-01-06 13:53:14 +02:00
parent 02e7bff882
commit a993310593
5 changed files with 30 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
extra/mariabackup/xtrabackup.cc
View File

@ -4,7 +4,7 @@ MariaBackup: hot backup tool for InnoDB
Originally Created 3/3/2009 Yasufumi Kinoshita
Written by Alexey Kopytov, Aleksandr Kuzminsky, Stewart Smith, Vadim Tkachenko,
Yasufumi Kinoshita, Ignacio Nin and Baron Schwartz.
(c) 2017, 2020, MariaDB Corporation.
(c) 2017, 2021, MariaDB Corporation.
Portions written by Marko Mäkelä.
This program is free software; you can redistribute it and/or modify
@ -2183,6 +2183,14 @@ error:
static bool innodb_init()
{
bool create_new_db = false;
if (srv_io_capacity >= SRV_MAX_IO_CAPACITY_LIMIT / 2) {
/* Avoid overflow. */
srv_max_io_capacity = SRV_MAX_IO_CAPACITY_LIMIT;
} else {
srv_max_io_capacity = std::max(2 * srv_io_capacity, 2000UL);
}
/* Check if the data files exist or not. */
dberr_t err = srv_sys_space.check_file_spec(&create_new_db, 5U << 20);

2
mysql-test/suite/sys_vars/r/sysvars_innodb.result
View File

@ -1322,7 +1322,7 @@ SESSION_VALUE NULL
DEFAULT_VALUE 0.000000
VARIABLE_SCOPE GLOBAL
VARIABLE_TYPE DOUBLE
VARIABLE_COMMENT Percentage of dirty pages at which flushing kicks in.
VARIABLE_COMMENT Percentage of dirty pages at which flushing kicks in. The value 0 (default) means 'refer to innodb_max_dirty_pages_pct'.
NUMERIC_MIN_VALUE 0
NUMERIC_MAX_VALUE 99.999
NUMERIC_BLOCK_SIZE NULL

24
storage/innobase/buf/buf0flu.cc
View File

@ -1,7 +1,7 @@
/*****************************************************************************
Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2013, 2020, MariaDB Corporation.
Copyright (c) 2013, 2021, MariaDB Corporation.
Copyright (c) 2013, 2014, Fusion-io
This program is free software; you can redistribute it and/or modify it under
@ -129,11 +129,13 @@ static void buf_flush_validate_skip()
/** Wake up the page cleaner if needed */
inline void buf_pool_t::page_cleaner_wakeup()
{
if (page_cleaner_idle() &&
(srv_max_dirty_pages_pct_lwm == 0.0 ||
srv_max_dirty_pages_pct_lwm <=
double(UT_LIST_GET_LEN(buf_pool.flush_list)) * 100.0 /
double(UT_LIST_GET_LEN(buf_pool.LRU) + UT_LIST_GET_LEN(buf_pool.free))))
if (!page_cleaner_idle())
return;
double dirty_pct= double(UT_LIST_GET_LEN(buf_pool.flush_list)) * 100.0 /
double(UT_LIST_GET_LEN(buf_pool.LRU) + UT_LIST_GET_LEN(buf_pool.free));
double pct_lwm= srv_max_dirty_pages_pct_lwm;
if ((pct_lwm != 0.0 && pct_lwm <= dirty_pct) ||
srv_max_buf_pool_modified_pct <= dirty_pct)
{
page_cleaner_is_idle= false;
mysql_cond_signal(&do_flush_list);
@ -1989,7 +1991,9 @@ static ulint page_cleaner_flush_pages_recommendation(ulint last_pages_in,
sum_pages = 0;
}
const ulint pct_for_dirty = static_cast<ulint>
const ulint pct_for_dirty = srv_max_dirty_pages_pct_lwm == 0
? (dirty_pct >= max_pct ? 100 : 0)
: static_cast<ulint>
(max_pct > 0.0 ? dirty_pct / max_pct : dirty_pct);
ulint pct_total = std::max(pct_for_dirty, pct_for_lsn);
@ -2129,7 +2133,11 @@ unemployed:
const double dirty_pct= double(dirty_blocks) * 100.0 /
double(UT_LIST_GET_LEN(buf_pool.LRU) + UT_LIST_GET_LEN(buf_pool.free));
if (dirty_pct < srv_max_dirty_pages_pct_lwm && !lsn_limit)
if (lsn_limit);
else if (dirty_pct < srv_max_buf_pool_modified_pct)
goto unemployed;
else if (srv_max_dirty_pages_pct_lwm == 0.0 ||
dirty_pct < srv_max_dirty_pages_pct_lwm)
goto unemployed;
const lsn_t oldest_lsn= buf_pool.get_oldest_modified()

3
storage/innobase/handler/ha_innodb.cc
View File

@ -19032,7 +19032,8 @@ static MYSQL_SYSVAR_DOUBLE(max_dirty_pages_pct, srv_max_buf_pool_modified_pct,
static MYSQL_SYSVAR_DOUBLE(max_dirty_pages_pct_lwm,
srv_max_dirty_pages_pct_lwm,
PLUGIN_VAR_RQCMDARG,
"Percentage of dirty pages at which flushing kicks in.",
"Percentage of dirty pages at which flushing kicks in. "
"The value 0 (default) means 'refer to innodb_max_dirty_pages_pct'.",
NULL, innodb_max_dirty_pages_pct_lwm_update, 0, 0, 99.999, 0);
static MYSQL_SYSVAR_DOUBLE(adaptive_flushing_lwm,

6
storage/innobase/include/srv0srv.h
View File

@ -3,7 +3,7 @@
Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
Copyright (c) 2008, 2009, Google Inc.
Copyright (c) 2009, Percona Inc.
Copyright (c) 2013, 2020, MariaDB Corporation.
Copyright (c) 2013, 2021, MariaDB Corporation.
Portions of this file contain modifications contributed and copyrighted by
Google, Inc. Those modifications are gratefully acknowledged and are described
@ -373,7 +373,7 @@ extern ulong srv_innodb_stats_method;
extern ulint srv_max_n_open_files;
extern double srv_max_dirty_pages_pct;
extern double srv_max_buf_pool_modified_pct;
extern double srv_max_dirty_pages_pct_lwm;
extern double srv_adaptive_flushing_lwm;
@ -400,10 +400,8 @@ extern my_bool srv_stats_sample_traditional;
extern my_bool srv_use_doublewrite_buf;
extern ulong srv_checksum_algorithm;
extern double srv_max_buf_pool_modified_pct;
extern my_bool srv_force_primary_key;
extern double srv_max_buf_pool_modified_pct;
extern ulong srv_max_purge_lag;
extern ulong srv_max_purge_lag_delay;