From 28098420317bc2efe082df799c917babde879242 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Sat, 19 Oct 2019 15:16:47 +0300
Subject: [PATCH] MDEV-20864 Introduce debug option innodb_change_buffer_dump
To diagnose a hang in slow shutdown (innodb_fast_shutdown=0),
let us introduce a Boolean startup option in debug builds
that will cause the contents of the InnoDB change buffer
to be dumped to the server error log at startup.
---
mysql-test/suite/innodb/t/ibuf_not_empty.test | 2 +-
.../suite/sys_vars/r/sysvars_innodb.result | 12 +++++++++++
storage/innobase/handler/ha_innodb.cc | 6 ++++++
storage/innobase/ibuf/ibuf0ibuf.cc | 21 +++++++++++++++++++
storage/innobase/include/dict0types.h | 4 +++-
5 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/mysql-test/suite/innodb/t/ibuf_not_empty.test b/mysql-test/suite/innodb/t/ibuf_not_empty.test
index a1a2da1f903..9ee0b180f44 100644
--- a/mysql-test/suite/innodb/t/ibuf_not_empty.test
+++ b/mysql-test/suite/innodb/t/ibuf_not_empty.test
@@ -41,7 +41,7 @@ INSERT INTO t1 SELECT 0,b,c FROM t1;
INSERT INTO t1 SELECT 0,b,c FROM t1;
INSERT INTO t1 SELECT 0,b,c FROM t1;
---let $restart_parameters= --innodb-force-recovery=6
+--let $restart_parameters= --innodb-force-recovery=6 --innodb-change-buffer-dump
--source include/restart_mysqld.inc
--replace_regex /contains \d+ entries/contains #### entries/
diff --git a/mysql-test/suite/sys_vars/r/sysvars_innodb.result b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
index 1808cfb6ea3..65d47347a15 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_innodb.result
+++ b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
@@ -354,6 +354,18 @@ NUMERIC_BLOCK_SIZE 0
ENUM_VALUE_LIST NULL
READ_ONLY NO
COMMAND_LINE_ARGUMENT REQUIRED
+VARIABLE_NAME INNODB_CHANGE_BUFFER_DUMP
+SESSION_VALUE NULL
+DEFAULT_VALUE OFF
+VARIABLE_SCOPE GLOBAL
+VARIABLE_TYPE BOOLEAN
+VARIABLE_COMMENT Dump the change buffer at startup.
+NUMERIC_MIN_VALUE NULL
+NUMERIC_MAX_VALUE NULL
+NUMERIC_BLOCK_SIZE NULL
+ENUM_VALUE_LIST OFF,ON
+READ_ONLY YES
+COMMAND_LINE_ARGUMENT NONE
VARIABLE_NAME INNODB_CHANGE_BUFFER_MAX_SIZE
SESSION_VALUE NULL
DEFAULT_VALUE 25
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index a556b5875df..3ad12c455bf 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -20642,6 +20642,11 @@ static MYSQL_SYSVAR_ENUM(stats_method, srv_innodb_stats_method,
NULL, NULL, SRV_STATS_NULLS_EQUAL, &innodb_stats_method_typelib);
#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
+static MYSQL_SYSVAR_BOOL(change_buffer_dump, ibuf_dump,
+ PLUGIN_VAR_NOCMDARG | PLUGIN_VAR_READONLY,
+ "Dump the change buffer at startup.",
+ NULL, NULL, FALSE);
+
static MYSQL_SYSVAR_UINT(change_buffering_debug, ibuf_debug,
PLUGIN_VAR_RQCMDARG,
"Debug flags for InnoDB change buffering (0=none, 1=try to buffer)",
@@ -21158,6 +21163,7 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
MYSQL_SYSVAR(change_buffering),
MYSQL_SYSVAR(change_buffer_max_size),
#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
+ MYSQL_SYSVAR(change_buffer_dump),
MYSQL_SYSVAR(change_buffering_debug),
MYSQL_SYSVAR(disable_background_merge),
#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
diff --git a/storage/innobase/ibuf/ibuf0ibuf.cc b/storage/innobase/ibuf/ibuf0ibuf.cc
index d3fdd46c29b..e701271379e 100644
--- a/storage/innobase/ibuf/ibuf0ibuf.cc
+++ b/storage/innobase/ibuf/ibuf0ibuf.cc
@@ -188,6 +188,8 @@ access order rules. */
ibuf_use_t ibuf_use = IBUF_USE_ALL;
#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
+/** Dump the change buffer at startup */
+my_bool ibuf_dump;
/** Flag to control insert buffer debugging. */
uint ibuf_debug;
#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
@@ -506,6 +508,25 @@ ibuf_init_at_db_start(void)
#endif /* BTR_CUR_ADAPT */
ibuf->index->page = FSP_IBUF_TREE_ROOT_PAGE_NO;
ut_d(ibuf->index->cached = TRUE);
+
+#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
+ if (!ibuf_dump) {
+ return error;
+ }
+ ib::info() << "Dumping the change buffer";
+ ibuf_mtr_start(&mtr);
+ btr_pcur_t pcur;
+ if (DB_SUCCESS == btr_pcur_open_at_index_side(
+ true, ibuf->index, BTR_SEARCH_LEAF, &pcur,
+ true, 0, &mtr)) {
+ while (btr_pcur_move_to_next_user_rec(&pcur, &mtr)) {
+ rec_print_old(stderr, btr_pcur_get_rec(&pcur));
+ }
+ }
+ ibuf_mtr_commit(&mtr);
+ ib::info() << "Dumped the change buffer";
+#endif
+
return (error);
}
diff --git a/storage/innobase/include/dict0types.h b/storage/innobase/include/dict0types.h
index 93c2f570e54..bea08f398de 100644
--- a/storage/innobase/include/dict0types.h
+++ b/storage/innobase/include/dict0types.h
@@ -1,7 +1,7 @@
/*****************************************************************************
Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2013, 2017, MariaDB Corporation.
+Copyright (c) 2013, 2019, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
@@ -96,6 +96,8 @@ typedef ib_mutex_t DictSysMutex;
#define TEMP_TABLE_PATH_PREFIX "/" TEMP_TABLE_PREFIX
#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
+/** Dump the change buffer at startup */
+extern my_bool ibuf_dump;
/** Flag to control insert buffer debugging. */
extern uint ibuf_debug;
#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
--
2.30.9