From 28e166d6435741c46e0ea789657b739f78eb0425 Mon Sep 17 00:00:00 2001
From: Thirunarayanan Balathandayuthapani <thiru@mariadb.com>
Date: Thu, 20 Jan 2022 16:30:18 +0530
Subject: [PATCH] MDEV-26784 [Warning] InnoDB: Difficult to find free blocks in
 the buffer pool

Problem:
=======
  InnoDB ran out of memory during recovery and it fails to
flush the dirty LRU blocks. The reason is that buffer pool
can ran out before the LRU list length reaches
BUF_LRU_OLD_MIN_LEN(256) threshold.

Fix:
====
During recovery, InnoDB should write out and evict all
dirty blocks.
---
 .../suite/innodb/r/recovery_memory.result     | 12 +++++++++++
 mysql-test/suite/innodb/t/recovery_memory.opt |  1 +
 .../suite/innodb/t/recovery_memory.test       | 21 +++++++++++++++++++
 storage/innobase/buf/buf0flu.cc               |  8 ++++---
 4 files changed, 39 insertions(+), 3 deletions(-)
 create mode 100644 mysql-test/suite/innodb/r/recovery_memory.result
 create mode 100644 mysql-test/suite/innodb/t/recovery_memory.opt
 create mode 100644 mysql-test/suite/innodb/t/recovery_memory.test

diff --git a/mysql-test/suite/innodb/r/recovery_memory.result b/mysql-test/suite/innodb/r/recovery_memory.result
new file mode 100644
index 00000000000..4fa31009130
--- /dev/null
+++ b/mysql-test/suite/innodb/r/recovery_memory.result
@@ -0,0 +1,12 @@
+CREATE TABLE t1(c TEXT, KEY(c(3072)))ENGINE=InnoDB;
+CREATE PROCEDURE dorepeat()
+LOOP
+INSERT INTO t1 VALUES ('abc');
+UPDATE t1 SET c='cba';
+END LOOP
+|
+connect con1,localhost,root,,,;
+CALL dorepeat();
+connection default;
+# restart: --innodb_buffer_pool_size=5242880
+DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/t/recovery_memory.opt b/mysql-test/suite/innodb/t/recovery_memory.opt
new file mode 100644
index 00000000000..7207fd27a42
--- /dev/null
+++ b/mysql-test/suite/innodb/t/recovery_memory.opt
@@ -0,0 +1 @@
+--innodb_buffer_pool_size=1073741824
diff --git a/mysql-test/suite/innodb/t/recovery_memory.test b/mysql-test/suite/innodb/t/recovery_memory.test
new file mode 100644
index 00000000000..d9afd52c499
--- /dev/null
+++ b/mysql-test/suite/innodb/t/recovery_memory.test
@@ -0,0 +1,21 @@
+--source include/have_innodb.inc
+--source include/big_test.inc
+CREATE TABLE t1(c TEXT, KEY(c(3072)))ENGINE=InnoDB;
+DELIMITER |;
+
+CREATE PROCEDURE dorepeat()
+  LOOP
+   INSERT INTO t1 VALUES ('abc');
+   UPDATE t1 SET c='cba';
+  END LOOP
+|
+
+DELIMITER ;|
+connect(con1,localhost,root,,,);
+send CALL dorepeat();
+connection default;
+sleep 10;
+let $shutdown_timeout=0;
+let $restart_parameters=--innodb_buffer_pool_size=5242880;
+--source include/restart_mysqld.inc
+DROP TABLE t1;
diff --git a/storage/innobase/buf/buf0flu.cc b/storage/innobase/buf/buf0flu.cc
index c14b274645d..ce8f8dc34c4 100644
--- a/storage/innobase/buf/buf0flu.cc
+++ b/storage/innobase/buf/buf0flu.cc
@@ -1288,9 +1288,11 @@ static void buf_flush_LRU_list_batch(ulint max, flush_counters_t *n)
   static_assert(FIL_NULL > SRV_SPACE_ID_UPPER_BOUND, "consistency");
 
   for (buf_page_t *bpage= UT_LIST_GET_LAST(buf_pool.LRU);
-       bpage && n->flushed + n->evicted < max &&
-       UT_LIST_GET_LEN(buf_pool.LRU) > BUF_LRU_MIN_LEN &&
-       UT_LIST_GET_LEN(buf_pool.free) < free_limit; ++scanned)
+       bpage &&
+       ((UT_LIST_GET_LEN(buf_pool.LRU) > BUF_LRU_MIN_LEN &&
+         UT_LIST_GET_LEN(buf_pool.free) < free_limit &&
+         n->flushed + n->evicted < max) ||
+        recv_recovery_is_on()); ++scanned)
   {
     buf_page_t *prev= UT_LIST_GET_PREV(LRU, bpage);
     const lsn_t oldest_modification= bpage->oldest_modification();