From a0e7bd735b5bc1fd458766c2005d5ac349682d9f Mon Sep 17 00:00:00 2001
From: Sergei Petrunia <sergey@mariadb.com>
Date: Thu, 1 Jun 2023 14:06:06 +0300
Subject: [PATCH 1/6] MDEV-31380: Assertion `s->table->opt_range_condition_rows
 <= s->found_records' failed

LooseScan code set opt_range_condition_rows to be the

  MIN(loose_scan_plan->records, table->records)

totally ignoring possible quick range selects.  If there was a quick
select $QUICK on another index with

  $QUICK->records < loose_scan_plan->records

this would create a situation where

   opt_range_condition_rows > $QUICK->records

which causes an assert in 10.6+ and potentially wrong query plan
choice in 10.5.

Fixed by making opt_range_condition_rows to be the minimum #rows
of any quick select.

Approved-by: Monty <monty@mariadb.org>
---
 mysql-test/main/group_min_max.result | 24 ++++++++++++++++++++++++
 mysql-test/main/group_min_max.test   | 25 +++++++++++++++++++++++++
 sql/opt_range.cc                     |  4 ++--
 3 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/mysql-test/main/group_min_max.result b/mysql-test/main/group_min_max.result
index 712466c8afb..0df9abc7a25 100644
--- a/mysql-test/main/group_min_max.result
+++ b/mysql-test/main/group_min_max.result
@@ -4204,6 +4204,30 @@ a	b	s1
 2	2	t2:t2a-null;min_t3_b:t3b-null
 3	3	t2:1;min_t3_b:3
 drop table t1,t2,t3;
+# 
+# MDEV-31380: Assertion `s->table->opt_range_condition_rows <= s->found_records' failed
+#  (assertion in 10.6+, DBL_MAX costs in 10.5)
+# 
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY(a), KEY(b)) ENGINE=InnoDB;
+INSERT INTO t1 SELECT seq, seq FROM seq_1_to_100;
+SET
+@tmp=@@optimizer_use_condition_selectivity,
+optimizer_use_condition_selectivity = 1,
+@tmp2=@@optimizer_trace,
+optimizer_trace=1;
+SELECT DISTINCT * FROM t1 WHERE a IN (1, 2);
+a	b
+1	1
+2	2
+select 
+CAST(json_value(json_extract(trace, '$**.chosen_access_method.cost'), '$[0]')
+as DOUBLE) < 1.0e100
+from information_schema.optimizer_trace;
+CAST(json_value(json_extract(trace, '$**.chosen_access_method.cost'), '$[0]')
+as DOUBLE) < 1.0e100
+1
+set optimizer_use_condition_selectivity = @tmp, optimizer_trace=@tmp2;
+drop table t1;
 #
 # End of 10.5 tests
 #
diff --git a/mysql-test/main/group_min_max.test b/mysql-test/main/group_min_max.test
index 1fc2be6231a..482235571db 100644
--- a/mysql-test/main/group_min_max.test
+++ b/mysql-test/main/group_min_max.test
@@ -6,6 +6,7 @@
 --source include/no_valgrind_without_big.inc
 --source include/default_optimizer_switch.inc
 --source include/have_innodb.inc
+--source include/have_sequence.inc
 #
 # TODO:
 # Add queries with:
@@ -1858,6 +1859,30 @@ from t1;
 
 drop table t1,t2,t3;
 
+--echo # 
+--echo # MDEV-31380: Assertion `s->table->opt_range_condition_rows <= s->found_records' failed
+--echo #  (assertion in 10.6+, DBL_MAX costs in 10.5)
+--echo # 
+
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY(a), KEY(b)) ENGINE=InnoDB;
+INSERT INTO t1 SELECT seq, seq FROM seq_1_to_100;
+
+SET
+  @tmp=@@optimizer_use_condition_selectivity,
+  optimizer_use_condition_selectivity = 1,
+  @tmp2=@@optimizer_trace,
+  optimizer_trace=1;
+
+SELECT DISTINCT * FROM t1 WHERE a IN (1, 2);
+
+select 
+  CAST(json_value(json_extract(trace, '$**.chosen_access_method.cost'), '$[0]')
+       as DOUBLE) < 1.0e100
+from information_schema.optimizer_trace;
+
+set optimizer_use_condition_selectivity = @tmp, optimizer_trace=@tmp2;
+drop table t1;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 7b6f373eea4..905d5aa5ef9 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -3030,8 +3030,8 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
         restore_nonrange_trees(&param, tree, backup_keys);
       if ((group_trp= get_best_group_min_max(&param, tree, read_time)))
       {
-        param.table->opt_range_condition_rows= MY_MIN(group_trp->records,
-                                                  head->stat_records());
+        set_if_smaller(param.table->opt_range_condition_rows,
+                       group_trp->records);
         Json_writer_object grp_summary(thd, "best_group_range_summary");
 
         if (unlikely(thd->trace_started()))

From 91367e82f10fde14ad2eb42928626cabcc0d49cd Mon Sep 17 00:00:00 2001
From: Daniel Bartholomew <db@dbart.us>
Date: Wed, 7 Jun 2023 08:10:48 -0400
Subject: [PATCH 2/6] bump the VERSION

---
 VERSION | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/VERSION b/VERSION
index 2806542e3ac..e1357a38a48 100644
--- a/VERSION
+++ b/VERSION
@@ -1,4 +1,4 @@
 MYSQL_VERSION_MAJOR=10
 MYSQL_VERSION_MINOR=5
-MYSQL_VERSION_PATCH=21
+MYSQL_VERSION_PATCH=22
 SERVER_MATURITY=stable

From 3e40f9a7f3bbe82d96c8acccbb017deebfa00647 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Thu, 8 Jun 2023 09:17:52 +0300
Subject: [PATCH 3/6] MDEV-31355 innodb_undo_log_truncate=ON fails to wait for
 purge of enough transaction history

purge_sys_t::sees(): Wrapper for view.sees().

trx_purge_truncate_history(): Invoke purge_sys.sees() instead of
comparing to head.trx_no, to determine if undo pages can be safely freed.

The test innodb.cursor-restore-locking was adjusted by Vladislav Lesin,
as was the the debug instrumentation in row_purge_del_mark().

Reviewed by: Vladislav Lesin
---
 .../gcol/r/innodb_virtual_debug_purge.result  |  2 +-
 .../gcol/t/innodb_virtual_debug_purge.test    |  2 ++
 .../innodb/r/cursor-restore-locking.result    | 13 ++++---
 mysql-test/suite/innodb/r/dml_purge.result    |  2 +-
 .../r/instant_alter_debug,dynamic.rdiff       |  6 ----
 .../suite/innodb/r/instant_alter_debug.result |  3 +-
 .../suite/innodb/r/instant_alter_purge.result |  3 +-
 .../innodb/t/cursor-restore-locking.test      | 35 ++++++++++---------
 mysql-test/suite/innodb/t/dml_purge.test      |  2 +-
 .../suite/innodb/t/instant_alter_debug.test   |  3 ++
 .../suite/innodb/t/instant_alter_purge.test   |  4 +--
 storage/innobase/include/trx0purge.h          | 12 +++++++
 storage/innobase/row/row0purge.cc             | 14 +++++++-
 storage/innobase/trx/trx0purge.cc             |  4 +--
 14 files changed, 68 insertions(+), 37 deletions(-)
 delete mode 100644 mysql-test/suite/innodb/r/instant_alter_debug,dynamic.rdiff

diff --git a/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result b/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
index 4a204532630..2820aa7cdbb 100644
--- a/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
+++ b/mysql-test/suite/gcol/r/innodb_virtual_debug_purge.result
@@ -76,7 +76,7 @@ SET DEBUG_SYNC= 'now WAIT_FOR uncommitted';
 # enable purge
 COMMIT;
 # wait for purge to process the deleted records.
-InnoDB		0 transactions not purged
+InnoDB		1 transactions not purged
 SET DEBUG_SYNC= 'now SIGNAL purged';
 connection default;
 /* connection default */ ALTER TABLE t1 ADD COLUMN c INT GENERATED ALWAYS AS(a+b), ADD INDEX idx (c), ALGORITHM=INPLACE, LOCK=SHARED;
diff --git a/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test b/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
index ca60ed84a98..c8f0cc4c414 100644
--- a/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
+++ b/mysql-test/suite/gcol/t/innodb_virtual_debug_purge.test
@@ -111,7 +111,9 @@ SET DEBUG_SYNC= 'now WAIT_FOR uncommitted';
 COMMIT;
 
 --echo # wait for purge to process the deleted records.
+let $wait_all_purged = 1;
 --source ../../innodb/include/wait_all_purged.inc
+let $wait_all_purged = 0;
 
 SET DEBUG_SYNC= 'now SIGNAL purged';
 
diff --git a/mysql-test/suite/innodb/r/cursor-restore-locking.result b/mysql-test/suite/innodb/r/cursor-restore-locking.result
index fc56f0935fa..a792babe5cd 100644
--- a/mysql-test/suite/innodb/r/cursor-restore-locking.result
+++ b/mysql-test/suite/innodb/r/cursor-restore-locking.result
@@ -1,31 +1,34 @@
 SET @save_freq=@@GLOBAL.innodb_purge_rseg_truncate_frequency;
 SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
-CREATE TABLE t (a int PRIMARY KEY, b int NOT NULL UNIQUE) engine = InnoDB;
+CREATE TABLE t (a int PRIMARY KEY, b int NOT NULL UNIQUE) engine = InnoDB, STATS_PERSISTENT=0;
 InnoDB		0 transactions not purged
 connect prevent_purge,localhost,root,,;
 start transaction with consistent snapshot;
 connect con_del_1,localhost,root,,;
 INSERT INTO t VALUES (20,20);
 SET DEBUG_SYNC = 'innodb_row_search_for_mysql_exit SIGNAL first_del_row_search_mvcc_finished WAIT_FOR first_del_cont';
-DELETE FROM t WHERE b = 20;
+DELETE FROM t WHERE b = 20 # trx_1;
 connect con_ins_1,localhost,root,,;
 SET DEBUG_SYNC = 'now WAIT_FOR first_del_row_search_mvcc_finished';
 SET DEBUG_SYNC = 'lock_wait_suspend_thread_enter SIGNAL first_ins_locked';
 SET DEBUG_SYNC = 'ib_after_row_insert SIGNAL first_ins_row_inserted WAIT_FOR first_ins_cont';
-INSERT INTO t VALUES(10, 20);
+INSERT INTO t VALUES(10, 20) # trx_2;
 connect con_del_2,localhost,root,,;
 SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
 SET DEBUG_SYNC = 'now WAIT_FOR first_ins_locked';
 SET DEBUG_SYNC = 'lock_wait_suspend_thread_enter SIGNAL second_del_locked';
-DELETE FROM t WHERE b = 20;
+DELETE FROM t WHERE b = 20 # trx_3;
 connection default;
 SET DEBUG_SYNC = 'now WAIT_FOR second_del_locked';
+SET @saved_dbug = @@GLOBAL.debug_dbug;
+SET @@GLOBAL.debug_dbug="d,enable_row_purge_del_mark_exit_sync_point";
 SET DEBUG_SYNC = 'now SIGNAL first_del_cont';
 SET DEBUG_SYNC = 'now WAIT_FOR first_ins_row_inserted';
 connection con_del_1;
 connection default;
 disconnect prevent_purge;
-InnoDB		0 transactions not purged
+SET DEBUG_SYNC = 'now WAIT_FOR row_purge_del_mark_finished';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 SET DEBUG_SYNC = 'now SIGNAL first_ins_cont';
 connection con_del_2;
 connection con_ins_1;
diff --git a/mysql-test/suite/innodb/r/dml_purge.result b/mysql-test/suite/innodb/r/dml_purge.result
index 38273d571c0..75a5f0fec6c 100644
--- a/mysql-test/suite/innodb/r/dml_purge.result
+++ b/mysql-test/suite/innodb/r/dml_purge.result
@@ -19,7 +19,7 @@ BEGIN;
 UPDATE t1 SET b=4 WHERE a=3;
 disconnect prevent_purge;
 connection default;
-InnoDB		0 transactions not purged
+SET GLOBAL innodb_max_purge_lag_wait=1;
 connection con1;
 ROLLBACK;
 disconnect con1;
diff --git a/mysql-test/suite/innodb/r/instant_alter_debug,dynamic.rdiff b/mysql-test/suite/innodb/r/instant_alter_debug,dynamic.rdiff
deleted file mode 100644
index 379514edad9..00000000000
--- a/mysql-test/suite/innodb/r/instant_alter_debug,dynamic.rdiff
+++ /dev/null
@@ -1,6 +0,0 @@
-@@ -470,4 +470,4 @@
- FROM information_schema.global_status
- WHERE variable_name = 'innodb_instant_alter_column';
- instants
--33
-+32
diff --git a/mysql-test/suite/innodb/r/instant_alter_debug.result b/mysql-test/suite/innodb/r/instant_alter_debug.result
index 82230573c44..39846a0e329 100644
--- a/mysql-test/suite/innodb/r/instant_alter_debug.result
+++ b/mysql-test/suite/innodb/r/instant_alter_debug.result
@@ -391,11 +391,12 @@ connection stop_purge;
 COMMIT;
 disconnect stop_purge;
 connection default;
-InnoDB		0 transactions not purged
+InnoDB		1 transactions not purged
 SET DEBUG_SYNC='now SIGNAL s2';
 connection dml;
 disconnect dml;
 connection default;
+InnoDB		0 transactions not purged
 SET DEBUG_SYNC=RESET;
 DROP TABLE t1;
 # End of 10.3 tests
diff --git a/mysql-test/suite/innodb/r/instant_alter_purge.result b/mysql-test/suite/innodb/r/instant_alter_purge.result
index 1179ff62ecc..261356bad12 100644
--- a/mysql-test/suite/innodb/r/instant_alter_purge.result
+++ b/mysql-test/suite/innodb/r/instant_alter_purge.result
@@ -1,5 +1,6 @@
 SET @saved_frequency = @@GLOBAL.innodb_purge_rseg_truncate_frequency;
 SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
+InnoDB		0 transactions not purged
 #
 # MDEV-17793 Crash in purge after instant DROP and emptying the table
 #
@@ -16,7 +17,7 @@ COMMIT;
 START TRANSACTION WITH CONSISTENT SNAPSHOT;
 connection default;
 ALTER TABLE t1 ADD COLUMN extra TINYINT UNSIGNED NOT NULL DEFAULT 42;
-InnoDB		1 transactions not purged
+SET GLOBAL innodb_max_purge_lag_wait=1;
 ALTER TABLE t1 DROP extra;
 disconnect prevent_purge;
 InnoDB		0 transactions not purged
diff --git a/mysql-test/suite/innodb/t/cursor-restore-locking.test b/mysql-test/suite/innodb/t/cursor-restore-locking.test
index 0f083f9295b..815542c32db 100644
--- a/mysql-test/suite/innodb/t/cursor-restore-locking.test
+++ b/mysql-test/suite/innodb/t/cursor-restore-locking.test
@@ -5,7 +5,7 @@ source include/have_debug_sync.inc;
 
 SET @save_freq=@@GLOBAL.innodb_purge_rseg_truncate_frequency;
 SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
-CREATE TABLE t (a int PRIMARY KEY, b int NOT NULL UNIQUE) engine = InnoDB;
+CREATE TABLE t (a int PRIMARY KEY, b int NOT NULL UNIQUE) engine = InnoDB, STATS_PERSISTENT=0;
 
 --source include/wait_all_purged.inc
 --connect(prevent_purge,localhost,root,,)
@@ -14,20 +14,20 @@ start transaction with consistent snapshot;
 --connect(con_del_1,localhost,root,,)
 INSERT INTO t VALUES (20,20);
 SET DEBUG_SYNC = 'innodb_row_search_for_mysql_exit SIGNAL first_del_row_search_mvcc_finished WAIT_FOR first_del_cont';
---send DELETE FROM t WHERE b = 20
+--send DELETE FROM t WHERE b = 20 # trx_1
 
 --connect(con_ins_1,localhost,root,,)
 SET DEBUG_SYNC = 'now WAIT_FOR first_del_row_search_mvcc_finished';
 # It's supposed the following INSERT will be suspended just after
 # lock_wait_suspend_thread_enter syncpoint, and will be awaken
-# after the previous DELETE commits. ib_after_row_insert will be executed
-# after the INSERT is woken up. The previous DELETE will wait for
+# after trx_1 DELETE commits. ib_after_row_insert will be executed
+# after the trx_2 INSERT is woken up. The trx_1 DELETE will wait for
 # first_del_cont signal before commit, and this signal will be sent later.
 # So it's safe to use two signals in a row here, it's guaranted the first
 # signal will be received before the second signal is sent.
 SET DEBUG_SYNC = 'lock_wait_suspend_thread_enter SIGNAL first_ins_locked';
 SET DEBUG_SYNC = 'ib_after_row_insert SIGNAL first_ins_row_inserted WAIT_FOR first_ins_cont';
---send INSERT INTO t VALUES(10, 20)
+--send INSERT INTO t VALUES(10, 20) # trx_2
 
 --connect(con_del_2,localhost,root,,)
 # After MDEV-30225 is fixed, the following DELETE creates next-key lock for
@@ -36,24 +36,26 @@ SET DEBUG_SYNC = 'ib_after_row_insert SIGNAL first_ins_row_inserted WAIT_FOR fir
 SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
 SET DEBUG_SYNC = 'now WAIT_FOR first_ins_locked';
 SET DEBUG_SYNC = 'lock_wait_suspend_thread_enter SIGNAL second_del_locked';
-###############################################################################
-# This DELETE is locked by the previous DELETE, after that DELETE is
-# committed, it will still be locked by the next INSERT on delete-marked
-# heap_no 2 record. After that INSERT inserted the record with heap_no 3,
-# and after heap_no 2 record is purged, this DELETE will be unlocked and
+##############################################################################
+# trx_3 DELETE is locked by trx_1 DELETE, after trx_1 DELETE is
+# committed, it will still be locked by trx_2 INSERT on delete-marked
+# heap_no 2 record. After trx_2 INSERT inserted the record with heap_no 3,
+# and after heap_no 2 record is purged, trx_3 DELETE will be unlocked and
 # must restore persistent cursor position at heap_no 3 record, as it has the
 # same secondary key value as former heap_no 2 record. Then it must be blocked
-# by the previous INSERT, and after the INSERT is committed, it must
-# delete the record, inserted by the previous INSERT, and the last INSERT(see
+# by trx_2 INSERT, and after trx_2 INSERT is committed, it must
+# delete the record, inserted by trx_2 INSERT, and trx_4 INSERT(see
 # below) must be finished without error. But instead this DELETE restores
 # persistent cursor position to supremum, as a result, it does not delete the
-# record, inserted by the previous INSERT, and the last INSERT is finished with
+# record, inserted by trx_2 INSERT, and trx_4 INSERT is finished with
 # duplicate key check error.
 ###############################################################################
---send DELETE FROM t WHERE b = 20
+--send DELETE FROM t WHERE b = 20 # trx_3
 
 --connection default
 SET DEBUG_SYNC = 'now WAIT_FOR second_del_locked';
+SET @saved_dbug = @@GLOBAL.debug_dbug;
+SET @@GLOBAL.debug_dbug="d,enable_row_purge_del_mark_exit_sync_point";
 SET DEBUG_SYNC = 'now SIGNAL first_del_cont';
 SET DEBUG_SYNC = 'now WAIT_FOR first_ins_row_inserted';
 --connection con_del_1
@@ -61,7 +63,8 @@ SET DEBUG_SYNC = 'now WAIT_FOR first_ins_row_inserted';
 
 --connection default
 --disconnect prevent_purge
---source include/wait_all_purged.inc
+SET DEBUG_SYNC = 'now WAIT_FOR row_purge_del_mark_finished';
+SET @@GLOBAL.debug_dbug = @saved_dbug;
 SET DEBUG_SYNC = 'now SIGNAL first_ins_cont';
 
 --connection con_del_2
@@ -74,7 +77,7 @@ SET DEBUG_SYNC = 'now SIGNAL first_ins_cont';
 ###############################################################################
 # Duplicate key error is expected if the bug is not fixed.
 ###############################################################################
-INSERT INTO t VALUES(30, 20);
+INSERT INTO t VALUES(30, 20); # trx_4
 
 --disconnect con_ins_1
 --disconnect con_del_1
diff --git a/mysql-test/suite/innodb/t/dml_purge.test b/mysql-test/suite/innodb/t/dml_purge.test
index 7034939aa4e..c13ff22572b 100644
--- a/mysql-test/suite/innodb/t/dml_purge.test
+++ b/mysql-test/suite/innodb/t/dml_purge.test
@@ -32,7 +32,7 @@ UPDATE t1 SET b=4 WHERE a=3;
 
 --connection default
 # Initiate a full purge, which should reset the DB_TRX_ID except for a=3.
---source include/wait_all_purged.inc
+SET GLOBAL innodb_max_purge_lag_wait=1;
 # Initiate a ROLLBACK of the update, which should reset the DB_TRX_ID for a=3.
 --connection con1
 ROLLBACK;
diff --git a/mysql-test/suite/innodb/t/instant_alter_debug.test b/mysql-test/suite/innodb/t/instant_alter_debug.test
index f102185c27f..c49ab758f24 100644
--- a/mysql-test/suite/innodb/t/instant_alter_debug.test
+++ b/mysql-test/suite/innodb/t/instant_alter_debug.test
@@ -451,7 +451,9 @@ COMMIT;
 disconnect stop_purge;
 
 connection default;
+let $wait_all_purged = 1;
 --source include/wait_all_purged.inc
+let $wait_all_purged = 0;
 SET DEBUG_SYNC='now SIGNAL s2';
 
 connection dml;
@@ -459,6 +461,7 @@ reap;
 disconnect dml;
 
 connection default;
+--source include/wait_all_purged.inc
 SET DEBUG_SYNC=RESET;
 DROP TABLE t1;
 
diff --git a/mysql-test/suite/innodb/t/instant_alter_purge.test b/mysql-test/suite/innodb/t/instant_alter_purge.test
index 9ccf3347d7b..88a56141a1f 100644
--- a/mysql-test/suite/innodb/t/instant_alter_purge.test
+++ b/mysql-test/suite/innodb/t/instant_alter_purge.test
@@ -6,6 +6,7 @@ if ($have_debug) {
 
 SET @saved_frequency = @@GLOBAL.innodb_purge_rseg_truncate_frequency;
 SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
+--source include/wait_all_purged.inc
 
 --echo #
 --echo # MDEV-17793 Crash in purge after instant DROP and emptying the table
@@ -27,8 +28,7 @@ START TRANSACTION WITH CONSISTENT SNAPSHOT;
 connection default;
 
 ALTER TABLE t1 ADD COLUMN extra TINYINT UNSIGNED NOT NULL DEFAULT 42;
-let $wait_all_purged= 1;
---source include/wait_all_purged.inc
+SET GLOBAL innodb_max_purge_lag_wait=1;
 ALTER TABLE t1 DROP extra;
 disconnect prevent_purge;
 let $wait_all_purged= 0;
diff --git a/storage/innobase/include/trx0purge.h b/storage/innobase/include/trx0purge.h
index 14cf6a2958b..b8d349af2b0 100644
--- a/storage/innobase/include/trx0purge.h
+++ b/storage/innobase/include/trx0purge.h
@@ -253,6 +253,18 @@ public:
 #endif
     return view.low_limit_no();
   }
+  /** A wrapper around ReadView::sees(). */
+  trx_id_t sees(trx_id_t id) const
+  {
+    /* This function may only be called by purge_coordinator_callback().
+
+    The purge coordinator task may call this without holding any latch,
+    because it is the only thread that may modify purge_sys.view.
+
+    Any other threads that access purge_sys.view must hold purge_sys.latch,
+    typically via purge_sys_t::view_guard. */
+    return view.sees(id);
+  }
   /** A wrapper around trx_sys_t::clone_oldest_view(). */
   void clone_oldest_view()
   {
diff --git a/storage/innobase/row/row0purge.cc b/storage/innobase/row/row0purge.cc
index 74bbc61df52..6942f5b7af8 100644
--- a/storage/innobase/row/row0purge.cc
+++ b/storage/innobase/row/row0purge.cc
@@ -46,6 +46,7 @@ Created 3/14/1997 Heikki Tuuri
 #include "handler.h"
 #include "ha_innodb.h"
 #include "fil0fil.h"
+#include "debug_sync.h"
 
 /*************************************************************************
 IMPORTANT NOTE: Any operation that generates redo MUST check that there
@@ -646,7 +647,18 @@ row_purge_del_mark(
 
 	mem_heap_free(heap);
 
-	return(row_purge_remove_clust_if_poss(node));
+	bool result = row_purge_remove_clust_if_poss(node);
+
+#ifdef ENABLED_DEBUG_SYNC
+	DBUG_EXECUTE_IF(
+		"enable_row_purge_del_mark_exit_sync_point",
+		debug_sync_set_action(
+			current_thd,
+			STRING_WITH_LEN(
+				"now SIGNAL row_purge_del_mark_finished")););
+#endif
+
+	return result;
 }
 
 /** Reset DB_TRX_ID, DB_ROLL_PTR of a clustered index record
diff --git a/storage/innobase/trx/trx0purge.cc b/storage/innobase/trx/trx0purge.cc
index 2f21a4de1e6..7140b2c8816 100644
--- a/storage/innobase/trx/trx0purge.cc
+++ b/storage/innobase/trx/trx0purge.cc
@@ -547,7 +547,7 @@ static void trx_purge_truncate_history()
       mutex_enter(&rseg->mutex);
       trx_purge_truncate_rseg_history(*rseg, head,
                                       !rseg->trx_ref_count &&
-                                      rseg->needs_purge <= head.trx_no);
+                                      purge_sys.sees(rseg->needs_purge));
       mutex_exit(&rseg->mutex);
     }
   }
@@ -604,7 +604,7 @@ static void trx_purge_truncate_history()
       transactions to finish and to be purged. */
       rseg->skip_allocation = true;
 
-      if (rseg->trx_ref_count || rseg->needs_purge > head.trx_no)
+      if (rseg->trx_ref_count || !purge_sys.sees(rseg->needs_purge))
       {
       not_free:
         mutex_exit(&rseg->mutex);

From c25b4967244b1ed7fefbc11ba7e069f5d56daed2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Thu, 8 Jun 2023 09:18:21 +0300
Subject: [PATCH 4/6] MDEV-31382 SET GLOBAL innodb_undo_log_truncate=ON has no
 effect on logically empty undo logs

innodb_undo_log_truncate_update(): A callback function. If
SET GLOBAL innodb_undo_log_truncate=ON, invoke
srv_wake_purge_thread_if_not_active().

srv_wake_purge_thread_if_not_active(): If innodb_undo_log_truncate=ON,
always wake up the purge subsystem.

srv_do_purge(): If the history is empty, invoke
trx_purge_truncate_history() in order to free undo log pages.

trx_purge_truncate_history(): If head.trx_no==0, consider the
cached undo logs to be free.

trx_purge(): Remove the parameter "bool truncate" and let the
caller invoke trx_purge_truncate_history() directly.

Reviewed by: Vladislav Lesin
---
 storage/innobase/handler/ha_innodb.cc |  9 ++++++-
 storage/innobase/include/trx0purge.h  | 11 ++++++--
 storage/innobase/srv/srv0srv.cc       | 37 ++++++++++++++-------------
 storage/innobase/trx/trx0purge.cc     | 18 +++++--------
 4 files changed, 43 insertions(+), 32 deletions(-)

diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 98385e3b5dd..20200515060 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -19684,10 +19684,17 @@ static MYSQL_SYSVAR_ULONG(purge_rseg_truncate_frequency,
   " purge rollback segment(s) on every Nth iteration of purge invocation",
   NULL, NULL, 128, 1, 128, 0);
 
+static void innodb_undo_log_truncate_update(THD *thd, struct st_mysql_sys_var*,
+                                            void*, const void *save)
+{
+  if ((srv_undo_log_truncate= *static_cast<const my_bool*>(save)))
+    srv_wake_purge_thread_if_not_active();
+}
+
 static MYSQL_SYSVAR_BOOL(undo_log_truncate, srv_undo_log_truncate,
   PLUGIN_VAR_OPCMDARG,
   "Enable or Disable Truncate of UNDO tablespace.",
-  NULL, NULL, FALSE);
+  NULL, innodb_undo_log_truncate_update, FALSE);
 
 static MYSQL_SYSVAR_LONG(autoinc_lock_mode, innobase_autoinc_lock_mode,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
diff --git a/storage/innobase/include/trx0purge.h b/storage/innobase/include/trx0purge.h
index b8d349af2b0..b693f784ffb 100644
--- a/storage/innobase/include/trx0purge.h
+++ b/storage/innobase/include/trx0purge.h
@@ -43,12 +43,19 @@ Remove the undo log segment from the rseg slot if it is too big for reuse.
 @param[in,out]	mtr		mini-transaction */
 void
 trx_purge_add_undo_to_history(const trx_t* trx, trx_undo_t*& undo, mtr_t* mtr);
+
+/**
+Remove unnecessary history data from rollback segments. NOTE that when this
+function is called, the caller (purge_coordinator_callback)
+must not have any latches on undo log pages!
+*/
+void trx_purge_truncate_history();
+
 /**
 Run a purge batch.
 @param n_tasks   number of purge tasks to submit to the queue
-@param truncate  whether to truncate the history at the end of the batch
 @return number of undo log pages handled in the batch */
-ulint trx_purge(ulint n_tasks, bool truncate);
+ulint trx_purge(ulint n_tasks);
 
 /** Rollback segements from a given transaction with trx-no
 scheduled for purge. */
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index 50569f810ea..c3e1f6084a8 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -1346,17 +1346,14 @@ static tpool::waitable_task purge_coordinator_task
 static tpool::timer *purge_coordinator_timer;
 
 /** Wake up the purge threads if there is work to do. */
-void
-srv_wake_purge_thread_if_not_active()
+void srv_wake_purge_thread_if_not_active()
 {
-	ut_ad(!srv_read_only_mode);
+  ut_ad(!srv_read_only_mode);
 
-	if (purge_sys.enabled() && !purge_sys.paused()
-	    && trx_sys.rseg_history_len) {
-		if(++purge_state.m_running == 1) {
-			srv_thread_pool->submit_task(&purge_coordinator_task);
-		}
-	}
+  if (purge_sys.enabled() && !purge_sys.paused() &&
+      (srv_undo_log_truncate || trx_sys.rseg_history_len) &&
+      ++purge_state.m_running == 1)
+    srv_thread_pool->submit_task(&purge_coordinator_task);
 }
 
 /** @return whether the purge tasks are active */
@@ -1811,8 +1808,8 @@ static size_t srv_do_purge(ulint* n_total_purged)
 			n_threads = n_use_threads = srv_n_purge_threads;
 			srv_purge_thread_count_changed = 0;
 		} else if (trx_sys.rseg_history_len > rseg_history_len
-		    || (srv_max_purge_lag > 0
-			&& rseg_history_len > srv_max_purge_lag)) {
+			   || (srv_max_purge_lag > 0
+			       && rseg_history_len > srv_max_purge_lag)) {
 
 			/* History length is now longer than what it was
 			when we took the last snapshot. Use more threads. */
@@ -1838,15 +1835,19 @@ static size_t srv_do_purge(ulint* n_total_purged)
 
 		/* Take a snapshot of the history list before purge. */
 		if (!(rseg_history_len = trx_sys.rseg_history_len)) {
-			break;
+			n_pages_purged = 0;
+			goto truncate;
 		}
 
-		n_pages_purged = trx_purge(
-			n_use_threads,
-			!(++count % srv_purge_rseg_truncate_frequency)
-			|| purge_sys.truncate.current
-			|| (srv_shutdown_state != SRV_SHUTDOWN_NONE
-			    && srv_fast_shutdown == 0));
+		n_pages_purged = trx_purge(n_use_threads);
+
+		if (!(++count % srv_purge_rseg_truncate_frequency)
+		    || purge_sys.truncate.current
+		    || (srv_shutdown_state != SRV_SHUTDOWN_NONE
+			&& srv_fast_shutdown == 0)) {
+truncate:
+			trx_purge_truncate_history();
+		}
 
 		*n_total_purged += n_pages_purged;
 	} while (n_pages_purged > 0 && !purge_sys.paused()
diff --git a/storage/innobase/trx/trx0purge.cc b/storage/innobase/trx/trx0purge.cc
index 7140b2c8816..c6adaf5f2bf 100644
--- a/storage/innobase/trx/trx0purge.cc
+++ b/storage/innobase/trx/trx0purge.cc
@@ -522,10 +522,11 @@ __attribute__((optimize(0)))
 # endif
 #endif
 /**
-Removes unnecessary history data from rollback segments. NOTE that when this
-function is called, the caller must not have any latches on undo log pages!
+Remove unnecessary history data from rollback segments. NOTE that when this
+function is called, the caller (purge_coordinator_callback)
+must not have any latches on undo log pages!
 */
-static void trx_purge_truncate_history()
+void trx_purge_truncate_history()
 {
   ut_ad(purge_sys.head <= purge_sys.tail);
   purge_sys_t::iterator &head= purge_sys.head.trx_no
@@ -618,7 +619,7 @@ static void trx_purge_truncate_history()
       for (const trx_undo_t *undo= UT_LIST_GET_FIRST(rseg->undo_cached); undo;
            undo= UT_LIST_GET_NEXT(undo_list, undo))
       {
-        if (head.trx_no < undo->trx_id)
+        if (head.trx_no && head.trx_no < undo->trx_id)
           goto not_free;
         else
           cached+= undo->size;
@@ -731,7 +732,7 @@ static void trx_purge_truncate_history()
       ut_ad(rseg->id == i);
       ut_ad(rseg->is_persistent());
       ut_ad(!rseg->trx_ref_count);
-      ut_ad(rseg->needs_purge <= head.trx_no);
+      ut_ad(!head.trx_no || rseg->needs_purge <= head.trx_no);
       ut_d(const auto old_page= rseg->page_no);
 
       buf_block_t *rblock= trx_rseg_header_create(&space, i,
@@ -1235,9 +1236,8 @@ static void trx_purge_wait_for_workers_to_complete()
 /**
 Run a purge batch.
 @param n_tasks   number of purge tasks to submit to the queue
-@param truncate  whether to truncate the history at the end of the batch
 @return number of undo log pages handled in the batch */
-ulint trx_purge(ulint n_tasks, bool truncate)
+ulint trx_purge(ulint n_tasks)
 {
 	que_thr_t*	thr = NULL;
 	ulint		n_pages_handled;
@@ -1271,10 +1271,6 @@ ulint trx_purge(ulint n_tasks, bool truncate)
 
 	trx_purge_wait_for_workers_to_complete();
 
-	if (truncate) {
-		trx_purge_truncate_history();
-	}
-
 	MONITOR_INC_VALUE(MONITOR_PURGE_INVOKED, 1);
 	MONITOR_INC_VALUE(MONITOR_PURGE_N_PAGE_HANDLED, n_pages_handled);
 

From 21031b24fc6d10921edbe2f57a212bf48dc02969 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Thu, 8 Jun 2023 09:38:03 +0300
Subject: [PATCH 5/6] Suppress an occasional buffer pool warning

---
 mysql-test/suite/innodb/t/purge_secondary.test | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mysql-test/suite/innodb/t/purge_secondary.test b/mysql-test/suite/innodb/t/purge_secondary.test
index 1a0d178f66a..a7f75f56b53 100644
--- a/mysql-test/suite/innodb/t/purge_secondary.test
+++ b/mysql-test/suite/innodb/t/purge_secondary.test
@@ -1,6 +1,10 @@
 --source include/have_innodb.inc
 --source include/have_sequence.inc
 
+--disable_query_log
+call mtr.add_suppression("InnoDB: Difficult to find free blocks in the buffer pool");
+--enable_query_log
+
 # Ensure that the history list length will actually be decremented by purge.
 SET @saved_frequency = @@GLOBAL.innodb_purge_rseg_truncate_frequency;
 SET GLOBAL innodb_purge_rseg_truncate_frequency = 1;

From d3eefbaa55edb585e4fbf8f09ad4141c3be900e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Thu, 8 Jun 2023 10:40:48 +0300
Subject: [PATCH 6/6] MDEV-31355 fixup: Adjust one more test

The test gcol.gcol_purge would reliably hang on 10.6 on a
Microsoft Windows builder without this adjustment.
A similar adjustment was applied in
commit 3e40f9a7f3bbe82d96c8acccbb017deebfa00647
to the tests innodb.dml_purge and innodb.instant_alter_purge.
---
 mysql-test/suite/gcol/r/gcol_purge.result | 2 +-
 mysql-test/suite/gcol/t/gcol_purge.test   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mysql-test/suite/gcol/r/gcol_purge.result b/mysql-test/suite/gcol/r/gcol_purge.result
index 11063c7cd6f..a130485f219 100644
--- a/mysql-test/suite/gcol/r/gcol_purge.result
+++ b/mysql-test/suite/gcol/r/gcol_purge.result
@@ -16,7 +16,7 @@ INSERT INTO t1 (f1, f2) VALUES(1,2);
 set global debug_dbug="+d,ib_purge_virtual_index_callback";
 connection con1;
 COMMIT;
-InnoDB		0 transactions not purged
+SET GLOBAL innodb_max_purge_lag_wait=1;
 connection con2;
 commit;
 disconnect con1;
diff --git a/mysql-test/suite/gcol/t/gcol_purge.test b/mysql-test/suite/gcol/t/gcol_purge.test
index ecfd89f4469..8fff375cdc2 100644
--- a/mysql-test/suite/gcol/t/gcol_purge.test
+++ b/mysql-test/suite/gcol/t/gcol_purge.test
@@ -23,7 +23,7 @@ set global debug_dbug="+d,ib_purge_virtual_index_callback";
 connection con1;
 COMMIT;
 
---source ../innodb/include/wait_all_purged.inc
+SET GLOBAL innodb_max_purge_lag_wait=1;
 
 connection con2;
 commit;