Merge 10.1 into 10.2

mysql-test/r/subselect.result

@@ -7215,6 +7215,32 @@ NULL
 # SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 #
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 # End of 10.0 tests
 #
 # MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops

mysql-test/r/subselect_no_exists_to_in.result

@@ -7215,6 +7215,32 @@ NULL
 # SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 #
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 # End of 10.0 tests
 #
 # MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops

mysql-test/r/subselect_no_mat.result

@@ -7208,6 +7208,32 @@ NULL
 # SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 #
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 # End of 10.0 tests
 #
 # MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops

mysql-test/r/subselect_no_opts.result

@@ -7206,6 +7206,32 @@ NULL
 # SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 #
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 # End of 10.0 tests
 #
 # MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops

mysql-test/r/subselect_no_scache.result

@@ -7221,6 +7221,32 @@ NULL
 # SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 #
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 # End of 10.0 tests
 #
 # MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops

mysql-test/r/subselect_no_semijoin.result

@@ -7206,6 +7206,32 @@ NULL
 # SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 #
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 # End of 10.0 tests
 #
 # MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops

mysql-test/suite/innodb/r/innodb-lru-force-no-free-page.result

+call mtr.add_suppression("\\[Warning\\] InnoDB: Difficult to find free blocks in the buffer pool.");
+SET SESSION debug_dbug="+d,ib_lru_force_no_free_page";
+CREATE TABLE t1 (j LONGBLOB) ENGINE = InnoDB;
+BEGIN;
+INSERT INTO t1 VALUES (repeat('abcdefghijklmnopqrstuvwxyz',200));
+COMMIT;
+SET SESSION debug_dbug="";
+DROP TABLE t1;
+FOUND 1 /InnoDB: Difficult to find free blocks / in mysqld.1.err

mysql-test/suite/innodb/t/innodb-lru-force-no-free-page.test

+--source include/have_innodb.inc
+--source include/have_debug.inc
+
+call mtr.add_suppression("\\[Warning\\] InnoDB: Difficult to find free blocks in the buffer pool.");
+
+SET SESSION debug_dbug="+d,ib_lru_force_no_free_page";
+
+CREATE TABLE t1 (j LONGBLOB) ENGINE = InnoDB;
+BEGIN;
+INSERT INTO t1 VALUES (repeat('abcdefghijklmnopqrstuvwxyz',200));
+COMMIT;
+
+SET SESSION debug_dbug="";
+
+DROP TABLE t1;
+
+#
+# There should be only one message
+#
+let SEARCH_RANGE= -50000;
+let SEARCH_FILE= $MYSQLTEST_VARDIR/log/mysqld.1.err;
+--let SEARCH_PATTERN=InnoDB: Difficult to find free blocks 
+--source include/search_pattern_in_file.inc
+

mysql-test/suite/innodb/t/innodb-master.opt

@@ -2,3 +2,5 @@
 --default-storage-engine=MyISAM
 --innodb-strict-mode=0
 --innodb-file-per-table=0
+--loose-innodb-track-changed-pages
+--loose-innodb-log-archive

mysql-test/suite/mariabackup/huge_lsn.test

 --source include/not_embedded.inc
+--source include/have_file_key_management.inc
 
 --echo #
 --echo # MDEV-13416 mariabackup fails with EFAULT "Bad Address"

mysql-test/t/subselect.test

@@ -6076,6 +6076,33 @@ SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 --echo #
 drop table t1, t2;
 
+--echo #
+--echo # MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+--echo # (5.5 test)
+--echo #
+SET @optimiser_switch_save= @@optimizer_switch;
+ 
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+ 
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+ 
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+ 
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+ 
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+ 
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+
+--echo End of 5.5 tests
 --echo # End of 10.0 tests
 
 --echo #

sql/opt_subselect.cc

@@ -2701,7 +2701,8 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
     LooseScan detector in best_access_path)
   */
   remaining_tables &= ~new_join_tab->table->map;
-  table_map dups_producing_tables;
+  table_map dups_producing_tables, prev_dups_producing_tables,
+            prev_sjm_lookup_tables;
 
   if (idx == join->const_tables)
     dups_producing_tables= 0;
@@ -2712,7 +2713,7 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
   if ((emb_sj_nest= new_join_tab->emb_sj_nest))
     dups_producing_tables |= emb_sj_nest->sj_inner_tables;
 
-  Semi_join_strategy_picker **strategy;
+  Semi_join_strategy_picker **strategy, **prev_strategy;
   if (idx == join->const_tables)
   {
     /* First table, initialize pickers */
@@ -2764,23 +2765,54 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
                 3. We have no clue what to do about fanount of semi-join Y.
         */
         if ((dups_producing_tables & handled_fanout) ||
-            (read_time < *current_read_time && 
+            (read_time < *current_read_time &&
              !(handled_fanout & pos->inner_tables_handled_with_other_sjs)))
         {
-          /* Mark strategy as used */ 
-          (*strategy)->mark_used();
-          pos->sj_strategy= sj_strategy;
-          if (sj_strategy == SJ_OPT_MATERIALIZE)
-            join->sjm_lookup_tables |= handled_fanout;
+          DBUG_ASSERT(pos->sj_strategy != sj_strategy);
+          /*
+            If the strategy choosen first time or
+            the strategy replace strategy which was used to exectly the same
+            tables
+          */
+          if (pos->sj_strategy == SJ_OPT_NONE ||
+              handled_fanout ==
+                (prev_dups_producing_tables ^ dups_producing_tables))
+          {
+            prev_strategy= strategy;
+            if (pos->sj_strategy == SJ_OPT_NONE)
+            {
+              prev_dups_producing_tables= dups_producing_tables;
+              prev_sjm_lookup_tables= join->sjm_lookup_tables;
+            }
+            /* Mark strategy as used */
+            (*strategy)->mark_used();
+            pos->sj_strategy= sj_strategy;
+            if (sj_strategy == SJ_OPT_MATERIALIZE)
+              join->sjm_lookup_tables |= handled_fanout;
+            else
+              join->sjm_lookup_tables &= ~handled_fanout;
+            *current_read_time= read_time;
+            *current_record_count= rec_count;
+            dups_producing_tables &= ~handled_fanout;
+            //TODO: update bitmap of semi-joins that were handled together with
+            // others.
+            if (is_multiple_semi_joins(join, join->positions, idx,
+                                       handled_fanout))
+              pos->inner_tables_handled_with_other_sjs |= handled_fanout;
+          }
           else
-            join->sjm_lookup_tables &= ~handled_fanout;
-          *current_read_time= read_time;
-          *current_record_count= rec_count;
-          dups_producing_tables &= ~handled_fanout;
-          //TODO: update bitmap of semi-joins that were handled together with
-          // others.
-          if (is_multiple_semi_joins(join, join->positions, idx, handled_fanout))
-            pos->inner_tables_handled_with_other_sjs |= handled_fanout;
+          {
+            /* Conflict fall to most general variant */
+            (*prev_strategy)->set_empty();
+            dups_producing_tables= prev_dups_producing_tables;
+            join->sjm_lookup_tables= prev_sjm_lookup_tables;
+            // mark it 'none' to avpoid loops
+            pos->sj_strategy= SJ_OPT_NONE;
+            // next skip to last;
+            strategy= pickers +
+              (sizeof(pickers)/sizeof(Semi_join_strategy_picker*) - 3);
+            continue;
+          }
         }
         else
         {

storage/innobase/buf/buf0lru.cc

 /*****************************************************************************
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, MariaDB Corporation.
+Copyright (c) 2017, 2018, 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
@@ -80,6 +80,10 @@ static const ulint BUF_LRU_SEARCH_SCAN_THRESHOLD = 100;
 frames in the buffer pool, we set this to TRUE */
 static bool buf_lru_switched_on_innodb_mon = false;
 
+/** True if diagnostic message about difficult to find free blocks
+in the buffer bool has already printed. */
+static bool	buf_lru_free_blocks_error_printed;
+
 /******************************************************************//**
 These statistics are not 'of' LRU but 'for' LRU.  We keep count of I/O
 and page_zip_decompress() operations.  Based on the statistics,
@@ -1079,8 +1083,6 @@ buf_LRU_get_free_block(
 	bool		freed		= false;
 	ulint		n_iterations	= 0;
 	ulint		flush_failures	= 0;
-	bool		mon_value_was	= false;
-	bool		started_monitor	= false;
 
 	MONITOR_INC(MONITOR_LRU_GET_FREE_SEARCH);
 loop:
@@ -1088,6 +1090,11 @@ buf_LRU_get_free_block(
 
 	buf_LRU_check_size_of_non_data_objects(buf_pool);
 
+	DBUG_EXECUTE_IF("ib_lru_force_no_free_page",
+		if (!buf_lru_free_blocks_error_printed) {
+			n_iterations = 21;
+			goto not_found;});
+
 	/* If there is a block in the free list, take it */
 	block = buf_LRU_get_free_only(buf_pool);
 
@@ -1097,11 +1104,6 @@ buf_LRU_get_free_block(
 		ut_ad(buf_pool_from_block(block) == buf_pool);
 		memset(&block->page.zip, 0, sizeof block->page.zip);
 
-		if (started_monitor) {
-			srv_print_innodb_monitor =
-				static_cast<my_bool>(mon_value_was);
-		}
-
 		block->skip_flush_check = false;
 		block->page.flush_observer = NULL;
 		return(block);
@@ -1131,24 +1133,24 @@ buf_LRU_get_free_block(
 		}
 	}
 
+#ifndef DBUG_OFF
+not_found:
+#endif
+
 	buf_pool_mutex_exit(buf_pool);
 
 	if (freed) {
 		goto loop;
 	}
 
-	if (n_iterations > 20
+	if (n_iterations > 20 && !buf_lru_free_blocks_error_printed
 	    && srv_buf_pool_old_size == srv_buf_pool_size) {
 
 		ib::warn() << "Difficult to find free blocks in the buffer pool"
 			" (" << n_iterations << " search iterations)! "
 			<< flush_failures << " failed attempts to"
-			" flush a page! Consider increasing the buffer pool"
-			" size. It is also possible that in your Unix version"
-			" fsync is very slow, or completely frozen inside"
-			" the OS kernel. Then upgrading to a newer version"
-			" of your operating system may help. Look at the"
-			" number of fsyncs in diagnostic info below."
+			" flush a page!"
+			" Consider increasing innodb_buffer_pool_size."
 			" Pending flushes (fsync) log: "
 			<< fil_n_pending_log_flushes
 			<< "; buffer pool: "
@@ -1156,13 +1158,9 @@ buf_LRU_get_free_block(
 			<< ". " << os_n_file_reads << " OS file reads, "
 			<< os_n_file_writes << " OS file writes, "
 			<< os_n_fsyncs
-			<< " OS fsyncs. Starting InnoDB Monitor to print"
-			" further diagnostics to the standard output.";
+			<< " OS fsyncs.";
 
-		mon_value_was = srv_print_innodb_monitor;
-		started_monitor = true;
-		srv_print_innodb_monitor = true;
-		os_event_set(srv_monitor_event);
+		buf_lru_free_blocks_error_printed = true;
 	}
 
 	/* If we have scanned the whole LRU and still are unable to

storage/innobase/trx/trx0purge.cc

@@ -1162,28 +1162,6 @@ trx_purge_rseg_get_next_history_log(
 
 		mutex_exit(&(rseg->mutex));
 		mtr_commit(&mtr);
-
-		trx_sys_mutex_enter();
-
-		/* Add debug code to track history list corruption reported
-		on the MySQL mailing list on Nov 9, 2004. The fut0lst.cc
-		file-based list was corrupt. The prev node pointer was
-		FIL_NULL, even though the list length was over 8 million nodes!
-		We assume that purge truncates the history list in large
-		size pieces, and if we here reach the head of the list, the
-		list cannot be longer than 2000 000 undo logs now. */
-
-		if (trx_sys->rseg_history_len > 2000000) {
-			ib::warn() << "Purge reached the head of the history"
-				" list, but its length is still reported as "
-				<< trx_sys->rseg_history_len << "! Make"
-				" a detailed bug report, and submit it to"
-				" https://jira.mariadb.org/";
-			ut_ad(0);
-		}
-
-		trx_sys_mutex_exit();
-
 		return;
 	}
 

storage/xtradb/buf/buf0lru.cc

 /*****************************************************************************
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, MariaDB Corporation.
+Copyright (c) 2017, 2018, 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
@@ -87,6 +87,10 @@ buffer pools. */
 frames in the buffer pool, we set this to TRUE */
 static ibool	buf_lru_switched_on_innodb_mon	= FALSE;
 
+/** True if diagnostic message about difficult to find free blocks
+in the buffer bool has already printed. */
+static bool	buf_lru_free_blocks_error_printed;
+
 /******************************************************************//**
 These statistics are not 'of' LRU but 'for' LRU.  We keep count of I/O
 and page_zip_decompress() operations.  Based on the statistics,
@@ -1080,68 +1084,39 @@ buf_LRU_check_size_of_non_data_objects(
 }
 
 /** Diagnose failure to get a free page and request InnoDB monitor output in
-the error log if more than two seconds have been spent already.
+the error log if it has not yet printed.
 @param[in]	n_iterations	how many buf_LRU_get_free_page iterations
                                 already completed
-@param[in]	started_ms	timestamp in ms of when the attempt to get the
-                                free page started
 @param[in]	flush_failures	how many times single-page flush, if allowed,
                                 has failed
-@param[out]	mon_value_was	previous srv_print_innodb_monitor value
-@param[out]	started_monitor	whether InnoDB monitor print has been requested
 */
 static
 void
-buf_LRU_handle_lack_of_free_blocks(ulint n_iterations, ulint started_ms,
-				   ulint flush_failures,
-				   ibool *mon_value_was,
-				   ibool *started_monitor)
+buf_LRU_handle_lack_of_free_blocks(
+	ulint n_iterations,
+	ulint flush_failures)
 {
-	static ulint last_printout_ms = 0;
-
-	/* Legacy algorithm started warning after at least 2 seconds, we
-	emulate	this. */
-	const ulint current_ms = ut_time_ms();
-
-	if ((current_ms > started_ms + 2000)
-	    && (current_ms > last_printout_ms + 2000)) {
-
-		ut_print_timestamp(stderr);
-		fprintf(stderr,
-			"  InnoDB: Warning: difficult to find free blocks in\n"
-			"InnoDB: the buffer pool (%lu search iterations)!\n"
-			"InnoDB: %lu failed attempts to flush a page!"
-			" Consider\n"
-			"InnoDB: increasing the buffer pool size.\n"
-			"InnoDB: It is also possible that"
-			" in your Unix version\n"
-			"InnoDB: fsync is very slow, or"
-			" completely frozen inside\n"
-			"InnoDB: the OS kernel. Then upgrading to"
-			" a newer version\n"
-			"InnoDB: of your operating system may help."
-			" Look at the\n"
-			"InnoDB: number of fsyncs in diagnostic info below.\n"
-			"InnoDB: Pending flushes (fsync) log: %lu;"
-			" buffer pool: %lu\n"
-			"InnoDB: %lu OS file reads, %lu OS file writes,"
-			" %lu OS fsyncs\n"
-			"InnoDB: Starting InnoDB Monitor to print further\n"
-			"InnoDB: diagnostics to the standard output.\n",
-			(ulong) n_iterations,
-			(ulong)	flush_failures,
-			(ulong) fil_n_pending_log_flushes,
-			(ulong) fil_n_pending_tablespace_flushes,
-			(ulong) os_n_file_reads, (ulong) os_n_file_writes,
-			(ulong) os_n_fsyncs);
-
-		last_printout_ms = current_ms;
-		*mon_value_was = srv_print_innodb_monitor;
-		*started_monitor = TRUE;
-		srv_print_innodb_monitor = TRUE;
-		os_event_set(lock_sys->timeout_event);
+	if (n_iterations > 20 && !buf_lru_free_blocks_error_printed) {
+		ib_logf(IB_LOG_LEVEL_WARN,
+			"Difficult to find free blocks in"
+			" the buffer pool (" ULINTPF " search iterations)! "
+			ULINTPF " failed attempts to flush a page!",
+			n_iterations, flush_failures);
+		ib_logf(IB_LOG_LEVEL_INFO,
+			"Consider increasing the buffer pool size.");
+		ib_logf(IB_LOG_LEVEL_INFO,
+			"Pending flushes (fsync) log: " ULINTPF
+			" buffer pool: " ULINTPF
+			" OS file reads: " ULINTPF " OS file writes: "
+			ULINTPF " OS fsyncs: " ULINTPF "",
+			fil_n_pending_log_flushes,
+			fil_n_pending_tablespace_flushes,
+			os_n_file_reads,
+			os_n_file_writes,
+			os_n_fsyncs);
+
+		buf_lru_free_blocks_error_printed = true;
 	}
-
 }
 
 /** The maximum allowed backoff sleep time duration, microseconds */
@@ -1189,9 +1164,6 @@ buf_LRU_get_free_block(
 	ibool		freed		= FALSE;
 	ulint		n_iterations	= 0;
 	ulint		flush_failures	= 0;
-	ibool		mon_value_was	= FALSE;
-	ibool		started_monitor	= FALSE;
-	ulint		started_ms	= 0;
 
 	ut_ad(!mutex_own(&buf_pool->LRU_list_mutex));
 
@@ -1199,42 +1171,20 @@ buf_LRU_get_free_block(
 loop:
 	buf_LRU_check_size_of_non_data_objects(buf_pool);
 
-	/* If there is a block in the free list, take it */
-	if (DBUG_EVALUATE_IF("simulate_lack_of_pages", true, false)) {
-
-		block = NULL;
-
-		if (srv_debug_monitor_printed)
-			DBUG_SET("-d,simulate_lack_of_pages");
-
-	} else if (DBUG_EVALUATE_IF("simulate_recovery_lack_of_pages",
-				    recv_recovery_on, false)) {
-
-		block = NULL;
-
-		if (srv_debug_monitor_printed)
-			DBUG_SUICIDE();
-	} else {
+	DBUG_EXECUTE_IF("ib_lru_force_no_free_page",
+		if (!buf_lru_free_blocks_error_printed) {
+			n_iterations = 21;
+			goto not_found;});
 
-		block = buf_LRU_get_free_only(buf_pool);
-	}
+	block = buf_LRU_get_free_only(buf_pool);
 
 	if (block) {
 
 		ut_ad(buf_pool_from_block(block) == buf_pool);
 		memset(&block->page.zip, 0, sizeof block->page.zip);
-
-		if (started_monitor) {
-			srv_print_innodb_monitor =
-				static_cast<my_bool>(mon_value_was);
-		}
-
 		return(block);
 	}
 
-	if (!started_ms)
-		started_ms = ut_time_ms();
-
 	if (srv_empty_free_list_algorithm == SRV_EMPTY_FREE_LIST_BACKOFF
 	    && buf_lru_manager_is_active
 	    && (srv_shutdown_state == SRV_SHUTDOWN_NONE
@@ -1272,10 +1222,7 @@ buf_LRU_get_free_block(
 				: FREE_LIST_BACKOFF_LOW_PRIO_DIVIDER));
 		}
 
-		buf_LRU_handle_lack_of_free_blocks(n_iterations, started_ms,
-						   flush_failures,
-						   &mon_value_was,
-						   &started_monitor);
+		buf_LRU_handle_lack_of_free_blocks(n_iterations, flush_failures);
 
 		n_iterations++;
 
@@ -1314,13 +1261,8 @@ buf_LRU_get_free_block(
 
 	mutex_exit(&buf_pool->flush_state_mutex);
 
-	if (DBUG_EVALUATE_IF("simulate_recovery_lack_of_pages", true, false)
-	    || DBUG_EVALUATE_IF("simulate_lack_of_pages", true, false)) {
-
-		buf_pool->try_LRU_scan = false;
-	}
-
 	freed = FALSE;
+
 	if (buf_pool->try_LRU_scan || n_iterations > 0) {
 
 		/* If no block was in the free list, search from the
@@ -1345,9 +1287,11 @@ buf_LRU_get_free_block(
 
 	}
 
-	buf_LRU_handle_lack_of_free_blocks(n_iterations, started_ms,
-					   flush_failures, &mon_value_was,
-					   &started_monitor);
+#ifndef DBUG_OFF
+not_found:
+#endif
+
+	buf_LRU_handle_lack_of_free_blocks(n_iterations, flush_failures);
 
 	/* If we have scanned the whole LRU and still are unable to
 	find a free block then we should sleep here to let the

storage/xtradb/trx/trx0purge.cc

@@ -584,32 +584,6 @@ trx_purge_rseg_get_next_history_log(
 
 		mutex_exit(&(rseg->mutex));
 		mtr_commit(&mtr);
-
-		mutex_enter(&trx_sys->mutex);
-
-		/* Add debug code to track history list corruption reported
-		on the MySQL mailing list on Nov 9, 2004. The fut0lst.cc
-		file-based list was corrupt. The prev node pointer was
-		FIL_NULL, even though the list length was over 8 million nodes!
-		We assume that purge truncates the history list in large
-		size pieces, and if we here reach the head of the list, the
-		list cannot be longer than 2000 000 undo logs now. */
-
-		if (trx_sys->rseg_history_len > 2000000) {
-			ut_print_timestamp(stderr);
-			fprintf(stderr,
-				"  InnoDB: Warning: purge reached the"
-				" head of the history list,\n"
-				"InnoDB: but its length is still"
-				" reported as %lu! Make a detailed bug\n"
-				"InnoDB: report, and submit it"
-				" to https://jira.mariadb.org/\n",
-				(ulong) trx_sys->rseg_history_len);
-			ut_ad(0);
-		}
-
-		mutex_exit(&trx_sys->mutex);
-
 		return;
 	}