Kristian Nielsen added a comment - 2024-01-24 12:32 Ouch, this is not supposed to occur. Thanks for the report, confirmed that this can occur with the very simple test provided. Here is a mysql-test-run testcase that reproduces, the below patch makes it easier to trigger: --source include/have_innodb.inc --source include/have_binlog_format_row.inc --source include/master-slave.inc   --connection slave --source include/stop_slave.inc SET @old_retry=@@GLOBAL.slave_transaction_retries; SET GLOBAL slave_parallel_threads=4; SET @old_mode= @@GLOBAL.slave_parallel_mode; SET GLOBAL slave_parallel_mode= optimistic;   --connection master drop database if exists my_table_test; create database if not exists my_table_test; use my_table_test; drop table if exists test; create table test(a int, b varchar(123)) ENGINE=InnoDB; SET gtid_seq_no= 100; insert into test values(1, 'asdf'); update test set b='zxf1' where a=1; update test set b='\n' where a=1;   --connection slave --source include/start_slave.inc   --connection master --sync_slave_with_master   --connection master DROP DATABASE my_table_test;   --connection slave --source include/stop_slave.inc SET GLOBAL slave_transaction_retries= @old_retry; SET GLOBAL slave_parallel_threads=0; SET GLOBAL slave_parallel_mode= @old_mode; --source include/start_slave.inc   --source include/rpl_end.inc diff --git a/sql/log_event_server.cc b/sql/log_event_server.cc index 13a981d4381..426d4ee481e 100644 --- a/sql/log_event_server.cc +++ b/sql/log_event_server.cc @@ -7325,6 +7325,7 @@ Rows_log_event::write_row(rpl_group_info *rgi, TODO: Add safety measures against infinite looping. */ +my_sleep(20000); if (table->s->sequence) error= update_sequence(); else while (unlikely(error= table->file->ha_write_row(table->record[0])))

Kristian Nielsen added a comment - 2024-01-24 13:51 This was supposed to be fixed in MDEV-13577 . However, the fix for that overlooked the case where the table has no unique (or primary) key. Then the missing row is caught from an index/table scan returning the error HA_ERR_END_OF_FILE (the patch for MDEV-13577 handled only an index lookup that returns HA_ERR_KEY_NOT_FOUND). This patch seems to fix the bug and avoid the errorneous messages in the error log: diff --git a/sql/log_event_server.cc b/sql/log_event_server.cc index 13a981d4381..28b1dd13658 100644 --- a/sql/log_event_server.cc +++ b/sql/log_event_server.cc @@ -7814,6 +7815,12 @@ static int row_not_found_error(rpl_group_info *rgi) ? HA_ERR_KEY_NOT_FOUND : HA_ERR_RECORD_CHANGED; } +static int end_of_file_error(rpl_group_info *rgi) +{ + return rgi->speculation != rpl_group_info::SPECULATE_OPTIMISTIC + ? HA_ERR_END_OF_FILE : HA_ERR_RECORD_CHANGED; +} + /** Locate the current row in event's table. @@ -8061,6 +8068,8 @@ int Rows_log_event::find_row(rpl_group_info *rgi) while ((error= table->file->ha_index_next(table->record[0]))) { DBUG_PRINT("info",("no record matching the given row found")); + if (error == HA_ERR_END_OF_FILE) + error= end_of_file_error(rgi); table->file->print_error(error, MYF(0)); table->file->ha_index_end(); goto end; @@ -8097,6 +8106,7 @@ int Rows_log_event::find_row(rpl_group_info *rgi) break; case HA_ERR_END_OF_FILE: + error= end_of_file_error(rgi); DBUG_PRINT("info", ("Record not found")); table->file->ha_rnd_end(); goto end;

liujia added a comment - 2024-01-25 03:41 I used sysbench to reproduce the error. This is the content of the sysbench script, named read_only.lua. ``` require("oltp_common") function prepare_statements() end function event() con:query("update test set b='zxf1' where a=1;") con:query("update test set b='\n' where a=1;") end ``` This is the sysbench command. ``` sysbench ./read_only.lua --db-driver=mysql --mysql-host=127.0.0.1 --mysql-port=3633 --mysql-user=root --mysql-password=123456 --mysql-db=my_table_test --threads=10 --time=0 --report-interval=1 run > my_table_test.log 2>&1 & ``` Run the sysbench command to quickly reproduce the problem.

Kristian Nielsen added a comment - 2024-03-08 10:36 Hi serg , Can you review a small patch for MDEV-33303 ? It's a follow-up to an earlier patch of yours: commit bb24663f5ad955a615172512c04779d219bb6645 Author: Sergei Golubchik <serg@mariadb.org> Date: Wed Jun 20 10:45:57 2018 +0200   MDEV-13577 slave_parallel_mode=optimistic should not report the mode's specific temporary errors The MDEV-13577 patch missed one code path which occurs for a table without primary key. So I added similar code for this case. Patch in branch bb-10.6-knielsen and in mail: https://lists.mariadb.org/hyperkitty/list/commits@lists.mariadb.org/thread/YBVEM3I4ZC4UMZOPJDU7BCGVJI36CIY6/ The bug is present in 10.4, but I suggest to fix in 10.6 as the bug is not very serious (it occurs only in rare situations, and only results in a stray message in the error log). - Kristian.