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MDEV-31646 Online alter applies binlog cache limit to cache writes

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1. Make online disk writes unlimited, same as filesort does.
2. Make proper error handling -- in 32-bit build IO_CACHE capacity limit is
4GB, so it is quite possible to overfill there.
3. Event_log::write_cache complicated with event reparsing, and as it was
proven by QA, contains some mistakes. Rewrite introbuce a simpler and much
faster version, not featuring reparsing and therefore copying a whole
buffer at once. This also disables checksums and crypto.
4. Handle read_log_event errors correctly: error returned is -1 (eof
signal for alter table), and my_error is not called. Call my_error and
always return 1. There's no test for this, since it shouldn't happen,
see the next bullet.
5. An event could be written partially in case of error, if it's bigger
than the IO_CACHE buffer. Restore the position where it was before the
error was emitted.

As a result, online alter is untied of several binlog variables, which was
a second aim of this patch.
This commit is contained in:
Nikita Malyavin
2023-07-13 18:15:28 +04:00
committed by Sergei Golubchik
parent 2cecb5a638
commit d5e59c983f
5 changed files with 176 additions and 22 deletions
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69
mysql-test/main/alter_table_online_debug.test
View File

@ -2,6 +2,7 @@
--source include/not_embedded.inc
--source include/binlog_combinations.inc
--source include/have_innodb.inc
--source include/have_sequence.inc
--source include/have_partition.inc
set default_storage_engine= innodb;
@ -1331,7 +1332,7 @@ select a, b from t;
# Cleanup
drop table t;
set debug_sync= reset;
set debug_dbug= @old_debug;
set debug_dbug= @old_dbug;
--connection default
--echo #
@ -1551,11 +1552,73 @@ drop table t;
set debug_sync= reset;
--disconnect con1
--disconnect con2
let SEARCH_FILE= $MYSQLTEST_VARDIR/log/mysqld.1.err;
let SEARCH_PATTERN= Slave SQL;
--source include/search_pattern_in_file.inc
--echo #
--echo # MDEV-31646 Online alter applies binlog cache limit to cache writes
--echo #
create table t (pk int primary key, a varchar(100)) engine=MyISAM;
insert into t select seq, repeat('x', 100) from seq_1_to_500;
set @cache.size= @@max_binlog_cache_size;
set global max_binlog_cache_size= 4096;
send set debug_sync= 'now wait_for do_updates';
--connection con1
set debug_sync= 'alter_table_online_progress signal do_updates wait_for go';
send alter table t add b int, algorithm=copy, lock=none;
--connection default
--reap
update t set a = repeat('y', 100);
show warnings;
set debug_sync= 'now signal go';
--connection con1
--reap
show warnings;
--connection default
drop table t;
set debug_sync= reset;
set global max_binlog_cache_size= @cache.size;
--echo # Now make sure that smaller limits will be processed fine
set @old_dbug=@@debug_dbug;
create table t (pk int primary key, a text) engine=MyISAM;
insert into t select seq, repeat('x', 1000) from seq_1_to_50;
--connection con1
set debug_sync= 'alter_table_online_progress signal do_updates wait_for go';
--send
alter table t add b int, algorithm=copy, lock=none;
--connection default
set debug_sync= 'now wait_for do_updates';
set debug_dbug="+d,online_alter_small_cache";
--error ER_STMT_CACHE_FULL
update t set a = repeat('y', 1000);
show warnings;
set debug_sync= 'now signal go';
--connection con1
--reap
show warnings;
--connection default
drop table t;
set debug_sync= reset;
set debug_dbug= @old_dbug;
--disconnect con1
--disconnect con2
--echo #
--echo # End of 11.2 tests
--echo #