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72cc58bb71
for large transaction
Description
===========
When a transaction commits, it copies the binlog events from
binlog cache to binlog file. Very large transactions
(eg. gigabytes) can stall other transactions for a long time
because the data is copied while holding LOCK_log, which blocks
other commits from binlogging.
The solution in this patch is to rename the binlog cache file to
a binlog file instead of copy, if the commiting transaction has
large binlog cache. Rename is a very fast operation, it doesn't
block other transactions a long time.
Design
======
* binlog_large_commit_threshold
type: ulonglong
scope: global
dynamic: yes
default: 128MB
Only the binlog cache temporary files large than 128MB are
renamed to binlog file.
* #binlog_cache_files directory
To support rename, all binlog cache temporary files are managed
as normal files now. `#binlog_cache_files` directory is in the same
directory with binlog files. It is created at server startup if it doesn't
exist. Otherwise, all files in the directory is deleted at startup.
The temporary files are named with ML_ prefix and the memorary address
of the binlog_cache_data object which guarantees it is unique.
* Reserve space
To supprot rename feature, It must reserve enough space at the
begin of the binlog cache file. The space is required for
Format description, Gtid list, checkpoint and Gtid events when
renaming it to a binlog file.
Since binlog_cache_data's cache_log is directly accessed by binlog log,
online alter and wsrep. It is not easy to update all the code. Thus
binlog cache will not reserve space if it is not session binlog cache or
wsrep session is enabled.
- m_file_reserved_bytes
Stores the bytes reserved at the begin of the cache file.
It is initialized in write_prepare() and cleared by reset().
The reserved file header is hide to callers. Thus there is no
change for callers. E.g.
- get_byte_position() still get the length of binlog data
written to the cache, but not the file length.
- truncate(0) will truncate the file to m_file_reserved_bytes but not 0.
- write_prepare()
write_prepare() is called everytime when anything is being written
into the cache. It will call init_file_reserved_bytes() to create
the cache file (if it doesn't exist) and reserve suitable space if
the data written exceeds buffer's size.
* Binlog_commit_by_rotate
It is used to encapsulate the code for remaing a binlog cache
tempoary file to binlog file.
- should_commit_by_rotate()
it is called by write_transaction_to_binlog_events() to check if
a binlog cache should be rename to a binlog file.
- commit()
That is the entry to rename a binlog cache and commit the
transaction. Both rename and commit are protected by LOCK_log,
Thus not other transactions can write anything into the renamed
binlog before it.
Rename happens in a rotation. After the new binlog file is generated,
replace_binlog_file() is called to:
- copy data from the new binlog file to its binlog cache file.
- write gtid event.
- rename the binlog cache file to binlog file.
After that the rotation will continue to succeed. Then the transaction
is committed in a seperated group itself. Its cache file will be
detached and cache log will be reset before calling
trx_group_commit_with_engines(). Thus only Xid event be written.
174 lines
6.6 KiB
Plaintext
174 lines
6.6 KiB
Plaintext
include/master-slave.inc
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[connection master]
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# Prepare
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SET @saved_binlog_large_commit_threshold= @@GLOBAL.binlog_large_commit_threshold;
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SET @saved_binlog_checksum= @@GLOBAL.binlog_checksum;
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SET GLOBAL binlog_checksum = "NONE";
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CREATE TABLE t1 (c1 LONGTEXT) ENGINE = InnoDB;
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CREATE TABLE t2 (c1 LONGTEXT) ENGINE = MyISAM;
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INSERT INTO t1 values(repeat("1", 5242880));
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INSERT INTO t1 values(repeat("1", 5242880));
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INSERT INTO t2 values(repeat("1", 5242880));
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INSERT INTO t2 values(repeat("1", 5242880));
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FLUSH BINARY LOGS;
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# Not renamed to binlog, since the binlog cache is not larger than the
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# threshold. And it should works well after ROLLBACK TO SAVEPOINT
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BEGIN;
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SAVEPOINT s1;
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UPDATE t1 SET c1 = repeat('1', 5242880);
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ROLLBACK TO SAVEPOINT s1;
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UPDATE t1 SET c1 = repeat('2', 5242880);
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SAVEPOINT s2;
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UPDATE t1 SET c1 = repeat('3', 5242880);
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UPDATE t1 SET c1 = repeat('4', 5242880);
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ROLLBACK TO SAVEPOINT s2;
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COMMIT;
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include/assert.inc [Binlog is not rotated]
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#
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# Test binlog cache rename to binlog file with checksum off
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#
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include/sync_slave_sql_with_master.inc
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include/stop_slave.inc
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SET @saved_binlog_large_commit_threshold = @@GLOBAL.binlog_large_commit_threshold;
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SET @saved_slave_parallel_workers = @@GLOBAL.slave_parallel_workers;
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SET @saved_slave_parallel_mode = @@GLOBAL.slave_parallel_mode;
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SET @saved_slave_parallel_max_queued = @@GLOBAL.slave_parallel_max_queued;
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SET GLOBAL binlog_large_commit_threshold = 10 * 1024 * 1024;
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SET GLOBAL slave_parallel_max_queued = 100 * 1024 * 1024;
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SET GLOBAL slave_parallel_workers = 4;
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SET GLOBAL slave_parallel_mode = "aggressive";
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include/start_slave.inc
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BEGIN;
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DELETE FROM t1;
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connection master;
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SET GLOBAL binlog_large_commit_threshold = 10 * 1024 * 1024;
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# Transaction cache can be renamed and works well with ROLLBACK TO SAVEPOINT
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BEGIN;
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SAVEPOINT s1;
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UPDATE t1 SET c1 = repeat('2', 5242880);
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ROLLBACK TO s1;
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UPDATE t1 SET c1 = repeat('3', 5242880);
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SAVEPOINT s2;
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UPDATE t1 SET c1 = repeat('4', 5242880);
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UPDATE t1 SET c1 = repeat('5', 5242880);
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UPDATE t1 SET c1 = repeat('6', 5242880);
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ROLLBACK TO SAVEPOINT s2;
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COMMIT;
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INSERT INTO t1 VALUES("after_update_t1");
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include/assert.inc [Rename is executed.]
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# statement cache can be renamed
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connection master;
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BEGIN;
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UPDATE t2 SET c1 = repeat('4', 5242880);
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INSERT INTO t1 VALUES("after_update_t2");
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COMMIT;
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include/assert.inc [Rename is executed.]
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connection slave;
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ROLLBACK;
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connection master;
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include/sync_slave_sql_with_master.inc
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include/assert.inc [Rename is executed.]
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include/assert.inc [Rename is executed.]
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include/show_binlog_events.inc
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Log_name Pos Event_type Server_id End_log_pos Info
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slave-bin.000002 # Gtid # # BEGIN GTID #-#-#
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slave-bin.000002 # Annotate_rows # # UPDATE t1 SET c1 = repeat('3', 5242880)
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slave-bin.000002 # Table_map # # table_id: # (test.t1)
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slave-bin.000002 # Update_rows_v1 # # table_id: #
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slave-bin.000002 # Update_rows_v1 # # table_id: # flags: STMT_END_F
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slave-bin.000002 # Query # # SAVEPOINT `s2`
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slave-bin.000002 # Xid # # COMMIT /* XID */
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slave-bin.000002 # Gtid # # BEGIN GTID #-#-#
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slave-bin.000002 # Annotate_rows # # INSERT INTO t1 VALUES("after_update_t1")
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slave-bin.000002 # Table_map # # table_id: # (test.t1)
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slave-bin.000002 # Write_rows_v1 # # table_id: # flags: STMT_END_F
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slave-bin.000002 # Xid # # COMMIT /* XID */
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slave-bin.000002 # Rotate # # slave-bin.000003;pos=POS
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include/show_binlog_events.inc
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Log_name Pos Event_type Server_id End_log_pos Info
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slave-bin.000003 # Gtid # # BEGIN GTID #-#-#
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slave-bin.000003 # Annotate_rows # # UPDATE t2 SET c1 = repeat('4', 5242880)
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slave-bin.000003 # Table_map # # table_id: # (test.t2)
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slave-bin.000003 # Update_rows_v1 # # table_id: #
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slave-bin.000003 # Update_rows_v1 # # table_id: # flags: STMT_END_F
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slave-bin.000003 # Query # # COMMIT
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slave-bin.000003 # Gtid # # BEGIN GTID #-#-#
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slave-bin.000003 # Annotate_rows # # INSERT INTO t1 VALUES("after_update_t2")
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slave-bin.000003 # Table_map # # table_id: # (test.t1)
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slave-bin.000003 # Write_rows_v1 # # table_id: # flags: STMT_END_F
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slave-bin.000003 # Xid # # COMMIT /* XID */
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include/stop_slave.inc
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SET GLOBAL binlog_large_commit_threshold = @saved_binlog_large_commit_threshold;
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SET GLOBAL slave_parallel_workers = @saved_slave_parallel_workers;
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SET GLOBAL slave_parallel_max_queued = @saved_slave_parallel_max_queued;
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SET GLOBAL slave_parallel_mode = @saved_slave_parallel_mode;
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include/start_slave.inc
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# CREATE SELECT works well
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connection master;
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CREATE TABLE t3 SELECT * FROM t1;
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include/assert.inc [Rename is executed.]
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CREATE TABLE t4 SELECT * FROM t2;
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include/assert.inc [Rename is executed.]
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# XA statement works well
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XA START "test-a-long-xid========================================";
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UPDATE t1 SET c1 = repeat('1', 5242880);
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XA END "test-a-long-xid========================================";
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XA PREPARE "test-a-long-xid========================================";
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XA COMMIT "test-a-long-xid========================================";
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include/assert.inc [Rename is executed.]
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XA START "test-xid";
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UPDATE t1 SET c1 = repeat('2', 5242880);
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XA END "test-xid";
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XA COMMIT "test-xid" ONE PHASE;
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include/assert.inc [Rename is executed.]
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#
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# It works well in the situation that binlog header is larger than
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# IO_SIZE and binlog file's buffer.
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#
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FLUSH BINARY LOGS;
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SET SESSION server_id = 1;
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UPDATE t1 SET c1 = repeat('3', 5242880);
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include/assert.inc [Rename is executed.]
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#
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# RESET MASTER should work well. It also verifies binlog checksum mechanism.
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#
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include/rpl_reset.inc
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#
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# Test binlog cache rename to binlog file with checksum on
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#
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SET GLOBAL binlog_checksum = "CRC32";
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# It will not rename the cache to file, since the cache's checksum was
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# initialized when reset the cache at the end of previous transaction.
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UPDATE t1 SET c1 = repeat('5', 5242880);
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include/assert.inc [Binlog is not rotated]
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#
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# Not rename to binlog file If the cache's checksum is not same
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# to binlog_checksum
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#
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BEGIN;
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UPDATE t1 SET c1 = repeat('6', 5242880);
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SET GLOBAL binlog_checksum = "NONE";
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COMMIT;
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include/assert.inc [Binlog is not rotated]
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BEGIN;
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UPDATE t1 SET c1 = repeat('7', 5242880);
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SET GLOBAL binlog_checksum = "CRC32";
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COMMIT;
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include/assert.inc [Binlog is not rotated]
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#
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# Not rename to binlog file If both stmt and trx cache are not empty
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#
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UPDATE t1, t2 SET t1.c1 = repeat('8', 5242880), t2.c1 = repeat('7', 5242880);
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include/assert.inc [Binlog is not rotated]
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#
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# Not rename to binlog file If binlog_legacy_event_pos is on
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#
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SET GLOBAL binlog_legacy_event_pos = ON;
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UPDATE t1 SET c1 = repeat('9', 5242880);
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SET GLOBAL binlog_legacy_event_pos = OFF;
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include/assert.inc [Binlog is not rotated]
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DROP TABLE t1, t2, t3, t4;
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SET GLOBAL binlog_large_commit_threshold = @saved_binlog_large_commit_threshold;
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SET GLOBAL binlog_checksum = @saved_binlog_checksum;
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include/rpl_end.inc
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