pt-table-checksums with interrupted connection

Polyglot Projects Percona Toolkit
1

My scenario:
Master-Server with a database named “management” and a table “teamdriveinvitation”
And there is a slave-server with row-based replication enabled. All logins and passwords are the same.

I find that the update of the checksum-table is NOT done with the logged-in session of the percona-tool, but the newly generated checksums are transported via the replication-statements.
Is this intended?

I logged this on the slave with the mysql.log:
root@EUHQTMSQL001-1A:/usr/local/scripts# tail -n1 -f mysql.log |grep -i teamdriveinvitation
17137 Query SHOW TABLES FROM management LIKE ‘teamdriveinvitation’
17137 Query SHOW CREATE TABLE management.teamdriveinvitation
17137 Query EXPLAIN SELECT * FROM management.teamdriveinvitation WHERE 1=1
3 Query REPLACE INTO percona.euirtmsql001_1a (db, tbl, chunk, chunk_index, lower_boundary, upper_boundary, this_cnt, this_crc) SELECT ‘management’, ‘teamdriveinvitation’, ‘1’, NULL, NULL, NULL, COUNT(*) AS cnt, COALESCE(LOWER(CONV(BIT_XOR(CAST(CRC32(CONCAT_WS(‘#’, id, teamdriveid, invitedby, invited, message, dateinvited, role, CONCAT(ISNULL(invitedby), ISNULL(message)))) AS UNSIGNED)), 10, 16)), 0) AS crc FROM management.teamdriveinvitation /checksum table/
3 Query UPDATE percona.euirtmsql001_1a SET chunk_time = ‘0.001044’, master_crc = ‘91204457’, master_cnt = ‘32’ WHERE db = ‘management’ AND tbl = ‘teamdriveinvitation’ AND chunk = ‘1’
17137 Query SELECT MAX(chunk) FROM percona.euirtmsql001_1a WHERE db=‘management’ AND tbl=‘teamdriveinvitation’ AND master_crc IS NOT NULL
17137 Query SELECT CONCAT(db, ‘.’, tbl) AS table, chunk, chunk_index, lower_boundary, upper_boundary, COALESCE(this_cnt-master_cnt, 0) AS cnt_diff, COALESCE(this_crc <> master_crc OR ISNULL(master_crc) <> ISNULL(this_crc), 0) AS crc_diff, this_cnt, master_cnt, this_crc, master_crc FROM percona.euirtmsql001_1a WHERE (master_cnt <> this_cnt OR master_crc <> this_crc OR ISNULL(master_crc) <> ISNULL(this_crc)) AND (db=‘management’ AND tbl=‘teamdriveinvitation’)

As you can see, there is a connection “17137” which was recently opened by the percona-tool. Then suddenly the update of the checksum-table is done from the connection “3”, which is the normal replication-stream. Then it switches back to connection “17137” to check for any differences.

2

Hi Harald;

Yes this is expected. The tool performs the checksums on the master, and then replicates them to the slaves, where it then checks for differences.

-Scott

3

Thank you Scott, that clarifies a lot.
Then my next problem is, that one command won’t be replicated: It is the “delete percona.checksumtableWithMySpecialName”. It won’t get replicated because on the executing Server, there is a “use percona” shortly before the delete, and having suppressed the replication of the percona-database, these commands are ignored.

4

Hi Harald;

Are you saying that you set replication-ignore-db=percona and that is causing the issue, or do you mean that the tool is doing it all on its own?

-Scott