Not dropping old table while the option "--no-drop-old-table" is not specified

[Paul Namuag]

This is on version 3.0.5.

We did a pt-online-schema-change successfully, however, the message seemed to be confusing:

Copying `xxxx_schema`.`user_transactions`: 99% 00:15 remain
Replica lag is 8 seconds on opskins-phxdb17.mcmxi.services. Waiting.
Copying `xxxx_schema`.`user_transactions`: 99% 00:08 remain
2017-11-29T03:31:54 Copied rows OK.
Determining the method to update foreign keys...
2017-11-29T03:31:54 `xxxx_schema`.`fxeE4_cashouts`: too many rows: 2205426; must use drop_swap
2017-11-29T03:31:54 Drop-swapping tables...
2017-11-29T03:31:54 Analyzing new table...
SET foreign_key_checks=0
DROP TABLE IF EXISTS `xxxx_schema`.`user_transactions`
RENAME TABLE `xxxx_schema`.`_user_transactions_new` TO `xxxx_schema`.`user_transactions`
2017-11-29T03:31:55 Dropped and swapped tables OK.
Not dropping old table because --no-drop-old-table was specified.
2017-11-29T03:31:55 Dropping triggers...
DROP TRIGGER IF EXISTS `xxxx_schema`.`pt_osc_xxxx_schema_user_transactions_del`
DROP TRIGGER IF EXISTS `xxxx_schema`.`pt_osc_xxxx_schema_user_transactions_upd`
DROP TRIGGER IF EXISTS `xxxx_schema`.`pt_osc_xxxx_schema_user_transactions_ins`
2017-11-29T03:31:55 Dropped triggers OK.
Successfully altered `xxxx_schema`.`user_transactions`.

There, it says "Not dropping old table because --no-drop-old-table was specified.". However, the command we used is:
$ pt-online-schema-change --alter-foreign-keys-method=auto --print --progress time,10 --pause-file=/tmp/pt-osc.pause --alter=" \
CHARSET='utf8mb4', \
COLLATE='utf8mb4_unicode_ci', \
CHANGE COLUMN currency_type currency_type TINYINT(3) UNSIGNED NOT NULL DEFAULT '1', \
CHANGE COLUMN coins coins DECIMAL(30, 18) NOT NULL, \
CHANGE COLUMN amount_coins_nocashout amount_coins_nocashout DECIMAL(30, 18) NOT NULL DEFAULT '0', \
CHANGE COLUMN new_coins_balance new_coins_balance DECIMAL(30, 18) NOT NULL, \
CHANGE COLUMN new_amount_coins_nocashout new_amount_coins_nocashout DECIMAL(30, 18) NOT NULL, \
CHANGE COLUMN coins_reverted coins_reverted DECIMAL(30, 18) NOT NULL DEFAULT '0', \
CHANGE COLUMN coins_nocashout_reverted coins_nocashout_reverted DECIMAL(30, 18) NOT NULL DEFAULT '0', \
CHANGE COLUMN comment comment VARCHAR(255) NULL DEFAULT NULL, \
ADD COLUMN flags INT UNSIGNED NOT NULL DEFAULT '0' AFTER comment \
" --tries copy_rows:1000:1,create_triggers:5:0.5,drop_triggers:5:0.5 --set-vars tx_isolation=\'READ-COMMITTED\',lock_wait_timeout=3600 h=100.0.1.14,D=xxxx_schema,t=user_transactions --recursion-method=dsn=h=100.0.1.14,D=percona,t=osc_dsns --critical-load threads_running=50 --max-load Threads_running=40 --max-lag 2 --execute

When I checked the code, there's only one line there but under "else" which I bet its the reason why it's printing this:
 9951 }
 9952 elsif ( !$drop_triggers ) {
 9953 print "Not dropping old table because --no-drop-triggers was specified.\n";
 9954 }
 9955 else {
 9956 print "Not dropping old table because --no-drop-old-table was specified.\n";
 9957 }
 9958

Solution: I see if we just have to enclosed that line 9956 to another "elseif" statement, might filter and avoid that from printing a false positive log information.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-1463