pt-online-schema-change pausing because {something}=0, bug?

[Suvorov_Artem]

I run pt-online-schema-change like this:
pt-online-schema-change --alter ‘ADD test TEXT CHARACTER SET utf8 COLLATE utf8_general_ci’ --charset ‘utf8’ --host ‘localhost’ --user ‘root’ --password ‘password’ --max-load wsrep_flow_control_recv=1,wsrep_local_send_queue=1 --critical-load Threads_running=400 --null-to-not-null --no-check-alter --execute --alter-foreign-keys-method none --force --statistics D=database,t=table

Comand output:

No slaves found. See --recursion-method if host loaclhosthas slaves.
Not checking slave lag because no slaves were found and --check-slave-lag was not specified.
Operation, tries, wait:
analyze_table, 10, 1
copy_rows, 10, 0.25
create_triggers, 10, 1
drop_triggers, 10, 1
swap_tables, 10, 1
update_foreign_keys, 10, 1
Not updating foreign keys because --alter-foreign-keys-method=none. Foreign keys that reference the table will no longer work.
Altering database.table…
Creating new table…
Created new table database._table_new OK.
Altering new table…
Altered database._table_new OK.
2016-08-31T09:54:45 Creating triggers…
2016-08-31T09:54:45 Created triggers OK.
2016-08-31T09:54:45 Copying approximately 85 rows…
Pausing because wsrep_flow_control_recv=0, wsrep_local_send_queue=0.
Pausing because wsrep_flow_control_recv=0, wsrep_local_send_queue=0.
Pausing because wsrep_flow_control_recv=0, wsrep_local_send_queue=0.
Pausing because wsrep_flow_control_recv=0, wsrep_local_send_queue=0.
^C# Exiting on SIGINT.
Not dropping triggers because the tool was interrupted. To drop the triggers, execute:
DROP TRIGGER IF EXISTS database.pt_osc_database_table_del;
DROP TRIGGER IF EXISTS database.pt_osc_database_table_upd;
DROP TRIGGER IF EXISTS database.pt_osc_database_table_ins;
Not dropping the new table database._table_new because the tool was interrupted. To drop the new table, execute:
DROP TABLE IF EXISTS database._table_new;

Event Count

====== =====

INSERT 1

database.table was not altered.

From doc for --max_load “pause if any status variables are higher than their thresholds” - nothing about zero value.

So, how use max_load with variables whitch can take zero value in normal state of db?

I look into source code and found, as i think, reason why this happend:
https://github.com/percona/percona-toolkit/blob/2.2/bin/pt-online-schema-change#L5188
[PHP]if ( !$val || $val >= $self->{max_val_for}->{$var} ) {
$vals_too_high{$var} = $val;
}
[/PHP]
$val - current value of status variable

[Peter]

Hi Artem,

Thank you for taking a time to look into the code! Assuming you’re using latest version it would be great if you can report it as a bug [url]https://launchpad.net/percona-toolkit[/url] If you already found fix for it feel free to propose the patch!