| Bug #98863 | No refresh of metadata when primary changes and gr notifications are used | ||
|---|---|---|---|
| Submitted: | 6 Mar 2020 16:22 | Modified: | 28 May 2020 21:39 |
| Reporter: | Florian Apolloner | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Router | Severity: | S2 (Serious) |
| Version: | 8.019 | OS: | CentOS (Centos 8.1) |
| Assigned to: | CPU Architecture: | x86 | |
| Tags: | group_replication, notifications, router | ||
[11 Mar 2020 10:53]
MySQL Verification Team
Hello Florian, Thank you for the report and steps. Verified as described with 3 node cluster (8.0.19) and MySQL router version 8.0.19. regards, Umesh
[28 May 2020 21:39]
Philip Olson
Posted by developer: Fixed as of the upcoming MySQL Router 8.0.21 release, and here's the proposed changelog entry from the documentation team: Router assumed that each new GR change notified by X Protocol notifications has a new view id, but that is not always the case; for example, for changes like switching the primary or change of the role. The view id is no longer used for notification debouncing. Thank you for the bug report.
Description: I have configured an InnoDB Cluster in single-primary mode (also version 8.0.19). When forcing a change of the primary (r/w node) through mysqlsh via "cluster.setPrimaryInstance('user@new_rw_node:3306')" mysqlrouter fails to pick up this change via group notifications. The mysqlrouter is configured to use ttl=60 and use_gr_notifications=1. I have attached a commented logfile in https://gist.github.com/apollo13/43cbc99aa443226e46fbb7b72d82125e To verify the bug I have a simple program running that connects to the router every two seconds and requests an R/W connection. In lines 4-15 you can see that the current master is centos2. Around line 17 I am switching the primary via mysqlsh. Lines 19-29 show that the cluster notifies the router about MEMBER_ROLE_CHANGE (type=3). Imo this should trigger a metadata refresh but it does not because the view id did not change ( https://github.com/mysql/mysql-server/blob/ea7d2e2d16ac03afdd9cb72a972a95981107bf51/router... ). It takes till line 97 after the metadata refresh due to TTL timeout that the new primary is queried. I am not really sure if that is a bug in mysqlrouter or mysqld How to repeat: - Install an innodb cluster. - Configure one mysqlrouter with --conf-use-gr-notifications, a log level of debug and start it (or simply change an existing config to ttl=60 and use_gr_notifications=1 + a router restart). - tail the mysqlrouter log file - Execute a query every two seconds, in my case I executed via (I wanted to test how SUPER_READ_ONLY changes): watch 'echo "SELECT @@global.SUPER_READ_ONLY;" | mysql -h 127.0.0.1 -u replication_admin -P 6446' - Force a primary change via dba.getCluster().setPrimaryInstance('user@new_rw_node:3306') in mysqlsh - Wait for the router to react…