[MXS-2700] Maxscale needs to check how up-to-date the slave is, before move traffic to it. Created: 2019-09-25 Updated: 2020-08-26 Resolved: 2020-08-26 |
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| Status: | Closed |
| Project: | MariaDB MaxScale |
| Component/s: | mariadbmon |
| Affects Version/s: | None |
| Fix Version/s: | 2.5.0 |
| Type: | New Feature | Priority: | Major |
| Reporter: | Nilnandan Joshi | Assignee: | Todd Stoffel (Inactive) |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Description |
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If somehow, slave (node1) can't connect to master and it's retrying again and again Slave_IO_Running: Connecting In maxscale 'list servers' we could see the node1 status as 'Slave, Running' and maxscale is routing connections to the slave in which replication is broken.
Since this 'node 1' replication is already broken maxscale status for this node should be in 'Running' state and no connections should be routed to this slave. But this is the current behaviour which needs to be changed. On the long run, we probably need to implement some kind of grading system, where the monitor or router checks how "up-to-date" the slave is. |
| Comments |
| Comment by Johan Wikman [ 2019-09-25 ] |
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niljoshi Shouldn't this be considered a bug and not a new feature? |
| Comment by Nilnandan Joshi [ 2019-09-26 ] |
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Hi johan.wikman, as per my discussion with esa.korhonen, the current behaviour is default. |
| Comment by markus makela [ 2019-10-03 ] |
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Wouldn't this be fixed by changing the value of master-retry-count on the server? |
| Comment by Nilnandan Joshi [ 2019-10-04 ] |
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Hi markus makela, wasn't that a workaround and not the solution? Btw, we didn't get any update if master-retry-count has fixed the problem. |
| Comment by markus makela [ 2019-10-07 ] |
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One option would be to detect that a slave is trying to connect for a long time and then treat it as a failed server if it can never connect to the master. In the end, you still have to define a timeout somewhere and this can already be done with master-retry-count. |
| Comment by markus makela [ 2020-08-26 ] |
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Fixed with the new 2.5 parameter: https://mariadb.com/kb/en/mariadb-maxscale-25-mariadb-monitor/#slave_conditions |