Bug Report: Wait for DBA grants can cause restore to get stuck if there's an unexpected crash

[dbussink]

Overview of the Issue

Since #14565, if you have a backup restore and for some reason vttablet crashes mid-restore, things get stuck. vttablet can crash due to things like an OOM error, a crashing server or anything else.

When this happens mysqld will still be shut down as the restore phase shuts it down. The new vttablet started after the crash will fail to start up, because it can't connect to MySQL to verify the DBA grants.

Before the change in #14565 this was not a problem, since the restore step doesn't actually depend on connecting to MySQL at all, so it would be able to retry. It would only warn MySQL was already shut down, but otherwise continue.

Reproduction Steps

Binary Version

since #14565

Operating System and Environment details

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Log Fragments

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