vttablet: don't shutdown on too many connections #7039
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Fixes vitessio#7038 This change makes IsConnErr treat "Too man connections" as a normal error, allowing vttablet to continue serving. The same check is also added to IsMySQLReachable in case it happens to get called through a different code path. The error code returned by mysql (2012) is more generic. So, we also have to check for the specific substring. It's hard to reliably test this using automated testing. Instead, I manually created a state where mysql ran out of connections, verified that vttablet did shut down, and also verified that vttablet continued to serve after this fix. Signed-off-by: Sugu Sougoumarane <ssougou@gmail.com>
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shlomi-noach
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Nov 15, 2020
harshit-gangal
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Nov 16, 2020
deepthi
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Nov 16, 2020
| // IsTooManyConnectionsErr returns true if the error is due to too many connections. | ||
| func IsTooManyConnectionsErr(err error) bool { | ||
| if sqlErr, ok := err.(*SQLError); ok { | ||
| if sqlErr.Number() == CRServerHandshakeErr && strings.Contains(sqlErr.Message, "Too many connections") { |
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nit: string literal should be made into a constant.
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Fixes #7038
This change makes IsConnErr treat "Too many connections" as a normal
error, allowing vttablet to continue serving. The same check is also
added to IsMySQLReachable in case it happens to get called through
a different code path.
The error code returned by mysql (2012) is more generic. So, we also
have to check for the specific substring.
It's hard to reliably test this using automated testing. Instead, I
manually created a state where mysql ran out of connections, verified
that vttablet did shut down, and also verified that vttablet continued
to serve after this fix.
Signed-off-by: Sugu Sougoumarane ssougou@gmail.com