"mysql" "Packets out of sync" - workaround

help
1

Ref: CodecError { Packets out of sync } - possible failed reconnect after timeout · Issue #412 · blackbeam/rust-mysql-simple · GitHub

I have something that connects to a remote MySQL database and sometimes computes for over an hour with no transaction in progress but the MySQL connection pool still alive. Then the next MySQL request fails with

Failed: CodecError { Packets out of sync }

probably because the server closed the connection.

This is probably a bug in lost idle connection recovery; if there's a connection pool, it's the pool manager's job to handle this. So I sent in a bug report.

Known bug? Known workaround?

(What I really need to do is speed up that hour-long compute. I'm scaling something up and it turned out to have a part that's too slow. I can fix that, but would like to see this run to completion before diving into optimization.)

2

I think that happens when the statement / query results are not fully drained out. For example, if you run a query that returns 10 rows, only fetch 8 rows, then try to insert, an out-of-sync is triggered. But, it has been a great long while so I could easily be mistaken.

3

You can definitely cause it that way. But this code works fine until it has a really long compute period.

(Real fix: came up with an algorithm to reduce the compute from O(2^N) to O(N), which should reduce the hours-long delay to seconds.l)

4

So maybe there is a timeout on the database side, and that error isn't being handled?