Re: improving wraparound behavior

Em sex, 3 de mai de 2019 às 17:27, Robert Haas <robertmhaas@gmail.com> escreveu:
>
> HINT:  Commit or roll back old prepared transactions, drop stale
> replication slots, or kill long-running sessions.
> Ensure that autovacuum is progressing, or run a manual database-wide VACUUM.
>
First of all, +1 for this patch. But after reading this email, I
couldn't resist to expose an idea about stale XID horizon. [A cup of
tea...] I realized that there is no automatic way to recover from old
prepared transactions, stale replication slots or even long-running
sessions when we have a wraparound situation. Isn't it the case to add
a parameter that recover from stale XID horizon? I mean if we reach a
critical situation (xidStopLimit), free resource that is preventing
the XID advance (and hope autovacuum have some time to prevent a
stop-assigning-xids situation). The situation is analogous to OOM
killer that it kills some processes that are starving resources.


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   Euler Taveira                                   Timbira -
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