Exposing some hidden serializable transaction costs

Started by Christophe Pettus7 months ago2 messages
#1Christophe Pettus
xof@thebuild.com

Serialized transactions have a cost that is currently not accounted for in planning time: Rows that are retrieved to be filtered by a query get SIReadLocks. This can made an otherwise-good query plan problematic, since it contributes to query cancellations. Would it be appropriate to add some kind of cost constant to filtered rows to reflect that?

#2Greg Sabino Mullane
htamfids@gmail.com
In reply to: Christophe Pettus (#1)
Re: Exposing some hidden serializable transaction costs

I would imagine you'd need a pretty edge case query with a ton of rows
before you would really be able to have enough difference to change plans.
And what would it change to?

Cheers,
Greg

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