Re: Protect a table against concurrent data changes while allowing to vacuum it

Vlad Arkhipov wrote:
> I have a constraint that requires a table to be locked before checking
> it (i.e. no more than 2 records with the same value in the same column).
> If I lock the table in the SHARE ROW EXCLUSIVE mode, any vacuuming (or
> autovacuuming) process prevents me from checking the constraint. What
> are possible solutions?

Can you describe your check in more detail?
Why don't you use simple unique constraints?

Yours,
Laurenz Albe