Re: Transaction isolation and constraints - Mailing list pgsql-general

From cliff@krumvieda.com
Subject Re: Transaction isolation and constraints
Date
Msg-id 200712052035.lB5KZTQB024956@phumos.tgtaft.emc.com
Whole thread Raw
In response to Re: Transaction isolation and constraints  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Transaction isolation and constraints
List pgsql-general
Hi, Tom:

>Whichever one manages to get to the index page first will go through.
>The second one will block waiting to see if the first one commits,
>and will error out if so --- or proceed, if it aborts.

I see, this makes sense.  What if the two transactions insert rows
that don't violate the constraint: will they be able to proceed in
parallel?  Or will one wait for the other, because they both need to
update the shared index?  I.e., does the mechanism work by waiting for
one index update to commit before permitting the next?

                   --Cliff

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