Re: Access to transaction status - Mailing list pgsql-hackers

From Christian Plattner
Subject Re: Access to transaction status
Date
Msg-id 00c201c33700$de187ba0$6e828481@ethz.ch
Whole thread Raw
In response to Access to transaction status  ("Christian Plattner" <postgresql@sioux.ch>)
Responses Re: Access to transaction status
List pgsql-hackers
----- Original Message ----- 
From: "Tom Lane" <tgl@sss.pgh.pa.us>

> How much later?  clog is not kept forever.

Due to my setup, I could assure, that for the XID I ask for always

(ShmemVariableCache->nextXid - XID) < C   (and C is in my case something
around 150).

holds. A possible solution could be to (dynamically) announce this constant
C to the clog code,
so that the information is kept for a while. Ofcourse one should not do a
VACUUM FULL while not being sure about the status of a transaction in the
past :)

Until now, I did not investigate what happens when
ShmemVariableCache->nextXid wraps around.

- Christian



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