pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Gregory Stark <stark@enterprisedb.com>
Cc: Alvaro Herrera <alvherre@commandprompt.com>
Cc: ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>
Cc: Bruce Momjian <bruce@momjian.us>
Cc: pgsql-hackers@postgresql.org
Subject: Re: CSStorm occurred again by postgreSQL8.2
Date: Thu, 14 Sep 2006 11:30:52 -0400
Message-ID: <29565.1158247852@sss.pgh.pa.us> (raw)
In-Reply-To: <87psdyqy2v.fsf@enterprisedb.com>
References: <20060808110913.50FA.ITAGAKI.TAKAHIRO@oss.ntt.co.jp>
	<200608260346.k7Q3k2g06954@momjian.us>
	<20060828181312.5638.ITAGAKI.TAKAHIRO@oss.ntt.co.jp>
	<13251.1157299738@sss.pgh.pa.us>
	<22080.1158198335@sss.pgh.pa.us>
	<87mz92so6n.fsf@enterprisedb.com>
	<27509.1158237711@sss.pgh.pa.us>
	<28167.1158241250@sss.pgh.pa.us>
	<28515.1158242279@sss.pgh.pa.us>
	<20060914142222.GA525@alvh.no-ip.org>
	<29128.1158244999@sss.pgh.pa.us>
	<87psdyqy2v.fsf@enterprisedb.com>

Gregory Stark <stark@enterprisedb.com> writes:
> Tom Lane <tgl@sss.pgh.pa.us> writes:
>> --- and because the entries are surely added in increasing XID order,
>> such an array could be binary-searched.  

> If they're only added if they write to disk then isn't it possible to add them
> out of order? Start a child transaction, start a child of that one and write
> to disk, then exit the grandchild and write to disk in the first
> child?

No, because we enforce child XID > parent XID.  In the case above, the
child xact would be given an XID when the grandchild needs one --- see
recursion in AssignSubTransactionId().  The actually slightly shaky
assumption above is that children of the same parent xact must subcommit
in numerical order ... but as long as we have strict nesting of subxacts
I think this must be so.

			regards, tom lane



view thread (22+ messages)  latest in thread

Message-ID: <29565.1158247852@sss.pgh.pa.us>
Permalink:  ../29565.1158247852@sss.pgh.pa.us/
Also on:    postgresql.org/message-id/29565.1158247852@sss.pgh.pa.us

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: tgl@sss.pgh.pa.us, stark@enterprisedb.com, alvherre@commandprompt.com, itagaki.takahiro@oss.ntt.co.jp, bruce@momjian.us
  Subject: Re: CSStorm occurred again by postgreSQL8.2
  In-Reply-To: <29565.1158247852@sss.pgh.pa.us>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox