Re: Terrible performance on wide selects

From: "Dann Corbit" <DCorbit(at)connx(dot)com>
To: "Dann Corbit" <DCorbit(at)connx(dot)com>, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Steve Crawford" <scrawford(at)pinpointresearch(dot)com>, <pgsql-performance(at)postgreSQL(dot)org>, <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: Terrible performance on wide selects
Date: 2003-01-23 00:39:57
Message-ID: D90A5A6C612A39408103E6ECDD77B8294CD866@voyager.corporate.connx.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers pgsql-performance

[snip]
> For the disk case, why not have the start of the record
> contain an array of offsets to the start of the data for each
> column? It would only be necessary to have a list for
> variable fields.
>
> So (for instance) if you have 12 variable fields, you would
> store 12 integers at the start of the record.

You have to store this information anyway (for variable length objects).
By storing it at the front of the record you would lose nothing (except
the logical coupling of an object with its length). But I would think
that it would not consume any additional storage.

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Christopher Kings-Lynne 2003-01-23 00:40:28 Re: Call for objections: put back OIDs in CREATE TABLE AS/SELECT INTO
Previous Message Tom Lane 2003-01-23 00:30:04 Re: Terrible performance on wide selects

Browse pgsql-performance by date

  From Date Subject
Next Message Stephan Szabo 2003-01-23 00:59:13 Re: Query plan and Inheritance. Weird behavior
Previous Message Tom Lane 2003-01-23 00:30:04 Re: Terrible performance on wide selects