From: Siddharth Anand <sid@etsy.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: sid@etsy.com
Cc: pgsql-performance@postgresql.org
Subject: Re: How can fixed and variable width columns perform similarly?
Date: Fri, 27 Apr 2007 09:19:04 -0700 (PDT)
Message-ID: <50516.209.51.183.100.1177690744.squirrel@mailbox.etsy.com> (raw)
In-Reply-To: <15873.1177691157@sss.pgh.pa.us>
References: <50444.209.51.183.100.1177687911.squirrel@mailbox.etsy.com>
<15873.1177691157@sss.pgh.pa.us>
Hi Tom,
My question wasn't phrased clearly. Oracle exhibits a performance
degradation for very large-sized fields (CLOB types that I equate to
PostGres' text type) when compared with the performance of field types
like varchar that handle a max character limit of a few thousand bytes in
Oracle.
It sounds like PostGres doesn't exhibit this same difference. I wanted to
understand how this could be and whether there was a trade-off.
Cheers!
Sid
> "Siddharth Anand" <sid@etsy.com> writes:
>> How can a field that doesn't have a limit like "text" perform similarly
>> to
>> char varying(128), for example? At some point, we need to write data to
>> disk. The more data that needs to be written, the longer the disk write
>> will take, especially when it requires finding free sectors to write to.
>
> What's your point? If you're not going to put more than 128 characters
> in the field, there's no difference in the amount of data involved.
>
> regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>
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-performance@postgresql.org
Cc: sid@etsy.com, tgl@sss.pgh.pa.us
Subject: Re: How can fixed and variable width columns perform similarly?
In-Reply-To: <50516.209.51.183.100.1177690744.squirrel@mailbox.etsy.com>
* 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