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	<15873.1177691157@sss.pgh.pa.us>
Date: Fri, 27 Apr 2007 09:19:04 -0700 (PDT)
Subject: Re: How can fixed and variable width columns perform similarly?
From: "Siddharth Anand" <sid@etsy.com>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: sid@etsy.com,
 pgsql-performance@postgresql.org
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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
>
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