Message-ID: <54354D6F.1080002@encs.concordia.ca>
Date: Wed, 08 Oct 2014 10:42:55 -0400
From: Emi Lu <emilu@encs.concordia.ca>
Reply-To: emilu@encs.concordia.ca
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To: Andrew Dunstan <andrew@dunslane.net>
CC: "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: char(N), varchar(N), varchar, text
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 <54354A73.6030607@dunslane.net>
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>
>>
>> For performance point of view, are there big differences between: 
>> char(N), varchar(N), varchar, text?
>>
>> Some comments from google shows:
>> No difference, under the hood it's all varlena. Check this article 
>> from Depesz: 
>> http://www.depesz.com/index.php/2010/03/02/charx-vs-varcharx-vs-varchar-vs-text/
>> A couple of highlights:
>>
>>     To sum it all up:
>>
>>       * char(n) – takes too much space when dealing with values
>>         shorter than n, and can lead to subtle errors because of
>>         adding trailing spaces, plus it is problematic to change the 
>> limit
>>       * varchar(n) – it's problematic to change the limit in live
>>         environment
>>       * varchar – just like text
>>       * text – for me a winner – over (n) data types because it lacks
>>         their problems, and over varchar – because it has distinct name
>>
>>     So, can I assume no big performance differences?
>>     Thanks alot!
>>     Emi
>>
>
>
> Why do you need to ask if you already have the answer? Depesz is right.
Good to hear this. Well, sorry I saw the time is:/2010/03 (might changes 
for diff/newer versions).

Thank you for the confirmation.
Emi


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