Richard, thanks for the answer. In fact, I double-quoted identifiers only because PgSQL forced me to do so when using capitalized letters in table/column name. I'm OK with this if it's PgSQL requirement (app runs on NHibernate so I just change column="MyColumn" to column="`MyColumn`" in mapping files). In fact I like capitalized column/table names (more readable for me), but the point is if this affect performance when running queries (for example PgSQL engine might take more time to analyze query with double-quoted identifiers or so). Is there any performance penalty for this ? S pozdravom / Best regards, Jozef Ševčík sevcik@xxxxxxxxxxxxxxx +420 608 782 813 -----Original Message----- From: Richard Huxton [mailto:dev@xxxxxxxxxxxx] Sent: Wednesday, April 09, 2008 5:49 PM To: Jozef Ševčík Cc: pgsql-general@xxxxxxxxxxxxxx Subject: Re: [GENERAL] Quoting table/column names vs performance Jozef Ševčík wrote: > Hi all, > > I just switched from MS SQL to PostgreSQL on project and have > question about double-quoting names of fields/tables regarding to > performance. If the cost of quoting column-names is a significant part of your query costs, you must have some very fast queries. I would not worry. > In MSSQL I had something like: SELECT Column1,Column2 from MyTable > > In PgSQL I write: SELECT "Column1", "Column2" from "MyTable" > > Which is fine and working, I have no doubt about it. I'm just > guessing if this does not affect performance in any way. I know I may > rename tables/fields to lowercase and avoid double-quotting, but it > double-quotting has no affect on perf. is it worth it ? Or are there > any advantages of using 'non-quoted' identifiers agains double-quoted If you double-quote identifiers when you create them you'll want to double-quote them everywhere they are used. That's OK with a new sytem, but can be awkward if you have a lot of existing code that isn't already quoted. -- Richard Huxton Archonet Ltd
