Re: text field

Frank,

> >Otherwise, TEXT and VARCHAR perform the same in PostgreSQL.
>
> Almost the same?  I read recently that VARCHAR(n) has a minor
>  overhead on
> UPDATE to enforce the max length.

Hmmm ... yes, probably.  I was comparing with SQL-Server, where large
 text fields are stored as attached files and thus have vastly slower
 performance than VARCHAR.   I suppose that it would be an amusing
 turnabout if, thanks to TOAST, TEXT was marginally faster than VARCHAR
 for INSERT & UPDATE in Postgres.

Warning, though; despite TOAST, you will still see a significant
 degradation is database performance with very large text fields if
 your machine has limited disk access (such as an IDE drive).
  Basically, if the size of your text file exceeds the buffer size
 you've set in postgresql.conf (default is 8k I think) then you'll see
 queries slow down 10-fold as the database engine shuttles your data to
 and from the swap files on disk.  You can fix this by increasing the
 buffer (which may require buying more memory for the computer!) and/or
 adding more/faster disks to the computer.

-Josh

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