Nice try ... it should return immediately with zero rows, but it doesn't.

This query performed a table space scan, requiring 23 minutes to complete compared to 0.076 seconds for "select min(OID) from mytable", even though there will definitely never be any results.

One-shot performance at startup is not a big deal to me. 23 minutes per table is a bit much to swallow though.

This looks like a query optimizer bug to me.

----- Original Message -----
From: Maciek BOROWKA
To: firebird-support@yahoogroups.com
Sent: Thursday, January 15, 2004 5:24 AM
Subject: Rép. : Re: [firebird-support] Firebird/Internet performance questions


Perhaps a very naive question : why just don't use:

"select OID from MYTABLE where 1 = 2" to check the existence of a table?
This should be fast!

./Maciek


>>> d_johnson@... 15/01/04 15h05 >>>
[snip]
I can determine table existence by "select the min(OID) from table". This will work quickly in all DBMS.
[snip]


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