Re: HASH_JOIN on RBO?

From: Chuck Hamilton <chuck_hamilton_at_yahoo.com>
Date: Wed, 13 Sep 2000 09:14:52 -0700 (PDT)
Message-Id: <10618.116847@fatcity.com>

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It referneces a view but the view has no hints. Not only is the query hinted to the rbo, but I checked the optimizer_goal in the init file and it's set to RULE also. I'm still scratching my head.

MTPConsulting_at_aol.com wrote:
Chuck,
Could you be referencing a view that uses a CBO hint? I've seen it happen where the query had a RULE hint, but used a view with a CBO hint and that caused the whole query to use CBO.

Marc Perkowitz
MTP Systems Consulting, Ltd.

In a message dated 9/12/00 8:36:24 PM Central Daylight Time, chuck_hamilton_at_yahoo.com writes:

<< I have a query with a RULE hint, but the execution plan is show hash
joins. Is this something new in the 8.1.5 optimizer? It used to be that you could only get HASH joins with CBO. Also, each of the operations is showing a cost and cardinality even though none of the tables have stats. The net result is I'm getting a horrible execution plan that includes cartesian merges and runs for hours when previously this query ran in minutes. Any ideas? >>

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It referneces a view but the view has no hints. Not only is the query hinted to the rbo, but I checked the optimizer_goal in the init file and it's set to RULE also. I'm still scratching my head. 
  MTPConsulting_at_aol.com wrote: 
<BLOCKQUOTE style="BORDER-LEFT: #1010ff 2px solid; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">Chuck, Could you be referencing a view that uses a CBO hint? I've seen it happen where the query had a RULE hint, but used a view with a CBO hint and that caused the whole query to use CBO. Marc Perkowitz MTP Systems Consulting, Ltd. In a message dated 9/12/00 8:36:24 PM Central Daylight Time, chuck_hamilton_at_yahoo.com writes: <joins. Is this something new in the 8.1.5 optimizer? It used to be that you could only get HASH joins with CBO. Also, each of the operations is showing a cost and cardinality even though none of the tables have stats. The net result is I'm getting a horrible execution plan that includes cartesian merges and runs for hours when previously this query ran in minutes. Any ideas? >></BLOCKQUOTE> <hr size=1>Do You Yahoo!?!
 
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Received on Wed Sep 13 2000 - 11:14:52 CDT