Comments on: Bloom Filters http://structureddata.org/2007/10/23/bloom-filters/?utm_source=rss&utm_medium=rss&utm_campaign=bloom-filters Oracle Database Performance and Scalability Blog Thu, 02 Sep 2010 21:47:56 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Greg Rahnhttp://structureddata.org/2007/10/23/bloom-filters/comment-page-1/#comment-11442 Greg Rahn Mon, 14 Jun 2010 13:57:34 +0000 http://structureddata.org/2007/10/23/bloom-filters/#comment-11442 @IchiroThe SALES tables is partitioned on CUST_ID and you can tell this because the execution plan has BF0000 in the Pstart/Pstop column and CUST_ID is the only predicate on SALES (see Predicate Information section). In this case the BF populated by CUST_IDs from CUSTOMER and applied to SALES to prune on the partitioned table (we call this bloom pruning). The BF has nothing to do with the HASH GROUP BY row source. @Ichiro

The SALES tables is partitioned on CUST_ID and you can tell this because the execution plan has BF0000 in the Pstart/Pstop column and CUST_ID is the only predicate on SALES (see Predicate Information section). In this case the BF populated by CUST_IDs from CUSTOMER and applied to SALES to prune on the partitioned table (we call this bloom pruning). The BF has nothing to do with the HASH GROUP BY row source.

]]> By: Ichirohttp://structureddata.org/2007/10/23/bloom-filters/comment-page-1/#comment-11441 Ichiro Mon, 14 Jun 2010 09:17:46 +0000 http://structureddata.org/2007/10/23/bloom-filters/#comment-11441 I agree if SALES and/or CUSTOMERS were created as partitioned tables. But I'm not sure if they're not partitioned. In your test, BF was usefule as "HASH GROUP BY" execution. I agree if SALES and/or CUSTOMERS were created as partitioned tables. But I’m not sure if they’re not partitioned. In your test, BF was usefule as “HASH GROUP BY” execution.

]]> By: Greg Rahnhttp://structureddata.org/2007/10/23/bloom-filters/comment-page-1/#comment-48 Greg Rahn Wed, 24 Oct 2007 15:13:39 +0000 http://structureddata.org/2007/10/23/bloom-filters/#comment-48 You are correct Christian, bloom filters are in 10gR2 and I don't believe they were specifically documented but probably fell under "Optimizer Enhancements" or similar. You are correct Christian, bloom filters are in 10gR2 and I don’t believe they were specifically documented but probably fell under “Optimizer Enhancements” or similar.

]]> By: Christian Antogninihttp://structureddata.org/2007/10/23/bloom-filters/comment-page-1/#comment-47 Christian Antognini Wed, 24 Oct 2007 06:04:55 +0000 http://structureddata.org/2007/10/23/bloom-filters/#comment-47 Hi GregI guess you know it... But for the other readers that might ignore it just a short information from my part. Bloom filters are already available in 10gR2. Unfortunately, for some unknown reasons (at least for me), Oracle never documented such a wonderful feature!Take care, Chris Hi Greg

I guess you know it… But for the other readers that might ignore it just a short information from my part. Bloom filters are already available in 10gR2. Unfortunately, for some unknown reasons (at least for me), Oracle never documented such a wonderful feature!

Take care,
Chris

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