RE: Bloom Filter Partition Pruning
Date: Fri, 16 Mar 2018 07:48:20 +0100
Message-ID: <16d601d3bcf2$c72ed8c0$558c8a40$_at_db-nemec.com>
Hi Sayan,
That answers my question only indirectly.
Yes, a given set of keys from TABLEB can be mapped using ORA_HASH() to a (exact) list of partitions of TABLEA, that contains those keys.
The cross (in my understanding) is that only the Bloom Filter is passed – not the exact key set from TABLEB.
I can only speculate that along the BF also the list of partitions from TABLEA that are relevant is passed (constructed as described above) - this is the point I’d like to clarify.
Kind Regards,
Jaromir D.B. Nemec
<http://www.db-nemec.com> http://www.db-nemec.com
From: Sayan Malakshinov [mailto:xt.and.r_at_gmail.com]
Sent: Freitag, 16. März 2018 00:29
To: jaromir_at_db-nemec.com
Cc: ORACLE-L <oracle-l_at_freelists.org>
Subject: Re: Bloom Filter Partition Pruning
Jaromir,
That's pretty simple for HASH partitioning:
Oracle can use hashes of elements for BF the same way as it uses them for usual partition pruning for hash-partitioned tables, so all that we need is just number of partitions (https://jonathanlewis.wordpress.com/2009/11/21/ora_hash-function/)
-- Best regards, Sayan Malakshinov http://orasql.org -- http://www.freelists.org/webpage/oracle-lReceived on Fri Mar 16 2018 - 07:48:20 CET