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"Partition pruning dramatically reduces the amount of data retrieved from disk and shortens the use of processing time, improving query performance and resource utilization. If you partition the index and table on different columns (with a global, partitioned index), partition pruning also eliminates index partitions even when the partitions of the underlying table cannot be eliminated."

I not positive I understand the second sentence. Could someone give an example?

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  • Bobak, Mark at Mar 22, 2004 at 1:43 pm
    Well, I'm certainly not the partitioning expert, but I think what it's saying is that if the index is partitioned differently from the table, then for index access paths, they are eligible for partition pruning, even if said pruning is not compatible with the table's partition scheme. This makes sense, since the index is global and partitioned, partition pruning can happen at index access time, then whatever index access operation is dictated, then the requisite table access by rowid to get any required data from the table. Since it's a global index, the rowids in the index entries from the index partition that was utilized, may point to any table rows in any table partition.

    -Mark

    -----Original Message-----
    From: david wendelken
    Sent: Monday, March 22, 2004 1:36 PM
    To: oracle-l_at_freelists.org
    Subject: Partitioning Question (1 of several)

    "Partition pruning dramatically reduces the amount of data retrieved from disk and shortens the use of processing time, improving query performance and resource utilization. If you partition the index and table on different columns (with a global, partitioned index), partition pruning also eliminates index partitions even when the partitions of the underlying table cannot be eliminated."

    I not positive I understand the second sentence. Could someone give an example?

    Please see the official ORACLE-L FAQ: http://www.orafaq.com

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  • Ryan.gaffuri_at_cox.net at Mar 22, 2004 at 5:25 pm
    was that right out of the oracle docs? That is horrible.

    My understanding is that partitioning pruning = partition elimination. Say have a table with 3 partitions.

    Based on your where clause Oracle will know in advance which partition(s) are needed for the sql statement and their by 'pruning' or eliminating the other partitions from being scanned.
    From: david wendelken
    Date: 2004/03/22 Mon PM 01:35:43 EST
    To: oracle-l_at_freelists.org
    Subject: Partitioning Question (1 of several)


    "Partition pruning dramatically reduces the amount of data retrieved from disk and shortens the use of processing time, improving query performance and resource utilization. If you partition the index and table on different columns (with a global, partitioned index), partition pruning also eliminates index partitions even when the partitions of the underlying table cannot be eliminated."

    I not positive I understand the second sentence. Could someone give an example?


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  • Igor Neyman at Mar 23, 2004 at 9:06 am
    Why is it "horrible"?
    What's wrong with this quote from oracle docs?

    Igor Neyman, OCP DBA
    ineyman_at_perceptron.com

    -----Original Message-----
    From: oracle-l-bounce_at_freelists.org
    On Behalf Of ryan.gaffuri_at_cox.net
    Sent: Monday, March 22, 2004 5:42 PM
    To: oracle-l_at_freelists.org
    Subject: Re: Partitioning Question (1 of several)

    was that right out of the oracle docs? That is horrible.

    My understanding is that partitioning pruning = partition elimination.
    Say have a table with 3 partitions.

    Based on your where clause Oracle will know in advance which
    partition(s) are needed for the sql statement and their by 'pruning' or
    eliminating the other partitions from being scanned.
    From: david wendelken
    Date: 2004/03/22 Mon PM 01:35:43 EST
    To: oracle-l_at_freelists.org
    Subject: Partitioning Question (1 of several)


    "Partition pruning dramatically reduces the amount of data retrieved
    from disk and shortens the use of processing time, improving query
    performance and resource utilization. If you partition the index and
    table on different columns (with a global, partitioned index), partition
    pruning also eliminates index partitions even when the partitions of the
    underlying table cannot be eliminated."
    I not positive I understand the second sentence. Could someone give
    an example?

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