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Re: [ADMIN] OUTER JOIN IS SLOW

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Just to make things more clear I ran EXPLAIN ANALYZE on the slow query. I got

Merge Full Join (cost=62.33..73.36 rows=1000 width=19) (actual time=39.205..8521.644 rows=272 loops=1)
  Merge Cond: ("outer".pkey = "inner".d1)
-> Index Scan using mutualfd_weekday_qbid_pkey_idx on mutualfd_weekday_qbid (cost=0.00..6.01 rows=1 width=19) (actual time=34.579..8510.801 rows=253 loops=1) Index Cond: ((pkey >= '2005-12-15'::date) AND (pkey <= '2006-12-15'::date))
        Filter: (cusip = '92193920'::text)
-> Sort (cost=62.33..64.83 rows=1000 width=4) (actual time=4.604..5.674 rows=262 loops=1)
        Sort Key: d1.d1
-> Function Scan on "getDateRange" d1 (cost=0.00..12.50 rows=1000 width=4) (actual time=2.591..3.591 rows=262 loops=1)
Total runtime: 8522.894 ms
(9 rows)

It looks like this line:

"-> Index Scan using mutualfd_weekday_qbid_pkey_idx on mutualfd_weekday_qbid (cost=0.00..6.01 rows=1 width=19) (actual time=34.579..8510.801 rows=253 loops=1)"

is the problem. As I understand it is using the index but it is low as dirt. Hopefully, the -z will fix this. I also ran the same query but with earlier dates in the table and the query ran much faster.

Merge Full Join (cost=3492.48..3505.60 rows=1034 width=19) (actual time=7.605..12.851 rows=273 loops=1)
  Merge Cond: ("outer".d1 = "inner".pkey)
-> Sort (cost=62.33..64.83 rows=1000 width=4) (actual time=4.586..5.530 rows=263 loops=1)
        Sort Key: d1.d1
-> Function Scan on "getDateRange" d1 (cost=0.00..12.50 rows=1000 width=4) (actual time=2.493..3.515 rows=263 loops=1) -> Sort (cost=3430.15..3432.74 rows=1034 width=19) (actual time=2.998..3.971 rows=263 loops=1)
        Sort Key: mutualfd_weekday_qbid.pkey
-> Index Scan using mutualfd_weekday_qbid_pkey on mutualfd_weekday_qbid (cost=0.00..3378.38 rows=1034 width=19) (actual time=0.075..1.843 rows=263 loops=1) Index Cond: ((cusip = '92193920'::text) AND (pkey >= '1999-12-15'::date) AND (pkey <= '2000-12-15'::date))
Total runtime: 13.935 ms
(10 rows)

In this case it only took 13.935ms as compared to 8522.894 ms for the newer data.

Benjamin

Shoaib Mir wrote:
....adding to the last email, for now try the work_mem but you should be adding ANALYZE along with the VACUUM (with a cron job I guess) you do regularly.

------------
Shoaib Mir
EntperpriseDB ( www.enterprisedb.com <http://www.enterprisedb.com>)

On 12/24/06, *Shoaib Mir* <shoaibmir@xxxxxxxxx <mailto:shoaibmir@xxxxxxxxx>> wrote:

    Try increasing the work_mem first to see the change, that might help.

    -------------
    Shoaib Mir
    EnterpriseDB ( www.enterprisedb.com <http://www.enterprisedb.com>)

    On 12/24/06, *Benjamin Arai* <benjamin@xxxxxxxxxxxx
    <mailto:benjamin@xxxxxxxxxxxx>> wrote:

        I have been running pieces of my PL function by hand and I
        have found
        that the following queries work by themselves taking less than
        a second
        to execute.

        getDateRange"('12/1/2005','12/1/2006')  <- simply generates a
        date
        list.  Doesn't even access a table

        SELECT * FROM mutualfd_weekday_qbid WHERE cusip='92193920'
        AND  pkey >=
        '12/15/2005' AND pkey <= '12/15/2006';

        But when combined as below it takes 10 seconds to execute.

        SELECT d1 as date, d2.data as data FROM
        "getDateRange"('12/1/2005','12/1/2006') d1 FULL OUTER JOIN
        (SELECT *
        FROM mutualfd_weekday_qbid WHERE cusip='92193920' AND  pkey >=
        '12/15/2005' AND pkey <= '12/15/2006') d2 ON d1=d2.pkey;

        Do I need to increase the work_mem or is this possible still a
        ANALYZE
        issue?

        Benjamin

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