Query Fails with error calloc - Cannot alocate memory - Mailing list pgsql-performance

Hi …

I am trying to run a query that selects 26 million rows from a

table with 68 byte rows.

When run on the Server via psql the following error occurs:

calloc : Cannot allocate memory

When run via ODBC from Cognos Framework Manager only works

if we limit the retrieval to 3 million rows.

I notice that the memory used by the query when run on the Server increases

to about 2.4 GB before the query fails.

Postgres version is 7.3.4

Running on Linux Redhat 7.2

4 GB memory

7 Processor 2.5 Ghz

Shmmax set to 2 GB

Configuration Parameters

Shared Buffers                  12 288

Max Connections         16

Wal buffers                             24

Sort Mem                                40960

Vacuum Mem                      80192

Checkpoint Timeout              600

Enable Seqscan          false

Effective Cache Size    200000

Results of explain analyze and expain analyze verbose:

explain analyze select * from flash_by_branches;

                                                                  QUERY PLAN                                                 

----------------------------------------------------------------------------------------------------------------------------------------------

 Seq Scan on flash_by_branches  (cost=100000000.00..100567542.06 rows=26854106 width=68) (actual time=12.14..103936.35 rows=26854106 loops=1)

 Total runtime: 122510.02 msec

(2 rows)

explain analyze verbose:

{ SEQSCAN

    :startup_cost 100000000.00

    :total_cost 100567542.06

    :rows 26854106

    :width 68

    :qptargetlist (

       { TARGETENTRY

       :resdom

          { RESDOM

          :resno 1

          :restype 1043

          :restypmod 8

          :resname br_code

          :reskey 0

          :reskeyop 0

          :ressortgroupref 0

          :resjunk false

          }

       :expr

          { VAR

          :varno 1

          :varattno 1

          :vartype 1043

          :vartypmod 8

          :varlevelsup 0

          :varnoold 1

          :varoattno 1

          }

       }

       { TARGETENTRY

       :resdom

          { RESDOM

          :resno 2

          :restype 23

          :restypmod -1

          :resname fty_code

          :reskey 0

          :reskeyop 0

          :ressortgroupref 0

          :resjunk false

          }

       :expr

          { VAR

          :varno 1

          :varattno 2

          :vartype 23

          :vartypmod -1

          :varlevelsup 0

          :varnoold 1

          :varoattno 2

        }

       }

       { TARGETENTRY

       :resdom

          { RESDOM

          :resno 3

          :restype 1082

          :restypmod -1

          :resname period

          :reskey 0

          :reskeyop 0

          :ressortgroupref 0

          :resjunk false

          }

       :expr

          { VAR

          :varno 1

          :varattno 3

          :vartype 1082

          :vartypmod -1

          :varlevelsup 0

          :varnoold 1

          :varoattno 3

          }

       }

       { TARGETENTRY

       :resdom

          { RESDOM

          :resno 4

          :restype 1700

          :restypmod 786436

          :resname value

          :reskey 0

          :reskeyop 0

          :ressortgroupref 0

          :resjunk false

          }

       :expr

          { VAR

          :varno 1

          :varattno 4

          :vartype 1700

          :vartypmod 786436

          :varlevelsup 0

          :varnoold 1

          :varoattno 4

          }

       }

       { TARGETENTRY

       :resdom

      { RESDOM

          :resno 7

          :restype 1700

          :restypmod 786438

          :resname value1

          :reskey 0

          :reskeyop 0

          :ressortgroupref 0

          :resjunk false

          }

       :expr

          { VAR

          :varno 1

          :varattno 7

          :vartype 1700

          :vartypmod 786438

          :varlevelsup 0

          :varnoold 1

          :varoattno 7

          }

       }

    )

    :qpqual <>

    :lefttree <>

    :righttree <>

    :extprm ()

    :locprm ()

    :initplan <>

    :nprm 0

    :scanrelid 1

    }

 Seq Scan on flash_by_branches  (cost=100000000.00..100567542.06 rows=26854106 width=68) (actual time=6.59..82501.15 rows=2685

4106 loops=1)

 Total runtime: 102089.00 msec

(196 rows)

Please assist.

Thanks,

Howard Oblowitz

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