Oracle Spatial doesn't scale well with concurrent connections

[ivanopicco]

Hi all, I perform some performance tests on mapserv (CGI and FASTCGI), using Oracle and SDE connections to retrieve a simple feature layer from the same oracle (SDO) table (the layer was registered on SDE). I use Microsoft Web Strees Tool (WAST) to make the concurrent getmap requests. As the results show (see attach), Oracle doesn't scale well with concurrent connections. Mapserv can serve 12 concurrent SDE connections, but only 3 from Oracle.

The web server has 2 Intel Xeon 3.40GHz and 2GB of RAM and Linux CentOS 4.5. The database server is a Sun-Fire-V210 with Solaris 9, it has 2 sparcv9 processor operates at 1002 MHz and 2GB of RAM.

This is an extract from my mapfile:

LAYER
    NAME "CTR-SDE"
    STATUS ON
    DEBUG ON
    DATA "ctr_sde.comuni,SHAPE"
    TYPE POLYGON
    CONNECTIONTYPE SDE
    CONNECTION "bubble,port:5153,esri_sde,ctr_sde,ctr_sde"
    PROCESSING "CLOSE_CONNECTION=DEFER"
    TEMPLATE "template.html"
    METADATA
      "WMS_SRS"    "EPSG:32632"
      "WMS_NAME"    "Comuni_SDE"
      "WMS_TITLE"    "Comuni_SDE"
      "WMS_ABSTRACT"    "Comuni SDE"
    END
    CLASS
      STYLE
        OUTLINECOLOR 0 0 0
        ANTIALIAS TRUE
      END
    END
  END

  LAYER
    NAME "CTR-SDO"
    STATUS ON
    DEBUG ON
    DATA "GEOMETRY FROM comuni USING UNIQUE OBJECTID SRID 82344 FILTER
VERSION 10G"
    TYPE POLYGON
    CONNECTIONTYPE oraclespatial
    CONNECTION 'ctr_sdo/ctr_sdo@bubble:1522/OLYMPIA'
    PROCESSING "CLOSE_CONNECTION=DEFER"
    TEMPLATE "template.html"
    METADATA
      "WMS_SRS"    "EPSG:32632"
      "WMS_NAME"    "Comuni_SDO"
      "WMS_TITLE"    "Comuni_SDO"
      "WMS_ABSTRACT"    "Comuni SDO"
    END
    CLASS
      STYLE
        OUTLINECOLOR 0 0 0
        ANTIALIAS TRUE
      END
    END
   END

In attach you find an extract from debug log regarding a stress test with 16 concurrent connections.