User Guide

/var/lib/pgsql/data/ for Red Hat Linux installations.
For a new installation, the directory for Microsoft Windows is C:\Program Files\PostgreSQL\8.4.2\data\ or in
opt/PostgreSQL/8.4.2/data/ for Red Hat Linux.
Two configuration variables may be set in that file:
• The shared_buffers variable sets the amount of memory cache used by all PostgreSQL processes. It should be
set to 10-25% of total memory available to the database server.
• The following example is from the postgresql.conf file that is configured to reserve 2GB of memory. Please
note that changes in this file require restarting the database to take effect.
Resource usage (except WAL)
Memory - shared_buffers = 2GB min 128kB or max_connections at 16kB (This change requires a restart.)
The effective cache size is the amount of kernel cache that can be dedicated to PostgreSQL. Setting this depends
on what else is running on the machine. For a dedicated machine, set this to 75% of total memory.
Query tuning
Planner method configuration
• enable_bitmapscan = on
• enable_hashagg = on
• enable_hashjoin = on
• enable_indexscan = on
• enable_mergejoin = on
• enable_nestloop = on
• enable_seqscan = on
• enable_sort = on
• enable_tidscan = on
Planner cost constants
• seq_page_cost = 1.0 measured on an arbitrary scale
• random_page_cost = 4.0 same scale as above
• cpu_tuple_cost = 0.01 same scale as above
• cpu_index_tuple_cost = 0.005 same scale as above
• cpu_operator_cost = 0.0025 same scale as above
• effective_cache_size = 6GB
Microsoft SQL Server 2005
The default memory settings for Microsoft SQL Server 2005 are usually more than adequate. If you have other
applications installed on the server machine and wish to change the default settings, adjustments may be made
by using the MS SQL Server management studio application.
8 Data Center Planner Installer/User Guide