Thread: Performance question..

All,
    I'm looking for ideas on tweaking pgsql.. here is my machine stats

Processor 0 runs at 550 MHz
Processor 1 runs at 550 MHz
Page Size : 4096
Phys Pages: 131072
Total Physical memory = 536870912 (512MB)

This is running on HPUX 11

Below is my postmaster.conf file

#
#    Connection Parameters
#
#tcpip_socket = false
tcpip_socket = true
#ssl = false

max_connections = 64

#port = 5432
#hostname_lookup = false
#show_source_port = false

#unix_socket_directory = ''
#unix_socket_group = ''
#unix_socket_permissions = 0777

#virtual_host = ''

#krb_server_keyfile = ''


#
#    Shared Memory Size
#
shared_buffers = 128        # 2*max_connections, min 16
#max_fsm_relations = 100    # min 10, fsm is free space map
#max_fsm_pages = 10000      # min 1000, fsm is free space map
#max_locks_per_transaction = 64 # min 10
#wal_buffers = 8            # min 4

#
#    Non-shared Memory Sizes
#
#sort_mem = 512             # min 32
#vacuum_mem = 8192          # min 1024


#
#    Write-ahead log (WAL)
#
#wal_files = 0 # range 0-64
#wal_sync_method = fsync   # the default varies across platforms:
#               # fsync, fdatasync, open_sync, or open_datasync
#wal_debug = 0             # range 0-16
#commit_delay = 0          # range 0-100000
#commit_siblings = 5       # range 1-1000
#checkpoint_segments = 3   # in logfile segments (16MB each), min 1
#checkpoint_timeout = 300  # in seconds, range 30-3600
#fsync = true


#
#    Optimizer Parameters
#
#enable_seqscan = true
#enable_indexscan = true
#enable_tidscan = true
#enable_sort = true
#enable_nestloop = true
#enable_mergejoin = true
#enable_hashjoin = true

#ksqo = false

#effective_cache_size = 1000  # default in 8k pages
#random_page_cost = 4
#cpu_tuple_cost = 0.01
#cpu_index_tuple_cost = 0.001
#cpu_operator_cost = 0.0025


#
#    GEQO Optimizer Parameters
#
#geqo = true
#geqo_selection_bias = 2.0 # range 1.5-2.0
#geqo_threshold = 11
#geqo_pool_size = 0        # default based on #tables in query, range 128-1024
#geqo_effort = 1
#geqo_generations = 0
#geqo_random_seed = -1     # auto-compute seed


#
#    Debug display
#
#silent_mode = false

#log_connections = false
#log_timestamp = false
#log_pid = false

#debug_level = 0 # range 0-16

#debug_print_query = false
#debug_print_parse = false
#debug_print_rewritten = false
#debug_print_plan = false
#debug_pretty_print = false

# requires USE_ASSERT_CHECKING
#debug_assertions = true


#
#    Syslog
#
# requires ENABLE_SYSLOG
#syslog = 0 # range 0-2
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'


#
#    Statistics
#
#show_parser_stats = false
#show_planner_stats = false
#show_executor_stats = false
#show_query_stats = false

# requires BTREE_BUILD_STATS
#show_btree_build_stats = false


#
#    Access statistics collection
#
#stats_start_collector = true
#stats_reset_on_server_start = true
#stats_command_string = false
#stats_row_level = false
#stats_block_level = false


#
#    Lock Tracing
#
#trace_notify = false

# requires LOCK_DEBUG
#trace_locks = false
#trace_userlocks = false
#trace_lwlocks = false
#debug_deadlocks = false
#trace_lock_oidmin = 16384
#trace_lock_table = 0


#
#    Misc
#
#dynamic_library_path = '$libdir'
#australian_timezones = false
#authentication_timeout = 60    # min 1, max 600
#deadlock_timeout = 1000
#default_transaction_isolation = 'read committed'
#max_expr_depth = 10000         # min 10
#max_files_per_process = 1000   # min 25
#password_encryption = false
#sql_inheritance = true
#transform_null_equals = false

On Wed, Jun 11, 2003 at 02:39:05PM -0400, Williams, Travis L, NPONS wrote:
> All,
>     I'm looking for ideas on tweaking pgsql.. here is my machine stats

Looked here at all? :

http://techdocs.postgresql.org/
http://www.argudo.org/postgresql/soft-tuning.html
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> "the West won the world not by the superiority of its ideas or values or
> religion but rather by its superiority in applying organized violence.
> Westerners often forget this fact, non-Westerners never do."
>   - Samuel P. Huntington

On Wed, 11 Jun 2003, Williams, Travis L, NPONS wrote:

> All,
>     I'm looking for ideas on tweaking pgsql.. here is my machine stats
>
> Processor 0 runs at 550 MHz
> Processor 1 runs at 550 MHz
> Page Size : 4096
> Phys Pages: 131072
> Total Physical memory = 536870912 (512MB)

SNIP

> #    Shared Memory Size
> #
> shared_buffers = 128        # 2*max_connections, min 16

WAYYYY too small.  Try 500 to 2000 for starters. Note that bigger isn't
always better, it's about fitting shared_buffers to your usage.  This is
set in 8k blocks, so 1000 is really only about 8 meg.  Bigger servers have
settings as high as 32768 which is 256 Megs.

SNIP

> #    Non-shared Memory Sizes
> #
> #sort_mem = 512             # min 32
> #vacuum_mem = 8192          # min 1024

Try setting your sort mem a little higher.  It's measured in k, so 8192
would be 8 megs.


> #    Write-ahead log (WAL)
> #
> #wal_files = 0 # range 0-64
> #wal_sync_method = fsync   # the default varies across platforms:
> #               # fsync, fdatasync, open_sync, or open_datasync
> #wal_debug = 0             # range 0-16
> #commit_delay = 0          # range 0-100000
> #commit_siblings = 5       # range 1-1000
> #checkpoint_segments = 3   # in logfile segments (16MB each), min 1
> #checkpoint_timeout = 300  # in seconds, range 30-3600
> #fsync = true

If you're doing a lot of writing, look at using more than one WAL file and
putting the pg_xlog directory on another drive.  You have to shutdown the
postmaster, copy over the pg_xlog dir, move the on in $PGDATA out of the
way, and link to the "new" directory then restart the postmaster.

Also, if you're doing lots of writes, setting a higher commit_delay and
commit_siblings can help.

> #effective_cache_size = 1000  # default in 8k pages

If your machine has 512 Meg of ram, you want to see how much
(approximately) is used by the OS as file cache/buffer.  Divide that by 8k
and put that number into effective_cache_size.

> #random_page_cost = 4

For machines with fast RAID subsystems, random_page_cost may need to be
lowered.  somewhere between 1 and 2.  If all your dataset fits in memory,
set it to 1.  I use 1.4 as a setting on my machine with 1.5 gig.

> #cpu_tuple_cost = 0.01
> #cpu_index_tuple_cost = 0.001
> #cpu_operator_cost = 0.0025

SNIP

That's all I can think of.  If you can afford more memory, that would be
your best upgrade right now.