Perhaps a suboptimal plan is picked due to configuration issues, e.g.
memory constraints? Could you post your postgresql.conf as well?
Below is the postgresql.conf file for 8.2.4. The server has 2 GB of RAM and it was not maxed out when I ran the query.
As I mentioned, I tried running both 8.0.11 and 8.2.4 on the same hardware, so that I would see if it was a difference in the hardware or the database.
Sim
# -----------------------------
# PostgreSQL configuration file
# -----------------------------
#
# This file consists of lines of the form:
#
# name = value
#
# (The '=' is optional.) White space may be used. Comments are introduced
# with '#' anywhere on a line. The complete list of option names and
# allowed values can be found in the PostgreSQL documentation. The
# commented-out settings shown in this file represent the default values.
#
# Please note that re-commenting a setting is NOT sufficient to revert it
# to the default value, unless you restart the server.
#
# Any option can also be given as a command line switch to the server,
# e.g., 'postgres -c log_connections=on'. Some options can be changed at
# run-time with the 'SET' SQL command.
#
# This file is read on server startup and when the server receives a
# SIGHUP. If you edit the file on a running system, you have to SIGHUP the
# server for the changes to take effect, or use "pg_ctl reload". Some
# settings, which are marked below, require a server shutdown and restart
# to take effect.
#
# Memory units: kB = kilobytes MB = megabytes GB = gigabytes
# Time units: ms = milliseconds s = seconds min = minutes h = hours d = days
#---------------------------------------------------------------------------
# FILE LOCATIONS
#---------------------------------------------------------------------------
# The default values of these variables are driven from the -D command line
# switch or PGDATA environment variable, represented here as ConfigDir.
#data_directory = 'ConfigDir'# use data in another directory
# (change requires restart)
#hba_file = 'ConfigDir/pg_hba.conf'# host-based authentication file
# (change requires restart)
#ident_file = 'ConfigDir/pg_ident.conf'# ident configuration file
# (change requires restart)
# If external_pid_file is not explicitly set, no extra PID file is written.
#external_pid_file = '(none)'# write an extra PID file
# (change requires restart)
#---------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#---------------------------------------------------------------------------
# - Connection Settings -
listen_addresses = '*'# what IP address(es) to listen on;
# comma-separated list of addresses;
# defaults to 'localhost', '*' = all
# (change requires restart)
#port = 5432# (change requires restart)
max_connections = 100# (change requires restart)
# Note: increasing max_connections costs ~400 bytes of shared memory per
# connection slot, plus lock space (see max_locks_per_transaction). You
# might also need to raise shared_buffers to support more connections.
#superuser_reserved_connections = 3# (change requires restart)
#unix_socket_directory = ''# (change requires restart)
#unix_socket_group = ''# (change requires restart)
#unix_socket_permissions = 0777# octal
# (change requires restart)
#bonjour_name = ''# defaults to the computer name
# (change requires restart)
# - Security & Authentication -
#authentication_timeout = 1min# 1s-600s
#ssl = off# (change requires restart)
#password_encryption = on
#db_user_namespace = off
# Kerberos
#krb_server_keyfile = ''# (change requires restart)
#krb_srvname = 'postgres'# (change requires restart)
#krb_server_hostname = ''# empty string matches any keytab entry
# (change requires restart)
#krb_caseins_users = off# (change requires restart)
# - TCP Keepalives -
# see 'man 7 tcp' for details
#tcp_keepalives_idle = 0# TCP_KEEPIDLE, in seconds;
# 0 selects the system default
#tcp_keepalives_interval = 0# TCP_KEEPINTVL, in seconds;
# 0 selects the system default
#tcp_keepalives_count = 0# TCP_KEEPCNT;
# 0 selects the system default
#---------------------------------------------------------------------------
# RESOURCE USAGE (except WAL)
#---------------------------------------------------------------------------
# - Memory -
shared_buffers = 24MB# min 128kB or max_connections*16kB
# (change requires restart)
#temp_buffers = 8MB# min 800kB
#max_prepared_transactions = 5# can be 0 or more
# (change requires restart)
# Note: increasing max_prepared_transactions costs ~600 bytes of shared memory
# per transaction slot, plus lock space (see max_locks_per_transaction).
#work_mem = 1MB# min 64kB
#maintenance_work_mem = 16MB# min 1MB
#max_stack_depth = 2MB# min 100kB
# - Free Space Map -
max_fsm_pages = 153600# min max_fsm_relations*16, 6 bytes each
# (change requires restart)
#max_fsm_relations = 1000# min 100, ~70 bytes each
# (change requires restart)
# - Kernel Resource Usage -
#max_files_per_process = 1000# min 25
# (change requires restart)
#shared_preload_libraries = ''# (change requires restart)
# - Cost-Based Vacuum Delay -
#vacuum_cost_delay = 0# 0-1000 milliseconds
#vacuum_cost_page_hit = 1# 0-10000 credits
#vacuum_cost_page_miss = 10# 0-10000 credits
#vacuum_cost_page_dirty = 20# 0-10000 credits
#vacuum_cost_limit = 200# 0-10000 credits
# - Background writer -
#bgwriter_delay = 200ms# 10-10000ms between rounds
#bgwriter_lru_percent = 1.0# 0-100% of LRU buffers scanned/round
#bgwriter_lru_maxpages = 5# 0-1000 buffers max written/round
#bgwriter_all_percent = 0.333# 0-100% of all buffers scanned/round
#bgwriter_all_maxpages = 5# 0-1000 buffers max written/round
#---------------------------------------------------------------------------
# WRITE AHEAD LOG
#---------------------------------------------------------------------------
# - Settings -
#fsync = on# turns forced synchronization on or off
#wal_sync_method = fsync# the default is the first option
# supported by the operating system:
# open_datasync
# fdatasync
# fsync
# fsync_writethrough
# open_sync
#full_page_writes = on# recover from partial page writes
#wal_buffers = 64kB# min 32kB
# (change requires restart)
#commit_delay = 0# range 0-100000, in microseconds
#commit_siblings = 5# range 1-1000
# - Checkpoints -
#checkpoint_segments = 3# in logfile segments, min 1, 16MB each
#checkpoint_timeout = 5min# range 30s-1h
#checkpoint_warning = 30s# 0 is off
# - Archiving -
#archive_command = ''# command to use to archive a logfile segment
#archive_timeout = 0# force a logfile segment switch after this
# many seconds; 0 is off
#---------------------------------------------------------------------------
# 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 = 128MB
# - Genetic Query Optimizer -
#geqo = on
#geqo_threshold = 12
#geqo_effort = 5# range 1-10
#geqo_pool_size = 0# selects default based on effort
#geqo_generations = 0# selects default based on effort
#geqo_selection_bias = 2.0# range 1.5-2.0
# - Other Planner Options -
#default_statistics_target = 10# range 1-1000
#constraint_exclusion = off
#from_collapse_limit = 8
#join_collapse_limit = 8# 1 disables collapsing of explicit
# JOINs
#---------------------------------------------------------------------------
# ERROR REPORTING AND LOGGING
#---------------------------------------------------------------------------
# - Where to Log -
#log_destination = 'stderr'# Valid values are combinations of
# stderr, syslog and eventlog,
# depending on platform.
# This is used when logging to stderr:
#redirect_stderr = off# Enable capturing of stderr into log
# files
# (change requires restart)
# These are only used if redirect_stderr is on:
#log_directory = 'pg_log'# Directory where log files are written
# Can be absolute or relative to PGDATA
#log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' # Log file name pattern.
# Can include strftime() escapes
#log_truncate_on_rotation = off # If on, any existing log file of the same
# name as the new log file will be
# truncated rather than appended to. But
# such truncation only occurs on
# time-driven rotation, not on restarts
# or size-driven rotation. Default is
# off, meaning append to existing files
# in all cases.
#log_rotation_age = 1d# Automatic rotation of logfiles will
# happen after that time. 0 to
# disable.
#log_rotation_size = 10MB# Automatic rotation of logfiles will
# happen after that much log
# output. 0 to disable.
# These are relevant when logging to syslog:
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'
# - When to Log -
#client_min_messages = notice# Values, in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# log
# notice
# warning
# error
#log_min_messages = notice# Values, in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# info
# notice
# warning
# error
# log
# fatal
# panic
#log_error_verbosity = default# terse, default, or verbose messages
#log_min_error_statement = error# Values in order of increasing severity:
# debug5
# debug4
# debug3
# debug2
# debug1
# info
# notice
# warning
# error
# fatal
# panic (effectively off)
#log_min_duration_statement = -1# -1 is disabled, 0 logs all statements
# and their durations.
#silent_mode = off# DO NOT USE without syslog or
# redirect_stderr
# (change requires restart)
# - What to Log -
#debug_print_parse = off
#debug_print_rewritten = off
#debug_print_plan = off
#debug_pretty_print = off
#log_connections = off
#log_disconnections = off
#log_duration = off
#log_line_prefix = ''# Special values:
# %u = user name
# %d = database name
# %r = remote host and port
# %h = remote host
# %p = PID
# %t = timestamp (no milliseconds)
# %m = timestamp with milliseconds
# %i = command tag
# %c = session id
# %l = session line number
# %s = session start timestamp
# %x = transaction id
# %q = stop here in non-session
# processes
# %% = '%'
# e.g. '<%u%%%d> '
#log_statement = 'none'# none, ddl, mod, all
#log_hostname = off
#---------------------------------------------------------------------------
# RUNTIME STATISTICS
#---------------------------------------------------------------------------
# - Query/Index Statistics Collector -
#stats_command_string = on
#update_process_title = on
#stats_start_collector = on# needed for block or row stats
# (change requires restart)
#stats_block_level = off
stats_row_level = on
#stats_reset_on_server_start = off# (change requires restart)
# - Statistics Monitoring -
#log_parser_stats = off
#log_planner_stats = off
#log_executor_stats = off
#log_statement_stats = off
#---------------------------------------------------------------------------
# AUTOVACUUM PARAMETERS
#---------------------------------------------------------------------------
autovacuum = on# enable autovacuum subprocess?
# 'on' requires stats_start_collector
# and stats_row_level to also be on
#autovacuum_naptime = 1min# time between autovacuum runs
autovacuum_vacuum_threshold = 250# min # of tuple updates before
# vacuum
autovacuum_analyze_threshold = 125# min # of tuple updates before
# analyze
autovacuum_vacuum_scale_factor = 0.1# fraction of rel size before
# vacuum
autovacuum_analyze_scale_factor = 0.05# fraction of rel size before
# analyze
#autovacuum_freeze_max_age = 200000000# maximum XID age before forced vacuum
# (change requires restart)
#autovacuum_vacuum_cost_delay = -1# default vacuum cost delay for
# autovacuum, -1 means use
# vacuum_cost_delay
#autovacuum_vacuum_cost_limit = -1 # default vacuum cost limit for
# autovacuum, -1 means use
# vacuum_cost_limit
#---------------------------------------------------------------------------
# CLIENT CONNECTION DEFAULTS
#---------------------------------------------------------------------------
# - Statement Behavior -
#search_path = '"$user",public' # schema names
#default_tablespace = '' # a tablespace name, '' uses
# the default
#check_function_bodies = on
#default_transaction_isolation = 'read committed'
#default_transaction_read_only = off
#statement_timeout = 0 # 0 is disabled
#vacuum_freeze_min_age = 100000000
# - Locale and Formatting -
datestyle = 'iso, mdy'
#timezone = unknown # actually, defaults to TZ
# environment setting
#timezone_abbreviations = 'Default' # select the set of available timezone
# abbreviations. Currently, there are
# Default
# Australia
# India
# However you can also create your own
# file in share/timezonesets/.
#extra_float_digits = 0 # min -15, max 2
#client_encoding = sql_ascii # actually, defaults to database
# encoding
# These settings are initialized by initdb -- they might be changed
lc_messages = 'C' # locale for system error message
# strings
lc_monetary = 'C' # locale for monetary formatting
lc_numeric = 'C' # locale for number formatting
lc_time = 'C' # locale for time formatting
# - Other Defaults -
#explain_pretty_print = on
#dynamic_library_path = '$libdir'
#local_preload_libraries = ''
#---------------------------------------------------------------------------
# LOCK MANAGEMENT
#---------------------------------------------------------------------------
#deadlock_timeout = 1s
#max_locks_per_transaction = 64 # min 10
# (change requires restart)
# Note: each lock table slot uses ~270 bytes of shared memory, and there are
# max_locks_per_transaction * (max_connections + max_prepared_transactions)
# lock table slots.
#---------------------------------------------------------------------------
# VERSION/PLATFORM COMPATIBILITY
#---------------------------------------------------------------------------
# - Previous Postgres Versions -
add_missing_from = on
#array_nulls = on
#backslash_quote = safe_encoding # on, off, or safe_encoding
#default_with_oids = off
#escape_string_warning = on
#standard_conforming_strings = off
#regex_flavor = advanced # advanced, extended, or basic
#sql_inheritance = on
# - Other Platforms & Clients -
#transform_null_equals = off
#---------------------------------------------------------------------------
# CUSTOMIZED OPTIONS
#---------------------------------------------------------------------------
#custom_variable_classes = '' # list of custom variable class names
---------------------------(end of broadcast)---------------------------
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