Yes.
Look this... and please, tell me if you can help me...
Thanks
Query
EXPLAIN
ANALYZE
select
to_char(data_encerramento,'mm/yyyy') as opcoes_mes,
to_char(data_encerramento,'yyyy-mm') as ordem from detalhamento_bas
where
to_char( data_encerramento ,'yyyy-mm')
between '2006-12' and '2007-01'
GROUP BY opcoes_mes, ordem
ORDER BY ordem DESC
QUERY RESULT
QUERY PLAN
Sort (cost=11449.37..11449.40 rows=119 width=8) (actual
time=14431.537..14431.538 rows=2 loops=1)
Sort Key: to_char(data_encerramento, 'yyyy-mm'::text)
-> HashAggregate (cost=11448.79..11448.96 rows=119 width=8) (actual
time=14431.521..14431.523 rows=2 loops=1)
-> Index Scan using detalhamento_bas_idx3003 on detalhamento_bas
(cost=0.00..11442.95 rows=11679 width=8) (actual time=0.135..12719.155
rows=2335819 loops=1)
Index Cond: ((to_char(data_encerramento, 'yyyy-mm'::text) >=
'2006-12'::text) AND (to_char(data_encerramento, 'yyyy-mm'::text) <=
'2007-01'::text))
Total runtime: 14431.605 ms
SERVER
DELL PowerEdge 2950
XEON Quad-Core 3.0Ghz
4Gb RAM
Linux CentOS 5.0 64-bits
Postgres 8.1.4
Postgresql.conf
# -----------------------------
# 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 postmaster.
#
# Any option can also be given as a command line switch to the # postmaster,
e.g. 'postmaster -c log_connections=on'. Some options # can be changed at
run-time with the 'SET' SQL command.
#
# This file is read on postmaster startup and when the postmaster # receives
a SIGHUP. If you edit the file on a running system, you have # to SIGHUP the
postmaster for the changes to take effect, or use # "pg_ctl reload". Some
settings, such as listen_addresses, require # a postmaster shutdown and
restart to take effect.
#---------------------------------------------------------------------------
# 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
#hba_file = 'ConfigDir/pg_hba.conf' # host-based authentication file
#ident_file = 'ConfigDir/pg_ident.conf' # IDENT configuration file
# If external_pid_file is not explicitly set, no extra pid file is written.
#external_pid_file = '(none)' # write an extra pid file
#---------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#---------------------------------------------------------------------------
# - Connection Settings -
listen_addresses = '*' # what IP address(es) to listen on;
# comma-separated list of addresses;
# defaults to 'localhost', '*' = all
#port = 5432 max_connections = 10 # 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 = 2
#unix_socket_directory = ''
#unix_socket_group = ''
#unix_socket_permissions = 0777 # octal
#bonjour_name = '' # defaults to the computer name
# - Security & Authentication -
#authentication_timeout = 60 # 1-600, in seconds
#ssl = off
#password_encryption = on
#db_user_namespace = off
# Kerberos
#krb_server_keyfile = ''
#krb_srvname = 'postgres'
#krb_server_hostname = '' # empty string matches any keytab
entry
#krb_caseins_users = off
# - 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 = 50000 # min 16 or max_connections*2, 8KB
each
temp_buffers = 1000 # min 100, 8KB each
#max_prepared_transactions = 5 # can be 0 or more
# note: increasing max_prepared_transactions costs ~600 bytes of shared
memory # per transaction slot, plus lock space (see
max_locks_per_transaction).
work_mem = 3145728 # min 64, size in KB
maintenance_work_mem = 4194304 # min 1024, size in KB
max_stack_depth = 2048 # min 100, size in KB
# - Free Space Map -
max_fsm_pages = 208000 # min max_fsm_relations*16, 6 bytes
each
max_fsm_relations = 10000 # min 100, ~70 bytes each
# - Kernel Resource Usage -
#max_files_per_process = 1000 # min 25
#preload_libraries = ''
# - Cost-Based Vacuum Delay -
vacuum_cost_delay = 50 # 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 = 200 # 10-10000 milliseconds between
rounds
bgwriter_lru_percent = 20.0 # 0-100% of LRU buffers
scanned/round
bgwriter_lru_maxpages = 100 # 0-1000 buffers max written/round
bgwriter_all_percent = 3 # 0-100% of all buffers
scanned/round
bgwriter_all_maxpages = 600 # 0-1000 buffers max written/round
#---------------------------------------------------------------------------
# WRITE AHEAD LOG
#---------------------------------------------------------------------------
# - Settings -
fsync = off # 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 = off # recover from partial page writes
wal_buffers = 2300 # min 4, 8KB each
commit_delay = 10 # range 0-100000, in microseconds
#commit_siblings = 5 # range 1-1000
# - Checkpoints -
checkpoint_segments = 256 # in logfile segments, min 1, 16MB
each
checkpoint_timeout = 300 # range 30-3600, in seconds
checkpoint_warning = 99 # in seconds, 0 is off
# - Archiving -
#archive_command = '' # command to use to archive a
logfile
# segment
#---------------------------------------------------------------------------
# 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 -
effective_cache_size = 41943040 # typically 8KB each
random_page_cost = 1 # units are one sequential page
fetch
# cost
cpu_tuple_cost = 0.001 # (same)
cpu_index_tuple_cost = 0.0005 # (same)
cpu_operator_cost = 0.00025 # (same)
# - 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 = on
#from_collapse_limit = 8
join_collapse_limit = 1 # 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 = on # Enable capturing of stderr into
log
# files
# 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-%a.log' # Log file name pattern.
# Can include strftime() escapes
log_truncate_on_rotation = on # 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 = 1440 # Automatic rotation of logfiles
will
# happen after so many minutes. 0
to
# disable.
log_rotation_size = 0 # Automatic rotation of logfiles
will
# happen after so many kilobytes of
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 = panic # Values in order of increasing
severity:
# debug5
# debug4
# debug3
# debug2
# debug1
# info
# notice
# warning
# error
# panic(off)
#log_min_duration_statement = -1 # -1 is disabled, 0 logs all
statements
# and their durations, in
milliseconds.
#silent_mode = off # DO NOT USE without syslog or
# redirect_stderr
# - 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, mod, ddl, all
#log_hostname = off
#---------------------------------------------------------------------------
# RUNTIME STATISTICS
#---------------------------------------------------------------------------
# - Statistics Monitoring -
#log_parser_stats = off
#log_planner_stats = off
#log_executor_stats = off
#log_statement_stats = off
# - Query/Index Statistics Collector -
stats_start_collector = off
#stats_command_string = off
#stats_block_level = off
#stats_row_level = off
#stats_reset_on_server_start = off
#---------------------------------------------------------------------------
# AUTOVACUUM PARAMETERS
#---------------------------------------------------------------------------
autovacuum = on # enable autovacuum subprocess?
#autovacuum_naptime = 60 # time between autovacuum runs, in
secs
#autovacuum_vacuum_threshold = 1000 # min # of tuple updates before
# vacuum
#autovacuum_analyze_threshold = 500 # min # of tuple updates before
# analyze
#autovacuum_vacuum_scale_factor = 0.4 # fraction of rel size before
# vacuum
#autovacuum_analyze_scale_factor = 0.2 # fraction of rel size before
# analyze
#autovacuum_vacuum_cost_delay = -1 # default vacuum cost delay for
# autovac, -1 means use
# vacuum_cost_delay
#autovacuum_vacuum_cost_limit = -1 # default vacuum cost limit for
# autovac, -1 means use
# vacuum_cost_limit
#---------------------------------------------------------------------------
# CLIENT CONNECTION DEFAULTS
#---------------------------------------------------------------------------
# - Statement Behavior -
#search_path = '$user,public' # schema names
#default_tablespace = '' # a tablespace name, '' uses
# the default
#check_function_bodies = on
default_transaction_isolation = 'read committed'
#default_transaction_read_only = off
#statement_timeout = 0 # 0 is disabled, in milliseconds
# - Locale and Formatting -
datestyle = 'iso, dmy'
#timezone = unknown # actually, defaults to TZ
# environment setting
#australian_timezones = off
#extra_float_digits = 0 # min -15, max 2
client_encoding = LATIN1 # actually, defaults to database
# encoding
# These settings are initialized by initdb -- they might be changed
lc_messages = 'pt_BR.ISO-8859-1' # locale for system
error message
# strings
lc_monetary = 'pt_BR.ISO-8859-1' # locale for
monetary formatting
lc_numeric = 'pt_BR.ISO-8859-1' # locale for number
formatting
lc_time = 'pt_BR.ISO-8859-1' # locale for time
formatting
# - Other Defaults -
#explain_pretty_print = on
#dynamic_library_path = '$libdir'
#---------------------------------------------------------------------------
# LOCK MANAGEMENT
#---------------------------------------------------------------------------
deadlock_timeout = 1000 # in milliseconds
#max_locks_per_transaction = 64 # min 10
# note: each lock table slot uses ~220 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 = off
#backslash_quote = safe_encoding # on, off, or safe_encoding
#default_with_oids = off
#escape_string_warning = 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
-----Mensagem original-----
De: Hervé Piedvache [mailto:bill.footcow@xxxxxxxxx]
Enviada em: sábado, 28 de julho de 2007 16:57
Para: pgsql-performance@xxxxxxxxxxxxxx
Cc: Bruno Rodrigues Siqueira
Assunto: Re: select on 1milion register = 6s
Do you have analyzed your table before doing this ?
Le samedi 28 juillet 2007, Bruno Rodrigues Siqueira a écrit :
> Friends,
>
>
>
>
>
>
>
> Who can help me? My SELECT in a base with 1 milion register,
> using expression index = 6seconds.
>
>
>
>
>
> Please, I don't know how to makes it better.
>
>
>
>
>
> Thanks
--
Hervé Piedvache
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