RES: select on 1milion register = 6s - Mailing list pgsql-performance

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 #
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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
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                    # 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@gmail.com]
Enviada em: sábado, 28 de julho de 2007 16:57
Para: pgsql-performance@postgresql.org
Cc: Bruno Rodrigues Siqueira
Assunto: Re: [PERFORM] 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