在PHP 5.4.1中，我使用本机PostgreSQL驱动程序连接到SQL服务器。即使我尝试PDO方式也是一样的。这里只有一个例外。如果我使用pg_pconnect(持久(，它非常快，正如我预期的那样。
我从PHP到PostgreSQL的连接很慢。此外，有些查询也很慢。
例如，请看一下这张表。
id type active serverip
1 1 0 127.0.0.1
2 10 1 127.0.0.1
3 4 1 127.0.0.1
4 7 1 127.0.0.1
5 13 1 127.0.0.1
6 2 1 127.0.0.1
7 11 1 127.0.0.1
8 6 1 127.0.0.1
9 9 1 127.0.0.1
10 3 0 192.168.1.202
11 5 1 127.0.0.1
12 8 1 127.0.0.1
13 12 1 127.0.0.1
14 14 1 127.0.0.1
我的查询是select * from mytable order by id desc.所以
此表在 id 上具有索引和主键。此表在 MySQL 5.5.23 和 PostgreSQL 9.1.3 中相同 (1：1(
MySQL连接这个数据库并在0.0019 sec.中读取这个表(整个数据(，但是PostgreSQL需要0.0069 sec。这可能看起来像往常一样，但如果MySQL可以非常快速地做到这一点，为什么PostgreSQL不能呢？
在我的大桌子上，它花费的时间比这太长了。在大表中MySQL连接并获取0.09601 sec, PostgreSQL连接并在0.11260秒0.14201 sec.获取它(现已测试(
如您所见，在这个非常简单的数据库表中，PostgreSQL只是很慢。这是我的postgresql.conf文件：
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).
#superuser_reserved_connections = 3 # (change requires restart)
#unix_socket_directory = '' # (change requires restart)
#unix_socket_group = '' # (change requires restart)
#unix_socket_permissions = 0777 # begin with 0 to use octal notation
# (change requires restart)
#bonjour = off # advertise server via Bonjour
# (change requires restart)
#bonjour_name = '' # defaults to the computer name
# (change requires restart)
# - Security and Authentication -
authentication_timeout = 20s # 1s-600s
ssl = off # (change requires restart)
#ssl_ciphers = 'ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH' # allowed SSL ciphers
# (change requires restart)
#ssl_renegotiation_limit = 512MB # amount of data between renegotiations
#password_encryption = on
#db_user_namespace = off
# Kerberos and GSSAPI
#krb_server_keyfile = ''
#krb_srvname = 'postgres' # (Kerberos only)
#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 = 1GB # min 128kB
# (change requires restart)
temp_buffers = 16MB # min 800kB
max_prepared_transactions = 0 # zero disables the feature
# (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).
# It is not advisable to set max_prepared_transactions nonzero unless you
# actively intend to use prepared transactions.
work_mem = 64MB # min 64kB
maintenance_work_mem = 32MB # min 1MB
max_stack_depth = 8MB # min 100kB
# - 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 = 0ms # 0-100 milliseconds
vacuum_cost_page_hit = 100 # 0-10000 credits
vacuum_cost_page_miss = 100 # 0-10000 credits
vacuum_cost_page_dirty = 200 # 0-10000 credits
vacuum_cost_limit = 2000 # 1-10000 credits
# - Background Writer -
bgwriter_delay = 200ms # 10-10000ms between rounds
bgwriter_lru_maxpages = 100 # 0-1000 max buffers written/round
bgwriter_lru_multiplier = 2.0 # 0-10.0 multipler on buffers scanned/round
# - Asynchronous Behavior -
#effective_io_concurrency = 1 # 1-1000. 0 disables prefetching
#------------------------------------------------------------------------------
# WRITE AHEAD LOG
#------------------------------------------------------------------------------
# - Settings -
#wal_level = minimal # minimal, archive, or hot_standby
# (change requires restart)
#fsync = on # turns forced synchronization on or off
#synchronous_commit = on # synchronization level; on, off, or local
#wal_sync_method = fsync # the default is the first option
# supported by the operating system:
# open_datasync
# fdatasync (default on Linux)
# fsync
# fsync_writethrough
# open_sync
#full_page_writes = on # recover from partial page writes
#wal_buffers = -1 # min 32kB, -1 sets based on shared_buffers
# (change requires restart)
#wal_writer_delay = 200ms # 1-10000 milliseconds
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_completion_target = 0.5 # checkpoint target duration, 0.0 - 1.0
#checkpoint_warning = 30s # 0 disables
# - Archiving -
#archive_mode = off # allows archiving to be done
# (change requires restart)
#archive_command = '' # command to use to archive a logfile segment
#archive_timeout = 0 # force a logfile segment switch after this
# number of seconds; 0 disables
#------------------------------------------------------------------------------
# REPLICATION
#------------------------------------------------------------------------------
# - Master Server -
# These settings are ignored on a standby server
#max_wal_senders = 0 # max number of walsender processes
# (change requires restart)
#wal_sender_delay = 1s # walsender cycle time, 1-10000 milliseconds
#wal_keep_segments = 0 # in logfile segments, 16MB each; 0 disables
#vacuum_defer_cleanup_age = 0 # number of xacts by which cleanup is delayed
#replication_timeout = 60s # in milliseconds; 0 disables
#synchronous_standby_names = '' # standby servers that provide sync rep
# comma-separated list of application_name
# from standby(s); '*' = all
# - Standby Servers -
# These settings are ignored on a master server
#hot_standby = off # "on" allows queries during recovery
# (change requires restart)
#max_standby_archive_delay = 30s # max delay before canceling queries
# when reading WAL from archive;
# -1 allows indefinite delay
#max_standby_streaming_delay = 30s # max delay before canceling queries
# when reading streaming WAL;
# -1 allows indefinite delay
#wal_receiver_status_interval = 10s # send replies at least this often
# 0 disables
#hot_standby_feedback = off # send info from standby to prevent
# query conflicts
#------------------------------------------------------------------------------
# QUERY TUNING
#------------------------------------------------------------------------------
# - Planner Method Configuration -
enable_bitmapscan = on
enable_hashagg = on
enable_hashjoin = on
enable_indexscan = on
enable_material = 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 = 512MB
# - 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
geqo_seed = 0.0 # range 0.0-1.0
# - Other Planner Options -
#default_statistics_target = 100 # range 1-10000
#constraint_exclusion = partition # on, off, or partition
#cursor_tuple_fraction = 0.1 # range 0.0-1.0
#from_collapse_limit = 8
#join_collapse_limit = 8 # 1 disables collapsing of explicit
# JOIN clauses
#------------------------------------------------------------------------------
# ERROR REPORTING AND LOGGING
#------------------------------------------------------------------------------
# - Where to Log -
log_destination = 'stderr' # Valid values are combinations of
# stderr, csvlog, syslog, and eventlog,
# depending on platform. csvlog
# requires logging_collector to be on.
# This is used when logging to stderr:
logging_collector = on # Enable capturing of stderr and csvlog
# into log files. Required to be on for
# csvlogs.
# (change requires restart)
# These are only used if logging_collector 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_file_mode = 0777 # creation mode for log files,
# begin with 0 to use octal notation
log_truncate_on_rotation = on # If on, an existing log file with 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 disables.
log_rotation_size = 0 # Automatic rotation of logfiles will
# happen after that much log output.
# 0 disables.
# These are relevant when logging to syslog:
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'
#silent_mode = off # Run server silently.
# DO NOT USE without syslog or
# logging_collector
# (change requires restart)
# - 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 = warning # values in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# info
# notice
# warning
# error
# log
# fatal
# panic
#log_min_error_statement = error # values in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# info
# notice
# warning
# error
# log
# fatal
# panic (effectively off)
#log_min_duration_statement = -1 # -1 is disabled, 0 logs all statements
# and their durations, > 0 logs only
# statements running at least this number
# of milliseconds
# - What to Log -
#debug_print_parse = off
#debug_print_rewritten = off
#debug_print_plan = off
#debug_pretty_print = on
log_checkpoints = off
#log_connections = off
log_disconnections = off
log_duration = off
log_error_verbosity = default # terse, default, or verbose messages
log_hostname = off
#log_line_prefix = '' # special values:
# %a = application name
# %u = user name
# %d = database name
# %r = remote host and port
# %h = remote host
# %p = process ID
# %t = timestamp without milliseconds
# %m = timestamp with milliseconds
# %i = command tag
# %e = SQL state
# %c = session ID
# %l = session line number
# %s = session start timestamp
# %v = virtual transaction ID
# %x = transaction ID (0 if none)
# %q = stop here in non-session
# processes
# %% = '%'
# e.g. '<%u%%%d> '
log_lock_waits = off # log lock waits >= deadlock_timeout
#log_statement = 'none' # none, ddl, mod, all
#log_temp_files = -1 # log temporary files equal or larger
# than the specified size in kilobytes;
# -1 disables, 0 logs all temp files
#log_timezone = '(defaults to server environment setting)'
#------------------------------------------------------------------------------
# RUNTIME STATISTICS
#------------------------------------------------------------------------------
# - Query/Index Statistics Collector -
track_activities = on
track_counts = on
track_functions = none # none, pl, all
track_activity_query_size = 1024 # (change requires restart)
update_process_title = on
stats_temp_directory = 'pg_stat_tmp'
# - 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 track_counts to also be on.
log_autovacuum_min_duration = -1 # -1 disables, 0 logs all actions and
# their durations, > 0 logs only
# actions running at least this number
# of milliseconds.
autovacuum_max_workers = 3 # max number of autovacuum subprocesses
# (change requires restart)
autovacuum_naptime = 1min # time between autovacuum runs
autovacuum_vacuum_threshold = 50 # min number of row updates before
# vacuum
autovacuum_analyze_threshold = 50 # min number of row updates before
# analyze
autovacuum_vacuum_scale_factor = 0.2 # fraction of table size before vacuum
autovacuum_analyze_scale_factor = 0.1 # fraction of table size before analyze
autovacuum_freeze_max_age = 200000000 # maximum XID age before forced vacuum
# (change requires restart)
autovacuum_vacuum_cost_delay = 20ms # default vacuum cost delay for
# autovacuum, in milliseconds;
# -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 = '"$user",public' # schema names
default_tablespace = '' # a tablespace name, '' uses the default
temp_tablespaces = '' # a list of tablespace names, '' uses
# only default tablespace
check_function_bodies = on
default_transaction_isolation = 'read committed'
default_transaction_read_only = off
default_transaction_deferrable = off
session_replication_role = 'origin'
statement_timeout = 0 # in milliseconds, 0 is disabled
vacuum_freeze_min_age = 50000000
vacuum_freeze_table_age = 150000000
bytea_output = 'hex' # hex, escape
xmlbinary = 'base64'
xmloption = 'content'
# - Locale and Formatting -
datestyle = 'iso, mdy'
#intervalstyle = 'postgres'
#timezone = '(defaults to server environment setting)'
#timezone_abbreviations = 'Default' # Select the set of available time zone
# abbreviations. Currently, there are
# Default
# Australia
# India
# You can create your own file in
# share/timezonesets/.
#extra_float_digits = 0 # min -15, max 3
#client_encoding = sql_ascii # actually, defaults to database
# encoding
# These settings are initialized by initdb, but they can be changed.
lc_messages = 'en_US.UTF-8' # locale for system error message
# strings
lc_monetary = 'en_US.UTF-8' # locale for monetary formatting
lc_numeric = 'en_US.UTF-8' # locale for number formatting
lc_time = 'en_US.UTF-8' # locale for time formatting
# default configuration for text search
default_text_search_config = 'pg_catalog.english'
# - Other Defaults -
#dynamic_library_path = '$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.
max_pred_locks_per_transaction = 64 # min 10
# (change requires restart)
#------------------------------------------------------------------------------
# VERSION/PLATFORM COMPATIBILITY
#------------------------------------------------------------------------------
# - Previous PostgreSQL Versions -
#array_nulls = on
#backslash_quote = safe_encoding # on, off, or safe_encoding
#default_with_oids = off
#escape_string_warning = on
#lo_compat_privileges = off
#quote_all_identifiers = off
#sql_inheritance = on
#standard_conforming_strings = on
#synchronize_seqscans = on
# - Other Platforms and Clients -
#transform_null_equals = off
#------------------------------------------------------------------------------
# ERROR HANDLING
#------------------------------------------------------------------------------
exit_on_error = off # terminate session on any error?
restart_after_crash = on # reinitialize after backend crash?
#------------------------------------------------------------------------------
# CUSTOMIZED OPTIONS
#------------------------------------------------------------------------------
custom_variable_classes = '' # list of custom variable class names
这是 pg_hba.conf 文件：
local all postgres trust
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all trust
host all postgres 192.168.1.0/24 trust
host all all 127.0.0.0/24 trust
我尝试启用/禁用自动真空，禁用日志记录等。M 系统有 8 个 CPU 和 3GB 内存，我有 1 TB 的专用空间用于此 SQL 服务器。
任何想法和帮助都值得赞赏。
注意：此页面不能解决我的问题。
结论：获取PGPool-II 3.x.非常容易设置(如答案中所述(并且非常快！
有趣的是，MySQL在建立连接方面已经更快了。在像PHP这样的环境中，连接被设置和拆除的速度如此之快，而不是在Rails或JVM等应用程序环境中运行时间更长的连接。
在这种情况下，对 Postgres 使用连接池可能是有意义的。我想到了两个：
PGPool-II： http://www.pgpool.net/mediawiki/index.php/Main_Page
保镖：http://pgfoundry.org/projects/pgbouncer/
我使用过PGPool-II，它很容易设置。
嗯....我不是这里的专家，但您是否不想将 hba 绑定到 NIC 或本地主机而不是网络？
在 Windows 机器上，
# IPv4 local connections:
host all all 127.0.0.1/32 md5
# IPv6 local connections:
host all all ::1/128 md5
您有多少内存？ 多少虚拟内存？ 如果 VM 变得太大，可能会降低计算机的速度。 但有时你只是需要它。
我对PostgreSQL了解不多，但我可以告诉你为什么MySQL对于这个特定的查询速度很快。
使用 InnoDB，主键索引是聚集索引，这意味着页面以与主键相同的物理顺序存储。
最后，当你请求ORDER BY DESC时，MySQL只是向后读取索引，所以性能与ASC相同。