Performance Postgresql.conf变量

我已经玩了几天postgresql.conf文件了。我想知道你们喜欢定制什么变量，为什么

以下是该文件的示例：

# - 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 = 64MB           # 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 = 204800          # 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 = '$libdir/plugins/plugin_debugger.dll'        # (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        # 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


#------------------------------------------------------------------------------
# WRITE AHEAD LOG
#------------------------------------------------------------------------------

# - Settings -

#fsync = on             # turns forced synchronization on or off
#synchronous_commit = on        # immediate fsync at commit
#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)
#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 is off

# - 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
                # time; 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 = 32768

# - 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 
                    # 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-%Y-%m-%d_%H%M%S.log'    # log file name pattern,
                    # can include strftime() escapes
#log_truncate_on_rotation = off     # If on, an 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 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 time.

#silent_mode = off          # DO NOT USE without syslog or
                    # logging_collector
                    # (change requires restart)

# - What to Log -

#debug_print_parse = off
#debug_print_rewritten = off
#debug_print_plan = off
#debug_pretty_print = off
#log_checkpoints = off
#log_connections = off
#log_disconnections = off
#log_duration = off
#log_hostname = off
log_line_prefix = '%t '         # special values:
                    #   %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
                    #   %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 specified size;
                    # -1 disables, 0 logs all temp files
#log_timezone = unknown         # actually, defaults to TZ environment
                    # setting


#------------------------------------------------------------------------------
# RUNTIME STATISTICS
#------------------------------------------------------------------------------

# - Query/Index Statistics Collector -

#track_activities = on
#track_counts = on
#update_process_title = on


# - 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 that time.
#autovacuum_max_workers = 3     # max number of autovacuum subprocesses
#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 = 20  # 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
#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
#session_replication_role = 'origin'
#statement_timeout = 0          # 0 is disabled
#vacuum_freeze_min_age = 100000000
#xmlbinary = 'base64'
#xmloption = 'content'

# - Locale and Formatting -

datestyle = 'iso, dmy'
#timezone = unknown         # actually, defaults to TZ 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 2
#client_encoding = sql_ascii        # actually, defaults to database
                    # encoding

# These settings are initialized by initdb, but they can be changed.
lc_messages = 'English_Canada'          # locale for system error message
                    # strings
lc_monetary = 'English_Canada'          # locale for monetary formatting
lc_numeric = 'English_Canada'           # locale for number formatting
lc_time = 'English_Canada'              # locale for time formatting

# default configuration for text search
default_text_search_config = 'pg_catalog.english'

# - 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 PostgreSQL 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
#regex_flavor = advanced        # advanced, extended, or basic
#sql_inheritance = on
#standard_conforming_strings = off
#synchronize_seqscans = on

# - Other Platforms and Clients -

#transform_null_equals = off

#-TCP保持活动-
#有关详细信息，请参阅“man 7 tcp”
#tcp_keepalives_idle=0#tcp_KEEPIDLE，以秒为单位；
#0选择系统默认值
#tcp_keepalives_interval=0#tcp_KEEPINTVL，以秒为单位；
#0选择系统默认值
#tcp_keepalives_count=0#tcp_keepnt；
#0选择系统默认值
#------------------------------------------------------------------------------
#资源使用情况（WAL除外）
#------------------------------------------------------------------------------
#-记忆-
共享缓冲区=64MB#最小128kB或最大连接数*16kB
#（更改需要重新启动）
#温度缓冲区=8MB最小800kB
#max_prepared_transactions=5#可以是0或更多
#（更改需要重新启动）
#注意：增加max_prepared_事务需要约600字节的共享内存
#每个事务插槽，加上锁空间（请参阅每个事务的最大锁数）。
#工作内存=1MB最小64kB
#维护工作内存=16MB最小1MB
#最大堆栈深度=2MB最小100kB
#-自由空间地图-
max_fsm_pages=204800#min max_fsm_关系*16，每个6字节
#（更改需要重新启动）
#最大fsm_关系=1000#最小100，~70字节
#（更改需要重新启动）
#-内核资源使用-
#每个进程的最大文件数=1000，最小25
#（更改需要重新启动）
shared_preload_libraries='$libdir/plugins/plugin_debugger.dll'#（更改需要重新启动）
#-基于成本的真空延迟-
#真空成本延迟=0-1000毫秒
#吸尘器成本页面点击率=1#0-10000学分
#真空成本页面未命中率=10#0-10000学分
#真空成本页面脏=20#0-10000学分
#真空成本限额=200#1-10000学分
#-背景作家-
#BGU延迟=200ms#10-10000ms
#bgwriter_lru_maxpages=100#0-1000最大写入缓冲区/轮
#bgwriter_lru_乘数=2.0#0-10.0缓冲器上的乘数扫描/取整
#------------------------------------------------------------------------------
#预写日志
#------------------------------------------------------------------------------
#-设置-
#fsync=on#打开或关闭强制同步
#synchronous_commit=on#提交时立即fsync
#wal_sync_method=fsync#默认为第一个选项
#由操作系统支持：
#开放式数据同步
#数据同步
#同步
#fsync_writethrough
#开放式同步
#完整页面写入=打开#从部分页面写入恢复
#wal_缓冲区=64kB#最小32kB
#（更改需要重新启动）
#wal_writer_延迟=200ms#1-10000毫秒
#提交延迟=0#范围0-100000，以微秒为单位
#提交兄弟姐妹=5#范围1-1000
#-检查站-
#检查点_段=3#在日志文件段中，每个段的最小值为1，16MB
#检查点超时=5分钟#范围30s-1h
#检查点_完成_目标=0.5#检查点目标持续时间，0.0-1.0
#检查点警告=30s#0关闭
#-存档-
#归档模式=关闭#允许进行归档
#（更改需要重新启动）
#archive_command=''用于归档日志文件段的命令
#存档超时=0#在此之后强制切换日志文件段
#时间；0关闭
#------------------------------------------------------------------------------
#查询调优
#------------------------------------------------------------------------------
#-规划器方法配置-
#启用\u bitmapscan=on
#启用\u hashagg=on
#启用\u hashjoin=on
#启用_indexscan=on
#启用\u mergejoin=on
#启用_nestloop=on
#启用\u seqscan=on
#启用\排序=打开
#启用\u tidscan=on
#-规划师成本常量-
#seq_page_cost=1.0#按任意比例测量
#随机页面成本=4.0#与上述比例相同
#cpu单元成本=0.01#与上述规模相同
#cpu_指数_元组_成本=0.005#与上述规模相同
#cpu_操作员_成本=0.0025#与上述规模相同
有效缓存大小=32768
#-遗传查询优化器-
#geqo=on
#geqo_阈值=12
#geqo_努力=5#范围1-10
#geqo_pool_size=0#根据工作量选择默认值
#geqo_generations=0#根据工作量选择默认值
#geqo_选择_偏差=2.0#范围1.5-2.0
#-其他规划器选项-
#默认_统计_目标=10#范围1-1000
#约束\排除=关闭
#从\u折叠\u限制=8
#join_collapse_limit=8#1禁用显式
#连接子句
#------------------------------------------------------------------------------
#错误报告和日志记录
#------------------------------------------------------------------------------
#-在哪里登录-
log_destination='stderr'#有效值是
#stderr、csvlog、syslog和eventlog，
#取决于平台。csvlog
#需要打开日志\u收集器。
#这在登录到stderr时使用：
日志记录_collector=on#启用对stderr和csvlog的捕获
#进入日志文件。需要打开的
#csvlogs。
#（更改需要重新启动）
#仅当logging_collector打开时才使用这些选项：
#log_directory='pg_log'#写入日志文件的目录，
#可以是绝对的，也可以是相对于PGDATA的
#日志文件名='postgresql-%Y-%m-%d\uh