Postgresql 中文操作指南

vacuumdb

vacuumdb — 清理和分析 PostgreSQL 数据库

vacuumdb — garbage-collect and analyze a PostgreSQL database

Synopsis

vacuumdb [ connection-option …​] [ option …​] [ -t | —​table table [( column [,…​] )] ] …​ [ dbname ]

vacuumdb [connection-option…​] [option…​] [ -t | —​table table [( column [,…​] )] ] …​ [dbname]

vacuumdb [ connection-option …​] [ option …​] [ [ -n | —​schema schema ] | [ -N | —​exclude-schema schema ] ] …​ [ dbname ]

vacuumdb [connection-option…​] [option…​] [ [ -n | —​schema schema ] | [ -N | —​exclude-schema schema ] ] …​ [dbname]

vacuumdb [ connection-option …​] [ option …​] -a | —​all

vacuumdb [connection-option…​] [option…​] -a | —​all

Description

vacuumdb 是用于清理 PostgreSQL 数据库的实用程序。vacuumdb 还可以生成 PostgreSQL 查询优化器使用的内部统计信息。

vacuumdb is a utility for cleaning a PostgreSQL database. vacuumdb will also generate internal statistics used by the PostgreSQL query optimizer.

vacuumdb 是一个包装器，用于包裹 SQL 命令 VACUUM 。通过此实用程序和通过其他方法访问服务器来清理和分析数据库，中间没有任何有效差异。

vacuumdb is a wrapper around the SQL command VACUUM. There is no effective difference between vacuuming and analyzing databases via this utility and via other methods for accessing the server.

Options

vacuumdb 接受以下命令行参数：

vacuumdb accepts the following command-line arguments:

  • -a_—​all_

    • Vacuum all databases.

  • —​buffer-usage-limit _size_

    • Specifies the [role="bare"]glossary.html#GLOSSARY-BUFFER-ACCESS-STRATEGYBuffer Access Strategy ring buffer size for a given invocation of vacuumdb. This size is used to calculate the number of shared buffers which will be reused as part of this strategy. See VACUUM.

  • [-d] _dbname[--dbname=]_dbname

    • Specifies the name of the database to be cleaned or analyzed, when -a/—​all is not used. If this is not specified, the database name is read from the environment variable PGDATABASE. If that is not set, the user name specified for the connection is used. The dbname can be a connection string. If so, connection string parameters will override any conflicting command line options.

  • —​disable-page-skipping

    • Disable skipping pages based on the contents of the visibility map.

  • -e_—​echo_

    • Echo the commands that vacuumdb generates and sends to the server.

  • -f_—​full_

    • Perform “full” vacuuming.

  • -F_—​freeze_

    • Aggressively “freeze” tuples.

  • —​force-index-cleanup

    • Always remove index entries pointing to dead tuples.

  • -j _njobs—​jobs=_njobs

    • Execute the vacuum or analyze commands in parallel by running njobs commands simultaneously. This option may reduce the processing time but it also increases the load on the database server.

    • vacuumdb will open njobs connections to the database, so make sure your max_connections setting is high enough to accommodate all connections.

    • Note that using this mode together with the -f (FULL) option might cause deadlock failures if certain system catalogs are processed in parallel.

  • —​min-mxid-age _mxid_age_

    • Only execute the vacuum or analyze commands on tables with a multixact ID age of at least mxid_age. This setting is useful for prioritizing tables to process to prevent multixact ID wraparound (see Section 25.1.5.1).

    • For the purposes of this option, the multixact ID age of a relation is the greatest of the ages of the main relation and its associated TOAST table, if one exists. Since the commands issued by vacuumdb will also process the TOAST table for the relation if necessary, it does not need to be considered separately.

  • —​min-xid-age _xid_age_

    • Only execute the vacuum or analyze commands on tables with a transaction ID age of at least xid_age. This setting is useful for prioritizing tables to process to prevent transaction ID wraparound (see Section 25.1.5).

    • For the purposes of this option, the transaction ID age of a relation is the greatest of the ages of the main relation and its associated TOAST table, if one exists. Since the commands issued by vacuumdb will also process the TOAST table for the relation if necessary, it does not need to be considered separately.

  • -n _schema—​schema=_schema

    • Clean or analyze all tables in schema only. Multiple schemas can be vacuumed by writing multiple -n switches.

  • -N _schema—​exclude-schema=_schema

    • Do not clean or analyze any tables in schema. Multiple schemas can be excluded by writing multiple -N switches.

  • —​no-index-cleanup

    • Do not remove index entries pointing to dead tuples.

  • —​no-process-main

    • Skip the main relation.

  • —​no-process-toast

    • Skip the TOAST table associated with the table to vacuum, if any.

  • —​no-truncate

    • Do not truncate empty pages at the end of the table.

  • -P _parallel_workers—​parallel=_parallel_workers

    • Specify the number of parallel workers for parallel vacuum. This allows the vacuum to leverage multiple CPUs to process indexes. See VACUUM.

  • -q_—​quiet_

    • Do not display progress messages.

  • —​skip-locked

    • Skip relations that cannot be immediately locked for processing.

  • -t _table [ (column [,…​]) ]—​table=_table [ (column_ [,…​]) ]_

    • Clean or analyze table only. Column names can be specified only in conjunction with the —​analyze or —​analyze-only options. Multiple tables can be vacuumed by writing multiple -t switches.

  • -v_—​verbose_

    • Print detailed information during processing.

  • -V_—​version_

    • Print the vacuumdb version and exit.

  • -z_—​analyze_

    • Also calculate statistics for use by the optimizer.

  • -Z_—​analyze-only_

    • Only calculate statistics for use by the optimizer (no vacuum).

  • —​analyze-in-stages

    • Only calculate statistics for use by the optimizer (no vacuum), like —​analyze-only. Run three stages of analyze; the first stage uses the lowest possible statistics target (see default_statistics_target) to produce usable statistics faster, and subsequent stages build the full statistics.

    • This option is only useful to analyze a database that currently has no statistics or has wholly incorrect ones, such as if it is newly populated from a restored dump or by pg_upgrade. Be aware that running with this option in a database with existing statistics may cause the query optimizer choices to become transiently worse due to the low statistics targets of the early stages.

  • -?_—​help_

    • Show help about vacuumdb command line arguments, and exit.

Tip

如果您指定列，则可能必须对括号使用转义符。 （请参见以下示例。）

If you specify columns, you probably have to escape the parentheses from the shell. (See examples below.)

vacuumdb 还接受以下用于连接参数的命令行参数：

vacuumdb also accepts the following command-line arguments for connection parameters:

  • -h _host—​host=_host

    • Specifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix domain socket.

  • -p _port—​port=_port

    • Specifies the TCP port or local Unix domain socket file extension on which the server is listening for connections.

  • -U _username—​username=_username

    • User name to connect as.

  • -w_—​no-password_

    • Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as a .pgpass file, the connection attempt will fail. This option can be useful in batch jobs and scripts where no user is present to enter a password.

  • -W_—​password_

    • Force vacuumdb to prompt for a password before connecting to a database.

    • This option is never essential, since vacuumdb will automatically prompt for a password if the server demands password authentication. However, vacuumdb will waste a connection attempt finding out that the server wants a password. In some cases it is worth typing -W to avoid the extra connection attempt.

  • —​maintenance-db=_dbname_

    • Specifies the name of the database to connect to to discover which databases should be vacuumed, when -a/—​all is used. If not specified, the postgres database will be used, or if that does not exist, template1 will be used. This can be a connection string. If so, connection string parameters will override any conflicting command line options. Also, connection string parameters other than the database name itself will be re-used when connecting to other databases.

Environment

  • PGDATABASE_PGHOST_PGPORT__PGUSER

    • Default connection parameters

  • PG_COLOR

    • Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

此实用程序与大多数其他 PostgreSQL 实用程序一样，还使用 libpq 支持的环境变量（请参阅 Section 34.15 ）。

This utility, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see Section 34.15).

Diagnostics

如果遇到困难，请参见 VACUUM 和 psql ，以了解有关潜在问题和错误消息的讨论。数据库服务器必须在目标主机上运行。此外，libpq 前端库使用的任何默认连接设置和环境变量都将应用。

In case of difficulty, see VACUUM and psql for discussions of potential problems and error messages. The database server must be running at the targeted host. Also, any default connection settings and environment variables used by the libpq front-end library will apply.

Notes

vacuumdb 可能需要连接到 PostgreSQL 服务器多次，每次都要求输入密码。在这种情况下，方便使用 ~/.pgpass 文件。有关详细信息，请参见 Section 34.16 。

vacuumdb might need to connect several times to the PostgreSQL server, asking for a password each time. It is convenient to have a ~/.pgpass file in such cases. See Section 34.16 for more information.

Examples

清理数据库 test ：

To clean the database test:

$ vacuumdb test

清理并为名为 bigdb 的数据库分析优化器：

To clean and analyze for the optimizer a database named bigdb:

$ vacuumdb --analyze bigdb

清理名为 xyzzy 的数据库中的单个表 foo ，并为优化器分析表的单列 bar ：

To clean a single table foo in a database named xyzzy, and analyze a single column bar of the table for the optimizer:

$ vacuumdb --analyze --verbose --table='foo(bar)' xyzzy

清理名为 xyzzy 的数据库中 foo 和 bar 架构中的所有表：

To clean all tables in the foo and bar schemas in a database named xyzzy:

$ vacuumdb --schema='foo' --schema='bar' xyzzy

See Also

VACUUM

VACUUM