Postgresql 中文操作指南
pg_dumpall
pg_dumpall — 将 PostgreSQL 数据库群集提取到脚本文件中
pg_dumpall — extract a PostgreSQL database cluster into a script file
Synopsis
pg_dumpall [ connection-option …] [ option …]
pg_dumpall [connection-option…] [option…]
Description
pg_dumpall 是一个将群集中的所有 PostgreSQL 数据库写入(“转储”)一个脚本文件的实用程序。脚本文件包含 SQL 命令,这些命令可用作 psql 的输入,以还原数据库。它通过为群集中的每个数据库调用 pg_dump 来执行此操作。pg_dumpall 还会转储所有数据库共有的全局对象,即数据库角色、表空间和配置参数的特权授予。(pg_dump 不会保存这些对象。)
pg_dumpall is a utility for writing out (“dumping”) all PostgreSQL databases of a cluster into one script file. The script file contains SQL commands that can be used as input to psql to restore the databases. It does this by calling pg_dump for each database in the cluster. pg_dumpall also dumps global objects that are common to all databases, namely database roles, tablespaces, and privilege grants for configuration parameters. (pg_dump does not save these objects.)
由于 pg_dumpall 需从所有数据库读取表,因此为了生成完整的转储文件,你很可能必须以数据库超级用户的身份连接。此外,你需要超级用户特权才能执行已保存的脚本,以便被允许添加角色和创建数据库。
Since pg_dumpall reads tables from all databases you will most likely have to connect as a database superuser in order to produce a complete dump. Also you will need superuser privileges to execute the saved script in order to be allowed to add roles and create databases.
SQL 脚本将被写到标准输出。使用 -f / —file 选项或 shell 运维符将它重定向到一个文件中。
The SQL script will be written to the standard output. Use the -f/—file option or shell operators to redirect it into a file.
pg_dumpall 需要连接到 PostgreSQL 服务器多次(每个数据库一次)。如果你使用密码身份验证,则它每次都会要求输入密码。在这些情况下,使用 ~/.pgpass 文件会比较方便。有关更多信息,请参阅 Section 34.16 。
pg_dumpall needs to connect several times to the PostgreSQL server (once per database). If you use password authentication it will ask for a password each time. It is convenient to have a ~/.pgpass file in such cases. See Section 34.16 for more information.
Options
以下命令行选项控制输出的内容和格式。
The following command-line options control the content and format of the output.
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-a_—data-only_
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Dump only the data, not the schema (data definitions).
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-c_—clean_
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Emit SQL commands to DROP all the dumped databases, roles, and tablespaces before recreating them. This option is useful when the restore is to overwrite an existing cluster. If any of the objects do not exist in the destination cluster, ignorable error messages will be reported during restore, unless —if-exists is also specified.
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-E _encoding—encoding=_encoding
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Create the dump in the specified character set encoding. By default, the dump is created in the database encoding. (Another way to get the same result is to set the PGCLIENTENCODING environment variable to the desired dump encoding.)
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-f _filename—file=_filename
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Send output to the specified file. If this is omitted, the standard output is used.
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-g_—globals-only_
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Dump only global objects (roles and tablespaces), no databases.
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-O_—no-owner_
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Do not output commands to set ownership of objects to match the original database. By default, pg_dumpall issues ALTER OWNER or SET SESSION AUTHORIZATION statements to set ownership of created schema elements. These statements will fail when the script is run unless it is started by a superuser (or the same user that owns all of the objects in the script). To make a script that can be restored by any user, but will give that user ownership of all the objects, specify -O.
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-r_—roles-only_
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Dump only roles, no databases or tablespaces.
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-s_—schema-only_
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Dump only the object definitions (schema), not data.
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-S _username—superuser=_username
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Specify the superuser user name to use when disabling triggers. This is relevant only if —disable-triggers is used. (Usually, it’s better to leave this out, and instead start the resulting script as superuser.)
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-t_—tablespaces-only_
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Dump only tablespaces, no databases or roles.
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-v_—verbose_
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Specifies verbose mode. This will cause pg_dumpall to output start/stop times to the dump file, and progress messages to standard error. Repeating the option causes additional debug-level messages to appear on standard error. The option is also passed down to pg_dump.
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-V_—version_
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Print the pg_dumpall version and exit.
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-x—no-privileges_—no-acl_
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Prevent dumping of access privileges (grant/revoke commands).
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—binary-upgrade
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This option is for use by in-place upgrade utilities. Its use for other purposes is not recommended or supported. The behavior of the option may change in future releases without notice.
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—column-inserts_—attribute-inserts_
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Dump data as INSERT commands with explicit column names (INSERT INTO _table (column, …) VALUES …_). This will make restoration very slow; it is mainly useful for making dumps that can be loaded into non-PostgreSQL databases.
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—disable-dollar-quoting
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This option disables the use of dollar quoting for function bodies, and forces them to be quoted using SQL standard string syntax.
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—disable-triggers
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This option is relevant only when creating a data-only dump. It instructs pg_dumpall to include commands to temporarily disable triggers on the target tables while the data is restored. Use this if you have referential integrity checks or other triggers on the tables that you do not want to invoke during data restore.
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Presently, the commands emitted for —disable-triggers must be done as superuser. So, you should also specify a superuser name with -S, or preferably be careful to start the resulting script as a superuser.
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—exclude-database=_pattern_
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Do not dump databases whose name matches pattern. Multiple patterns can be excluded by writing multiple —exclude-database switches. The pattern parameter is interpreted as a pattern according to the same rules used by psql’s \d commands (see Patterns), so multiple databases can also be excluded by writing wildcard characters in the pattern. When using wildcards, be careful to quote the pattern if needed to prevent shell wildcard expansion.
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—extra-float-digits=_ndigits_
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Use the specified value of extra_float_digits when dumping floating-point data, instead of the maximum available precision. Routine dumps made for backup purposes should not use this option.
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—if-exists
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Use DROP … IF EXISTS commands to drop objects in —clean mode. This suppresses “does not exist” errors that might otherwise be reported. This option is not valid unless —clean is also specified.
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—inserts
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Dump data as INSERT commands (rather than COPY). This will make restoration very slow; it is mainly useful for making dumps that can be loaded into non-PostgreSQL databases. Note that the restore might fail altogether if you have rearranged column order. The —column-inserts option is safer, though even slower.
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—load-via-partition-root
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When dumping data for a table partition, make the COPY or INSERT statements target the root of the partitioning hierarchy that contains it, rather than the partition itself. This causes the appropriate partition to be re-determined for each row when the data is loaded. This may be useful when restoring data on a server where rows do not always fall into the same partitions as they did on the original server. That could happen, for example, if the partitioning column is of type text and the two systems have different definitions of the collation used to sort the partitioning column.
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—lock-wait-timeout=_timeout_
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Do not wait forever to acquire shared table locks at the beginning of the dump. Instead, fail if unable to lock a table within the specified timeout. The timeout may be specified in any of the formats accepted by SET statement_timeout.
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—no-comments
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Do not dump comments.
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—no-publications
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Do not dump publications.
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—no-role-passwords
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Do not dump passwords for roles. When restored, roles will have a null password, and password authentication will always fail until the password is set. Since password values aren’t needed when this option is specified, the role information is read from the catalog view pg_roles instead of pg_authid. Therefore, this option also helps if access to pg_authid is restricted by some security policy.
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—no-security-labels
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Do not dump security labels.
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—no-subscriptions
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Do not dump subscriptions.
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—no-sync
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By default, pg_dumpall will wait for all files to be written safely to disk. This option causes pg_dumpall to return without waiting, which is faster, but means that a subsequent operating system crash can leave the dump corrupt. Generally, this option is useful for testing but should not be used when dumping data from production installation.
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—no-table-access-method
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Do not output commands to select table access methods. With this option, all objects will be created with whichever table access method is the default during restore.
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—no-tablespaces
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Do not output commands to create tablespaces nor select tablespaces for objects. With this option, all objects will be created in whichever tablespace is the default during restore.
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—no-toast-compression
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Do not output commands to set TOAST compression methods. With this option, all columns will be restored with the default compression setting.
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—no-unlogged-table-data
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Do not dump the contents of unlogged tables. This option has no effect on whether or not the table definitions (schema) are dumped; it only suppresses dumping the table data.
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—on-conflict-do-nothing
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Add ON CONFLICT DO NOTHING to INSERT commands. This option is not valid unless —inserts or —column-inserts is also specified.
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—quote-all-identifiers
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Force quoting of all identifiers. This option is recommended when dumping a database from a server whose PostgreSQL major version is different from pg_dumpall’s, or when the output is intended to be loaded into a server of a different major version. By default, pg_dumpall quotes only identifiers that are reserved words in its own major version. This sometimes results in compatibility issues when dealing with servers of other versions that may have slightly different sets of reserved words. Using —quote-all-identifiers prevents such issues, at the price of a harder-to-read dump script.
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—rows-per-insert=_nrows_
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Dump data as INSERT commands (rather than COPY). Controls the maximum number of rows per INSERT command. The value specified must be a number greater than zero. Any error during restoring will cause only rows that are part of the problematic INSERT to be lost, rather than the entire table contents.
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—use-set-session-authorization
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Output SQL-standard SET SESSION AUTHORIZATION commands instead of ALTER OWNER commands to determine object ownership. This makes the dump more standards compatible, but depending on the history of the objects in the dump, might not restore properly.
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-?_—help_
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Show help about pg_dumpall command line arguments, and exit.
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以下命令行选项控制数据库连接参数。
The following command-line options control the database connection parameters.
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-d _connstr—dbname=_connstr
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Specifies parameters used to connect to the server, as a connection string; these will override any conflicting command line options.
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The option is called —dbname for consistency with other client applications, but because pg_dumpall needs to connect to many databases, the database name in the connection string will be ignored. Use the -l option to specify the name of the database used for the initial connection, which will dump global objects and discover what other databases should be dumped.
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-h _host—host=_host
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Specifies the host name of the machine on which the database server is running. If the value begins with a slash, it is used as the directory for the Unix domain socket. The default is taken from the PGHOST environment variable, if set, else a Unix domain socket connection is attempted.
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-l _dbname—database=_dbname
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Specifies the name of the database to connect to for dumping global objects and discovering what other databases should be dumped. If not specified, the postgres database will be used, and if that does not exist, template1 will be used.
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-p _port—port=_port
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Specifies the TCP port or local Unix domain socket file extension on which the server is listening for connections. Defaults to the PGPORT environment variable, if set, or a compiled-in default.
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-U _username—username=_username
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User name to connect as.
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-w_—no-password_
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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.
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-W_—password_
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Force pg_dumpall to prompt for a password before connecting to a database.
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This option is never essential, since pg_dumpall will automatically prompt for a password if the server demands password authentication. However, pg_dumpall 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.
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Note that the password prompt will occur again for each database to be dumped. Usually, it’s better to set up a ~/.pgpass file than to rely on manual password entry.
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—role=_rolename_
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Specifies a role name to be used to create the dump. This option causes pg_dumpall to issue a SET ROLE rolename command after connecting to the database. It is useful when the authenticated user (specified by -U) lacks privileges needed by pg_dumpall, but can switch to a role with the required rights. Some installations have a policy against logging in directly as a superuser, and use of this option allows dumps to be made without violating the policy.
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Environment
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PGHOST_PGOPTIONS_PGPORT__PGUSER
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Default connection parameters
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PG_COLOR
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Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.
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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).
Notes
由于 pg_dumpall 在内部调用了 pg_dump,因此某些诊断消息将引用 pg_dump。
Since pg_dumpall calls pg_dump internally, some diagnostic messages will refer to pg_dump.
即使您打算将备份脚本恢复到一个全新的群集, —clean 选项仍然很有用。使用 —clean 授权脚本删除并重新创建内置的 postgres 和 template1 数据库,以确保这些数据库保留与源群集相同的属性(例如语言环境和编码)。没有这个选项,这些数据库将保留其现有的数据库级别属性,以及所有已存在的数据库内容。
The —clean option can be useful even when your intention is to restore the dump script into a fresh cluster. Use of —clean authorizes the script to drop and re-create the built-in postgres and template1 databases, ensuring that those databases will retain the same properties (for instance, locale and encoding) that they had in the source cluster. Without the option, those databases will retain their existing database-level properties, as well as any pre-existing contents.
恢复后,最好对每个数据库运行 ANALYZE ,以便优化器获取有用的统计信息。您还可以运行 vacuumdb -a -z 来分析所有数据库。
Once restored, it is wise to run ANALYZE on each database so the optimizer has useful statistics. You can also run vacuumdb -a -z to analyze all databases.
不应期望备份脚本完全运行不会出现错误。特别是,由于该脚本将为源群集中存在的每个角色发出 CREATE ROLE ,因此,除非目标群集使用不同的 bootstrap 超级用户名称初始化,否则肯定会获得“角色已存在”错误,这是针对 bootstrap 超级用户来说的。该错误无害,应当予以忽略。使用 —clean 选项可能会生成有关不存在的对象的其他无害错误消息,但您可以通过添加 —if-exists 来将这些消息最小化。
The dump script should not be expected to run completely without errors. In particular, because the script will issue CREATE ROLE for every role existing in the source cluster, it is certain to get a “role already exists” error for the bootstrap superuser, unless the destination cluster was initialized with a different bootstrap superuser name. This error is harmless and should be ignored. Use of the —clean option is likely to produce additional harmless error messages about non-existent objects, although you can minimize those by adding —if-exists.
在恢复之前,pg_dumpall 要求有所有需要的表空间目录;否则,不在默认位置的数据库的数据库创建将会失败。
pg_dumpall requires all needed tablespace directories to exist before the restore; otherwise, database creation will fail for databases in non-default locations.
Examples
要备份所有数据库:
To dump all databases:
$ pg_dumpall > db.out
要从此文件恢复数据库,您可以使用:
To restore database(s) from this file, you can use:
$ psql -f db.out postgres
将连接到哪个数据库并不重要,因为由 pg_dumpall 创建的脚本文件将包含适当的命令,以创建并连接到已保存的数据库。例外情况是,如果您指定了 —clean ,那么您必须首先连接到 postgres 数据库;脚本将尝试立即删除其他数据库,而这对于您已连接到的数据库会失败。
It is not important to which database you connect here since the script file created by pg_dumpall will contain the appropriate commands to create and connect to the saved databases. An exception is that if you specified —clean, you must connect to the postgres database initially; the script will attempt to drop other databases immediately, and that will fail for the database you are connected to.