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| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>pg_basebackup</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="app-pgamcheck.html" title="pg_amcheck" /><link rel="next" href="pgbench.html" title="pgbench" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center"><span class="application">pg_basebackup</span></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="app-pgamcheck.html" title="pg_amcheck">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="reference-client.html" title="PostgreSQL Client Applications">Up</a></td><th width="60%" align="center">PostgreSQL Client Applications</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="pgbench.html" title="pgbench">Next</a></td></tr></table><hr /></div><div class="refentry" id="APP-PGBASEBACKUP"><div class="titlepage"></div><a id="id-1.9.4.10.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle"><span class="application">pg_basebackup</span></span></h2><p>pg_basebackup — take a base backup of a <span class="productname">PostgreSQL</span> cluster</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p id="id-1.9.4.10.4.1"><code class="command">pg_basebackup</code> [<em class="replaceable"><code>option</code></em>...]</p></div></div><div class="refsect1" id="id-1.9.4.10.5"><h2>Description</h2><p> |
| <span class="application">pg_basebackup</span> is used to take a base backup of |
| a running <span class="productname">PostgreSQL</span> database cluster. The backup |
| is taken without affecting other clients of the database, and can be used |
| both for point-in-time recovery (see <a class="xref" href="continuous-archiving.html" title="26.3. Continuous Archiving and Point-in-Time Recovery (PITR)">Section 26.3</a>) |
| and as the starting point for a log-shipping or streaming-replication standby |
| server (see <a class="xref" href="warm-standby.html" title="27.2. Log-Shipping Standby Servers">Section 27.2</a>). |
| </p><p> |
| <span class="application">pg_basebackup</span> makes an exact copy of the database |
| cluster's files, while making sure the server is put into and |
| out of backup mode automatically. Backups are always taken of the entire |
| database cluster; it is not possible to back up individual databases or |
| database objects. For selective backups, another tool such as |
| <a class="xref" href="app-pgdump.html" title="pg_dump"><span class="refentrytitle"><span class="application">pg_dump</span></span></a> must be used. |
| </p><p> |
| The backup is made over a regular <span class="productname">PostgreSQL</span> |
| connection that uses the replication protocol. The connection must be made |
| with a user ID that has <code class="literal">REPLICATION</code> permissions |
| (see <a class="xref" href="role-attributes.html" title="22.2. Role Attributes">Section 22.2</a>) or is a superuser, |
| and <a class="link" href="auth-pg-hba-conf.html" title="21.1. The pg_hba.conf File"><code class="filename">pg_hba.conf</code></a> |
| must permit the replication connection. The server must also be configured |
| with <a class="xref" href="runtime-config-replication.html#GUC-MAX-WAL-SENDERS">max_wal_senders</a> set high enough to provide at |
| least one walsender for the backup plus one for WAL streaming (if used). |
| </p><p> |
| There can be multiple <code class="command">pg_basebackup</code>s running at the same time, but it is usually |
| better from a performance point of view to take only one backup, and copy |
| the result. |
| </p><p> |
| <span class="application">pg_basebackup</span> can make a base backup from |
| not only a primary server but also a standby. To take a backup from a standby, |
| set up the standby so that it can accept replication connections (that is, set |
| <code class="varname">max_wal_senders</code> and <a class="xref" href="runtime-config-replication.html#GUC-HOT-STANDBY">hot_standby</a>, |
| and configure its <code class="filename">pg_hba.conf</code> appropriately). |
| You will also need to enable <a class="xref" href="runtime-config-wal.html#GUC-FULL-PAGE-WRITES">full_page_writes</a> on the primary. |
| </p><p> |
| Note that there are some limitations in taking a backup from a standby: |
|
|
| </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> |
| The backup history file is not created in the database cluster backed up. |
| </p></li><li class="listitem"><p> |
| <span class="application">pg_basebackup</span> cannot force the standby |
| to switch to a new WAL file at the end of backup. |
| When you are using <code class="literal">-X none</code>, if write activity on |
| the primary is low, <span class="application">pg_basebackup</span> may |
| need to wait a long time for the last WAL file required for the backup |
| to be switched and archived. In this case, it may be useful to run |
| <code class="function">pg_switch_wal</code> on the primary in order to |
| trigger an immediate WAL file switch. |
| </p></li><li class="listitem"><p> |
| If the standby is promoted to be primary during backup, the backup fails. |
| </p></li><li class="listitem"><p> |
| All WAL records required for the backup must contain sufficient full-page writes, |
| which requires you to enable <code class="varname">full_page_writes</code> on the primary. |
| </p></li></ul></div><p> |
| </p><p> |
| Whenever <span class="application">pg_basebackup</span> is taking a base |
| backup, the server's <code class="structname">pg_stat_progress_basebackup</code> |
| view will report the progress of the backup. |
| See <a class="xref" href="progress-reporting.html#BASEBACKUP-PROGRESS-REPORTING" title="28.4.6. Base Backup Progress Reporting">Section 28.4.6</a> for details. |
| </p></div><div class="refsect1" id="id-1.9.4.10.6"><h2>Options</h2><p> |
| The following command-line options control the location and format of the |
| output: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-D <em class="replaceable"><code>directory</code></em></code><br /></span><span class="term"><code class="option">--pgdata=<em class="replaceable"><code>directory</code></em></code></span></dt><dd><p> |
| Sets the target directory to write the output to. |
| <span class="application">pg_basebackup</span> will create this directory |
| (and any missing parent directories) if it does not exist. If it |
| already exists, it must be empty. |
| </p><p> |
| When the backup is in tar format, the target directory may be |
| specified as <code class="literal">-</code> (dash), causing the tar file to be |
| written to <code class="literal">stdout</code>. |
| </p><p> |
| This option is required. |
| </p></dd><dt><span class="term"><code class="option">-F <em class="replaceable"><code>format</code></em></code><br /></span><span class="term"><code class="option">--format=<em class="replaceable"><code>format</code></em></code></span></dt><dd><p> |
| Selects the format for the output. <em class="replaceable"><code>format</code></em> |
| can be one of the following: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">p</code><br /></span><span class="term"><code class="literal">plain</code></span></dt><dd><p> |
| Write the output as plain files, with the same layout as the |
| source server's data directory and tablespaces. When the cluster has |
| no additional tablespaces, the whole database will be placed in |
| the target directory. If the cluster contains additional |
| tablespaces, the main data directory will be placed in the |
| target directory, but all other tablespaces will be placed |
| in the same absolute path as they have on the source server. |
| (See <code class="option">--tablespace-mapping</code> to change that.) |
| </p><p> |
| This is the default format. |
| </p></dd><dt><span class="term"><code class="literal">t</code><br /></span><span class="term"><code class="literal">tar</code></span></dt><dd><p> |
| Write the output as tar files in the target directory. The main |
| data directory's contents will be written to a file named |
| <code class="filename">base.tar</code>, and each other tablespace will be |
| written to a separate tar file named after that tablespace's OID. |
| </p><p> |
| If the target directory is specified as <code class="literal">-</code> |
| (dash), the tar contents will be written to |
| standard output, suitable for piping to (for example) |
| <span class="productname">gzip</span>. This is only allowed if |
| the cluster has no additional tablespaces and WAL |
| streaming is not used. |
| </p></dd></dl></div></dd><dt><span class="term"><code class="option">-R</code><br /></span><span class="term"><code class="option">--write-recovery-conf</code></span></dt><dd><p> |
| Creates a |
| <a class="link" href="warm-standby.html#FILE-STANDBY-SIGNAL"><code class="filename">standby.signal</code></a> |
| <a id="id-1.9.4.10.6.2.1.3.3.1.2" class="indexterm"></a> |
| file and appends |
| connection settings to the <code class="filename">postgresql.auto.conf</code> |
| file in the target directory (or within the base archive file when |
| using tar format). This eases setting up a standby server using the |
| results of the backup. |
| </p><p> |
| The <code class="filename">postgresql.auto.conf</code> file will record the connection |
| settings and, if specified, the replication slot |
| that <span class="application">pg_basebackup</span> is using, so that |
| streaming replication will use the same settings later on. |
| </p></dd><dt><span class="term"><code class="option">-t <em class="replaceable"><code>target</code></em></code><br /></span><span class="term"><code class="option">--target=<em class="replaceable"><code>target</code></em></code></span></dt><dd><p> |
| Instructs the server where to place the base backup. The default target |
| is <code class="literal">client</code>, which specifies that the backup should |
| be sent to the machine where <span class="application">pg_basebackup</span> |
| is running. If the target is instead set to |
| <code class="literal">server:/some/path</code>, the backup will be stored on |
| the machine where the server is running in the |
| <code class="literal">/some/path</code> directory. Storing a backup on the |
| server requires superuser privileges or having privileges of the |
| <code class="literal">pg_write_server_files</code> role. If the target is set to |
| <code class="literal">blackhole</code>, the contents are discarded and not |
| stored anywhere. This should only be used for testing purposes, as you |
| will not end up with an actual backup. |
| </p><p> |
| Since WAL streaming is implemented by |
| <span class="application">pg_basebackup</span> rather than by the server, |
| this option cannot be used together with <code class="literal">-Xstream</code>. |
| Since that is the default, when this option is specified, you must also |
| specify either <code class="literal">-Xfetch</code> or <code class="literal">-Xnone</code>. |
| </p></dd><dt><span class="term"><code class="option">-T <em class="replaceable"><code>olddir</code></em>=<em class="replaceable"><code>newdir</code></em></code><br /></span><span class="term"><code class="option">--tablespace-mapping=<em class="replaceable"><code>olddir</code></em>=<em class="replaceable"><code>newdir</code></em></code></span></dt><dd><p> |
| Relocates the tablespace in directory <em class="replaceable"><code>olddir</code></em> |
| to <em class="replaceable"><code>newdir</code></em> during the backup. To be |
| effective, <em class="replaceable"><code>olddir</code></em> must exactly match the |
| path specification of the tablespace as it is defined on the source |
| server. (But it is not an error if there is no tablespace |
| in <em class="replaceable"><code>olddir</code></em> on the source server.) |
| Meanwhile <em class="replaceable"><code>newdir</code></em> is a directory in the |
| receiving host's filesystem. As with the main target directory, |
| <em class="replaceable"><code>newdir</code></em> need not exist already, but if |
| it does exist it must be empty. |
| Both <em class="replaceable"><code>olddir</code></em> |
| and <em class="replaceable"><code>newdir</code></em> must be absolute paths. If |
| either path needs to contain an equal sign (<code class="literal">=</code>), |
| precede that with a backslash. This option can be specified multiple |
| times for multiple tablespaces. |
| </p><p> |
| If a tablespace is relocated in this way, the symbolic links inside |
| the main data directory are updated to point to the new location. So |
| the new data directory is ready to be used for a new server instance |
| with all tablespaces in the updated locations. |
| </p><p> |
| Currently, this option only works with plain output format; it is |
| ignored if tar format is selected. |
| </p></dd><dt><span class="term"><code class="option">--waldir=<em class="replaceable"><code>waldir</code></em></code></span></dt><dd><p> |
| Sets the directory to write WAL (write-ahead log) files to. |
| By default WAL files will be placed in |
| the <code class="filename">pg_wal</code> subdirectory of the target |
| directory, but this option can be used to place them elsewhere. |
| <em class="replaceable"><code>waldir</code></em> must be an absolute path. |
| As with the main target directory, |
| <em class="replaceable"><code>waldir</code></em> need not exist already, but if |
| it does exist it must be empty. |
| This option can only be specified when |
| the backup is in plain format. |
| </p></dd><dt><span class="term"><code class="option">-X <em class="replaceable"><code>method</code></em></code><br /></span><span class="term"><code class="option">--wal-method=<em class="replaceable"><code>method</code></em></code></span></dt><dd><p> |
| Includes the required WAL (write-ahead log) files in the |
| backup. This will include all write-ahead logs generated during |
| the backup. Unless the method <code class="literal">none</code> is specified, |
| it is possible to start a postmaster in the target |
| directory without the need to consult the WAL archive, thus |
| making the output a completely standalone backup. |
| </p><p> |
| The following <em class="replaceable"><code>method</code></em>s for collecting the |
| write-ahead logs are supported: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">n</code><br /></span><span class="term"><code class="literal">none</code></span></dt><dd><p> |
| Don't include write-ahead logs in the backup. |
| </p></dd><dt><span class="term"><code class="literal">f</code><br /></span><span class="term"><code class="literal">fetch</code></span></dt><dd><p> |
| The write-ahead log files are collected at the end of the backup. |
| Therefore, it is necessary for the source server's |
| <a class="xref" href="runtime-config-replication.html#GUC-WAL-KEEP-SIZE">wal_keep_size</a> parameter to be set high |
| enough that the required log data is not removed before the end |
| of the backup. If the required log data has been recycled |
| before it's time to transfer it, the backup will fail and be |
| unusable. |
| </p><p> |
| When tar format is used, the write-ahead log files will be |
| included in the <code class="filename">base.tar</code> file. |
| </p></dd><dt><span class="term"><code class="literal">s</code><br /></span><span class="term"><code class="literal">stream</code></span></dt><dd><p> |
| Stream write-ahead log data while the backup is being taken. |
| This method will open a second connection to the server and |
| start streaming the write-ahead log in parallel while running |
| the backup. Therefore, it will require two replication |
| connections not just one. As long as the client can keep up |
| with the write-ahead log data, using this method requires no |
| extra write-ahead logs to be saved on the source server. |
| </p><p> |
| When tar format is used, the write-ahead log files will be |
| written to a separate file named <code class="filename">pg_wal.tar</code> |
| (if the server is a version earlier than 10, the file will be named |
| <code class="filename">pg_xlog.tar</code>). |
| </p><p> |
| This value is the default. |
| </p></dd></dl></div></dd><dt><span class="term"><code class="option">-z</code><br /></span><span class="term"><code class="option">--gzip</code></span></dt><dd><p> |
| Enables gzip compression of tar file output, with the default |
| compression level. Compression is only available when using |
| the tar format, and the suffix <code class="filename">.gz</code> will |
| automatically be added to all tar filenames. |
| </p></dd><dt><span class="term"><code class="option">-Z <em class="replaceable"><code>level</code></em></code><br /></span><span class="term"><code class="option">-Z [{client|server}-]<em class="replaceable"><code>method</code></em>[:<em class="replaceable"><code>detail</code></em>]</code><br /></span><span class="term"><code class="option">--compress=<em class="replaceable"><code>level</code></em></code><br /></span><span class="term"><code class="option">--compress=[{client|server}-]<em class="replaceable"><code>method</code></em>[:<em class="replaceable"><code>detail</code></em>]</code></span></dt><dd><p> |
| Requests compression of the backup. If <code class="literal">client</code> or |
| <code class="literal">server</code> is included, it specifies where the |
| compression is to be performed. Compressing on the server will reduce |
| transfer bandwidth but will increase server CPU consumption. The |
| default is <code class="literal">client</code> except when |
| <code class="literal">--target</code> is used. In that case, the backup is not |
| being sent to the client, so only server compression is sensible. |
| When <code class="literal">-Xstream</code>, which is the default, is used, |
| server-side compression will not be applied to the WAL. To compress |
| the WAL, use client-side compression, or |
| specify <code class="literal">-Xfetch</code>. |
| </p><p> |
| The compression method can be set to <code class="literal">gzip</code>, |
| <code class="literal">lz4</code>, <code class="literal">zstd</code>, |
| <code class="literal">none</code> for no compression or an integer (no |
| compression if 0, <code class="literal">gzip</code> if greater than 0). |
| A compression detail string can optionally be specified. |
| If the detail string is an integer, it specifies the compression |
| level. Otherwise, it should be a comma-separated list of items, |
| each of the form <code class="literal">keyword</code> or |
| <code class="literal">keyword=value</code>. |
| Currently, the supported keywords are <code class="literal">level</code>, |
| <code class="literal">long</code>, and <code class="literal">workers</code>. |
| The detail string cannot be used when the compression method |
| is specified as a plain integer. |
| </p><p> |
| If no compression level is specified, the default compression level |
| will be used. If only a level is specified without mentioning an |
| algorithm, <code class="literal">gzip</code> compression will be used if the |
| level is greater than 0, and no compression will be used if the level |
| is 0. |
| </p><p> |
| When the tar format is used with <code class="literal">gzip</code>, |
| <code class="literal">lz4</code>, or <code class="literal">zstd</code>, the suffix |
| <code class="filename">.gz</code>, <code class="filename">.lz4</code>, or |
| <code class="filename">.zst</code>, respectively, will be automatically added to |
| all tar filenames. When the plain format is used, client-side |
| compression may not be specified, but it is still possible to request |
| server-side compression. If this is done, the server will compress the |
| backup for transmission, and the client will decompress and extract it. |
| </p><p> |
| When this option is used in combination with |
| <code class="literal">-Xstream</code>, <code class="literal">pg_wal.tar</code> will |
| be compressed using <code class="literal">gzip</code> if client-side gzip |
| compression is selected, but will not be compressed if any other |
| compression algorithm is selected, or if server-side compression |
| is selected. |
| </p></dd></dl></div><p> |
| </p><p> |
| The following command-line options control the generation of the |
| backup and the invocation of the program: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-c {fast|spread}</code><br /></span><span class="term"><code class="option">--checkpoint={fast|spread}</code></span></dt><dd><p> |
| Sets checkpoint mode to fast (immediate) or spread (the default) |
| (see <a class="xref" href="continuous-archiving.html#BACKUP-LOWLEVEL-BASE-BACKUP" title="26.3.3. Making a Base Backup Using the Low Level API">Section 26.3.3</a>). |
| </p></dd><dt><span class="term"><code class="option">-C</code><br /></span><span class="term"><code class="option">--create-slot</code></span></dt><dd><p> |
| Specifies that the replication slot named by the |
| <code class="literal">--slot</code> option should be created before starting |
| the backup. An error is raised if the slot already exists. |
| </p></dd><dt><span class="term"><code class="option">-l <em class="replaceable"><code>label</code></em></code><br /></span><span class="term"><code class="option">--label=<em class="replaceable"><code>label</code></em></code></span></dt><dd><p> |
| Sets the label for the backup. If none is specified, a default value of |
| <span class="quote">“<span class="quote"><code class="literal">pg_basebackup base backup</code></span>”</span> will be used. |
| </p></dd><dt><span class="term"><code class="option">-n</code><br /></span><span class="term"><code class="option">--no-clean</code></span></dt><dd><p> |
| By default, when <code class="command">pg_basebackup</code> aborts with an |
| error, it removes any directories it might have created before |
| discovering that it cannot finish the job (for example, the target |
| directory and write-ahead log directory). This option inhibits |
| tidying-up and is thus useful for debugging. |
| </p><p> |
| Note that tablespace directories are not cleaned up either way. |
| </p></dd><dt><span class="term"><code class="option">-N</code><br /></span><span class="term"><code class="option">--no-sync</code></span></dt><dd><p> |
| By default, <code class="command">pg_basebackup</code> will wait for all files |
| to be written safely to disk. This option causes |
| <code class="command">pg_basebackup</code> to return without waiting, which is |
| faster, but means that a subsequent operating system crash can leave |
| the base backup corrupt. Generally, this option is useful for testing |
| but should not be used when creating a production installation. |
| </p></dd><dt><span class="term"><code class="option">-P</code><br /></span><span class="term"><code class="option">--progress</code></span></dt><dd><p> |
| Enables progress reporting. Turning this on will deliver an approximate |
| progress report during the backup. Since the database may change during |
| the backup, this is only an approximation and may not end at exactly |
| <code class="literal">100%</code>. In particular, when WAL log is included in the |
| backup, the total amount of data cannot be estimated in advance, and |
| in this case the estimated target size will increase once it passes the |
| total estimate without WAL. |
| </p></dd><dt><span class="term"><code class="option">-r <em class="replaceable"><code>rate</code></em></code><br /></span><span class="term"><code class="option">--max-rate=<em class="replaceable"><code>rate</code></em></code></span></dt><dd><p> |
| Sets the maximum transfer rate at which data is collected from the |
| source server. This can be useful to limit the impact |
| of <span class="application">pg_basebackup</span> on the server. Values |
| are in kilobytes per second. Use a suffix of <code class="literal">M</code> |
| to indicate megabytes per second. A suffix of <code class="literal">k</code> |
| is also accepted, and has no effect. Valid values are between 32 |
| kilobytes per second and 1024 megabytes per second. |
| </p><p> |
| This option always affects transfer of the data directory. Transfer of |
| WAL files is only affected if the collection method |
| is <code class="literal">fetch</code>. |
| </p></dd><dt><span class="term"><code class="option">-S <em class="replaceable"><code>slotname</code></em></code><br /></span><span class="term"><code class="option">--slot=<em class="replaceable"><code>slotname</code></em></code></span></dt><dd><p> |
| This option can only be used together with <code class="literal">-X |
| stream</code>. It causes WAL streaming to use the specified |
| replication slot. If the base backup is intended to be used as a |
| streaming-replication standby using a replication slot, the standby |
| should then use the same replication slot name as |
| <a class="xref" href="runtime-config-replication.html#GUC-PRIMARY-SLOT-NAME">primary_slot_name</a>. This ensures that the |
| primary server does not remove any necessary WAL data in the time |
| between the end of the base backup and the start of streaming |
| replication on the new standby. |
| </p><p> |
| The specified replication slot has to exist unless the |
| option <code class="option">-C</code> is also used. |
| </p><p> |
| If this option is not specified and the server supports temporary |
| replication slots (version 10 and later), then a temporary replication |
| slot is automatically used for WAL streaming. |
| </p></dd><dt><span class="term"><code class="option">-v</code><br /></span><span class="term"><code class="option">--verbose</code></span></dt><dd><p> |
| Enables verbose mode. Will output some extra steps during startup and |
| shutdown, as well as show the exact file name that is currently being |
| processed if progress reporting is also enabled. |
| </p></dd><dt><span class="term"><code class="option">--manifest-checksums=<em class="replaceable"><code>algorithm</code></em></code></span></dt><dd><p> |
| Specifies the checksum algorithm that should be applied to each file |
| included in the backup manifest. Currently, the available |
| algorithms are <code class="literal">NONE</code>, <code class="literal">CRC32C</code>, |
| <code class="literal">SHA224</code>, <code class="literal">SHA256</code>, |
| <code class="literal">SHA384</code>, and <code class="literal">SHA512</code>. |
| The default is <code class="literal">CRC32C</code>. |
| </p><p> |
| If <code class="literal">NONE</code> is selected, the backup manifest will |
| not contain any checksums. Otherwise, it will contain a checksum |
| of each file in the backup using the specified algorithm. In addition, |
| the manifest will always contain a <code class="literal">SHA256</code> |
| checksum of its own contents. The <code class="literal">SHA</code> algorithms |
| are significantly more CPU-intensive than <code class="literal">CRC32C</code>, |
| so selecting one of them may increase the time required to complete |
| the backup. |
| </p><p> |
| Using a SHA hash function provides a cryptographically secure digest |
| of each file for users who wish to verify that the backup has not been |
| tampered with, while the CRC32C algorithm provides a checksum that is |
| much faster to calculate; it is good at catching errors due to accidental |
| changes but is not resistant to malicious modifications. Note that, to |
| be useful against an adversary who has access to the backup, the backup |
| manifest would need to be stored securely elsewhere or otherwise |
| verified not to have been modified since the backup was taken. |
| </p><p> |
| <a class="xref" href="app-pgverifybackup.html" title="pg_verifybackup"><span class="refentrytitle"><span class="application">pg_verifybackup</span></span></a> can be used to check the |
| integrity of a backup against the backup manifest. |
| </p></dd><dt><span class="term"><code class="option">--manifest-force-encode</code></span></dt><dd><p> |
| Forces all filenames in the backup manifest to be hex-encoded. |
| If this option is not specified, only non-UTF8 filenames are |
| hex-encoded. This option is mostly intended to test that tools which |
| read a backup manifest file properly handle this case. |
| </p></dd><dt><span class="term"><code class="option">--no-estimate-size</code></span></dt><dd><p> |
| Prevents the server from estimating the total |
| amount of backup data that will be streamed, resulting in the |
| <code class="structfield">backup_total</code> column in the |
| <code class="structname">pg_stat_progress_basebackup</code> view |
| always being <code class="literal">NULL</code>. |
| </p><p> |
| Without this option, the backup will start by enumerating |
| the size of the entire database, and then go back and send |
| the actual contents. This may make the backup take slightly |
| longer, and in particular it will take longer before the first |
| data is sent. This option is useful to avoid such estimation |
| time if it's too long. |
| </p><p> |
| This option is not allowed when using <code class="option">--progress</code>. |
| </p></dd><dt><span class="term"><code class="option">--no-manifest</code></span></dt><dd><p> |
| Disables generation of a backup manifest. If this option is not |
| specified, the server will generate and send a backup manifest |
| which can be verified using <a class="xref" href="app-pgverifybackup.html" title="pg_verifybackup"><span class="refentrytitle"><span class="application">pg_verifybackup</span></span></a>. |
| The manifest is a list of every file present in the backup with the |
| exception of any WAL files that may be included. It also stores the |
| size, last modification time, and an optional checksum for each file. |
| </p></dd><dt><span class="term"><code class="option">--no-slot</code></span></dt><dd><p> |
| Prevents the creation of a temporary replication slot |
| for the backup. |
| </p><p> |
| By default, if log streaming is selected but no slot name is given |
| with the <code class="option">-S</code> option, then a temporary replication |
| slot is created (if supported by the source server). |
| </p><p> |
| The main purpose of this option is to allow taking a base backup when |
| the server has no free replication slots. Using a replication slot |
| is almost always preferred, because it prevents needed WAL from being |
| removed by the server during the backup. |
| </p></dd><dt><span class="term"><code class="option">--no-verify-checksums</code></span></dt><dd><p> |
| Disables verification of checksums, if they are enabled on the server |
| the base backup is taken from. |
| </p><p> |
| By default, checksums are verified and checksum failures will result |
| in a non-zero exit status. However, the base backup will not be |
| removed in such a case, as if the <code class="option">--no-clean</code> option |
| had been used. Checksum verification failures will also be reported |
| in the <a class="link" href="monitoring-stats.html#MONITORING-PG-STAT-DATABASE-VIEW" title="28.2.16. pg_stat_database"> |
| <code class="structname">pg_stat_database</code></a> view. |
| </p></dd></dl></div><p> |
| </p><p> |
| The following command-line options control the connection to the source |
| server: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-d <em class="replaceable"><code>connstr</code></em></code><br /></span><span class="term"><code class="option">--dbname=<em class="replaceable"><code>connstr</code></em></code></span></dt><dd><p> |
| Specifies parameters used to connect to the server, as a <a class="link" href="libpq-connect.html#LIBPQ-CONNSTRING" title="34.1.1. Connection Strings">connection string</a>; these |
| will override any conflicting command line options. |
| </p><p> |
| The option is called <code class="literal">--dbname</code> for consistency with other |
| client applications, but because <span class="application">pg_basebackup</span> |
| doesn't connect to any particular database in the cluster, any database |
| name in the connection string will be ignored. |
| </p></dd><dt><span class="term"><code class="option">-h <em class="replaceable"><code>host</code></em></code><br /></span><span class="term"><code class="option">--host=<em class="replaceable"><code>host</code></em></code></span></dt><dd><p> |
| 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 a Unix domain socket. The default is taken |
| from the <code class="envar">PGHOST</code> environment variable, if set, |
| else a Unix domain socket connection is attempted. |
| </p></dd><dt><span class="term"><code class="option">-p <em class="replaceable"><code>port</code></em></code><br /></span><span class="term"><code class="option">--port=<em class="replaceable"><code>port</code></em></code></span></dt><dd><p> |
| Specifies the TCP port or local Unix domain socket file |
| extension on which the server is listening for connections. |
| Defaults to the <code class="envar">PGPORT</code> environment variable, if |
| set, or a compiled-in default. |
| </p></dd><dt><span class="term"><code class="option">-s <em class="replaceable"><code>interval</code></em></code><br /></span><span class="term"><code class="option">--status-interval=<em class="replaceable"><code>interval</code></em></code></span></dt><dd><p> |
| Specifies the number of seconds between status packets sent back to |
| the source server. Smaller values allow more accurate monitoring of |
| backup progress from the server. |
| A value of zero disables periodic status updates completely, |
| although an update will still be sent when requested by the server, to |
| avoid timeout-based disconnects. The default value is 10 seconds. |
| </p></dd><dt><span class="term"><code class="option">-U <em class="replaceable"><code>username</code></em></code><br /></span><span class="term"><code class="option">--username=<em class="replaceable"><code>username</code></em></code></span></dt><dd><p> |
| Specifies the user name to connect as. |
| </p></dd><dt><span class="term"><code class="option">-w</code><br /></span><span class="term"><code class="option">--no-password</code></span></dt><dd><p> |
| Prevents issuing a password prompt. If the server requires |
| password authentication and a password is not available by |
| other means such as a <code class="filename">.pgpass</code> 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. |
| </p></dd><dt><span class="term"><code class="option">-W</code><br /></span><span class="term"><code class="option">--password</code></span></dt><dd><p> |
| Forces <span class="application">pg_basebackup</span> to prompt for a |
| password before connecting to the source server. |
| </p><p> |
| This option is never essential, since |
| <span class="application">pg_basebackup</span> will automatically prompt |
| for a password if the server demands password authentication. |
| However, <span class="application">pg_basebackup</span> will waste a |
| connection attempt finding out that the server wants a password. |
| In some cases it is worth typing <code class="option">-W</code> to avoid the extra |
| connection attempt. |
| </p></dd></dl></div><p> |
| </p><p> |
| Other options are also available: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-V</code><br /></span><span class="term"><code class="option">--version</code></span></dt><dd><p> |
| Prints the <span class="application">pg_basebackup</span> version and exits. |
| </p></dd><dt><span class="term"><code class="option">-?</code><br /></span><span class="term"><code class="option">--help</code></span></dt><dd><p> |
| Shows help about <span class="application">pg_basebackup</span> command line |
| arguments, and exits. |
| </p></dd></dl></div><p> |
| </p></div><div class="refsect1" id="id-1.9.4.10.7"><h2>Environment</h2><p> |
| This utility, like most other <span class="productname">PostgreSQL</span> utilities, |
| uses the environment variables supported by <span class="application">libpq</span> |
| (see <a class="xref" href="libpq-envars.html" title="34.15. Environment Variables">Section 34.15</a>). |
| </p><p> |
| The environment variable <code class="envar">PG_COLOR</code> specifies whether to use |
| color in diagnostic messages. Possible values are |
| <code class="literal">always</code>, <code class="literal">auto</code> and |
| <code class="literal">never</code>. |
| </p></div><div class="refsect1" id="id-1.9.4.10.8"><h2>Notes</h2><p> |
| At the beginning of the backup, a checkpoint needs to be performed on the |
| source server. This can take some time (especially if the option |
| <code class="literal">--checkpoint=fast</code> is not used), during |
| which <span class="application">pg_basebackup</span> will appear to be idle. |
| </p><p> |
| The backup will include all files in the data directory and tablespaces, |
| including the configuration files and any additional files placed in the |
| directory by third parties, except certain temporary files managed by |
| PostgreSQL and operating system files. But only regular files and |
| directories are copied, except that |
| symbolic links used for tablespaces are preserved. Symbolic links pointing |
| to certain directories known to PostgreSQL are copied as empty directories. |
| Other symbolic links and special device files are skipped. |
| See <a class="xref" href="protocol-replication.html" title="55.4. Streaming Replication Protocol">Section 55.4</a> for the precise details. |
| </p><p> |
| In plain format, tablespaces will be backed up to the same path |
| they have on the source server, unless the |
| option <code class="literal">--tablespace-mapping</code> is used. Without |
| this option, running a plain format base backup on the same host as the |
| server will not work if tablespaces are in use, because the backup would |
| have to be written to the same directory locations as the original |
| tablespaces. |
| </p><p> |
| When tar format is used, it is the user's responsibility to unpack each |
| tar file before starting a PostgreSQL server that uses the data. If there |
| are additional tablespaces, the |
| tar files for them need to be unpacked in the correct locations. In this |
| case the symbolic links for those tablespaces will be created by the server |
| according to the contents of the <code class="filename">tablespace_map</code> file that is |
| included in the <code class="filename">base.tar</code> file. |
| </p><p> |
| <span class="application">pg_basebackup</span> works with servers of the same |
| or an older major version, down to 9.1. However, WAL streaming mode (<code class="literal">-X |
| stream</code>) only works with server version 9.3 and later, and tar format |
| (<code class="literal">--format=tar</code>) only works with server version 9.5 |
| and later. |
| </p><p> |
| <span class="application">pg_basebackup</span> will preserve group permissions |
| for data files if group permissions are enabled on the source cluster. |
| </p></div><div class="refsect1" id="id-1.9.4.10.9"><h2>Examples</h2><p> |
| To create a base backup of the server at <code class="literal">mydbserver</code> |
| and store it in the local directory |
| <code class="filename">/usr/local/pgsql/data</code>: |
| </p><pre class="screen"> |
| <code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -h mydbserver -D /usr/local/pgsql/data</code></strong> |
| </pre><p> |
| </p><p> |
| To create a backup of the local server with one compressed |
| tar file for each tablespace, and store it in the directory |
| <code class="filename">backup</code>, showing a progress report while running: |
| </p><pre class="screen"> |
| <code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D backup -Ft -z -P</code></strong> |
| </pre><p> |
| </p><p> |
| To create a backup of a single-tablespace local database and compress |
| this with <span class="productname">bzip2</span>: |
| </p><pre class="screen"> |
| <code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D - -Ft -X fetch | bzip2 > backup.tar.bz2</code></strong> |
| </pre><p> |
| (This command will fail if there are multiple tablespaces in the |
| database.) |
| </p><p> |
| To create a backup of a local database where the tablespace in |
| <code class="filename">/opt/ts</code> is relocated |
| to <code class="filename">./backup/ts</code>: |
| </p><pre class="screen"> |
| <code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D backup/data -T /opt/ts=$(pwd)/backup/ts</code></strong> |
| </pre><p> |
| To create a backup of a local server with one tar file for each tablespace |
| compressed with <span class="application">gzip</span> at level 9, stored in the |
| directory <code class="filename">backup</code>: |
| </p><pre class="screen"> |
| <code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D backup -Ft --compress=gzip:9</code></strong> |
| </pre></div><div class="refsect1" id="id-1.9.4.10.10"><h2>See Also</h2><span class="simplelist"><a class="xref" href="app-pgdump.html" title="pg_dump"><span class="refentrytitle"><span class="application">pg_dump</span></span></a>, <a class="xref" href="progress-reporting.html#BASEBACKUP-PROGRESS-REPORTING" title="28.4.6. Base Backup Progress Reporting">Section 28.4.6</a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="app-pgamcheck.html" title="pg_amcheck">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="reference-client.html" title="PostgreSQL Client Applications">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="pgbench.html" title="pgbench">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="application">pg_amcheck</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="40%" align="right" valign="top"> <span class="application">pgbench</span></td></tr></table></div></body></html> |
