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1<?xml version="1.0" encoding="UTF-8" standalone="no"?>2<!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>3   <span class="application">pg_basebackup</span> is used to take a base backup of4   a running <span class="productname">PostgreSQL</span> database cluster. The backup5   is taken without affecting other clients of the database, and can be used6   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>)7   and as the starting point for a log-shipping or streaming-replication standby8   server (see <a class="xref" href="warm-standby.html" title="27.2. Log-Shipping Standby Servers">Section 27.2</a>).9  </p><p>10   <span class="application">pg_basebackup</span> makes an exact copy of the database11   cluster's files, while making sure the server is put into and12   out of backup mode automatically. Backups are always taken of the entire13   database cluster; it is not possible to back up individual databases or14   database objects. For selective backups, another tool such as15   <a class="xref" href="app-pgdump.html" title="pg_dump"><span class="refentrytitle"><span class="application">pg_dump</span></span></a> must be used.16  </p><p>17   The backup is made over a regular <span class="productname">PostgreSQL</span>18   connection that uses the replication protocol. The connection must be made19   with a user ID that has <code class="literal">REPLICATION</code> permissions20   (see <a class="xref" href="role-attributes.html" title="22.2. Role Attributes">Section 22.2</a>) or is a superuser,21   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>22   must permit the replication connection. The server must also be configured23   with <a class="xref" href="runtime-config-replication.html#GUC-MAX-WAL-SENDERS">max_wal_senders</a> set high enough to provide at24   least one walsender for the backup plus one for WAL streaming (if used).25  </p><p>26   There can be multiple <code class="command">pg_basebackup</code>s running at the same time, but it is usually27   better from a performance point of view to take only one backup, and copy28   the result.29  </p><p>30   <span class="application">pg_basebackup</span> can make a base backup from31   not only a primary server but also a standby. To take a backup from a standby,32   set up the standby so that it can accept replication connections (that is, set33   <code class="varname">max_wal_senders</code> and <a class="xref" href="runtime-config-replication.html#GUC-HOT-STANDBY">hot_standby</a>,34   and configure its <code class="filename">pg_hba.conf</code> appropriately).35   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.36  </p><p>37   Note that there are some limitations in taking a backup from a standby:38 39   </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>40      The backup history file is not created in the database cluster backed up.41     </p></li><li class="listitem"><p>42      <span class="application">pg_basebackup</span> cannot force the standby43      to switch to a new WAL file at the end of backup.44      When you are using <code class="literal">-X none</code>, if write activity on45      the primary is low, <span class="application">pg_basebackup</span> may46      need to wait a long time for the last WAL file required for the backup47      to be switched and archived.  In this case, it may be useful to run48      <code class="function">pg_switch_wal</code> on the primary in order to49      trigger an immediate WAL file switch.50     </p></li><li class="listitem"><p>51      If the standby is promoted to be primary during backup, the backup fails.52     </p></li><li class="listitem"><p>53      All WAL records required for the backup must contain sufficient full-page writes,54      which requires you to enable <code class="varname">full_page_writes</code> on the primary.55     </p></li></ul></div><p>56  </p><p>57   Whenever <span class="application">pg_basebackup</span> is taking a base58   backup, the server's <code class="structname">pg_stat_progress_basebackup</code>59   view will report the progress of the backup.60   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.61  </p></div><div class="refsect1" id="id-1.9.4.10.6"><h2>Options</h2><p>62    The following command-line options control the location and format of the63    output:64 65    </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>66        Sets the target directory to write the output to.67        <span class="application">pg_basebackup</span> will create this directory68        (and any missing parent directories) if it does not exist.  If it69        already exists, it must be empty.70       </p><p>71        When the backup is in tar format, the target directory may be72        specified as <code class="literal">-</code> (dash), causing the tar file to be73        written to <code class="literal">stdout</code>.74       </p><p>75        This option is required.76       </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>77        Selects the format for the output. <em class="replaceable"><code>format</code></em>78        can be one of the following:79 80        </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>81            Write the output as plain files, with the same layout as the82            source server's data directory and tablespaces. When the cluster has83            no additional tablespaces, the whole database will be placed in84            the target directory. If the cluster contains additional85            tablespaces, the main data directory will be placed in the86            target directory, but all other tablespaces will be placed87            in the same absolute path as they have on the source server.88            (See <code class="option">--tablespace-mapping</code> to change that.)89           </p><p>90            This is the default format.91           </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>92            Write the output as tar files in the target directory. The main93            data directory's contents will be written to a file named94            <code class="filename">base.tar</code>, and each other tablespace will be95            written to a separate tar file named after that tablespace's OID.96           </p><p>97            If the target directory is specified as <code class="literal">-</code>98            (dash), the tar contents will be written to99            standard output, suitable for piping to (for example)100            <span class="productname">gzip</span>. This is only allowed if101            the cluster has no additional tablespaces and WAL102            streaming is not used.103           </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>104        Creates a105        <a class="link" href="warm-standby.html#FILE-STANDBY-SIGNAL"><code class="filename">standby.signal</code></a>106        <a id="id-1.9.4.10.6.2.1.3.3.1.2" class="indexterm"></a>107        file and appends108        connection settings to the <code class="filename">postgresql.auto.conf</code>109        file in the target directory (or within the base archive file when110        using tar format).  This eases setting up a standby server using the111        results of the backup.112       </p><p>113        The <code class="filename">postgresql.auto.conf</code> file will record the connection114        settings and, if specified, the replication slot115        that <span class="application">pg_basebackup</span> is using, so that116        streaming replication will use the same settings later on.117       </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>118        Instructs the server where to place the base backup. The default target119        is <code class="literal">client</code>, which specifies that the backup should120        be sent to the machine where <span class="application">pg_basebackup</span>121        is running. If the target is instead set to122        <code class="literal">server:/some/path</code>, the backup will be stored on123        the machine where the server is running in the124        <code class="literal">/some/path</code> directory. Storing a backup on the125        server requires superuser privileges or having privileges of the126        <code class="literal">pg_write_server_files</code> role. If the target is set to127        <code class="literal">blackhole</code>, the contents are discarded and not128        stored anywhere. This should only be used for testing purposes, as you129        will not end up with an actual backup.130       </p><p>131        Since WAL streaming is implemented by132        <span class="application">pg_basebackup</span> rather than by the server,133        this option cannot be used together with <code class="literal">-Xstream</code>.134        Since that is the default, when this option is specified, you must also135        specify either <code class="literal">-Xfetch</code> or <code class="literal">-Xnone</code>.136       </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>137        Relocates the tablespace in directory <em class="replaceable"><code>olddir</code></em>138        to <em class="replaceable"><code>newdir</code></em> during the backup.  To be139        effective, <em class="replaceable"><code>olddir</code></em> must exactly match the140        path specification of the tablespace as it is defined on the source141        server.  (But it is not an error if there is no tablespace142        in <em class="replaceable"><code>olddir</code></em> on the source server.)143        Meanwhile <em class="replaceable"><code>newdir</code></em> is a directory in the144        receiving host's filesystem.  As with the main target directory,145        <em class="replaceable"><code>newdir</code></em> need not exist already, but if146        it does exist it must be empty.147        Both <em class="replaceable"><code>olddir</code></em>148        and <em class="replaceable"><code>newdir</code></em> must be absolute paths.  If149        either path needs to contain an equal sign (<code class="literal">=</code>),150        precede that with a backslash.  This option can be specified multiple151        times for multiple tablespaces.152       </p><p>153        If a tablespace is relocated in this way, the symbolic links inside154        the main data directory are updated to point to the new location.  So155        the new data directory is ready to be used for a new server instance156        with all tablespaces in the updated locations.157       </p><p>158        Currently, this option only works with plain output format; it is159        ignored if tar format is selected.160       </p></dd><dt><span class="term"><code class="option">--waldir=<em class="replaceable"><code>waldir</code></em></code></span></dt><dd><p>161        Sets the directory to write WAL (write-ahead log) files to.162        By default WAL files will be placed in163        the <code class="filename">pg_wal</code> subdirectory of the target164        directory, but this option can be used to place them elsewhere.165        <em class="replaceable"><code>waldir</code></em> must be an absolute path.166        As with the main target directory,167        <em class="replaceable"><code>waldir</code></em> need not exist already, but if168        it does exist it must be empty.169        This option can only be specified when170        the backup is in plain format.171       </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>172        Includes the required WAL (write-ahead log) files in the173        backup. This will include all write-ahead logs generated during174        the backup. Unless the method <code class="literal">none</code> is specified,175        it is possible to start a postmaster in the target176        directory without the need to consult the WAL archive, thus177        making the output a completely standalone backup.178       </p><p>179        The following <em class="replaceable"><code>method</code></em>s for collecting the180        write-ahead logs are supported:181 182        </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>183            Don't include write-ahead logs in the backup.184           </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>185            The write-ahead log files are collected at the end of the backup.186            Therefore, it is necessary for the source server's187            <a class="xref" href="runtime-config-replication.html#GUC-WAL-KEEP-SIZE">wal_keep_size</a> parameter to be set high188            enough that the required log data is not removed before the end189            of the backup.  If the required log data has been recycled190            before it's time to transfer it, the backup will fail and be191            unusable.192           </p><p>193            When tar format is used, the write-ahead log files will be194            included in the <code class="filename">base.tar</code> file.195           </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>196            Stream write-ahead log data while the backup is being taken.197            This method will open a second connection to the server and198            start streaming the write-ahead log in parallel while running199            the backup.  Therefore, it will require two replication200            connections not just one.  As long as the client can keep up201            with the write-ahead log data, using this method requires no202            extra write-ahead logs to be saved on the source server.203           </p><p>204            When tar format is used, the write-ahead log files will be205            written to a separate file named <code class="filename">pg_wal.tar</code>206            (if the server is a version earlier than 10, the file will be named207            <code class="filename">pg_xlog.tar</code>).208           </p><p>209            This value is the default.210           </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>211        Enables gzip compression of tar file output, with the default212        compression level. Compression is only available when using213        the tar format, and the suffix <code class="filename">.gz</code> will214        automatically be added to all tar filenames.215       </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>216        Requests compression of the backup. If <code class="literal">client</code> or217        <code class="literal">server</code> is included, it specifies where the218        compression is to be performed. Compressing on the server will reduce219        transfer bandwidth but will increase server CPU consumption.  The220        default is <code class="literal">client</code> except when221        <code class="literal">--target</code> is used. In that case, the backup is not222        being sent to the client, so only server compression is sensible.223        When <code class="literal">-Xstream</code>, which is the default, is used,224        server-side compression will not be applied to the WAL. To compress225        the WAL, use client-side compression, or226        specify <code class="literal">-Xfetch</code>.227       </p><p>228        The compression method can be set to <code class="literal">gzip</code>,229        <code class="literal">lz4</code>, <code class="literal">zstd</code>,230        <code class="literal">none</code> for no compression or an integer (no231        compression if 0, <code class="literal">gzip</code> if greater than 0).232        A compression detail string can optionally be specified.233        If the detail string is an integer, it specifies the compression234        level.  Otherwise, it should be a comma-separated list of items,235        each of the form <code class="literal">keyword</code> or236        <code class="literal">keyword=value</code>.237        Currently, the supported keywords are <code class="literal">level</code>,238        <code class="literal">long</code>, and <code class="literal">workers</code>.239        The detail string cannot be used when the compression method240        is specified as a plain integer.241       </p><p>242        If no compression level is specified, the default compression level243        will be used. If only a level is specified without mentioning an244        algorithm, <code class="literal">gzip</code> compression will be used if the245        level is greater than 0, and no compression will be used if the level246        is 0.247       </p><p>248        When the tar format is used with <code class="literal">gzip</code>,249        <code class="literal">lz4</code>, or <code class="literal">zstd</code>, the suffix250        <code class="filename">.gz</code>, <code class="filename">.lz4</code>, or251        <code class="filename">.zst</code>, respectively, will be automatically added to252        all tar filenames. When the plain format is used, client-side253        compression may not be specified, but it is still possible to request254        server-side compression. If this is done, the server will compress the255        backup for transmission, and the client will decompress and extract it.256       </p><p>257        When this option is used in combination with258        <code class="literal">-Xstream</code>, <code class="literal">pg_wal.tar</code> will259        be compressed using <code class="literal">gzip</code> if client-side gzip260        compression is selected, but will not be compressed if any other261        compression algorithm is selected, or if server-side compression262        is selected.263       </p></dd></dl></div><p>264   </p><p>265    The following command-line options control the generation of the266    backup and the invocation of the program:267 268    </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>269        Sets checkpoint mode to fast (immediate) or spread (the default)270        (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>).271       </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>272        Specifies that the replication slot named by the273        <code class="literal">--slot</code> option should be created before starting274        the backup.  An error is raised if the slot already exists.275       </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>276        Sets the label for the backup. If none is specified, a default value of277        <span class="quote">“<span class="quote"><code class="literal">pg_basebackup base backup</code></span>”</span> will be used.278       </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>279        By default, when <code class="command">pg_basebackup</code> aborts with an280        error, it removes any directories it might have created before281        discovering that it cannot finish the job (for example, the target282        directory and write-ahead log directory). This option inhibits283        tidying-up and is thus useful for debugging.284       </p><p>285        Note that tablespace directories are not cleaned up either way.286       </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>287        By default, <code class="command">pg_basebackup</code> will wait for all files288        to be written safely to disk.  This option causes289        <code class="command">pg_basebackup</code> to return without waiting, which is290        faster, but means that a subsequent operating system crash can leave291        the base backup corrupt.  Generally, this option is useful for testing292        but should not be used when creating a production installation.293       </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>294        Enables progress reporting. Turning this on will deliver an approximate295        progress report during the backup. Since the database may change during296        the backup, this is only an approximation and may not end at exactly297        <code class="literal">100%</code>. In particular, when WAL log is included in the298        backup, the total amount of data cannot be estimated in advance, and299        in this case the estimated target size will increase once it passes the300        total estimate without WAL.301       </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>302        Sets the maximum transfer rate at which data is collected from the303        source server.  This can be useful to limit the impact304        of <span class="application">pg_basebackup</span> on the server.  Values305        are in kilobytes per second.  Use a suffix of <code class="literal">M</code>306        to indicate megabytes per second.  A suffix of <code class="literal">k</code>307        is also accepted, and has no effect.  Valid values are between 32308        kilobytes per second and 1024 megabytes per second.309       </p><p>310        This option always affects transfer of the data directory. Transfer of311        WAL files is only affected if the collection method312        is <code class="literal">fetch</code>.313       </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>314        This option can only be used together with <code class="literal">-X315        stream</code>.  It causes WAL streaming to use the specified316        replication slot.  If the base backup is intended to be used as a317        streaming-replication standby using a replication slot, the standby318        should then use the same replication slot name as319        <a class="xref" href="runtime-config-replication.html#GUC-PRIMARY-SLOT-NAME">primary_slot_name</a>.  This ensures that the320        primary server does not remove any necessary WAL data in the time321        between the end of the base backup and the start of streaming322        replication on the new standby.323       </p><p>324        The specified replication slot has to exist unless the325        option <code class="option">-C</code> is also used.326       </p><p>327        If this option is not specified and the server supports temporary328        replication slots (version 10 and later), then a temporary replication329        slot is automatically used for WAL streaming.330       </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>331        Enables verbose mode. Will output some extra steps during startup and332        shutdown, as well as show the exact file name that is currently being333        processed if progress reporting is also enabled.334       </p></dd><dt><span class="term"><code class="option">--manifest-checksums=<em class="replaceable"><code>algorithm</code></em></code></span></dt><dd><p>335        Specifies the checksum algorithm that should be applied to each file336        included in the backup manifest. Currently, the available337        algorithms are <code class="literal">NONE</code>, <code class="literal">CRC32C</code>,338        <code class="literal">SHA224</code>, <code class="literal">SHA256</code>,339        <code class="literal">SHA384</code>, and <code class="literal">SHA512</code>.340        The default is <code class="literal">CRC32C</code>.341       </p><p>342        If <code class="literal">NONE</code> is selected, the backup manifest will343        not contain any checksums. Otherwise, it will contain a checksum344        of each file in the backup using the specified algorithm. In addition,345        the manifest will always contain a <code class="literal">SHA256</code>346        checksum of its own contents. The <code class="literal">SHA</code> algorithms347        are significantly more CPU-intensive than <code class="literal">CRC32C</code>,348        so selecting one of them may increase the time required to complete349        the backup.350       </p><p>351        Using a SHA hash function provides a cryptographically secure digest352        of each file for users who wish to verify that the backup has not been353        tampered with, while the CRC32C algorithm provides a checksum that is354        much faster to calculate; it is good at catching errors due to accidental355        changes but is not resistant to malicious modifications.  Note that, to356        be useful against an adversary who has access to the backup, the backup357        manifest would need to be stored securely elsewhere or otherwise358        verified not to have been modified since the backup was taken.359       </p><p>360        <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 the361        integrity of a backup against the backup manifest.362       </p></dd><dt><span class="term"><code class="option">--manifest-force-encode</code></span></dt><dd><p>363        Forces all filenames in the backup manifest to be hex-encoded.364        If this option is not specified, only non-UTF8 filenames are365        hex-encoded. This option is mostly intended to test that tools which366        read a backup manifest file properly handle this case.367       </p></dd><dt><span class="term"><code class="option">--no-estimate-size</code></span></dt><dd><p>368        Prevents the server from estimating the total369        amount of backup data that will be streamed, resulting in the370        <code class="structfield">backup_total</code> column in the371        <code class="structname">pg_stat_progress_basebackup</code> view372        always being <code class="literal">NULL</code>.373       </p><p>374        Without this option, the backup will start by enumerating375        the size of the entire database, and then go back and send376        the actual contents. This may make the backup take slightly377        longer, and in particular it will take longer before the first378        data is sent. This option is useful to avoid such estimation379        time if it's too long.380       </p><p>381        This option is not allowed when using <code class="option">--progress</code>.382       </p></dd><dt><span class="term"><code class="option">--no-manifest</code></span></dt><dd><p>383        Disables generation of a backup manifest. If this option is not384        specified, the server will generate and send a backup manifest385        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>.386        The manifest is a list of every file present in the backup with the387        exception of any WAL files that may be included. It also stores the388        size, last modification time, and an optional checksum for each file.389       </p></dd><dt><span class="term"><code class="option">--no-slot</code></span></dt><dd><p>390        Prevents the creation of a temporary replication slot391        for the backup.392       </p><p>393        By default, if log streaming is selected but no slot name is given394        with the <code class="option">-S</code> option, then a temporary replication395        slot is created (if supported by the source server).396       </p><p>397        The main purpose of this option is to allow taking a base backup when398        the server has no free replication slots.  Using a replication slot399        is almost always preferred, because it prevents needed WAL from being400        removed by the server during the backup.401       </p></dd><dt><span class="term"><code class="option">--no-verify-checksums</code></span></dt><dd><p>402        Disables verification of checksums, if they are enabled on the server403        the base backup is taken from.404       </p><p>405        By default, checksums are verified and checksum failures will result406        in a non-zero exit status. However, the base backup will not be407        removed in such a case, as if the <code class="option">--no-clean</code> option408        had been used.  Checksum verification failures will also be reported409        in the <a class="link" href="monitoring-stats.html#MONITORING-PG-STAT-DATABASE-VIEW" title="28.2.16. pg_stat_database">410        <code class="structname">pg_stat_database</code></a> view.411       </p></dd></dl></div><p>412   </p><p>413    The following command-line options control the connection to the source414    server:415 416    </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>417        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>;  these418        will override any conflicting command line options.419       </p><p>420        The option is called <code class="literal">--dbname</code> for consistency with other421        client applications, but because <span class="application">pg_basebackup</span>422        doesn't connect to any particular database in the cluster, any database423        name in the connection string will be ignored.424       </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>425        Specifies the host name of the machine on which the server is426        running.  If the value begins with a slash, it is used as the427        directory for a Unix domain socket. The default is taken428        from the <code class="envar">PGHOST</code> environment variable, if set,429        else a Unix domain socket connection is attempted.430       </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>431        Specifies the TCP port or local Unix domain socket file432        extension on which the server is listening for connections.433        Defaults to the <code class="envar">PGPORT</code> environment variable, if434        set, or a compiled-in default.435       </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>436        Specifies the number of seconds between status packets sent back to437        the source server. Smaller values allow more accurate monitoring of438        backup progress from the server.439        A value of zero disables periodic status updates completely,440        although an update will still be sent when requested by the server, to441        avoid timeout-based disconnects. The default value is 10 seconds.442       </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>443        Specifies the user name to connect as.444       </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>445        Prevents issuing a password prompt.  If the server requires446        password authentication and a password is not available by447        other means such as a <code class="filename">.pgpass</code> file, the448        connection attempt will fail.  This option can be useful in449        batch jobs and scripts where no user is present to enter a450        password.451       </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>452        Forces <span class="application">pg_basebackup</span> to prompt for a453        password before connecting to the source server.454       </p><p>455        This option is never essential, since456        <span class="application">pg_basebackup</span> will automatically prompt457        for a password if the server demands password authentication.458        However, <span class="application">pg_basebackup</span> will waste a459        connection attempt finding out that the server wants a password.460        In some cases it is worth typing <code class="option">-W</code> to avoid the extra461        connection attempt.462       </p></dd></dl></div><p>463   </p><p>464    Other options are also available:465 466    </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>467       Prints the <span class="application">pg_basebackup</span> version and exits.468       </p></dd><dt><span class="term"><code class="option">-?</code><br /></span><span class="term"><code class="option">--help</code></span></dt><dd><p>469       Shows help about <span class="application">pg_basebackup</span> command line470       arguments, and exits.471       </p></dd></dl></div><p>472   </p></div><div class="refsect1" id="id-1.9.4.10.7"><h2>Environment</h2><p>473   This utility, like most other <span class="productname">PostgreSQL</span> utilities,474   uses the environment variables supported by <span class="application">libpq</span>475   (see <a class="xref" href="libpq-envars.html" title="34.15. Environment Variables">Section 34.15</a>).476  </p><p>477   The environment variable <code class="envar">PG_COLOR</code> specifies whether to use478   color in diagnostic messages. Possible values are479   <code class="literal">always</code>, <code class="literal">auto</code> and480   <code class="literal">never</code>.481  </p></div><div class="refsect1" id="id-1.9.4.10.8"><h2>Notes</h2><p>482   At the beginning of the backup, a checkpoint needs to be performed on the483   source server.  This can take some time (especially if the option484   <code class="literal">--checkpoint=fast</code> is not used), during485   which <span class="application">pg_basebackup</span> will appear to be idle.486  </p><p>487   The backup will include all files in the data directory and tablespaces,488   including the configuration files and any additional files placed in the489   directory by third parties, except certain temporary files managed by490   PostgreSQL and operating system files.  But only regular files and491   directories are copied, except that492   symbolic links used for tablespaces are preserved.  Symbolic links pointing493   to certain directories known to PostgreSQL are copied as empty directories.494   Other symbolic links and special device files are skipped.495   See <a class="xref" href="protocol-replication.html" title="55.4. Streaming Replication Protocol">Section 55.4</a> for the precise details.496  </p><p>497   In plain format, tablespaces will be backed up to the same path498   they have on the source server, unless the499   option <code class="literal">--tablespace-mapping</code> is used.  Without500   this option, running a plain format base backup on the same host as the501   server will not work if tablespaces are in use, because the backup would502   have to be written to the same directory locations as the original503   tablespaces.504  </p><p>505   When tar format is used, it is the user's responsibility to unpack each506   tar file before starting a PostgreSQL server that uses the data. If there507   are additional tablespaces, the508   tar files for them need to be unpacked in the correct locations. In this509   case the symbolic links for those tablespaces will be created by the server510   according to the contents of the <code class="filename">tablespace_map</code> file that is511   included in the <code class="filename">base.tar</code> file.512  </p><p>513   <span class="application">pg_basebackup</span> works with servers of the same514   or an older major version, down to 9.1. However, WAL streaming mode (<code class="literal">-X515   stream</code>) only works with server version 9.3 and later, and tar format516   (<code class="literal">--format=tar</code>) only works with server version 9.5517   and later.518  </p><p>519   <span class="application">pg_basebackup</span> will preserve group permissions520   for data files if group permissions are enabled on the source cluster.521  </p></div><div class="refsect1" id="id-1.9.4.10.9"><h2>Examples</h2><p>522   To create a base backup of the server at <code class="literal">mydbserver</code>523   and store it in the local directory524   <code class="filename">/usr/local/pgsql/data</code>:525</p><pre class="screen">526<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -h mydbserver -D /usr/local/pgsql/data</code></strong>527</pre><p>528  </p><p>529   To create a backup of the local server with one compressed530   tar file for each tablespace, and store it in the directory531   <code class="filename">backup</code>, showing a progress report while running:532</p><pre class="screen">533<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D backup -Ft -z -P</code></strong>534</pre><p>535  </p><p>536   To create a backup of a single-tablespace local database and compress537   this with <span class="productname">bzip2</span>:538</p><pre class="screen">539<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D - -Ft -X fetch | bzip2 &gt; backup.tar.bz2</code></strong>540</pre><p>541   (This command will fail if there are multiple tablespaces in the542   database.)543  </p><p>544   To create a backup of a local database where the tablespace in545   <code class="filename">/opt/ts</code> is relocated546   to <code class="filename">./backup/ts</code>:547</p><pre class="screen">548<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D backup/data -T /opt/ts=$(pwd)/backup/ts</code></strong>549</pre><p>550   To create a backup of a local server with one tar file for each tablespace551   compressed with <span class="application">gzip</span> at level 9, stored in the552   directory <code class="filename">backup</code>:553</p><pre class="screen">554<code class="prompt">$</code> <strong class="userinput"><code>pg_basebackup -D backup -Ft --compress=gzip:9</code></strong>555</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>