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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_amcheck</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-ecpg.html" title="ecpg" /><link rel="next" href="app-pgbasebackup.html" title="pg_basebackup" /></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_amcheck</span></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="app-ecpg.html" title="ecpg">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="app-pgbasebackup.html" title="pg_basebackup">Next</a></td></tr></table><hr /></div><div class="refentry" id="APP-PGAMCHECK"><div class="titlepage"></div><a id="id-1.9.4.9.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle"><span class="application">pg_amcheck</span></span></h2><p>pg_amcheck — checks for corruption in one or more |
| <span class="productname">PostgreSQL</span> databases</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p id="id-1.9.4.9.4.1"><code class="command">pg_amcheck</code> [<em class="replaceable"><code>option</code></em>...] [<em class="replaceable"><code>dbname</code></em>]</p></div></div><div class="refsect1" id="id-1.9.4.9.5"><h2>Description</h2><p> |
| <span class="application">pg_amcheck</span> supports running |
| <a class="xref" href="amcheck.html" title="F.2. amcheck — tools to verify table and index consistency">amcheck</a>'s corruption checking functions against one or |
| more databases, with options to select which schemas, tables and indexes to |
| check, which kinds of checking to perform, and whether to perform the checks |
| in parallel, and if so, the number of parallel connections to establish and |
| use. |
| </p><p> |
| Only ordinary and toast table relations, materialized views, sequences, and |
| btree indexes are currently supported. Other relation types are silently |
| skipped. |
| </p><p> |
| If <code class="literal">dbname</code> is specified, it should be the name of a |
| single database to check, and no other database selection options should |
| be present. Otherwise, if any database selection options are present, |
| all matching databases will be checked. If no such options are present, |
| the default database will be checked. Database selection options include |
| <code class="option">--all</code>, <code class="option">--database</code> and |
| <code class="option">--exclude-database</code>. They also include |
| <code class="option">--relation</code>, <code class="option">--exclude-relation</code>, |
| <code class="option">--table</code>, <code class="option">--exclude-table</code>, |
| <code class="option">--index</code>, and <code class="option">--exclude-index</code>, |
| but only when such options are used with a three-part pattern |
| (e.g. <code class="option">mydb*.myschema*.myrel*</code>). Finally, they include |
| <code class="option">--schema</code> and <code class="option">--exclude-schema</code> |
| when such options are used with a two-part pattern |
| (e.g. <code class="option">mydb*.myschema*</code>). |
| </p><p> |
| <em class="replaceable"><code>dbname</code></em> can also be a |
| <a class="link" href="libpq-connect.html#LIBPQ-CONNSTRING" title="34.1.1. Connection Strings">connection string</a>. |
| </p></div><div class="refsect1" id="id-1.9.4.9.6"><h2>Options</h2><p> |
| The following command-line options control what is checked: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-a</code><br /></span><span class="term"><code class="option">--all</code></span></dt><dd><p> |
| Check all databases, except for any excluded via |
| <code class="option">--exclude-database</code>. |
| </p></dd><dt><span class="term"><code class="option">-d <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--database=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Check databases matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>, |
| except for any excluded by <code class="option">--exclude-database</code>. |
| This option can be specified more than once. |
| </p></dd><dt><span class="term"><code class="option">-D <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--exclude-database=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Exclude databases matching the given |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>. |
| This option can be specified more than once. |
| </p></dd><dt><span class="term"><code class="option">-i <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--index=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Check indexes matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>, |
| unless they are otherwise excluded. |
| This option can be specified more than once. |
| </p><p> |
| This is similar to the <code class="option">--relation</code> option, except that |
| it applies only to indexes, not to other relation types. |
| </p></dd><dt><span class="term"><code class="option">-I <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--exclude-index=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Exclude indexes matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>. |
| This option can be specified more than once. |
| </p><p> |
| This is similar to the <code class="option">--exclude-relation</code> option, |
| except that it applies only to indexes, not other relation types. |
| </p></dd><dt><span class="term"><code class="option">-r <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--relation=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Check relations matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>, |
| unless they are otherwise excluded. |
| This option can be specified more than once. |
| </p><p> |
| Patterns may be unqualified, e.g. <code class="literal">myrel*</code>, or they |
| may be schema-qualified, e.g. <code class="literal">myschema*.myrel*</code> or |
| database-qualified and schema-qualified, e.g. |
| <code class="literal">mydb*.myschema*.myrel*</code>. A database-qualified |
| pattern will add matching databases to the list of databases to be |
| checked. |
| </p></dd><dt><span class="term"><code class="option">-R <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--exclude-relation=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Exclude relations matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>. |
| This option can be specified more than once. |
| </p><p> |
| As with <code class="option">--relation</code>, the |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a> may be unqualified, schema-qualified, |
| or database- and schema-qualified. |
| </p></dd><dt><span class="term"><code class="option">-s <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--schema=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Check tables and indexes in schemas matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>, unless they are otherwise excluded. |
| This option can be specified more than once. |
| </p><p> |
| To select only tables in schemas matching a particular pattern, |
| consider using something like |
| <code class="literal">--table=SCHEMAPAT.* --no-dependent-indexes</code>. |
| To select only indexes, consider using something like |
| <code class="literal">--index=SCHEMAPAT.*</code>. |
| </p><p> |
| A schema pattern may be database-qualified. For example, you may |
| write <code class="literal">--schema=mydb*.myschema*</code> to select |
| schemas matching <code class="literal">myschema*</code> in databases matching |
| <code class="literal">mydb*</code>. |
| </p></dd><dt><span class="term"><code class="option">-S <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--exclude-schema=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Exclude tables and indexes in schemas matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>. |
| This option can be specified more than once. |
| </p><p> |
| As with <code class="option">--schema</code>, the pattern may be |
| database-qualified. |
| </p></dd><dt><span class="term"><code class="option">-t <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--table=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Check tables matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>, |
| unless they are otherwise excluded. |
| This option can be specified more than once. |
| </p><p> |
| This is similar to the <code class="option">--relation</code> option, except that |
| it applies only to tables, materialized views, and sequences, not to |
| indexes. |
| </p></dd><dt><span class="term"><code class="option">-T <em class="replaceable"><code>pattern</code></em></code><br /></span><span class="term"><code class="option">--exclude-table=<em class="replaceable"><code>pattern</code></em></code></span></dt><dd><p> |
| Exclude tables matching the specified |
| <a class="link" href="app-psql.html#APP-PSQL-PATTERNS" title="Patterns"><em class="replaceable"><code>pattern</code></em></a>. |
| This option can be specified more than once. |
| </p><p> |
| This is similar to the <code class="option">--exclude-relation</code> option, |
| except that it applies only to tables, materialized views, and |
| sequences, not to indexes. |
| </p></dd><dt><span class="term"><code class="option">--no-dependent-indexes</code></span></dt><dd><p> |
| By default, if a table is checked, any btree indexes of that table |
| will also be checked, even if they are not explicitly selected by |
| an option such as <code class="literal">--index</code> or |
| <code class="literal">--relation</code>. This option suppresses that behavior. |
| </p></dd><dt><span class="term"><code class="option">--no-dependent-toast</code></span></dt><dd><p> |
| By default, if a table is checked, its toast table, if any, will also |
| be checked, even if it is not explicitly selected by an option |
| such as <code class="literal">--table</code> or <code class="literal">--relation</code>. |
| This option suppresses that behavior. |
| </p></dd><dt><span class="term"><code class="option">--no-strict-names</code></span></dt><dd><p> |
| By default, if an argument to <code class="literal">--database</code>, |
| <code class="literal">--table</code>, <code class="literal">--index</code>, |
| or <code class="literal">--relation</code> matches no objects, it is a fatal |
| error. This option downgrades that error to a warning. |
| </p></dd></dl></div><p> |
| </p><p> |
| The following command-line options control checking of tables: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">--exclude-toast-pointers</code></span></dt><dd><p> |
| By default, whenever a toast pointer is encountered in a table, |
| a lookup is performed to ensure that it references apparently-valid |
| entries in the toast table. These checks can be quite slow, and this |
| option can be used to skip them. |
| </p></dd><dt><span class="term"><code class="option">--on-error-stop</code></span></dt><dd><p> |
| After reporting all corruptions on the first page of a table where |
| corruption is found, stop processing that table relation and move on |
| to the next table or index. |
| </p><p> |
| Note that index checking always stops after the first corrupt page. |
| This option only has meaning relative to table relations. |
| </p></dd><dt><span class="term"><code class="option">--skip=<em class="replaceable"><code>option</code></em></code></span></dt><dd><p> |
| If <code class="literal">all-frozen</code> is given, table corruption checks |
| will skip over pages in all tables that are marked as all frozen. |
| </p><p> |
| If <code class="literal">all-visible</code> is given, table corruption checks |
| will skip over pages in all tables that are marked as all visible. |
| </p><p> |
| By default, no pages are skipped. This can be specified as |
| <code class="literal">none</code>, but since this is the default, it need not be |
| mentioned. |
| </p></dd><dt><span class="term"><code class="option">--startblock=<em class="replaceable"><code>block</code></em></code></span></dt><dd><p> |
| Start checking at the specified block number. An error will occur if |
| the table relation being checked has fewer than this number of blocks. |
| This option does not apply to indexes, and is probably only useful |
| when checking a single table relation. See <code class="literal">--endblock</code> |
| for further caveats. |
| </p></dd><dt><span class="term"><code class="option">--endblock=<em class="replaceable"><code>block</code></em></code></span></dt><dd><p> |
| End checking at the specified block number. An error will occur if the |
| table relation being checked has fewer than this number of blocks. |
| This option does not apply to indexes, and is probably only useful when |
| checking a single table relation. If both a regular table and a toast |
| table are checked, this option will apply to both, but higher-numbered |
| toast blocks may still be accessed while validating toast pointers, |
| unless that is suppressed using |
| <code class="option">--exclude-toast-pointers</code>. |
| </p></dd></dl></div><p> |
| </p><p> |
| The following command-line options control checking of B-tree indexes: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">--heapallindexed</code></span></dt><dd><p> |
| For each index checked, verify the presence of all heap tuples as index |
| tuples in the index using <a class="xref" href="amcheck.html" title="F.2. amcheck — tools to verify table and index consistency">amcheck</a>'s |
| <code class="option">heapallindexed</code> option. |
| </p></dd><dt><span class="term"><code class="option">--parent-check</code></span></dt><dd><p> |
| For each btree index checked, use <a class="xref" href="amcheck.html" title="F.2. amcheck — tools to verify table and index consistency">amcheck</a>'s |
| <code class="function">bt_index_parent_check</code> function, which performs |
| additional checks of parent/child relationships during index checking. |
| </p><p> |
| The default is to use <span class="application">amcheck</span>'s |
| <code class="function">bt_index_check</code> function, but note that use of the |
| <code class="option">--rootdescend</code> option implicitly selects |
| <code class="function">bt_index_parent_check</code>. |
| </p></dd><dt><span class="term"><code class="option">--rootdescend</code></span></dt><dd><p> |
| For each index checked, re-find tuples on the leaf level by performing a |
| new search from the root page for each tuple using |
| <a class="xref" href="amcheck.html" title="F.2. amcheck — tools to verify table and index consistency">amcheck</a>'s <code class="option">rootdescend</code> option. |
| </p><p> |
| Use of this option implicitly also selects the |
| <code class="option">--parent-check</code> option. |
| </p><p> |
| This form of verification was originally written to help in the |
| development of btree index features. It may be of limited use or even |
| of no use in helping detect the kinds of corruption that occur in |
| practice. It may also cause corruption checking to take considerably |
| longer and consume considerably more resources on the server. |
| </p></dd></dl></div><p> |
| </p><div class="warning"><h3 class="title">Warning</h3><p> |
| The extra checks performed against B-tree indexes when the |
| <code class="option">--parent-check</code> option or the |
| <code class="option">--rootdescend</code> option is specified require |
| relatively strong relation-level locks. These checks are the only |
| checks that will block concurrent data modification from |
| <code class="command">INSERT</code>, <code class="command">UPDATE</code>, and |
| <code class="command">DELETE</code> commands. |
| </p></div><p> |
| The following command-line options control the connection to the server: |
|
|
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="option">-h <em class="replaceable"><code>hostname</code></em></code><br /></span><span class="term"><code class="option">--host=<em class="replaceable"><code>hostname</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 the |
| Unix domain socket. |
| </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. |
| </p></dd><dt><span class="term"><code class="option">-U</code><br /></span><span class="term"><code class="option">--username=<em class="replaceable"><code>username</code></em></code></span></dt><dd><p> |
| 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> |
| Never issue 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> |
| Force <span class="application">pg_amcheck</span> to prompt for a password |
| before connecting to a database. |
| </p><p> |
| This option is never essential, since |
| <span class="application">pg_amcheck</span> will automatically prompt for a |
| password if the server demands password authentication. However, |
| <span class="application">pg_amcheck</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><dt><span class="term"><code class="option">--maintenance-db=<em class="replaceable"><code>dbname</code></em></code></span></dt><dd><p> |
| Specifies a database or |
| <a class="link" href="libpq-connect.html#LIBPQ-CONNSTRING" title="34.1.1. Connection Strings">connection string</a> to be |
| used to discover the list of databases to be checked. If neither |
| <code class="option">--all</code> nor any option including a database pattern is |
| used, no such connection is required and this option does nothing. |
| Otherwise, any connection string parameters other than |
| the database name which are included in the value for this option |
| will also be used when connecting to the databases |
| being checked. If this option is omitted, the default is |
| <code class="literal">postgres</code> or, if that fails, |
| <code class="literal">template1</code>. |
| </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">-e</code><br /></span><span class="term"><code class="option">--echo</code></span></dt><dd><p> |
| Echo to stdout all SQL sent to the server. |
| </p></dd><dt><span class="term"><code class="option">-j <em class="replaceable"><code>num</code></em></code><br /></span><span class="term"><code class="option">--jobs=<em class="replaceable"><code>num</code></em></code></span></dt><dd><p> |
| Use <em class="replaceable"><code>num</code></em> concurrent connections to the server, |
| or one per object to be checked, whichever is less. |
| </p><p> |
| The default is to use a single connection. |
| </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> |
| Show progress information. Progress information includes the number |
| of relations for which checking has been completed, and the total |
| size of those relations. It also includes the total number of relations |
| that will eventually be checked, and the estimated size of those |
| relations. |
| </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> |
| Print more messages. In particular, this will print a message for |
| each relation being checked, and will increase the level of detail |
| shown for server errors. |
| </p></dd><dt><span class="term"><code class="option">-V</code><br /></span><span class="term"><code class="option">--version</code></span></dt><dd><p> |
| Print the <span class="application">pg_amcheck</span> version and exit. |
| </p></dd><dt><span class="term"><code class="option">--install-missing</code><br /></span><span class="term"><code class="option">--install-missing=<em class="replaceable"><code>schema</code></em></code></span></dt><dd><p> |
| Install any missing extensions that are required to check the |
| database(s). If not yet installed, each extension's objects will be |
| installed into the given |
| <em class="replaceable"><code>schema</code></em>, or if not specified |
| into schema <code class="literal">pg_catalog</code>. |
| </p><p> |
| At present, the only required extension is <a class="xref" href="amcheck.html" title="F.2. amcheck — tools to verify table and index consistency">amcheck</a>. |
| </p></dd><dt><span class="term"><code class="option">-?</code><br /></span><span class="term"><code class="option">--help</code></span></dt><dd><p> |
| Show help about <span class="application">pg_amcheck</span> command line |
| arguments, and exit. |
| </p></dd></dl></div><p> |
| </p></div><div class="refsect1" id="id-1.9.4.9.7"><h2>Notes</h2><p> |
| <span class="application">pg_amcheck</span> is designed to work with |
| <span class="productname">PostgreSQL</span> 14.0 and later. |
| </p></div><div class="refsect1" id="id-1.9.4.9.8"><h2>See Also</h2><span class="simplelist"><a class="xref" href="amcheck.html" title="F.2. amcheck — tools to verify table and index consistency">amcheck</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-ecpg.html" title="ecpg">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="app-pgbasebackup.html" title="pg_basebackup">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="application">ecpg</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">pg_basebackup</span></td></tr></table></div></body></html> |
