pg_amcheck — checks for corruption in one or more PostgreSQL databases
pg_amcheck [option...] [dbname]
pg_amcheck supports running amcheck'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.
Only table relations and btree indexes are currently supported. Other relation types are silently skipped.
   If dbname 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
   --all, --database and
   --exclude-database. They also include
   --relation, --exclude-relation,
   --table, --exclude-table,
   --index, and --exclude-index,
   but only when such options are used with a three-part pattern
   (e.g. mydb*.myschema*.myrel*).  Finally, they include
   --schema and --exclude-schema
   when such options are used with a two-part pattern
   (e.g. mydb*.myschema*).
  
   dbname can also be a
   connection string.
  
The following command-line options control what is checked:
-a--all
       Check all databases, except for any excluded via
       --exclude-database.
      
-d pattern--database=pattern
       Check databases matching the specified
       pattern,
       except for any excluded by --exclude-database.
       This option can be specified more than once.
      
-D pattern--exclude-database=pattern
       Exclude databases matching the given
       pattern.
       This option can be specified more than once.
      
-i pattern--index=pattern
       Check indexes matching the specified
       pattern,
       unless they are otherwise excluded.
       This option can be specified more than once.
      
       This is similar to the --relation option, except that
       it applies only to indexes, not tables.
      
-I pattern--exclude-index=pattern
       Exclude indexes matching the specified
       pattern.
       This option can be specified more than once.
      
       This is similar to the --exclude-relation option,
       except that it applies only to indexes, not tables.
      
-r pattern--relation=pattern
       Check relations matching the specified
       pattern,
       unless they are otherwise excluded.
       This option can be specified more than once.
      
       Patterns may be unqualified, e.g. myrel*, or they
       may be schema-qualified, e.g. myschema*.myrel* or
       database-qualified and schema-qualified, e.g.
       mydb*.myschema*.myrel*. A database-qualified
       pattern will add matching databases to the list of databases to be
       checked.
      
-R pattern--exclude-relation=pattern
       Exclude relations matching the specified
       pattern.
       This option can be specified more than once.
      
       As with --relation, the
       pattern may be unqualified, schema-qualified,
       or database- and schema-qualified.
      
-s pattern--schema=pattern
       Check tables and indexes in schemas matching the specified
       pattern, unless they are otherwise excluded.
       This option can be specified more than once.
      
       To select only tables in schemas matching a particular pattern,
       consider using something like
       --table=SCHEMAPAT.* --no-dependent-indexes.
       To select only indexes, consider using something like
       --index=SCHEMAPAT.*.
      
       A schema pattern may be database-qualified. For example, you may
       write --schema=mydb*.myschema* to select
       schemas matching myschema* in databases matching
       mydb*.
      
-S pattern--exclude-schema=pattern
       Exclude tables and indexes in schemas matching the specified
       pattern.
       This option can be specified more than once.
      
       As with --schema, the pattern may be
       database-qualified.
      
-t pattern--table=pattern
       Check tables matching the specified
       pattern,
       unless they are otherwise excluded.
       This option can be specified more than once.
      
       This is similar to the --relation option, except that
       it applies only to tables, not indexes.
      
-T pattern--exclude-table=pattern
       Exclude tables matching the specified
       pattern.
       This option can be specified more than once.
      
       This is similar to the --exclude-relation option,
       except that it applies only to tables, not indexes.
      
--no-dependent-indexes
       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 --index or
       --relation. This option suppresses that behavior.
      
--no-dependent-toast
       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 --table or --relation.
       This option suppresses that behavior.
      
--no-strict-names
       By default, if an argument to --database,
       --table, --index,
       or --relation matches no objects, it is a fatal
       error. This option downgrades that error to a warning.
      
The following command-line options control checking of tables:
--exclude-toast-pointersBy 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.
--on-error-stopAfter 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.
Note that index checking always stops after the first corrupt page. This option only has meaning relative to table relations.
--skip=option
       If all-frozen is given, table corruption checks
       will skip over pages in all tables that are marked as all frozen.
      
       If all-visible is given, table corruption checks
       will skip over pages in all tables that are marked as all visible.
      
       By default, no pages are skipped.  This can be specified as
       none, but since this is the default, it need not be
       mentioned.
      
--startblock=block
       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 --endblock
       for further caveats.
      
--endblock=block
       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
       --exclude-toast-pointers.
      
The following command-line options control checking of B-tree indexes:
--heapallindexed
       For each index checked, verify the presence of all heap tuples as index
       tuples in the index using amcheck's
       heapallindexed option.
      
--parent-check
       For each btree index checked, use amcheck's
       bt_index_parent_check function, which performs
       additional checks of parent/child relationships during index checking.
      
       The default is to use amcheck's
       bt_index_check function, but note that use of the
       --rootdescend option implicitly selects
       bt_index_parent_check.
      
--rootdescend
       For each index checked, re-find tuples on the leaf level by performing a
       new search from the root page for each tuple using
       amcheck's rootdescend option.
      
       Use of this option implicitly also selects the
       --parent-check option.
      
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.
    The extra checks performed against B-tree indexes when the
    --parent-check option or the
    --rootdescend option is specified require
    relatively strong relation-level locks.  These checks are the only
    checks that will block concurrent data modification from
    INSERT, UPDATE, and
    DELETE commands.
   
The following command-line options control the connection to the server:
-h hostname--host=hostnameSpecifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix domain socket.
-p port--port=portSpecifies the TCP port or local Unix domain socket file extension on which the server is listening for connections.
-U--username=usernameUser name to connect as.
-w--no-password
       Never issue a password prompt.  If the server requires password
       authentication and a password is not available by other means such as
       a .pgpass file, the connection attempt will fail.
       This option can be useful in batch jobs and scripts where no user is
       present to enter a password.
      
-W--passwordForce pg_amcheck to prompt for a password before connecting to a database.
       This option is never essential, since
       pg_amcheck will automatically prompt for a
       password if the server demands password authentication.  However,
       pg_amcheck will waste a connection attempt
       finding out that the server wants a password.  In some cases it is
       worth typing -W to avoid the extra connection attempt.
      
--maintenance-db=dbname
       Specifies a database or
       connection string to be
       used to discover the list of databases to be checked. If neither
       --all 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
       postgres or, if that fails,
       template1.
      
Other options are also available:
-e--echoEcho to stdout all SQL sent to the server.
-j num--jobs=num
       Use num concurrent connections to the server,
       or one per object to be checked, whichever is less.
      
The default is to use a single connection.
-P--progressShow 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.
-v--verbosePrint 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.
-V--versionPrint the pg_amcheck version and exit.
--install-missing--install-missing=schema
       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
       schema, or if not specified
       into schema pg_catalog.
      
At present, the only required extension is amcheck.
-?--helpShow help about pg_amcheck command line arguments, and exit.
pg_amcheck is designed to work with PostgreSQL 14.0 and later.