diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 4f3f375a84..670a5406d6 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9580,4745 +9580,4 @@ SCRAM-SHA-256$<iteration count>:&l - - - System Views - - - In addition to the system catalogs, PostgreSQL - provides a number of built-in views. Some system views provide convenient - access to some commonly used queries on the system catalogs. Other views - provide access to internal server state. - - - - The information schema () provides - an alternative set of views which overlap the functionality of the system - views. Since the information schema is SQL-standard whereas the views - described here are PostgreSQL-specific, - it's usually better to use the information schema if it provides all - the information you need. - - - - lists the system views described here. - More detailed documentation of each view follows below. - There are some additional views that provide access to accumulated - statistics; they are described in - . - - - - Except where noted, all the views described here are read-only. - - - - System Views - - - - - View Name - Purpose - - - - - - pg_available_extensions - available extensions - - - - pg_available_extension_versions - available versions of extensions - - - - pg_backend_memory_contexts - backend memory contexts - - - - pg_config - compile-time configuration parameters - - - - pg_cursors - open cursors - - - - pg_file_settings - summary of configuration file contents - - - - pg_group - groups of database users - - - - pg_hba_file_rules - summary of client authentication configuration file contents - - - - pg_ident_file_mappings - summary of client user name mapping configuration file contents - - - - pg_indexes - indexes - - - - pg_locks - locks currently held or awaited - - - - pg_matviews - materialized views - - - - pg_policies - policies - - - - pg_prepared_statements - prepared statements - - - - pg_prepared_xacts - prepared transactions - - - - pg_publication_tables - publications and information of their associated tables - - - - pg_replication_origin_status - information about replication origins, including replication progress - - - - pg_replication_slots - replication slot information - - - - pg_roles - database roles - - - - pg_rules - rules - - - - pg_seclabels - security labels - - - - pg_sequences - sequences - - - - pg_settings - parameter settings - - - - pg_shadow - database users - - - - pg_shmem_allocations - shared memory allocations - - - - pg_stats - planner statistics - - - - pg_stats_ext - extended planner statistics - - - - pg_stats_ext_exprs - extended planner statistics for expressions - - - - pg_tables - tables - - - - pg_timezone_abbrevs - time zone abbreviations - - - - pg_timezone_names - time zone names - - - - pg_user - database users - - - - pg_user_mappings - user mappings - - - - pg_views - views - - - - -
- - - - <structname>pg_available_extensions</structname> - - - pg_available_extensions - - - - The pg_available_extensions view lists the - extensions that are available for installation. - See also the - pg_extension - catalog, which shows the extensions currently installed. - - - - <structname>pg_available_extensions</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name name - - - Extension name - - - - - - default_version text - - - Name of default version, or NULL if none is - specified - - - - - - installed_version text - - - Currently installed version of the extension, - or NULL if not installed - - - - - - comment text - - - Comment string from the extension's control file - - - - -
- - - The pg_available_extensions view is read-only. - - - - - <structname>pg_available_extension_versions</structname> - - - pg_available_extension_versions - - - - The pg_available_extension_versions view lists the - specific extension versions that are available for installation. - See also the pg_extension - catalog, which shows the extensions currently installed. - - - - <structname>pg_available_extension_versions</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name name - - - Extension name - - - - - - version text - - - Version name - - - - - - installed bool - - - True if this version of this extension is currently - installed - - - - - - superuser bool - - - True if only superusers are allowed to install this extension - (but see trusted) - - - - - - trusted bool - - - True if the extension can be installed by non-superusers - with appropriate privileges - - - - - - relocatable bool - - - True if extension can be relocated to another schema - - - - - - schema name - - - Name of the schema that the extension must be installed into, - or NULL if partially or fully relocatable - - - - - - requires name[] - - - Names of prerequisite extensions, - or NULL if none - - - - - - comment text - - - Comment string from the extension's control file - - - - -
- - - The pg_available_extension_versions view is - read-only. - - - - - <structname>pg_backend_memory_contexts</structname> - - - pg_backend_memory_contexts - - - - The view pg_backend_memory_contexts displays all - the memory contexts of the server process attached to the current session. - - - pg_backend_memory_contexts contains one row - for each memory context. - - - - <structname>pg_backend_memory_contexts</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name text - - - Name of the memory context - - - - - - ident text - - - Identification information of the memory context. This field is truncated at 1024 bytes - - - - - - parent text - - - Name of the parent of this memory context - - - - - - level int4 - - - Distance from TopMemoryContext in context tree - - - - - - total_bytes int8 - - - Total bytes allocated for this memory context - - - - - - total_nblocks int8 - - - Total number of blocks allocated for this memory context - - - - - - free_bytes int8 - - - Free space in bytes - - - - - - free_chunks int8 - - - Total number of free chunks - - - - - - used_bytes int8 - - - Used space in bytes - - - - -
- - - By default, the pg_backend_memory_contexts view can be - read only by superusers or roles with the privileges of the - pg_read_all_stats role. - - - - - <structname>pg_config</structname> - - - pg_config - - - - The view pg_config describes the - compile-time configuration parameters of the currently installed - version of PostgreSQL. It is intended, for example, to - be used by software packages that want to interface to - PostgreSQL to facilitate finding the required header - files and libraries. It provides the same basic information as the - PostgreSQL client - application. - - - - By default, the pg_config view can be read - only by superusers. - - - - <structname>pg_config</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name text - - - The parameter name - - - - - - setting text - - - The parameter value - - - - -
- - - - - <structname>pg_cursors</structname> - - - pg_cursors - - - - The pg_cursors view lists the cursors that - are currently available. Cursors can be defined in several ways: - - - - via the DECLARE - statement in SQL - - - - - - via the Bind message in the frontend/backend protocol, as - described in - - - - - - via the Server Programming Interface (SPI), as described in - - - - - - The pg_cursors view displays cursors - created by any of these means. Cursors only exist for the duration - of the transaction that defines them, unless they have been - declared WITH HOLD. Therefore non-holdable - cursors are only present in the view until the end of their - creating transaction. - - - - Cursors are used internally to implement some of the components - of PostgreSQL, such as procedural languages. - Therefore, the pg_cursors view might include cursors - that have not been explicitly created by the user. - - - - - - <structname>pg_cursors</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name text - - - The name of the cursor - - - - - - statement text - - - The verbatim query string submitted to declare this cursor - - - - - - is_holdable bool - - - true if the cursor is holdable (that is, it - can be accessed after the transaction that declared the cursor - has committed); false otherwise - - - - - - is_binary bool - - - true if the cursor was declared - BINARY; false - otherwise - - - - - - is_scrollable bool - - - true if the cursor is scrollable (that is, it - allows rows to be retrieved in a nonsequential manner); - false otherwise - - - - - - creation_time timestamptz - - - The time at which the cursor was declared - - - - -
- - - The pg_cursors view is read-only. - - - - - - <structname>pg_file_settings</structname> - - - pg_file_settings - - - - The view pg_file_settings provides a summary of - the contents of the server's configuration file(s). A row appears in - this view for each name = value entry appearing in the files, - with annotations indicating whether the value could be applied - successfully. Additional row(s) may appear for problems not linked to - a name = value entry, such as syntax errors in the files. - - - - This view is helpful for checking whether planned changes in the - configuration files will work, or for diagnosing a previous failure. - Note that this view reports on the current contents of the - files, not on what was last applied by the server. (The - pg_settings - view is usually sufficient to determine that.) - - - - By default, the pg_file_settings view can be read - only by superusers. - - - - <structname>pg_file_settings</structname> Columns - - - - - Column Type - - - Description - - - - - - - - sourcefile text - - - Full path name of the configuration file - - - - - - sourceline int4 - - - Line number within the configuration file where the entry appears - - - - - - seqno int4 - - - Order in which the entries are processed (1..n) - - - - - - name text - - - Configuration parameter name - - - - - - setting text - - - Value to be assigned to the parameter - - - - - - applied bool - - - True if the value can be applied successfully - - - - - - error text - - - If not null, an error message indicating why this entry could - not be applied - - - - -
- - - If the configuration file contains syntax errors or invalid parameter - names, the server will not attempt to apply any settings from it, and - therefore all the applied fields will read as false. - In such a case there will be one or more rows with - non-null error fields indicating the - problem(s). Otherwise, individual settings will be applied if possible. - If an individual setting cannot be applied (e.g., invalid value, or the - setting cannot be changed after server start) it will have an appropriate - message in the error field. Another way that - an entry might have applied = false is that it is - overridden by a later entry for the same parameter name; this case is not - considered an error so nothing appears in - the error field. - - - - See for more information about the various - ways to change run-time parameters. - - - - - - <structname>pg_group</structname> - - - pg_group - - - - - The view pg_group exists for backwards - compatibility: it emulates a catalog that existed in - PostgreSQL before version 8.1. - It shows the names and members of all roles that are marked as not - rolcanlogin, which is an approximation to the set - of roles that are being used as groups. - - - - <structname>pg_group</structname> Columns - - - - - Column Type - - - Description - - - - - - - - groname name - (references pg_authid.rolname) - - - Name of the group - - - - - - grosysid oid - (references pg_authid.oid) - - - ID of this group - - - - - - grolist oid[] - (references pg_authid.oid) - - - An array containing the IDs of the roles in this group - - - - -
- - - - - <structname>pg_hba_file_rules</structname> - - - pg_hba_file_rules - - - - The view pg_hba_file_rules provides a summary of - the contents of the client authentication configuration file, - pg_hba.conf. - A row appears in this view for each - non-empty, non-comment line in the file, with annotations indicating - whether the rule could be applied successfully. - - - - This view can be helpful for checking whether planned changes in the - authentication configuration file will work, or for diagnosing a previous - failure. Note that this view reports on the current contents - of the file, not on what was last loaded by the server. - - - - By default, the pg_hba_file_rules view can be read - only by superusers. - - - - <structname>pg_hba_file_rules</structname> Columns - - - - - Column Type - - - Description - - - - - - - - line_number int4 - - - Line number of this rule in pg_hba.conf - - - - - - type text - - - Type of connection - - - - - - database text[] - - - List of database name(s) to which this rule applies - - - - - - user_name text[] - - - List of user and group name(s) to which this rule applies - - - - - - address text - - - Host name or IP address, or one - of all, samehost, - or samenet, or null for local connections - - - - - - netmask text - - - IP address mask, or null if not applicable - - - - - - auth_method text - - - Authentication method - - - - - - options text[] - - - Options specified for authentication method, if any - - - - - - error text - - - If not null, an error message indicating why this - line could not be processed - - - - -
- - - Usually, a row reflecting an incorrect entry will have values for only - the line_number and error fields. - - - - See for more information about - client authentication configuration. - - - - - <structname>pg_ident_file_mappings</structname> - - - pg_ident_file_mappings - - - - The view pg_ident_file_mappings provides a summary - of the contents of the client user name mapping configuration file, - pg_ident.conf. - A row appears in this view for each non-empty, non-comment line in the file, - with annotations indicating whether the rule could be applied successfully. - - - - This view can be helpful for checking whether planned changes in the - authentication configuration file will work, or for diagnosing a previous - failure. Note that this view reports on the current - contents of the file, not on what was last loaded by the server. - - - - By default, the pg_ident_file_mappings view can be - read only by superusers. - - - - <structname>pg_ident_file_mappings</structname> Columns - - - - Column Type - - - Description - - - - - - - - line_number int4 - - - Line number of this rule in pg_ident.conf - - - - - - map_name text - - - Name of the map - - - - - - sys_name text - - - Detected user name of the client - - - - - - pg_username text - - - Requested PostgreSQL user name - - - - - - error text - - - If not NULL, an error message indicating why this - line could not be processed - - - - -
- - - Usually, a row reflecting an incorrect entry will have values for only - the line_number and error fields. - - - - See for more information about - client authentication configuration. - - - - - <structname>pg_indexes</structname> - - - pg_indexes - - - - The view pg_indexes provides access to - useful information about each index in the database. - - - - <structname>pg_indexes</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table and index - - - - - - tablename name - (references pg_class.relname) - - - Name of table the index is for - - - - - - indexname name - (references pg_class.relname) - - - Name of index - - - - - - tablespace name - (references pg_tablespace.spcname) - - - Name of tablespace containing index (null if default for database) - - - - - - indexdef text - - - Index definition (a reconstructed - command) - - - - -
- - - - - <structname>pg_locks</structname> - - - pg_locks - - - - The view pg_locks provides access to - information about the locks held by active processes within the - database server. See for more discussion - of locking. - - - - pg_locks contains one row per active lockable - object, requested lock mode, and relevant process. Thus, the same - lockable object might - appear many times, if multiple processes are holding or waiting - for locks on it. However, an object that currently has no locks on it - will not appear at all. - - - - There are several distinct types of lockable objects: - whole relations (e.g., tables), individual pages of relations, - individual tuples of relations, - transaction IDs (both virtual and permanent IDs), - and general database objects (identified by class OID and object OID, - in the same way as in pg_description or - pg_depend). Also, the right to extend a - relation is represented as a separate lockable object, as is the right to - update pg_database.datfrozenxid. - Also, advisory locks can be taken on numbers that have - user-defined meanings. - - - - <structname>pg_locks</structname> Columns - - - - - Column Type - - - Description - - - - - - - - locktype text - - - Type of the lockable object: - relation, - extend, - frozenid, - page, - tuple, - transactionid, - virtualxid, - spectoken, - object, - userlock, or - advisory. - (See also .) - - - - - - database oid - (references pg_database.oid) - - - OID of the database in which the lock target exists, or - zero if the target is a shared object, or - null if the target is a transaction ID - - - - - - relation oid - (references pg_class.oid) - - - OID of the relation targeted by the lock, or null if the target is not - a relation or part of a relation - - - - - - page int4 - - - Page number targeted by the lock within the relation, - or null if the target is not a relation page or tuple - - - - - - tuple int2 - - - Tuple number targeted by the lock within the page, - or null if the target is not a tuple - - - - - - virtualxid text - - - Virtual ID of the transaction targeted by the lock, - or null if the target is not a virtual transaction ID - - - - - - transactionid xid - - - ID of the transaction targeted by the lock, - or null if the target is not a transaction ID - - - - - - classid oid - (references pg_class.oid) - - - OID of the system catalog containing the lock target, or null if the - target is not a general database object - - - - - - objid oid - (references any OID column) - - - OID of the lock target within its system catalog, or null if the - target is not a general database object - - - - - - objsubid int2 - - - Column number targeted by the lock (the - classid and objid refer to the - table itself), - or zero if the target is some other general database object, - or null if the target is not a general database object - - - - - - virtualtransaction text - - - Virtual ID of the transaction that is holding or awaiting this lock - - - - - - pid int4 - - - Process ID of the server process holding or awaiting this - lock, or null if the lock is held by a prepared transaction - - - - - - mode text - - - Name of the lock mode held or desired by this process (see and ) - - - - - - granted bool - - - True if lock is held, false if lock is awaited - - - - - - fastpath bool - - - True if lock was taken via fast path, false if taken via main - lock table - - - - - - waitstart timestamptz - - - Time when the server process started waiting for this lock, - or null if the lock is held. - Note that this can be null for a very short period of time after - the wait started even though granted - is false. - - - - -
- - - granted is true in a row representing a lock - held by the indicated process. False indicates that this process is - currently waiting to acquire this lock, which implies that at least one - other process is holding or waiting for a conflicting lock mode on the same - lockable object. The waiting process will sleep until the other lock is - released (or a deadlock situation is detected). A single process can be - waiting to acquire at most one lock at a time. - - - - Throughout running a transaction, a server process holds an exclusive lock - on the transaction's virtual transaction ID. If a permanent ID is assigned - to the transaction (which normally happens only if the transaction changes - the state of the database), it also holds an exclusive lock on the - transaction's permanent transaction ID until it ends. When a process finds - it necessary to wait specifically for another transaction to end, it does - so by attempting to acquire share lock on the other transaction's ID - (either virtual or permanent ID depending on the situation). That will - succeed only when the other transaction terminates and releases its locks. - - - - Although tuples are a lockable type of object, - information about row-level locks is stored on disk, not in memory, - and therefore row-level locks normally do not appear in this view. - If a process is waiting for a - row-level lock, it will usually appear in the view as waiting for the - permanent transaction ID of the current holder of that row lock. - - - - Advisory locks can be acquired on keys consisting of either a single - bigint value or two integer values. - A bigint key is displayed with its - high-order half in the classid column, its low-order half - in the objid column, and objsubid equal - to 1. The original bigint value can be reassembled with the - expression (classid::bigint << 32) | - objid::bigint. Integer keys are displayed with the - first key in the - classid column, the second key in the objid - column, and objsubid equal to 2. The actual meaning of - the keys is up to the user. Advisory locks are local to each database, - so the database column is meaningful for an advisory lock. - - - - pg_locks provides a global view of all locks - in the database cluster, not only those relevant to the current database. - Although its relation column can be joined - against pg_class.oid to identify locked - relations, this will only work correctly for relations in the current - database (those for which the database column - is either the current database's OID or zero). - - - - The pid column can be joined to the - pid column of the - - pg_stat_activity - view to get more - information on the session holding or awaiting each lock, - for example - -SELECT * FROM pg_locks pl LEFT JOIN pg_stat_activity psa - ON pl.pid = psa.pid; - - Also, if you are using prepared transactions, the - virtualtransaction column can be joined to the - transaction column of the pg_prepared_xacts - view to get more information on prepared transactions that hold locks. - (A prepared transaction can never be waiting for a lock, - but it continues to hold the locks it acquired while running.) - For example: - -SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx - ON pl.virtualtransaction = '-1/' || ppx.transaction; - - - - - While it is possible to obtain information about which processes block - which other processes by joining pg_locks against - itself, this is very difficult to get right in detail. Such a query would - have to encode knowledge about which lock modes conflict with which - others. Worse, the pg_locks view does not expose - information about which processes are ahead of which others in lock wait - queues, nor information about which processes are parallel workers running - on behalf of which other client sessions. It is better to use - the pg_blocking_pids() function - (see ) to identify which - process(es) a waiting process is blocked behind. - - - - The pg_locks view displays data from both the - regular lock manager and the predicate lock manager, which are - separate systems; in addition, the regular lock manager subdivides its - locks into regular and fast-path locks. - This data is not guaranteed to be entirely consistent. - When the view is queried, - data on fast-path locks (with fastpath = true) - is gathered from each backend one at a time, without freezing the state of - the entire lock manager, so it is possible for locks to be taken or - released while information is gathered. Note, however, that these locks are - known not to conflict with any other lock currently in place. After - all backends have been queried for fast-path locks, the remainder of the - regular lock manager is locked as a unit, and a consistent snapshot of all - remaining locks is collected as an atomic action. After unlocking the - regular lock manager, the predicate lock manager is similarly locked and all - predicate locks are collected as an atomic action. Thus, with the exception - of fast-path locks, each lock manager will deliver a consistent set of - results, but as we do not lock both lock managers simultaneously, it is - possible for locks to be taken or released after we interrogate the regular - lock manager and before we interrogate the predicate lock manager. - - - - Locking the regular and/or predicate lock manager could have some - impact on database performance if this view is very frequently accessed. - The locks are held only for the minimum amount of time necessary to - obtain data from the lock managers, but this does not completely eliminate - the possibility of a performance impact. - - - - - - <structname>pg_matviews</structname> - - - pg_matviews - - - - materialized views - - - - The view pg_matviews provides access to - useful information about each materialized view in the database. - - - - <structname>pg_matviews</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing materialized view - - - - - - matviewname name - (references pg_class.relname) - - - Name of materialized view - - - - - - matviewowner name - (references pg_authid.rolname) - - - Name of materialized view's owner - - - - - - tablespace name - (references pg_tablespace.spcname) - - - Name of tablespace containing materialized view (null if default for database) - - - - - - hasindexes bool - - - True if materialized view has (or recently had) any indexes - - - - - - ispopulated bool - - - True if materialized view is currently populated - - - - - - definition text - - - Materialized view definition (a reconstructed query) - - - - -
- - - - - <structname>pg_policies</structname> - - - pg_policies - - - - The view pg_policies provides access to - useful information about each row-level security policy in the database. - - - - <structname>pg_policies</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table policy is on - - - - - - tablename name - (references pg_class.relname) - - - Name of table policy is on - - - - - - policyname name - (references pg_policy.polname) - - - Name of policy - - - - - - permissive text - - - Is the policy permissive or restrictive? - - - - - - roles name[] - - - The roles to which this policy applies - - - - - - cmd text - - - The command type to which the policy is applied - - - - - - qual text - - - The expression added to the security barrier qualifications for - queries that this policy applies to - - - - - - with_check text - - - The expression added to the WITH CHECK qualifications for - queries that attempt to add rows to this table - - - - -
- - - - - <structname>pg_prepared_statements</structname> - - - pg_prepared_statements - - - - The pg_prepared_statements view displays - all the prepared statements that are available in the current - session. See for more information about prepared - statements. - - - - pg_prepared_statements contains one row - for each prepared statement. Rows are added to the view when a new - prepared statement is created and removed when a prepared statement - is released (for example, via the DEALLOCATE command). - - - - <structname>pg_prepared_statements</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name text - - - The identifier of the prepared statement - - - - - - statement text - - - The query string submitted by the client to create this - prepared statement. For prepared statements created via SQL, - this is the PREPARE statement submitted by - the client. For prepared statements created via the - frontend/backend protocol, this is the text of the prepared - statement itself. - - - - - - prepare_time timestamptz - - - The time at which the prepared statement was created - - - - - - parameter_types regtype[] - - - The expected parameter types for the prepared statement in the - form of an array of regtype. The OID corresponding - to an element of this array can be obtained by casting the - regtype value to oid. - - - - - - result_types regtype[] - - - The types of the columns returned by the prepared statement in the - form of an array of regtype. The OID corresponding - to an element of this array can be obtained by casting the - regtype value to oid. - If the prepared statement does not provide a result (e.g., a DML - statement), then this field will be null. - - - - - - from_sql bool - - - true if the prepared statement was created - via the PREPARE SQL command; - false if the statement was prepared via the - frontend/backend protocol - - - - - - generic_plans int8 - - - Number of times generic plan was chosen - - - - - - custom_plans int8 - - - Number of times custom plan was chosen - - - - -
- - - The pg_prepared_statements view is read-only. - - - - - <structname>pg_prepared_xacts</structname> - - - pg_prepared_xacts - - - - The view pg_prepared_xacts displays - information about transactions that are currently prepared for two-phase - commit (see for details). - - - - pg_prepared_xacts contains one row per prepared - transaction. An entry is removed when the transaction is committed or - rolled back. - - - - <structname>pg_prepared_xacts</structname> Columns - - - - - Column Type - - - Description - - - - - - - - transaction xid - - - Numeric transaction identifier of the prepared transaction - - - - - - gid text - - - Global transaction identifier that was assigned to the transaction - - - - - - prepared timestamptz - - - Time at which the transaction was prepared for commit - - - - - - owner name - (references pg_authid.rolname) - - - Name of the user that executed the transaction - - - - - - database name - (references pg_database.datname) - - - Name of the database in which the transaction was executed - - - - -
- - - When the pg_prepared_xacts view is accessed, the - internal transaction manager data structures are momentarily locked, and - a copy is made for the view to display. This ensures that the - view produces a consistent set of results, while not blocking - normal operations longer than necessary. Nonetheless - there could be some impact on database performance if this view is - frequently accessed. - - - - - - <structname>pg_publication_tables</structname> - - - pg_publication_tables - - - - The view pg_publication_tables provides - information about the mapping between publications and information of - tables they contain. Unlike the underlying catalog - pg_publication_rel, - this view expands publications defined as FOR ALL TABLES - and FOR ALL TABLES IN SCHEMA, so for such publications - there will be a row for each eligible table. - - - - <structname>pg_publication_tables</structname> Columns - - - - - Column Type - - - Description - - - - - - - - pubname name - (references pg_publication.pubname) - - - Name of publication - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table - - - - - - tablename name - (references pg_class.relname) - - - Name of table - - - - - - attnames name[] - (references pg_attribute.attname) - - - Names of table columns included in the publication. This contains all - the columns of the table when the user didn't specify the column list - for the table. - - - - - - rowfilter text - - - Expression for the table's publication qualifying condition - - - - -
- - - - <structname>pg_replication_origin_status</structname> - - - pg_replication_origin_status - - - - The pg_replication_origin_status view - contains information about how far replay for a certain origin has - progressed. For more on replication origins - see . - - - - <structname>pg_replication_origin_status</structname> Columns - - - - - Column Type - - - Description - - - - - - - - local_id oid - (references pg_replication_origin.roident) - - - internal node identifier - - - - - - external_id text - (references pg_replication_origin.roname) - - - external node identifier - - - - - - remote_lsn pg_lsn - - - The origin node's LSN up to which data has been replicated. - - - - - - local_lsn pg_lsn - - - This node's LSN at which remote_lsn has - been replicated. Used to flush commit records before persisting - data to disk when using asynchronous commits. - - - - -
- - - - <structname>pg_replication_slots</structname> - - - pg_replication_slots - - - - The pg_replication_slots view provides a listing - of all replication slots that currently exist on the database cluster, - along with their current state. - - - - For more on replication slots, - see and . - - - - <structname>pg_replication_slots</structname> Columns - - - - - Column Type - - - Description - - - - - - - - slot_name name - - - A unique, cluster-wide identifier for the replication slot - - - - - - plugin name - - - The base name of the shared object containing the output plugin this logical slot is using, or null for physical slots. - - - - - - slot_type text - - - The slot type: physical or logical - - - - - - datoid oid - (references pg_database.oid) - - - The OID of the database this slot is associated with, or - null. Only logical slots have an associated database. - - - - - - database name - (references pg_database.datname) - - - The name of the database this slot is associated with, or - null. Only logical slots have an associated database. - - - - - - temporary bool - - - True if this is a temporary replication slot. Temporary slots are - not saved to disk and are automatically dropped on error or when - the session has finished. - - - - - - active bool - - - True if this slot is currently actively being used - - - - - - active_pid int4 - - - The process ID of the session using this slot if the slot - is currently actively being used. NULL if - inactive. - - - - - - xmin xid - - - The oldest transaction that this slot needs the database to - retain. VACUUM cannot remove tuples deleted - by any later transaction. - - - - - - catalog_xmin xid - - - The oldest transaction affecting the system catalogs that this - slot needs the database to retain. VACUUM cannot - remove catalog tuples deleted by any later transaction. - - - - - - restart_lsn pg_lsn - - - The address (LSN) of oldest WAL which still - might be required by the consumer of this slot and thus won't be - automatically removed during checkpoints unless this LSN - gets behind more than - from the current LSN. NULL - if the LSN of this slot has never been reserved. - - - - - - confirmed_flush_lsn pg_lsn - - - The address (LSN) up to which the logical - slot's consumer has confirmed receiving data. Data older than this is - not available anymore. NULL for physical slots. - - - - - - wal_status text - - - Availability of WAL files claimed by this slot. - Possible values are: - - - reserved means that the claimed files - are within max_wal_size. - - - extended means - that max_wal_size is exceeded but the files are - still retained, either by the replication slot or - by wal_keep_size. - - - - - unreserved means that the slot no longer - retains the required WAL files and some of them are to be removed at - the next checkpoint. This state can return - to reserved or extended. - - - - - lost means that some required WAL files have - been removed and this slot is no longer usable. - - - - The last two states are seen only when - is - non-negative. If restart_lsn is NULL, this - field is null. - - - - - - safe_wal_size int8 - - - The number of bytes that can be written to WAL such that this slot - is not in danger of getting in state "lost". It is NULL for lost - slots, as well as if max_slot_wal_keep_size - is -1. - - - - - - two_phase bool - - - True if the slot is enabled for decoding prepared transactions. Always - false for physical slots. - - - - -
- - - - <structname>pg_roles</structname> - - - pg_roles - - - - The view pg_roles provides access to - information about database roles. This is simply a publicly - readable view of - pg_authid - that blanks out the password field. - - - - <structname>pg_roles</structname> Columns - - - - - Column Type - - - Description - - - - - - - - rolname name - - - Role name - - - - - - rolsuper bool - - - Role has superuser privileges - - - - - - rolinherit bool - - - Role automatically inherits privileges of roles it is a - member of - - - - - - rolcreaterole bool - - - Role can create more roles - - - - - - rolcreatedb bool - - - Role can create databases - - - - - - rolcanlogin bool - - - Role can log in. That is, this role can be given as the initial - session authorization identifier - - - - - - rolreplication bool - - - Role is a replication role. A replication role can initiate replication - connections and create and drop replication slots. - - - - - - rolconnlimit int4 - - - For roles that can log in, this sets maximum number of concurrent - connections this role can make. -1 means no limit. - - - - - - rolpassword text - - - Not the password (always reads as ********) - - - - - - rolvaliduntil timestamptz - - - Password expiry time (only used for password authentication); - null if no expiration - - - - - - rolbypassrls bool - - - Role bypasses every row-level security policy, see - for more information. - - - - - - rolconfig text[] - - - Role-specific defaults for run-time configuration variables - - - - - - oid oid - (references pg_authid.oid) - - - ID of role - - - - -
- - - - - <structname>pg_rules</structname> - - - pg_rules - - - - The view pg_rules provides access to - useful information about query rewrite rules. - - - - <structname>pg_rules</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table - - - - - - tablename name - (references pg_class.relname) - - - Name of table the rule is for - - - - - - rulename name - (references pg_rewrite.rulename) - - - Name of rule - - - - - - definition text - - - Rule definition (a reconstructed creation command) - - - - -
- - - The pg_rules view excludes the ON SELECT rules - of views and materialized views; those can be seen in - pg_views and pg_matviews. - - - - - - <structname>pg_seclabels</structname> - - - pg_seclabels - - - - The view pg_seclabels provides information about - security labels. It as an easier-to-query version of the - pg_seclabel catalog. - - - - <structname>pg_seclabels</structname> Columns - - - - - Column Type - - - Description - - - - - - - - objoid oid - (references any OID column) - - - The OID of the object this security label pertains to - - - - - - classoid oid - (references pg_class.oid) - - - The OID of the system catalog this object appears in - - - - - - objsubid int4 - - - For a security label on a table column, this is the column number (the - objoid and classoid refer to - the table itself). For all other object types, this column is - zero. - - - - - - objtype text - - - The type of object to which this label applies, as text. - - - - - - objnamespace oid - (references pg_namespace.oid) - - - The OID of the namespace for this object, if applicable; - otherwise NULL. - - - - - - objname text - - - The name of the object to which this label applies, as text. - - - - - - provider text - (references pg_seclabel.provider) - - - The label provider associated with this label. - - - - - - label text - (references pg_seclabel.label) - - - The security label applied to this object. - - - - -
- - - - <structname>pg_sequences</structname> - - - pg_sequences - - - - The view pg_sequences provides access to - useful information about each sequence in the database. - - - - <structname>pg_sequences</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing sequence - - - - - - sequencename name - (references pg_class.relname) - - - Name of sequence - - - - - - sequenceowner name - (references pg_authid.rolname) - - - Name of sequence's owner - - - - - - data_type regtype - (references pg_type.oid) - - - Data type of the sequence - - - - - - start_value int8 - - - Start value of the sequence - - - - - - min_value int8 - - - Minimum value of the sequence - - - - - - max_value int8 - - - Maximum value of the sequence - - - - - - increment_by int8 - - - Increment value of the sequence - - - - - - cycle bool - - - Whether the sequence cycles - - - - - - cache_size int8 - - - Cache size of the sequence - - - - - - last_value int8 - - - The last sequence value written to disk. If caching is used, - this value can be greater than the last value handed out from the - sequence. Null if the sequence has not been read from yet. Also, if - the current user does not have USAGE - or SELECT privilege on the sequence, the value is - null. - - - - -
- - - - <structname>pg_settings</structname> - - - pg_settings - - - - The view pg_settings provides access to - run-time parameters of the server. It is essentially an alternative - interface to the SHOW - and SET commands. - It also provides access to some facts about each parameter that are - not directly available from SHOW, such as minimum and - maximum values. - - - - <structname>pg_settings</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name text - - - Run-time configuration parameter name - - - - - - setting text - - - Current value of the parameter - - - - - - unit text - - - Implicit unit of the parameter - - - - - - category text - - - Logical group of the parameter - - - - - - short_desc text - - - A brief description of the parameter - - - - - - extra_desc text - - - Additional, more detailed, description of the parameter - - - - - - context text - - - Context required to set the parameter's value (see below) - - - - - - vartype text - - - Parameter type (bool, enum, - integer, real, or string) - - - - - - source text - - - Source of the current parameter value - - - - - - min_val text - - - Minimum allowed value of the parameter (null for non-numeric - values) - - - - - - max_val text - - - Maximum allowed value of the parameter (null for non-numeric - values) - - - - - - enumvals text[] - - - Allowed values of an enum parameter (null for non-enum - values) - - - - - - boot_val text - - - Parameter value assumed at server startup if the parameter is - not otherwise set - - - - - - reset_val text - - - Value that RESET would reset the parameter to - in the current session - - - - - - sourcefile text - - - Configuration file the current value was set in (null for - values set from sources other than configuration files, or when - examined by a user who neither is a superuser nor has privileges of - pg_read_all_settings); helpful when using - include directives in configuration files - - - - - - sourceline int4 - - - Line number within the configuration file the current value was - set at (null for values set from sources other than configuration files, - or when examined by a user who neither is a superuser nor has privileges of - pg_read_all_settings). - - - - - - pending_restart bool - - - true if the value has been changed in the - configuration file but needs a restart; or false - otherwise. - - - - -
- - - There are several possible values of context. - In order of decreasing difficulty of changing the setting, they are: - - - - - - internal - - - These settings cannot be changed directly; they reflect internally - determined values. Some of them may be adjustable by rebuilding the - server with different configuration options, or by changing options - supplied to initdb. - - - - - - postmaster - - - These settings can only be applied when the server starts, so any change - requires restarting the server. Values for these settings are typically - stored in the postgresql.conf file, or passed on - the command line when starting the server. Of course, settings with any - of the lower context types can also be - set at server start time. - - - - - - sighup - - - Changes to these settings can be made in - postgresql.conf without restarting the server. - Send a SIGHUP signal to the postmaster to - cause it to re-read postgresql.conf and apply - the changes. The postmaster will also forward the - SIGHUP signal to its child processes so that - they all pick up the new value. - - - - - - superuser-backend - - - Changes to these settings can be made in - postgresql.conf without restarting the server. - They can also be set for a particular session in the connection request - packet (for example, via libpq's PGOPTIONS - environment variable), but only if the connecting user is a superuser - or has been granted the appropriate SET privilege. - However, these settings never change in a session after it is started. - If you change them in postgresql.conf, send a - SIGHUP signal to the postmaster to cause it to - re-read postgresql.conf. The new values will only - affect subsequently-launched sessions. - - - - - - backend - - - Changes to these settings can be made in - postgresql.conf without restarting the server. - They can also be set for a particular session in the connection request - packet (for example, via libpq's PGOPTIONS - environment variable); any user can make such a change for their session. - However, these settings never change in a session after it is started. - If you change them in postgresql.conf, send a - SIGHUP signal to the postmaster to cause it to - re-read postgresql.conf. The new values will only - affect subsequently-launched sessions. - - - - - - superuser - - - These settings can be set from postgresql.conf, - or within a session via the SET command; but only superusers - and users with the appropriate SET privilege - can change them via SET. Changes in - postgresql.conf will affect existing sessions - only if no session-local value has been established with SET. - - - - - - user - - - These settings can be set from postgresql.conf, - or within a session via the SET command. Any user is - allowed to change their session-local value. Changes in - postgresql.conf will affect existing sessions - only if no session-local value has been established with SET. - - - - - - - See for more information about the various - ways to change these parameters. - - - - This view does not display customized options - until the extension module that defines them has been loaded. - - - - This view cannot be inserted into or deleted from, but it can be updated. An - UPDATE applied to a row of pg_settings - is equivalent to executing the SET command on that named - parameter. The change only affects the value used by the current - session. If an UPDATE is issued within a transaction - that is later aborted, the effects of the UPDATE command - disappear when the transaction is rolled back. Once the surrounding - transaction is committed, the effects will persist until the end of the - session, unless overridden by another UPDATE or - SET. - - - - - - <structname>pg_shadow</structname> - - - pg_shadow - - - - The view pg_shadow exists for backwards - compatibility: it emulates a catalog that existed in - PostgreSQL before version 8.1. - It shows properties of all roles that are marked as - rolcanlogin in - pg_authid. - - - - The name stems from the fact that this table - should not be readable by the public since it contains passwords. - pg_user - is a publicly readable view on - pg_shadow that blanks out the password field. - - - - <structname>pg_shadow</structname> Columns - - - - - Column Type - - - Description - - - - - - - - usename name - (references pg_authid.rolname) - - - User name - - - - - - usesysid oid - (references pg_authid.oid) - - - ID of this user - - - - - - usecreatedb bool - - - User can create databases - - - - - - usesuper bool - - - User is a superuser - - - - - - userepl bool - - - User can initiate streaming replication and put the system in and - out of backup mode. - - - - - - usebypassrls bool - - - User bypasses every row-level security policy, see - for more information. - - - - - - passwd text - - - Password (possibly encrypted); null if none. See - pg_authid - for details of how encrypted passwords are stored. - - - - - - valuntil timestamptz - - - Password expiry time (only used for password authentication) - - - - - - useconfig text[] - - - Session defaults for run-time configuration variables - - - - -
- - - - - <structname>pg_shmem_allocations</structname> - - - pg_shmem_allocations - - - - The pg_shmem_allocations view shows allocations - made from the server's main shared memory segment. This includes both - memory allocated by PostgreSQL itself and memory - allocated by extensions using the mechanisms detailed in - . - - - - Note that this view does not include memory allocated using the dynamic - shared memory infrastructure. - - - - <structname>pg_shmem_allocations</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name text - - - The name of the shared memory allocation. NULL for unused memory - and <anonymous> for anonymous - allocations. - - - - - - off int8 - - - The offset at which the allocation starts. NULL for anonymous - allocations, since details related to them are not known. - - - - - - size int8 - - - Size of the allocation - - - - - - allocated_size int8 - - - Size of the allocation including padding. For anonymous - allocations, no information about padding is available, so the - size and allocated_size columns - will always be equal. Padding is not meaningful for free memory, so - the columns will be equal in that case also. - - - - -
- - - Anonymous allocations are allocations that have been made - with ShmemAlloc() directly, rather than via - ShmemInitStruct() or - ShmemInitHash(). - - - - By default, the pg_shmem_allocations view can be - read only by superusers or roles with privileges of the - pg_read_all_stats role. - - - - - <structname>pg_stats</structname> - - - pg_stats - - - - The view pg_stats provides access to - the information stored in the pg_statistic - catalog. This view allows access only to rows of - pg_statistic that correspond to tables the - user has permission to read, and therefore it is safe to allow public - read access to this view. - - - - pg_stats is also designed to present the - information in a more readable format than the underlying catalog - — at the cost that its schema must be extended whenever new slot types - are defined for pg_statistic. - - - - <structname>pg_stats</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table - - - - - - tablename name - (references pg_class.relname) - - - Name of table - - - - - - attname name - (references pg_attribute.attname) - - - Name of column described by this row - - - - - - inherited bool - - - If true, this row includes inheritance child columns, not just the - values in the specified table - - - - - - null_frac float4 - - - Fraction of column entries that are null - - - - - - avg_width int4 - - - Average width in bytes of column's entries - - - - - - n_distinct float4 - - - If greater than zero, the estimated number of distinct values in the - column. If less than zero, the negative of the number of distinct - values divided by the number of rows. (The negated form is used when - ANALYZE believes that the number of distinct values is - likely to increase as the table grows; the positive form is used when - the column seems to have a fixed number of possible values.) For - example, -1 indicates a unique column in which the number of distinct - values is the same as the number of rows. - - - - - - most_common_vals anyarray - - - A list of the most common values in the column. (Null if - no values seem to be more common than any others.) - - - - - - most_common_freqs float4[] - - - A list of the frequencies of the most common values, - i.e., number of occurrences of each divided by total number of rows. - (Null when most_common_vals is.) - - - - - - histogram_bounds anyarray - - - A list of values that divide the column's values into groups of - approximately equal population. The values in - most_common_vals, if present, are omitted from this - histogram calculation. (This column is null if the column data type - does not have a < operator or if the - most_common_vals list accounts for the entire - population.) - - - - - - correlation float4 - - - Statistical correlation between physical row ordering and - logical ordering of the column values. This ranges from -1 to +1. - When the value is near -1 or +1, an index scan on the column will - be estimated to be cheaper than when it is near zero, due to reduction - of random access to the disk. (This column is null if the column data - type does not have a < operator.) - - - - - - most_common_elems anyarray - - - A list of non-null element values most often appearing within values of - the column. (Null for scalar types.) - - - - - - most_common_elem_freqs float4[] - - - A list of the frequencies of the most common element values, i.e., the - fraction of rows containing at least one instance of the given value. - Two or three additional values follow the per-element frequencies; - these are the minimum and maximum of the preceding per-element - frequencies, and optionally the frequency of null elements. - (Null when most_common_elems is.) - - - - - - elem_count_histogram float4[] - - - A histogram of the counts of distinct non-null element values within the - values of the column, followed by the average number of distinct - non-null elements. (Null for scalar types.) - - - - -
- - - The maximum number of entries in the array fields can be controlled on a - column-by-column basis using the ALTER - TABLE SET STATISTICS - command, or globally by setting the - run-time parameter. - - - - - - <structname>pg_stats_ext</structname> - - - pg_stats_ext - - - - The view pg_stats_ext provides access to - information about each extended statistics object in the database, - combining information stored in the pg_statistic_ext - and pg_statistic_ext_data - catalogs. This view allows access only to rows of - pg_statistic_ext and pg_statistic_ext_data - that correspond to tables the user has permission to read, and therefore - it is safe to allow public read access to this view. - - - - pg_stats_ext is also designed to present the - information in a more readable format than the underlying catalogs - — at the cost that its schema must be extended whenever new types - of extended statistics are added to pg_statistic_ext. - - - - <structname>pg_stats_ext</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table - - - - - - tablename name - (references pg_class.relname) - - - Name of table - - - - - - statistics_schemaname name - (references pg_namespace.nspname) - - - Name of schema containing extended statistics object - - - - - - statistics_name name - (references pg_statistic_ext.stxname) - - - Name of extended statistics object - - - - - - statistics_owner name - (references pg_authid.rolname) - - - Owner of the extended statistics object - - - - - - attnames name[] - (references pg_attribute.attname) - - - Names of the columns included in the extended statistics object - - - - - - exprs text[] - - - Expressions included in the extended statistics object - - - - - - kinds char[] - - - Types of extended statistics object enabled for this record - - - - - - inherited bool - (references pg_statistic_ext_data.stxdinherit) - - - If true, the stats include inheritance child columns, not just the - values in the specified relation - - - - - - n_distinct pg_ndistinct - - - N-distinct counts for combinations of column values. If greater - than zero, the estimated number of distinct values in the combination. - If less than zero, the negative of the number of distinct values divided - by the number of rows. - (The negated form is used when ANALYZE believes that - the number of distinct values is likely to increase as the table grows; - the positive form is used when the column seems to have a fixed number - of possible values.) For example, -1 indicates a unique combination of - columns in which the number of distinct combinations is the same as the - number of rows. - - - - - - dependencies pg_dependencies - - - Functional dependency statistics - - - - - - most_common_vals text[] - - - A list of the most common combinations of values in the columns. - (Null if no combinations seem to be more common than any others.) - - - - - - most_common_val_nulls bool[] - - - A list of NULL flags for the most common combinations of values. - (Null when most_common_vals is.) - - - - - - most_common_freqs float8[] - - - A list of the frequencies of the most common combinations, - i.e., number of occurrences of each divided by total number of rows. - (Null when most_common_vals is.) - - - - - - most_common_base_freqs float8[] - - - A list of the base frequencies of the most common combinations, - i.e., product of per-value frequencies. - (Null when most_common_vals is.) - - - - -
- - - The maximum number of entries in the array fields can be controlled on a - column-by-column basis using the ALTER - TABLE SET STATISTICS command, or globally by setting the - run-time parameter. - - - - - - <structname>pg_stats_ext_exprs</structname> - - - pg_stats_ext_exprs - - - - The view pg_stats_ext_exprs provides access to - information about all expressions included in extended statistics objects, - combining information stored in the pg_statistic_ext - and pg_statistic_ext_data - catalogs. This view allows access only to rows of - pg_statistic_ext and pg_statistic_ext_data - that correspond to tables the user has permission to read, and therefore - it is safe to allow public read access to this view. - - - - pg_stats_ext_exprs is also designed to present - the information in a more readable format than the underlying catalogs - — at the cost that its schema must be extended whenever the structure - of statistics in pg_statistic_ext changes. - - - - <structname>pg_stats_ext_exprs</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table - - - - - - tablename name - (references pg_class.relname) - - - Name of table the statistics object is defined on - - - - - - statistics_schemaname name - (references pg_namespace.nspname) - - - Name of schema containing extended statistics object - - - - - - statistics_name name - (references pg_statistic_ext.stxname) - - - Name of extended statistics object - - - - - - statistics_owner name - (references pg_authid.rolname) - - - Owner of the extended statistics object - - - - - - expr text - - - Expression included in the extended statistics object - - - - - - inherited bool - (references pg_statistic_ext_data.stxdinherit) - - - If true, the stats include inheritance child columns, not just the - values in the specified relation - - - - - - null_frac float4 - - - Fraction of expression entries that are null - - - - - - avg_width int4 - - - Average width in bytes of expression's entries - - - - - - n_distinct float4 - - - If greater than zero, the estimated number of distinct values in the - expression. If less than zero, the negative of the number of distinct - values divided by the number of rows. (The negated form is used when - ANALYZE believes that the number of distinct values is - likely to increase as the table grows; the positive form is used when - the expression seems to have a fixed number of possible values.) For - example, -1 indicates a unique expression in which the number of distinct - values is the same as the number of rows. - - - - - - most_common_vals anyarray - - - A list of the most common values in the expression. (Null if - no values seem to be more common than any others.) - - - - - - most_common_freqs float4[] - - - A list of the frequencies of the most common values, - i.e., number of occurrences of each divided by total number of rows. - (Null when most_common_vals is.) - - - - - - histogram_bounds anyarray - - - A list of values that divide the expression's values into groups of - approximately equal population. The values in - most_common_vals, if present, are omitted from this - histogram calculation. (This expression is null if the expression data type - does not have a < operator or if the - most_common_vals list accounts for the entire - population.) - - - - - - correlation float4 - - - Statistical correlation between physical row ordering and - logical ordering of the expression values. This ranges from -1 to +1. - When the value is near -1 or +1, an index scan on the expression will - be estimated to be cheaper than when it is near zero, due to reduction - of random access to the disk. (This expression is null if the expression's - data type does not have a < operator.) - - - - - - most_common_elems anyarray - - - A list of non-null element values most often appearing within values of - the expression. (Null for scalar types.) - - - - - - most_common_elem_freqs float4[] - - - A list of the frequencies of the most common element values, i.e., the - fraction of rows containing at least one instance of the given value. - Two or three additional values follow the per-element frequencies; - these are the minimum and maximum of the preceding per-element - frequencies, and optionally the frequency of null elements. - (Null when most_common_elems is.) - - - - - - elem_count_histogram float4[] - - - A histogram of the counts of distinct non-null element values within the - values of the expression, followed by the average number of distinct - non-null elements. (Null for scalar types.) - - - - -
- - - The maximum number of entries in the array fields can be controlled on a - column-by-column basis using the ALTER - TABLE SET STATISTICS command, or globally by setting the - run-time parameter. - - - - - - <structname>pg_tables</structname> - - - pg_tables - - - - The view pg_tables provides access to - useful information about each table in the database. - - - - <structname>pg_tables</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing table - - - - - - tablename name - (references pg_class.relname) - - - Name of table - - - - - - tableowner name - (references pg_authid.rolname) - - - Name of table's owner - - - - - - tablespace name - (references pg_tablespace.spcname) - - - Name of tablespace containing table (null if default for database) - - - - - - hasindexes bool - (references pg_class.relhasindex) - - - True if table has (or recently had) any indexes - - - - - - hasrules bool - (references pg_class.relhasrules) - - - True if table has (or once had) rules - - - - - - hastriggers bool - (references pg_class.relhastriggers) - - - True if table has (or once had) triggers - - - - - - rowsecurity bool - (references pg_class.relrowsecurity) - - - True if row security is enabled on the table - - - - -
- - - - - <structname>pg_timezone_abbrevs</structname> - - - pg_timezone_abbrevs - - - - The view pg_timezone_abbrevs provides a list - of time zone abbreviations that are currently recognized by the datetime - input routines. The contents of this view change when the - run-time parameter is modified. - - - - <structname>pg_timezone_abbrevs</structname> Columns - - - - - Column Type - - - Description - - - - - - - - abbrev text - - - Time zone abbreviation - - - - - - utc_offset interval - - - Offset from UTC (positive means east of Greenwich) - - - - - - is_dst bool - - - True if this is a daylight-savings abbreviation - - - - -
- - - While most timezone abbreviations represent fixed offsets from UTC, - there are some that have historically varied in value - (see for more information). - In such cases this view presents their current meaning. - - - - - - <structname>pg_timezone_names</structname> - - - pg_timezone_names - - - - The view pg_timezone_names provides a list - of time zone names that are recognized by SET TIMEZONE, - along with their associated abbreviations, UTC offsets, - and daylight-savings status. (Technically, - PostgreSQL does not use UTC because leap - seconds are not handled.) - Unlike the abbreviations shown in pg_timezone_abbrevs, many of these names imply a set of daylight-savings transition - date rules. Therefore, the associated information changes across local DST - boundaries. The displayed information is computed based on the current - value of CURRENT_TIMESTAMP. - - - - <structname>pg_timezone_names</structname> Columns - - - - - Column Type - - - Description - - - - - - - - name text - - - Time zone name - - - - - - abbrev text - - - Time zone abbreviation - - - - - - utc_offset interval - - - Offset from UTC (positive means east of Greenwich) - - - - - - is_dst bool - - - True if currently observing daylight savings - - - - -
- - - - - <structname>pg_user</structname> - - - pg_user - - - - The view pg_user provides access to - information about database users. This is simply a publicly - readable view of - pg_shadow - that blanks out the password field. - - - - <structname>pg_user</structname> Columns - - - - - Column Type - - - Description - - - - - - - - usename name - - - User name - - - - - - usesysid oid - - - ID of this user - - - - - - usecreatedb bool - - - User can create databases - - - - - - usesuper bool - - - User is a superuser - - - - - - userepl bool - - - User can initiate streaming replication and put the system in and - out of backup mode. - - - - - - usebypassrls bool - - - User bypasses every row-level security policy, see - for more information. - - - - - - passwd text - - - Not the password (always reads as ********) - - - - - - valuntil timestamptz - - - Password expiry time (only used for password authentication) - - - - - - useconfig text[] - - - Session defaults for run-time configuration variables - - - - -
- - - - - <structname>pg_user_mappings</structname> - - - pg_user_mappings - - - - The view pg_user_mappings provides access - to information about user mappings. This is essentially a publicly - readable view of - pg_user_mapping - that leaves out the options field if the user has no rights to use - it. - - - - <structname>pg_user_mappings</structname> Columns - - - - - Column Type - - - Description - - - - - - - - umid oid - (references pg_user_mapping.oid) - - - OID of the user mapping - - - - - - srvid oid - (references pg_foreign_server.oid) - - - The OID of the foreign server that contains this mapping - - - - - - srvname name - (references pg_foreign_server.srvname) - - - Name of the foreign server - - - - - - umuser oid - (references pg_authid.oid) - - - OID of the local role being mapped, or zero if the user mapping is public - - - - - - usename name - - - Name of the local user to be mapped - - - - - - umoptions text[] - - - User mapping specific options, as keyword=value strings - - - - -
- - - To protect password information stored as a user mapping option, - the umoptions column will read as null - unless one of the following applies: - - - - current user is the user being mapped, and owns the server or - holds USAGE privilege on it - - - - - current user is the server owner and mapping is for PUBLIC - - - - - current user is a superuser - - - - - - - - - - <structname>pg_views</structname> - - - pg_views - - - - The view pg_views provides access to - useful information about each view in the database. - - - - <structname>pg_views</structname> Columns - - - - - Column Type - - - Description - - - - - - - - schemaname name - (references pg_namespace.nspname) - - - Name of schema containing view - - - - - - viewname name - (references pg_class.relname) - - - Name of view - - - - - - viewowner name - (references pg_authid.rolname) - - - Name of view's owner - - - - - - definition text - - - View definition (a reconstructed query) - - - - -
- - - diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml index 8216193009..de450cd661 100644 --- a/doc/src/sgml/filelist.sgml +++ b/doc/src/sgml/filelist.sgml @@ -83,6 +83,7 @@ + diff --git a/doc/src/sgml/postgres.sgml b/doc/src/sgml/postgres.sgml index 0b60e46d69..73439c049e 100644 --- a/doc/src/sgml/postgres.sgml +++ b/doc/src/sgml/postgres.sgml @@ -251,6 +251,7 @@ break is not needed in a wider output rendering. &arch-dev; &catalogs; + &system-views; &protocol; &sources; &nls; diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml new file mode 100644 index 0000000000..26ce83eb9b --- /dev/null +++ b/doc/src/sgml/system-views.sgml @@ -0,0 +1,4750 @@ + + + + + System Views + + + In addition to the system catalogs, PostgreSQL + provides a number of built-in views. Some system views provide convenient + access to some commonly used queries on the system catalogs. Other views + provide access to internal server state. + + + + The information schema () provides + an alternative set of views which overlap the functionality of the system + views. Since the information schema is SQL-standard whereas the views + described here are PostgreSQL-specific, + it's usually better to use the information schema if it provides all + the information you need. + + + + lists the system views described here. + More detailed documentation of each view follows below. + There are some additional views that provide access to accumulated + statistics; they are described in + . + + + + Overview + + + lists the system views. + More detailed documentation of each catalog follows below. + Except where noted, all the views described here are read-only. + + + + System Views + + + + + View Name + Purpose + + + + + + pg_available_extensions + available extensions + + + + pg_available_extension_versions + available versions of extensions + + + + pg_backend_memory_contexts + backend memory contexts + + + + pg_config + compile-time configuration parameters + + + + pg_cursors + open cursors + + + + pg_file_settings + summary of configuration file contents + + + + pg_group + groups of database users + + + + pg_hba_file_rules + summary of client authentication configuration file contents + + + + pg_ident_file_mappings + summary of client user name mapping configuration file contents + + + + pg_indexes + indexes + + + + pg_locks + locks currently held or awaited + + + + pg_matviews + materialized views + + + + pg_policies + policies + + + + pg_prepared_statements + prepared statements + + + + pg_prepared_xacts + prepared transactions + + + + pg_publication_tables + publications and information of their associated tables + + + + pg_replication_origin_status + information about replication origins, including replication progress + + + + pg_replication_slots + replication slot information + + + + pg_roles + database roles + + + + pg_rules + rules + + + + pg_seclabels + security labels + + + + pg_sequences + sequences + + + + pg_settings + parameter settings + + + + pg_shadow + database users + + + + pg_shmem_allocations + shared memory allocations + + + + pg_stats + planner statistics + + + + pg_stats_ext + extended planner statistics + + + + pg_stats_ext_exprs + extended planner statistics for expressions + + + + pg_tables + tables + + + + pg_timezone_abbrevs + time zone abbreviations + + + + pg_timezone_names + time zone names + + + + pg_user + database users + + + + pg_user_mappings + user mappings + + + + pg_views + views + + + + +
+ + + + <structname>pg_available_extensions</structname> + + + pg_available_extensions + + + + The pg_available_extensions view lists the + extensions that are available for installation. + See also the + pg_extension + catalog, which shows the extensions currently installed. + + + + <structname>pg_available_extensions</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name name + + + Extension name + + + + + + default_version text + + + Name of default version, or NULL if none is + specified + + + + + + installed_version text + + + Currently installed version of the extension, + or NULL if not installed + + + + + + comment text + + + Comment string from the extension's control file + + + + +
+ + + The pg_available_extensions view is read-only. + + + + + <structname>pg_available_extension_versions</structname> + + + pg_available_extension_versions + + + + The pg_available_extension_versions view lists the + specific extension versions that are available for installation. + See also the pg_extension + catalog, which shows the extensions currently installed. + + + + <structname>pg_available_extension_versions</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name name + + + Extension name + + + + + + version text + + + Version name + + + + + + installed bool + + + True if this version of this extension is currently + installed + + + + + + superuser bool + + + True if only superusers are allowed to install this extension + (but see trusted) + + + + + + trusted bool + + + True if the extension can be installed by non-superusers + with appropriate privileges + + + + + + relocatable bool + + + True if extension can be relocated to another schema + + + + + + schema name + + + Name of the schema that the extension must be installed into, + or NULL if partially or fully relocatable + + + + + + requires name[] + + + Names of prerequisite extensions, + or NULL if none + + + + + + comment text + + + Comment string from the extension's control file + + + + +
+ + + The pg_available_extension_versions view is + read-only. + + + + + <structname>pg_backend_memory_contexts</structname> + + + pg_backend_memory_contexts + + + + The view pg_backend_memory_contexts displays all + the memory contexts of the server process attached to the current session. + + + pg_backend_memory_contexts contains one row + for each memory context. + + + + <structname>pg_backend_memory_contexts</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + Name of the memory context + + + + + + ident text + + + Identification information of the memory context. This field is truncated at 1024 bytes + + + + + + parent text + + + Name of the parent of this memory context + + + + + + level int4 + + + Distance from TopMemoryContext in context tree + + + + + + total_bytes int8 + + + Total bytes allocated for this memory context + + + + + + total_nblocks int8 + + + Total number of blocks allocated for this memory context + + + + + + free_bytes int8 + + + Free space in bytes + + + + + + free_chunks int8 + + + Total number of free chunks + + + + + + used_bytes int8 + + + Used space in bytes + + + + +
+ + + By default, the pg_backend_memory_contexts view can be + read only by superusers or roles with the privileges of the + pg_read_all_stats role. + + + + + <structname>pg_config</structname> + + + pg_config + + + + The view pg_config describes the + compile-time configuration parameters of the currently installed + version of PostgreSQL. It is intended, for example, to + be used by software packages that want to interface to + PostgreSQL to facilitate finding the required header + files and libraries. It provides the same basic information as the + PostgreSQL client + application. + + + + By default, the pg_config view can be read + only by superusers. + + + + <structname>pg_config</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + The parameter name + + + + + + setting text + + + The parameter value + + + + +
+ + + + + <structname>pg_cursors</structname> + + + pg_cursors + + + + The pg_cursors view lists the cursors that + are currently available. Cursors can be defined in several ways: + + + + via the DECLARE + statement in SQL + + + + + + via the Bind message in the frontend/backend protocol, as + described in + + + + + + via the Server Programming Interface (SPI), as described in + + + + + + The pg_cursors view displays cursors + created by any of these means. Cursors only exist for the duration + of the transaction that defines them, unless they have been + declared WITH HOLD. Therefore non-holdable + cursors are only present in the view until the end of their + creating transaction. + + + + Cursors are used internally to implement some of the components + of PostgreSQL, such as procedural languages. + Therefore, the pg_cursors view might include cursors + that have not been explicitly created by the user. + + + + + + <structname>pg_cursors</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + The name of the cursor + + + + + + statement text + + + The verbatim query string submitted to declare this cursor + + + + + + is_holdable bool + + + true if the cursor is holdable (that is, it + can be accessed after the transaction that declared the cursor + has committed); false otherwise + + + + + + is_binary bool + + + true if the cursor was declared + BINARY; false + otherwise + + + + + + is_scrollable bool + + + true if the cursor is scrollable (that is, it + allows rows to be retrieved in a nonsequential manner); + false otherwise + + + + + + creation_time timestamptz + + + The time at which the cursor was declared + + + + +
+ + + The pg_cursors view is read-only. + + + + + + <structname>pg_file_settings</structname> + + + pg_file_settings + + + + The view pg_file_settings provides a summary of + the contents of the server's configuration file(s). A row appears in + this view for each name = value entry appearing in the files, + with annotations indicating whether the value could be applied + successfully. Additional row(s) may appear for problems not linked to + a name = value entry, such as syntax errors in the files. + + + + This view is helpful for checking whether planned changes in the + configuration files will work, or for diagnosing a previous failure. + Note that this view reports on the current contents of the + files, not on what was last applied by the server. (The + pg_settings + view is usually sufficient to determine that.) + + + + By default, the pg_file_settings view can be read + only by superusers. + + + + <structname>pg_file_settings</structname> Columns + + + + + Column Type + + + Description + + + + + + + + sourcefile text + + + Full path name of the configuration file + + + + + + sourceline int4 + + + Line number within the configuration file where the entry appears + + + + + + seqno int4 + + + Order in which the entries are processed (1..n) + + + + + + name text + + + Configuration parameter name + + + + + + setting text + + + Value to be assigned to the parameter + + + + + + applied bool + + + True if the value can be applied successfully + + + + + + error text + + + If not null, an error message indicating why this entry could + not be applied + + + + +
+ + + If the configuration file contains syntax errors or invalid parameter + names, the server will not attempt to apply any settings from it, and + therefore all the applied fields will read as false. + In such a case there will be one or more rows with + non-null error fields indicating the + problem(s). Otherwise, individual settings will be applied if possible. + If an individual setting cannot be applied (e.g., invalid value, or the + setting cannot be changed after server start) it will have an appropriate + message in the error field. Another way that + an entry might have applied = false is that it is + overridden by a later entry for the same parameter name; this case is not + considered an error so nothing appears in + the error field. + + + + See for more information about the various + ways to change run-time parameters. + + + + + + <structname>pg_group</structname> + + + pg_group + + + + + The view pg_group exists for backwards + compatibility: it emulates a catalog that existed in + PostgreSQL before version 8.1. + It shows the names and members of all roles that are marked as not + rolcanlogin, which is an approximation to the set + of roles that are being used as groups. + + + + <structname>pg_group</structname> Columns + + + + + Column Type + + + Description + + + + + + + + groname name + (references pg_authid.rolname) + + + Name of the group + + + + + + grosysid oid + (references pg_authid.oid) + + + ID of this group + + + + + + grolist oid[] + (references pg_authid.oid) + + + An array containing the IDs of the roles in this group + + + + +
+ + + + + <structname>pg_hba_file_rules</structname> + + + pg_hba_file_rules + + + + The view pg_hba_file_rules provides a summary of + the contents of the client authentication configuration file, + pg_hba.conf. + A row appears in this view for each + non-empty, non-comment line in the file, with annotations indicating + whether the rule could be applied successfully. + + + + This view can be helpful for checking whether planned changes in the + authentication configuration file will work, or for diagnosing a previous + failure. Note that this view reports on the current contents + of the file, not on what was last loaded by the server. + + + + By default, the pg_hba_file_rules view can be read + only by superusers. + + + + <structname>pg_hba_file_rules</structname> Columns + + + + + Column Type + + + Description + + + + + + + + line_number int4 + + + Line number of this rule in pg_hba.conf + + + + + + type text + + + Type of connection + + + + + + database text[] + + + List of database name(s) to which this rule applies + + + + + + user_name text[] + + + List of user and group name(s) to which this rule applies + + + + + + address text + + + Host name or IP address, or one + of all, samehost, + or samenet, or null for local connections + + + + + + netmask text + + + IP address mask, or null if not applicable + + + + + + auth_method text + + + Authentication method + + + + + + options text[] + + + Options specified for authentication method, if any + + + + + + error text + + + If not null, an error message indicating why this + line could not be processed + + + + +
+ + + Usually, a row reflecting an incorrect entry will have values for only + the line_number and error fields. + + + + See for more information about + client authentication configuration. + + + + + <structname>pg_ident_file_mappings</structname> + + + pg_ident_file_mappings + + + + The view pg_ident_file_mappings provides a summary + of the contents of the client user name mapping configuration file, + pg_ident.conf. + A row appears in this view for each non-empty, non-comment line in the file, + with annotations indicating whether the rule could be applied successfully. + + + + This view can be helpful for checking whether planned changes in the + authentication configuration file will work, or for diagnosing a previous + failure. Note that this view reports on the current + contents of the file, not on what was last loaded by the server. + + + + By default, the pg_ident_file_mappings view can be + read only by superusers. + + + + <structname>pg_ident_file_mappings</structname> Columns + + + + Column Type + + + Description + + + + + + + + line_number int4 + + + Line number of this rule in pg_ident.conf + + + + + + map_name text + + + Name of the map + + + + + + sys_name text + + + Detected user name of the client + + + + + + pg_username text + + + Requested PostgreSQL user name + + + + + + error text + + + If not NULL, an error message indicating why this + line could not be processed + + + + +
+ + + Usually, a row reflecting an incorrect entry will have values for only + the line_number and error fields. + + + + See for more information about + client authentication configuration. + + + + + <structname>pg_indexes</structname> + + + pg_indexes + + + + The view pg_indexes provides access to + useful information about each index in the database. + + + + <structname>pg_indexes</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table and index + + + + + + tablename name + (references pg_class.relname) + + + Name of table the index is for + + + + + + indexname name + (references pg_class.relname) + + + Name of index + + + + + + tablespace name + (references pg_tablespace.spcname) + + + Name of tablespace containing index (null if default for database) + + + + + + indexdef text + + + Index definition (a reconstructed + command) + + + + +
+ + + + + <structname>pg_locks</structname> + + + pg_locks + + + + The view pg_locks provides access to + information about the locks held by active processes within the + database server. See for more discussion + of locking. + + + + pg_locks contains one row per active lockable + object, requested lock mode, and relevant process. Thus, the same + lockable object might + appear many times, if multiple processes are holding or waiting + for locks on it. However, an object that currently has no locks on it + will not appear at all. + + + + There are several distinct types of lockable objects: + whole relations (e.g., tables), individual pages of relations, + individual tuples of relations, + transaction IDs (both virtual and permanent IDs), + and general database objects (identified by class OID and object OID, + in the same way as in pg_description or + pg_depend). Also, the right to extend a + relation is represented as a separate lockable object, as is the right to + update pg_database.datfrozenxid. + Also, advisory locks can be taken on numbers that have + user-defined meanings. + + + + <structname>pg_locks</structname> Columns + + + + + Column Type + + + Description + + + + + + + + locktype text + + + Type of the lockable object: + relation, + extend, + frozenid, + page, + tuple, + transactionid, + virtualxid, + spectoken, + object, + userlock, or + advisory. + (See also .) + + + + + + database oid + (references pg_database.oid) + + + OID of the database in which the lock target exists, or + zero if the target is a shared object, or + null if the target is a transaction ID + + + + + + relation oid + (references pg_class.oid) + + + OID of the relation targeted by the lock, or null if the target is not + a relation or part of a relation + + + + + + page int4 + + + Page number targeted by the lock within the relation, + or null if the target is not a relation page or tuple + + + + + + tuple int2 + + + Tuple number targeted by the lock within the page, + or null if the target is not a tuple + + + + + + virtualxid text + + + Virtual ID of the transaction targeted by the lock, + or null if the target is not a virtual transaction ID + + + + + + transactionid xid + + + ID of the transaction targeted by the lock, + or null if the target is not a transaction ID + + + + + + classid oid + (references pg_class.oid) + + + OID of the system catalog containing the lock target, or null if the + target is not a general database object + + + + + + objid oid + (references any OID column) + + + OID of the lock target within its system catalog, or null if the + target is not a general database object + + + + + + objsubid int2 + + + Column number targeted by the lock (the + classid and objid refer to the + table itself), + or zero if the target is some other general database object, + or null if the target is not a general database object + + + + + + virtualtransaction text + + + Virtual ID of the transaction that is holding or awaiting this lock + + + + + + pid int4 + + + Process ID of the server process holding or awaiting this + lock, or null if the lock is held by a prepared transaction + + + + + + mode text + + + Name of the lock mode held or desired by this process (see and ) + + + + + + granted bool + + + True if lock is held, false if lock is awaited + + + + + + fastpath bool + + + True if lock was taken via fast path, false if taken via main + lock table + + + + + + waitstart timestamptz + + + Time when the server process started waiting for this lock, + or null if the lock is held. + Note that this can be null for a very short period of time after + the wait started even though granted + is false. + + + + +
+ + + granted is true in a row representing a lock + held by the indicated process. False indicates that this process is + currently waiting to acquire this lock, which implies that at least one + other process is holding or waiting for a conflicting lock mode on the same + lockable object. The waiting process will sleep until the other lock is + released (or a deadlock situation is detected). A single process can be + waiting to acquire at most one lock at a time. + + + + Throughout running a transaction, a server process holds an exclusive lock + on the transaction's virtual transaction ID. If a permanent ID is assigned + to the transaction (which normally happens only if the transaction changes + the state of the database), it also holds an exclusive lock on the + transaction's permanent transaction ID until it ends. When a process finds + it necessary to wait specifically for another transaction to end, it does + so by attempting to acquire share lock on the other transaction's ID + (either virtual or permanent ID depending on the situation). That will + succeed only when the other transaction terminates and releases its locks. + + + + Although tuples are a lockable type of object, + information about row-level locks is stored on disk, not in memory, + and therefore row-level locks normally do not appear in this view. + If a process is waiting for a + row-level lock, it will usually appear in the view as waiting for the + permanent transaction ID of the current holder of that row lock. + + + + Advisory locks can be acquired on keys consisting of either a single + bigint value or two integer values. + A bigint key is displayed with its + high-order half in the classid column, its low-order half + in the objid column, and objsubid equal + to 1. The original bigint value can be reassembled with the + expression (classid::bigint << 32) | + objid::bigint. Integer keys are displayed with the + first key in the + classid column, the second key in the objid + column, and objsubid equal to 2. The actual meaning of + the keys is up to the user. Advisory locks are local to each database, + so the database column is meaningful for an advisory lock. + + + + pg_locks provides a global view of all locks + in the database cluster, not only those relevant to the current database. + Although its relation column can be joined + against pg_class.oid to identify locked + relations, this will only work correctly for relations in the current + database (those for which the database column + is either the current database's OID or zero). + + + + The pid column can be joined to the + pid column of the + + pg_stat_activity + view to get more + information on the session holding or awaiting each lock, + for example + +SELECT * FROM pg_locks pl LEFT JOIN pg_stat_activity psa + ON pl.pid = psa.pid; + + Also, if you are using prepared transactions, the + virtualtransaction column can be joined to the + transaction column of the pg_prepared_xacts + view to get more information on prepared transactions that hold locks. + (A prepared transaction can never be waiting for a lock, + but it continues to hold the locks it acquired while running.) + For example: + +SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx + ON pl.virtualtransaction = '-1/' || ppx.transaction; + + + + + While it is possible to obtain information about which processes block + which other processes by joining pg_locks against + itself, this is very difficult to get right in detail. Such a query would + have to encode knowledge about which lock modes conflict with which + others. Worse, the pg_locks view does not expose + information about which processes are ahead of which others in lock wait + queues, nor information about which processes are parallel workers running + on behalf of which other client sessions. It is better to use + the pg_blocking_pids() function + (see ) to identify which + process(es) a waiting process is blocked behind. + + + + The pg_locks view displays data from both the + regular lock manager and the predicate lock manager, which are + separate systems; in addition, the regular lock manager subdivides its + locks into regular and fast-path locks. + This data is not guaranteed to be entirely consistent. + When the view is queried, + data on fast-path locks (with fastpath = true) + is gathered from each backend one at a time, without freezing the state of + the entire lock manager, so it is possible for locks to be taken or + released while information is gathered. Note, however, that these locks are + known not to conflict with any other lock currently in place. After + all backends have been queried for fast-path locks, the remainder of the + regular lock manager is locked as a unit, and a consistent snapshot of all + remaining locks is collected as an atomic action. After unlocking the + regular lock manager, the predicate lock manager is similarly locked and all + predicate locks are collected as an atomic action. Thus, with the exception + of fast-path locks, each lock manager will deliver a consistent set of + results, but as we do not lock both lock managers simultaneously, it is + possible for locks to be taken or released after we interrogate the regular + lock manager and before we interrogate the predicate lock manager. + + + + Locking the regular and/or predicate lock manager could have some + impact on database performance if this view is very frequently accessed. + The locks are held only for the minimum amount of time necessary to + obtain data from the lock managers, but this does not completely eliminate + the possibility of a performance impact. + + + + + + <structname>pg_matviews</structname> + + + pg_matviews + + + + materialized views + + + + The view pg_matviews provides access to + useful information about each materialized view in the database. + + + + <structname>pg_matviews</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing materialized view + + + + + + matviewname name + (references pg_class.relname) + + + Name of materialized view + + + + + + matviewowner name + (references pg_authid.rolname) + + + Name of materialized view's owner + + + + + + tablespace name + (references pg_tablespace.spcname) + + + Name of tablespace containing materialized view (null if default for database) + + + + + + hasindexes bool + + + True if materialized view has (or recently had) any indexes + + + + + + ispopulated bool + + + True if materialized view is currently populated + + + + + + definition text + + + Materialized view definition (a reconstructed query) + + + + +
+ + + + + <structname>pg_policies</structname> + + + pg_policies + + + + The view pg_policies provides access to + useful information about each row-level security policy in the database. + + + + <structname>pg_policies</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table policy is on + + + + + + tablename name + (references pg_class.relname) + + + Name of table policy is on + + + + + + policyname name + (references pg_policy.polname) + + + Name of policy + + + + + + permissive text + + + Is the policy permissive or restrictive? + + + + + + roles name[] + + + The roles to which this policy applies + + + + + + cmd text + + + The command type to which the policy is applied + + + + + + qual text + + + The expression added to the security barrier qualifications for + queries that this policy applies to + + + + + + with_check text + + + The expression added to the WITH CHECK qualifications for + queries that attempt to add rows to this table + + + + +
+ + + + + <structname>pg_prepared_statements</structname> + + + pg_prepared_statements + + + + The pg_prepared_statements view displays + all the prepared statements that are available in the current + session. See for more information about prepared + statements. + + + + pg_prepared_statements contains one row + for each prepared statement. Rows are added to the view when a new + prepared statement is created and removed when a prepared statement + is released (for example, via the DEALLOCATE command). + + + + <structname>pg_prepared_statements</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + The identifier of the prepared statement + + + + + + statement text + + + The query string submitted by the client to create this + prepared statement. For prepared statements created via SQL, + this is the PREPARE statement submitted by + the client. For prepared statements created via the + frontend/backend protocol, this is the text of the prepared + statement itself. + + + + + + prepare_time timestamptz + + + The time at which the prepared statement was created + + + + + + parameter_types regtype[] + + + The expected parameter types for the prepared statement in the + form of an array of regtype. The OID corresponding + to an element of this array can be obtained by casting the + regtype value to oid. + + + + + + result_types regtype[] + + + The types of the columns returned by the prepared statement in the + form of an array of regtype. The OID corresponding + to an element of this array can be obtained by casting the + regtype value to oid. + If the prepared statement does not provide a result (e.g., a DML + statement), then this field will be null. + + + + + + from_sql bool + + + true if the prepared statement was created + via the PREPARE SQL command; + false if the statement was prepared via the + frontend/backend protocol + + + + + + generic_plans int8 + + + Number of times generic plan was chosen + + + + + + custom_plans int8 + + + Number of times custom plan was chosen + + + + +
+ + + The pg_prepared_statements view is read-only. + + + + + <structname>pg_prepared_xacts</structname> + + + pg_prepared_xacts + + + + The view pg_prepared_xacts displays + information about transactions that are currently prepared for two-phase + commit (see for details). + + + + pg_prepared_xacts contains one row per prepared + transaction. An entry is removed when the transaction is committed or + rolled back. + + + + <structname>pg_prepared_xacts</structname> Columns + + + + + Column Type + + + Description + + + + + + + + transaction xid + + + Numeric transaction identifier of the prepared transaction + + + + + + gid text + + + Global transaction identifier that was assigned to the transaction + + + + + + prepared timestamptz + + + Time at which the transaction was prepared for commit + + + + + + owner name + (references pg_authid.rolname) + + + Name of the user that executed the transaction + + + + + + database name + (references pg_database.datname) + + + Name of the database in which the transaction was executed + + + + +
+ + + When the pg_prepared_xacts view is accessed, the + internal transaction manager data structures are momentarily locked, and + a copy is made for the view to display. This ensures that the + view produces a consistent set of results, while not blocking + normal operations longer than necessary. Nonetheless + there could be some impact on database performance if this view is + frequently accessed. + + + + + + <structname>pg_publication_tables</structname> + + + pg_publication_tables + + + + The view pg_publication_tables provides + information about the mapping between publications and information of + tables they contain. Unlike the underlying catalog + pg_publication_rel, + this view expands publications defined as FOR ALL TABLES + and FOR ALL TABLES IN SCHEMA, so for such publications + there will be a row for each eligible table. + + + + <structname>pg_publication_tables</structname> Columns + + + + + Column Type + + + Description + + + + + + + + pubname name + (references pg_publication.pubname) + + + Name of publication + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table + + + + + + tablename name + (references pg_class.relname) + + + Name of table + + + + + + attnames name[] + (references pg_attribute.attname) + + + Names of table columns included in the publication. This contains all + the columns of the table when the user didn't specify the column list + for the table. + + + + + + rowfilter text + + + Expression for the table's publication qualifying condition + + + + +
+ + + + <structname>pg_replication_origin_status</structname> + + + pg_replication_origin_status + + + + The pg_replication_origin_status view + contains information about how far replay for a certain origin has + progressed. For more on replication origins + see . + + + + <structname>pg_replication_origin_status</structname> Columns + + + + + Column Type + + + Description + + + + + + + + local_id oid + (references pg_replication_origin.roident) + + + internal node identifier + + + + + + external_id text + (references pg_replication_origin.roname) + + + external node identifier + + + + + + remote_lsn pg_lsn + + + The origin node's LSN up to which data has been replicated. + + + + + + local_lsn pg_lsn + + + This node's LSN at which remote_lsn has + been replicated. Used to flush commit records before persisting + data to disk when using asynchronous commits. + + + + +
+ + + + <structname>pg_replication_slots</structname> + + + pg_replication_slots + + + + The pg_replication_slots view provides a listing + of all replication slots that currently exist on the database cluster, + along with their current state. + + + + For more on replication slots, + see and . + + + + <structname>pg_replication_slots</structname> Columns + + + + + Column Type + + + Description + + + + + + + + slot_name name + + + A unique, cluster-wide identifier for the replication slot + + + + + + plugin name + + + The base name of the shared object containing the output plugin this logical slot is using, or null for physical slots. + + + + + + slot_type text + + + The slot type: physical or logical + + + + + + datoid oid + (references pg_database.oid) + + + The OID of the database this slot is associated with, or + null. Only logical slots have an associated database. + + + + + + database name + (references pg_database.datname) + + + The name of the database this slot is associated with, or + null. Only logical slots have an associated database. + + + + + + temporary bool + + + True if this is a temporary replication slot. Temporary slots are + not saved to disk and are automatically dropped on error or when + the session has finished. + + + + + + active bool + + + True if this slot is currently actively being used + + + + + + active_pid int4 + + + The process ID of the session using this slot if the slot + is currently actively being used. NULL if + inactive. + + + + + + xmin xid + + + The oldest transaction that this slot needs the database to + retain. VACUUM cannot remove tuples deleted + by any later transaction. + + + + + + catalog_xmin xid + + + The oldest transaction affecting the system catalogs that this + slot needs the database to retain. VACUUM cannot + remove catalog tuples deleted by any later transaction. + + + + + + restart_lsn pg_lsn + + + The address (LSN) of oldest WAL which still + might be required by the consumer of this slot and thus won't be + automatically removed during checkpoints unless this LSN + gets behind more than + from the current LSN. NULL + if the LSN of this slot has never been reserved. + + + + + + confirmed_flush_lsn pg_lsn + + + The address (LSN) up to which the logical + slot's consumer has confirmed receiving data. Data older than this is + not available anymore. NULL for physical slots. + + + + + + wal_status text + + + Availability of WAL files claimed by this slot. + Possible values are: + + + reserved means that the claimed files + are within max_wal_size. + + + extended means + that max_wal_size is exceeded but the files are + still retained, either by the replication slot or + by wal_keep_size. + + + + + unreserved means that the slot no longer + retains the required WAL files and some of them are to be removed at + the next checkpoint. This state can return + to reserved or extended. + + + + + lost means that some required WAL files have + been removed and this slot is no longer usable. + + + + The last two states are seen only when + is + non-negative. If restart_lsn is NULL, this + field is null. + + + + + + safe_wal_size int8 + + + The number of bytes that can be written to WAL such that this slot + is not in danger of getting in state "lost". It is NULL for lost + slots, as well as if max_slot_wal_keep_size + is -1. + + + + + + two_phase bool + + + True if the slot is enabled for decoding prepared transactions. Always + false for physical slots. + + + + +
+ + + + <structname>pg_roles</structname> + + + pg_roles + + + + The view pg_roles provides access to + information about database roles. This is simply a publicly + readable view of + pg_authid + that blanks out the password field. + + + + <structname>pg_roles</structname> Columns + + + + + Column Type + + + Description + + + + + + + + rolname name + + + Role name + + + + + + rolsuper bool + + + Role has superuser privileges + + + + + + rolinherit bool + + + Role automatically inherits privileges of roles it is a + member of + + + + + + rolcreaterole bool + + + Role can create more roles + + + + + + rolcreatedb bool + + + Role can create databases + + + + + + rolcanlogin bool + + + Role can log in. That is, this role can be given as the initial + session authorization identifier + + + + + + rolreplication bool + + + Role is a replication role. A replication role can initiate replication + connections and create and drop replication slots. + + + + + + rolconnlimit int4 + + + For roles that can log in, this sets maximum number of concurrent + connections this role can make. -1 means no limit. + + + + + + rolpassword text + + + Not the password (always reads as ********) + + + + + + rolvaliduntil timestamptz + + + Password expiry time (only used for password authentication); + null if no expiration + + + + + + rolbypassrls bool + + + Role bypasses every row-level security policy, see + for more information. + + + + + + rolconfig text[] + + + Role-specific defaults for run-time configuration variables + + + + + + oid oid + (references pg_authid.oid) + + + ID of role + + + + +
+ + + + + <structname>pg_rules</structname> + + + pg_rules + + + + The view pg_rules provides access to + useful information about query rewrite rules. + + + + <structname>pg_rules</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table + + + + + + tablename name + (references pg_class.relname) + + + Name of table the rule is for + + + + + + rulename name + (references pg_rewrite.rulename) + + + Name of rule + + + + + + definition text + + + Rule definition (a reconstructed creation command) + + + + +
+ + + The pg_rules view excludes the ON SELECT rules + of views and materialized views; those can be seen in + pg_views and pg_matviews. + + + + + + <structname>pg_seclabels</structname> + + + pg_seclabels + + + + The view pg_seclabels provides information about + security labels. It as an easier-to-query version of the + pg_seclabel catalog. + + + + <structname>pg_seclabels</structname> Columns + + + + + Column Type + + + Description + + + + + + + + objoid oid + (references any OID column) + + + The OID of the object this security label pertains to + + + + + + classoid oid + (references pg_class.oid) + + + The OID of the system catalog this object appears in + + + + + + objsubid int4 + + + For a security label on a table column, this is the column number (the + objoid and classoid refer to + the table itself). For all other object types, this column is + zero. + + + + + + objtype text + + + The type of object to which this label applies, as text. + + + + + + objnamespace oid + (references pg_namespace.oid) + + + The OID of the namespace for this object, if applicable; + otherwise NULL. + + + + + + objname text + + + The name of the object to which this label applies, as text. + + + + + + provider text + (references pg_seclabel.provider) + + + The label provider associated with this label. + + + + + + label text + (references pg_seclabel.label) + + + The security label applied to this object. + + + + +
+ + + + <structname>pg_sequences</structname> + + + pg_sequences + + + + The view pg_sequences provides access to + useful information about each sequence in the database. + + + + <structname>pg_sequences</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing sequence + + + + + + sequencename name + (references pg_class.relname) + + + Name of sequence + + + + + + sequenceowner name + (references pg_authid.rolname) + + + Name of sequence's owner + + + + + + data_type regtype + (references pg_type.oid) + + + Data type of the sequence + + + + + + start_value int8 + + + Start value of the sequence + + + + + + min_value int8 + + + Minimum value of the sequence + + + + + + max_value int8 + + + Maximum value of the sequence + + + + + + increment_by int8 + + + Increment value of the sequence + + + + + + cycle bool + + + Whether the sequence cycles + + + + + + cache_size int8 + + + Cache size of the sequence + + + + + + last_value int8 + + + The last sequence value written to disk. If caching is used, + this value can be greater than the last value handed out from the + sequence. Null if the sequence has not been read from yet. Also, if + the current user does not have USAGE + or SELECT privilege on the sequence, the value is + null. + + + + +
+ + + + <structname>pg_settings</structname> + + + pg_settings + + + + The view pg_settings provides access to + run-time parameters of the server. It is essentially an alternative + interface to the SHOW + and SET commands. + It also provides access to some facts about each parameter that are + not directly available from SHOW, such as minimum and + maximum values. + + + + <structname>pg_settings</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + Run-time configuration parameter name + + + + + + setting text + + + Current value of the parameter + + + + + + unit text + + + Implicit unit of the parameter + + + + + + category text + + + Logical group of the parameter + + + + + + short_desc text + + + A brief description of the parameter + + + + + + extra_desc text + + + Additional, more detailed, description of the parameter + + + + + + context text + + + Context required to set the parameter's value (see below) + + + + + + vartype text + + + Parameter type (bool, enum, + integer, real, or string) + + + + + + source text + + + Source of the current parameter value + + + + + + min_val text + + + Minimum allowed value of the parameter (null for non-numeric + values) + + + + + + max_val text + + + Maximum allowed value of the parameter (null for non-numeric + values) + + + + + + enumvals text[] + + + Allowed values of an enum parameter (null for non-enum + values) + + + + + + boot_val text + + + Parameter value assumed at server startup if the parameter is + not otherwise set + + + + + + reset_val text + + + Value that RESET would reset the parameter to + in the current session + + + + + + sourcefile text + + + Configuration file the current value was set in (null for + values set from sources other than configuration files, or when + examined by a user who neither is a superuser nor has privileges of + pg_read_all_settings); helpful when using + include directives in configuration files + + + + + + sourceline int4 + + + Line number within the configuration file the current value was + set at (null for values set from sources other than configuration files, + or when examined by a user who neither is a superuser nor has privileges of + pg_read_all_settings). + + + + + + pending_restart bool + + + true if the value has been changed in the + configuration file but needs a restart; or false + otherwise. + + + + +
+ + + There are several possible values of context. + In order of decreasing difficulty of changing the setting, they are: + + + + + + internal + + + These settings cannot be changed directly; they reflect internally + determined values. Some of them may be adjustable by rebuilding the + server with different configuration options, or by changing options + supplied to initdb. + + + + + + postmaster + + + These settings can only be applied when the server starts, so any change + requires restarting the server. Values for these settings are typically + stored in the postgresql.conf file, or passed on + the command line when starting the server. Of course, settings with any + of the lower context types can also be + set at server start time. + + + + + + sighup + + + Changes to these settings can be made in + postgresql.conf without restarting the server. + Send a SIGHUP signal to the postmaster to + cause it to re-read postgresql.conf and apply + the changes. The postmaster will also forward the + SIGHUP signal to its child processes so that + they all pick up the new value. + + + + + + superuser-backend + + + Changes to these settings can be made in + postgresql.conf without restarting the server. + They can also be set for a particular session in the connection request + packet (for example, via libpq's PGOPTIONS + environment variable), but only if the connecting user is a superuser + or has been granted the appropriate SET privilege. + However, these settings never change in a session after it is started. + If you change them in postgresql.conf, send a + SIGHUP signal to the postmaster to cause it to + re-read postgresql.conf. The new values will only + affect subsequently-launched sessions. + + + + + + backend + + + Changes to these settings can be made in + postgresql.conf without restarting the server. + They can also be set for a particular session in the connection request + packet (for example, via libpq's PGOPTIONS + environment variable); any user can make such a change for their session. + However, these settings never change in a session after it is started. + If you change them in postgresql.conf, send a + SIGHUP signal to the postmaster to cause it to + re-read postgresql.conf. The new values will only + affect subsequently-launched sessions. + + + + + + superuser + + + These settings can be set from postgresql.conf, + or within a session via the SET command; but only superusers + and users with the appropriate SET privilege + can change them via SET. Changes in + postgresql.conf will affect existing sessions + only if no session-local value has been established with SET. + + + + + + user + + + These settings can be set from postgresql.conf, + or within a session via the SET command. Any user is + allowed to change their session-local value. Changes in + postgresql.conf will affect existing sessions + only if no session-local value has been established with SET. + + + + + + + See for more information about the various + ways to change these parameters. + + + + This view does not display customized options + until the extension module that defines them has been loaded. + + + + This view cannot be inserted into or deleted from, but it can be updated. An + UPDATE applied to a row of pg_settings + is equivalent to executing the SET command on that named + parameter. The change only affects the value used by the current + session. If an UPDATE is issued within a transaction + that is later aborted, the effects of the UPDATE command + disappear when the transaction is rolled back. Once the surrounding + transaction is committed, the effects will persist until the end of the + session, unless overridden by another UPDATE or + SET. + + + + + + <structname>pg_shadow</structname> + + + pg_shadow + + + + The view pg_shadow exists for backwards + compatibility: it emulates a catalog that existed in + PostgreSQL before version 8.1. + It shows properties of all roles that are marked as + rolcanlogin in + pg_authid. + + + + The name stems from the fact that this table + should not be readable by the public since it contains passwords. + pg_user + is a publicly readable view on + pg_shadow that blanks out the password field. + + + + <structname>pg_shadow</structname> Columns + + + + + Column Type + + + Description + + + + + + + + usename name + (references pg_authid.rolname) + + + User name + + + + + + usesysid oid + (references pg_authid.oid) + + + ID of this user + + + + + + usecreatedb bool + + + User can create databases + + + + + + usesuper bool + + + User is a superuser + + + + + + userepl bool + + + User can initiate streaming replication and put the system in and + out of backup mode. + + + + + + usebypassrls bool + + + User bypasses every row-level security policy, see + for more information. + + + + + + passwd text + + + Password (possibly encrypted); null if none. See + pg_authid + for details of how encrypted passwords are stored. + + + + + + valuntil timestamptz + + + Password expiry time (only used for password authentication) + + + + + + useconfig text[] + + + Session defaults for run-time configuration variables + + + + +
+ + + + + <structname>pg_shmem_allocations</structname> + + + pg_shmem_allocations + + + + The pg_shmem_allocations view shows allocations + made from the server's main shared memory segment. This includes both + memory allocated by PostgreSQL itself and memory + allocated by extensions using the mechanisms detailed in + . + + + + Note that this view does not include memory allocated using the dynamic + shared memory infrastructure. + + + + <structname>pg_shmem_allocations</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + The name of the shared memory allocation. NULL for unused memory + and <anonymous> for anonymous + allocations. + + + + + + off int8 + + + The offset at which the allocation starts. NULL for anonymous + allocations, since details related to them are not known. + + + + + + size int8 + + + Size of the allocation + + + + + + allocated_size int8 + + + Size of the allocation including padding. For anonymous + allocations, no information about padding is available, so the + size and allocated_size columns + will always be equal. Padding is not meaningful for free memory, so + the columns will be equal in that case also. + + + + +
+ + + Anonymous allocations are allocations that have been made + with ShmemAlloc() directly, rather than via + ShmemInitStruct() or + ShmemInitHash(). + + + + By default, the pg_shmem_allocations view can be + read only by superusers or roles with privileges of the + pg_read_all_stats role. + + + + + <structname>pg_stats</structname> + + + pg_stats + + + + The view pg_stats provides access to + the information stored in the pg_statistic + catalog. This view allows access only to rows of + pg_statistic that correspond to tables the + user has permission to read, and therefore it is safe to allow public + read access to this view. + + + + pg_stats is also designed to present the + information in a more readable format than the underlying catalog + — at the cost that its schema must be extended whenever new slot types + are defined for pg_statistic. + + + + <structname>pg_stats</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table + + + + + + tablename name + (references pg_class.relname) + + + Name of table + + + + + + attname name + (references pg_attribute.attname) + + + Name of column described by this row + + + + + + inherited bool + + + If true, this row includes inheritance child columns, not just the + values in the specified table + + + + + + null_frac float4 + + + Fraction of column entries that are null + + + + + + avg_width int4 + + + Average width in bytes of column's entries + + + + + + n_distinct float4 + + + If greater than zero, the estimated number of distinct values in the + column. If less than zero, the negative of the number of distinct + values divided by the number of rows. (The negated form is used when + ANALYZE believes that the number of distinct values is + likely to increase as the table grows; the positive form is used when + the column seems to have a fixed number of possible values.) For + example, -1 indicates a unique column in which the number of distinct + values is the same as the number of rows. + + + + + + most_common_vals anyarray + + + A list of the most common values in the column. (Null if + no values seem to be more common than any others.) + + + + + + most_common_freqs float4[] + + + A list of the frequencies of the most common values, + i.e., number of occurrences of each divided by total number of rows. + (Null when most_common_vals is.) + + + + + + histogram_bounds anyarray + + + A list of values that divide the column's values into groups of + approximately equal population. The values in + most_common_vals, if present, are omitted from this + histogram calculation. (This column is null if the column data type + does not have a < operator or if the + most_common_vals list accounts for the entire + population.) + + + + + + correlation float4 + + + Statistical correlation between physical row ordering and + logical ordering of the column values. This ranges from -1 to +1. + When the value is near -1 or +1, an index scan on the column will + be estimated to be cheaper than when it is near zero, due to reduction + of random access to the disk. (This column is null if the column data + type does not have a < operator.) + + + + + + most_common_elems anyarray + + + A list of non-null element values most often appearing within values of + the column. (Null for scalar types.) + + + + + + most_common_elem_freqs float4[] + + + A list of the frequencies of the most common element values, i.e., the + fraction of rows containing at least one instance of the given value. + Two or three additional values follow the per-element frequencies; + these are the minimum and maximum of the preceding per-element + frequencies, and optionally the frequency of null elements. + (Null when most_common_elems is.) + + + + + + elem_count_histogram float4[] + + + A histogram of the counts of distinct non-null element values within the + values of the column, followed by the average number of distinct + non-null elements. (Null for scalar types.) + + + + +
+ + + The maximum number of entries in the array fields can be controlled on a + column-by-column basis using the ALTER + TABLE SET STATISTICS + command, or globally by setting the + run-time parameter. + + + + + + <structname>pg_stats_ext</structname> + + + pg_stats_ext + + + + The view pg_stats_ext provides access to + information about each extended statistics object in the database, + combining information stored in the pg_statistic_ext + and pg_statistic_ext_data + catalogs. This view allows access only to rows of + pg_statistic_ext and pg_statistic_ext_data + that correspond to tables the user has permission to read, and therefore + it is safe to allow public read access to this view. + + + + pg_stats_ext is also designed to present the + information in a more readable format than the underlying catalogs + — at the cost that its schema must be extended whenever new types + of extended statistics are added to pg_statistic_ext. + + + + <structname>pg_stats_ext</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table + + + + + + tablename name + (references pg_class.relname) + + + Name of table + + + + + + statistics_schemaname name + (references pg_namespace.nspname) + + + Name of schema containing extended statistics object + + + + + + statistics_name name + (references pg_statistic_ext.stxname) + + + Name of extended statistics object + + + + + + statistics_owner name + (references pg_authid.rolname) + + + Owner of the extended statistics object + + + + + + attnames name[] + (references pg_attribute.attname) + + + Names of the columns included in the extended statistics object + + + + + + exprs text[] + + + Expressions included in the extended statistics object + + + + + + kinds char[] + + + Types of extended statistics object enabled for this record + + + + + + inherited bool + (references pg_statistic_ext_data.stxdinherit) + + + If true, the stats include inheritance child columns, not just the + values in the specified relation + + + + + + n_distinct pg_ndistinct + + + N-distinct counts for combinations of column values. If greater + than zero, the estimated number of distinct values in the combination. + If less than zero, the negative of the number of distinct values divided + by the number of rows. + (The negated form is used when ANALYZE believes that + the number of distinct values is likely to increase as the table grows; + the positive form is used when the column seems to have a fixed number + of possible values.) For example, -1 indicates a unique combination of + columns in which the number of distinct combinations is the same as the + number of rows. + + + + + + dependencies pg_dependencies + + + Functional dependency statistics + + + + + + most_common_vals text[] + + + A list of the most common combinations of values in the columns. + (Null if no combinations seem to be more common than any others.) + + + + + + most_common_val_nulls bool[] + + + A list of NULL flags for the most common combinations of values. + (Null when most_common_vals is.) + + + + + + most_common_freqs float8[] + + + A list of the frequencies of the most common combinations, + i.e., number of occurrences of each divided by total number of rows. + (Null when most_common_vals is.) + + + + + + most_common_base_freqs float8[] + + + A list of the base frequencies of the most common combinations, + i.e., product of per-value frequencies. + (Null when most_common_vals is.) + + + + +
+ + + The maximum number of entries in the array fields can be controlled on a + column-by-column basis using the ALTER + TABLE SET STATISTICS command, or globally by setting the + run-time parameter. + + + + + + <structname>pg_stats_ext_exprs</structname> + + + pg_stats_ext_exprs + + + + The view pg_stats_ext_exprs provides access to + information about all expressions included in extended statistics objects, + combining information stored in the pg_statistic_ext + and pg_statistic_ext_data + catalogs. This view allows access only to rows of + pg_statistic_ext and pg_statistic_ext_data + that correspond to tables the user has permission to read, and therefore + it is safe to allow public read access to this view. + + + + pg_stats_ext_exprs is also designed to present + the information in a more readable format than the underlying catalogs + — at the cost that its schema must be extended whenever the structure + of statistics in pg_statistic_ext changes. + + + + <structname>pg_stats_ext_exprs</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table + + + + + + tablename name + (references pg_class.relname) + + + Name of table the statistics object is defined on + + + + + + statistics_schemaname name + (references pg_namespace.nspname) + + + Name of schema containing extended statistics object + + + + + + statistics_name name + (references pg_statistic_ext.stxname) + + + Name of extended statistics object + + + + + + statistics_owner name + (references pg_authid.rolname) + + + Owner of the extended statistics object + + + + + + expr text + + + Expression included in the extended statistics object + + + + + + inherited bool + (references pg_statistic_ext_data.stxdinherit) + + + If true, the stats include inheritance child columns, not just the + values in the specified relation + + + + + + null_frac float4 + + + Fraction of expression entries that are null + + + + + + avg_width int4 + + + Average width in bytes of expression's entries + + + + + + n_distinct float4 + + + If greater than zero, the estimated number of distinct values in the + expression. If less than zero, the negative of the number of distinct + values divided by the number of rows. (The negated form is used when + ANALYZE believes that the number of distinct values is + likely to increase as the table grows; the positive form is used when + the expression seems to have a fixed number of possible values.) For + example, -1 indicates a unique expression in which the number of distinct + values is the same as the number of rows. + + + + + + most_common_vals anyarray + + + A list of the most common values in the expression. (Null if + no values seem to be more common than any others.) + + + + + + most_common_freqs float4[] + + + A list of the frequencies of the most common values, + i.e., number of occurrences of each divided by total number of rows. + (Null when most_common_vals is.) + + + + + + histogram_bounds anyarray + + + A list of values that divide the expression's values into groups of + approximately equal population. The values in + most_common_vals, if present, are omitted from this + histogram calculation. (This expression is null if the expression data type + does not have a < operator or if the + most_common_vals list accounts for the entire + population.) + + + + + + correlation float4 + + + Statistical correlation between physical row ordering and + logical ordering of the expression values. This ranges from -1 to +1. + When the value is near -1 or +1, an index scan on the expression will + be estimated to be cheaper than when it is near zero, due to reduction + of random access to the disk. (This expression is null if the expression's + data type does not have a < operator.) + + + + + + most_common_elems anyarray + + + A list of non-null element values most often appearing within values of + the expression. (Null for scalar types.) + + + + + + most_common_elem_freqs float4[] + + + A list of the frequencies of the most common element values, i.e., the + fraction of rows containing at least one instance of the given value. + Two or three additional values follow the per-element frequencies; + these are the minimum and maximum of the preceding per-element + frequencies, and optionally the frequency of null elements. + (Null when most_common_elems is.) + + + + + + elem_count_histogram float4[] + + + A histogram of the counts of distinct non-null element values within the + values of the expression, followed by the average number of distinct + non-null elements. (Null for scalar types.) + + + + +
+ + + The maximum number of entries in the array fields can be controlled on a + column-by-column basis using the ALTER + TABLE SET STATISTICS command, or globally by setting the + run-time parameter. + + + + + + <structname>pg_tables</structname> + + + pg_tables + + + + The view pg_tables provides access to + useful information about each table in the database. + + + + <structname>pg_tables</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing table + + + + + + tablename name + (references pg_class.relname) + + + Name of table + + + + + + tableowner name + (references pg_authid.rolname) + + + Name of table's owner + + + + + + tablespace name + (references pg_tablespace.spcname) + + + Name of tablespace containing table (null if default for database) + + + + + + hasindexes bool + (references pg_class.relhasindex) + + + True if table has (or recently had) any indexes + + + + + + hasrules bool + (references pg_class.relhasrules) + + + True if table has (or once had) rules + + + + + + hastriggers bool + (references pg_class.relhastriggers) + + + True if table has (or once had) triggers + + + + + + rowsecurity bool + (references pg_class.relrowsecurity) + + + True if row security is enabled on the table + + + + +
+ + + + + <structname>pg_timezone_abbrevs</structname> + + + pg_timezone_abbrevs + + + + The view pg_timezone_abbrevs provides a list + of time zone abbreviations that are currently recognized by the datetime + input routines. The contents of this view change when the + run-time parameter is modified. + + + + <structname>pg_timezone_abbrevs</structname> Columns + + + + + Column Type + + + Description + + + + + + + + abbrev text + + + Time zone abbreviation + + + + + + utc_offset interval + + + Offset from UTC (positive means east of Greenwich) + + + + + + is_dst bool + + + True if this is a daylight-savings abbreviation + + + + +
+ + + While most timezone abbreviations represent fixed offsets from UTC, + there are some that have historically varied in value + (see for more information). + In such cases this view presents their current meaning. + + + + + + <structname>pg_timezone_names</structname> + + + pg_timezone_names + + + + The view pg_timezone_names provides a list + of time zone names that are recognized by SET TIMEZONE, + along with their associated abbreviations, UTC offsets, + and daylight-savings status. (Technically, + PostgreSQL does not use UTC because leap + seconds are not handled.) + Unlike the abbreviations shown in pg_timezone_abbrevs, many of these names imply a set of daylight-savings transition + date rules. Therefore, the associated information changes across local DST + boundaries. The displayed information is computed based on the current + value of CURRENT_TIMESTAMP. + + + + <structname>pg_timezone_names</structname> Columns + + + + + Column Type + + + Description + + + + + + + + name text + + + Time zone name + + + + + + abbrev text + + + Time zone abbreviation + + + + + + utc_offset interval + + + Offset from UTC (positive means east of Greenwich) + + + + + + is_dst bool + + + True if currently observing daylight savings + + + + +
+ + + + + <structname>pg_user</structname> + + + pg_user + + + + The view pg_user provides access to + information about database users. This is simply a publicly + readable view of + pg_shadow + that blanks out the password field. + + + + <structname>pg_user</structname> Columns + + + + + Column Type + + + Description + + + + + + + + usename name + + + User name + + + + + + usesysid oid + + + ID of this user + + + + + + usecreatedb bool + + + User can create databases + + + + + + usesuper bool + + + User is a superuser + + + + + + userepl bool + + + User can initiate streaming replication and put the system in and + out of backup mode. + + + + + + usebypassrls bool + + + User bypasses every row-level security policy, see + for more information. + + + + + + passwd text + + + Not the password (always reads as ********) + + + + + + valuntil timestamptz + + + Password expiry time (only used for password authentication) + + + + + + useconfig text[] + + + Session defaults for run-time configuration variables + + + + +
+ + + + + <structname>pg_user_mappings</structname> + + + pg_user_mappings + + + + The view pg_user_mappings provides access + to information about user mappings. This is essentially a publicly + readable view of + pg_user_mapping + that leaves out the options field if the user has no rights to use + it. + + + + <structname>pg_user_mappings</structname> Columns + + + + + Column Type + + + Description + + + + + + + + umid oid + (references pg_user_mapping.oid) + + + OID of the user mapping + + + + + + srvid oid + (references pg_foreign_server.oid) + + + The OID of the foreign server that contains this mapping + + + + + + srvname name + (references pg_foreign_server.srvname) + + + Name of the foreign server + + + + + + umuser oid + (references pg_authid.oid) + + + OID of the local role being mapped, or zero if the user mapping is public + + + + + + usename name + + + Name of the local user to be mapped + + + + + + umoptions text[] + + + User mapping specific options, as keyword=value strings + + + + +
+ + + To protect password information stored as a user mapping option, + the umoptions column will read as null + unless one of the following applies: + + + + current user is the user being mapped, and owns the server or + holds USAGE privilege on it + + + + + current user is the server owner and mapping is for PUBLIC + + + + + current user is a superuser + + + + + + + + + + <structname>pg_views</structname> + + + pg_views + + + + The view pg_views provides access to + useful information about each view in the database. + + + + <structname>pg_views</structname> Columns + + + + + Column Type + + + Description + + + + + + + + schemaname name + (references pg_namespace.nspname) + + + Name of schema containing view + + + + + + viewname name + (references pg_class.relname) + + + Name of view + + + + + + viewowner name + (references pg_authid.rolname) + + + Name of view's owner + + + + + + definition text + + + View definition (a reconstructed query) + + + + +
+ + +