+ linkend="view-pg-prepared-xacts">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>
+
+
+
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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.
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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
+
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ The view pg_stats provides access to
+ the information stored in the
+ linkend="catalog-pg-statistic">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>
+
+
+
+
+ The view pg_stats_ext provides access to
+ information about each extended statistics object in the database,
+ combining information stored in the
+ linkend="catalog-pg-statistic-ext">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>
+
+
+
+
+ The view pg_stats_ext_exprs provides access to
+ information about all expressions included in extended statistics objects,
+ combining information stored in the
+ linkend="catalog-pg-statistic-ext">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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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
+ linkend="view-pg-timezone-abbrevs">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>
+
+
+
+
+ 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>
+
+
+
+
+ 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>
+
+
+
+
+ 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)
+
+
+
+
+
+
+
+
projects / postgresql.git / commitdiff