-
-
-
-UNLISTEN
-
-SQL - Language Statements
-
-
-
-UNLISTEN
-
-
-Stop listening for notification
-
-
-
-
-1998-10-19
-
-
-UNLISTEN { notifyname | * }
-
-
-
-
-1998-10-19
-
-
</div>
<div class="diff rem">-Inputs</div>
<div class="diff rem">-
-
-
-
-
-notifyname
-
-
-Name of previously registered notify condition.
-
-
-
-
-
-*
-
-
-All current listen registrations for this backend are cleared.
-
-
-
-
-
-
-
-
-
-
-1998-10-19
-
-
</div>
<div class="diff rem">-Outputs</div>
<div class="diff rem">-
-
-
-
-
+
+
+
+ UNLISTEN
+
+ SQL - Language Statements
+
+
+
+ UNLISTEN
+
+
+ Stop listening for notification
+
+
+
+
+ 1998-10-19
+
+
+UNLISTEN { notifyname | * }
+
+
+
+
+ 1998-10-19
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+ notifyname
+
+ Name of previously registered notify condition.
+
+
+
+
+ *
+
+ All current listen registrations for this backend are cleared.
+
+
+
+
+
+
+
+
+
+ 1998-10-19
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
UNLISTEN
-
-
-Acknowledgement that statement has executed.
-
-
-
-
-
-
-
-
-
-
-
-1998-10-19
-
-
</div>
<div class="diff rem">-Description</div>
<div class="diff rem">-
-UNLISTEN
-is used to remove an existing NOTIFY registration.
-UNLISTEN cancels any existing registration of the current
-
Postgres session as a listener on the notify
-condition notifyname.
-The special condition wildcard "*" cancels all listener registrations
-for the current session.
-
-
-contains a more extensive
-discussion of the use of LISTEN and
-NOTIFY.
-
-
-
-
-1998-10-19
-
-
</div>
<div class="diff rem">-Notes</div>
<div class="diff rem">-
-classname
-needs not to be a valid class name but can be any string valid
-as a name up to 32 characters long.
-
-The backend does not complain if you UNLISTEN something you were not
-listening for.
-Each backend will automatically execute UNLISTEN * when
-exiting.
-
-A restriction in some previous releases of
-classname
-which does not correspond to an actual table must be enclosed in double-quotes
-is no longer present.
-
-
-
-
-
-
</div>
<div class="diff rem">-Usage</div>
<div class="diff rem">-
-
+
+
+ Acknowledgement that statement has executed.
+
+
+
+
+
+
+
+
+
+
+ 1998-10-19
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+
+ UNLISTEN
+ is used to remove an existing NOTIFY registration.
+ UNLISTEN cancels any existing registration of the current
+
Postgres session as a listener on the notify
+ condition notifyname.
+ The special condition wildcard "*" cancels all listener registrations
+ for the current session.
+
+
+
+ contains a more extensive
+ discussion of the use of LISTEN and
+ NOTIFY.
+
+
+
+
+ 1998-10-19
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ classname
+ needs not to be a valid class name but can be any string valid
+ as a name up to 32 characters long.
+
+ The backend does not complain if you UNLISTEN something you were not
+ listening for.
+ Each backend will automatically execute UNLISTEN * when
+ exiting.
+
+ A restriction in some previous releases of
+ classname
+ which does not correspond to an actual table must be enclosed in double-quotes
+ is no longer present.
+
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+
+ To subscribe to an existing registration:
+
postgres=> LISTEN virtual;
LISTEN
postgres=> NOTIFY virtual;
NOTIFY
ASYNC NOTIFY of 'virtual' from backend pid '12317' received
-
+
+
+ Once UNLISTEN has been executed, further NOTIFY commands will be
+ ignored:
+
postgres=> UNLISTEN virtual;
UNLISTEN
postgres=> NOTIFY virtual;
NOTIFY
-- notice no NOTIFY event is received
-postgres=>
-
-
-
-
-
-
</div>
<div class="diff rem">-Compatibility</div>
<div class="diff rem">-
-
-
-
-1998-10-19
-
-
</div>
<div class="diff rem">-SQL92</div>
<div class="diff rem">-
- There is no
UNLISTEN in
SQL92.
-
-
-
-
+
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+ 1998-10-19
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no
UNLISTEN in
SQL92.
+
+
+
+
+
+
-
-
-
-UPDATE
-
-SQL - Language Statements
-
-
-
-UPDATE
-
-
-Replaces values of columns in a table
-
-
-
-
-1998-09-24
-
-
-UPDATE table SET column = expression [, ...]
- [ FROM fromlist ]
- [ WHERE condition ]
-
-
-
-
- 1998-09-24
-
-
</div>
<div class="diff rem">- Inputs</div>
<div class="diff rem">-
-
-
-
-
- table
-
-
- The name of an existing table.
-
-
-
-
-
- column
-
-
- The name of a column in table.
-
-
-
-
-
- expression
-
-
- A valid expression or value to assign to column.
-
-
-
-
-
- fromlist
-
-
- non-standard extension to allow columns
- from other tables to appear in the WHERE condition.
-
-
-
-
-
- condition
-
-
- Refer to the SELECT statement for a further description
- of the WHERE clause.
-
-
-
-
-
-
-
-
-
- 1998-09-24
-
-
</div>
<div class="diff rem">- Outputs</div>
<div class="diff rem">-
-
-
-
-
- UPDATE #
-
-
- Message returned if successful.
- The #
- means the number of rows updated.
- If #
- is equal 0 no rows are updated.
-
-
-
-
-
-
-
-
-
-
- 1998-09-24
-
-
</div>
<div class="diff rem">- Description</div>
<div class="diff rem">-
- UPDATE changes the values of the columns specified for
- all rows which satisfy condition. Only the columns
- to be modified need appear as column.
-
- Array references use the same syntax found in SELECT.
- That is, either single array elements, a range of array
- elements or the entire array may be replaced with a single
- query.
-
- You must have write access to the table in order to modify
- it, as well as read access to any table whose values are
- mentioned in the WHERE condition.
-
-
-
-
-
</div>
<div class="diff rem">- Usage</div>
<div class="diff rem">-
-
- --Change word "Drama" with "Dramatic" on column kind:
- --
- UPDATE films
- SET kind = 'Dramatic'
- WHERE kind = 'Drama';
-
- SELECT * FROM films WHERE kind = 'Dramatic' OR kind = 'Drama';
+
+
+
+ UPDATE
+
+ SQL - Language Statements
+
+
+
+ UPDATE
+
+
+ Replaces values of columns in a table
+
+
+
+
+ 1998-09-24
+
+
+UPDATE table SET R">colle> = expression [, ...]
+ [ FROM fromlist ]
+ [ WHERE condition ]
+
+
+
+
+ 1998-09-24
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+ table
+
+ The name of an existing table.
+
+
+
+
+ column
+
+ The name of a column in table.
+
+
+
+
+ expression
+
+ A valid expression or value to assign to column.
+
+
+
+
+ fromlist
+
+ non-standard extension to allow columns
+ from other tables to appear in the WHERE condition.
+
+
+
+
+ condition
+
+ Refer to the SELECT statement for a further description
+ of the WHERE clause.
+
+
+
+
+
+
+
+
+
+ 1998-09-24
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+UPDATE #
+
+
+ Message returned if successful.
+ The #
+ means the number of rows updated.
+ If #
+ is equal 0 no rows are updated.
+
+
+
+
+
+
+
+
+
+
+ 1998-09-24
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ UPDATE changes the values of the columns specified for
+ all rows which satisfy condition. Only the columns
+ to be modified need appear as column.
+
+
+ Array references use the same syntax found in SELECT.
+ That is, either single array elements, a range of array
+ elements or the entire array may be replaced with a single
+ query.
+
+
+ You must have write access to the table in order to modify
+ it, as well as read access to any table whose values are
+ mentioned in the WHERE condition.
+
+
+
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+
+ Change word "Drama" with "Dramatic" on column kind:
+
+UPDATE films
+ SET kind = 'Dramatic'
+ WHERE kind = 'Drama';
+SELECT * FROM films WHERE kind = 'Dramatic' OR kind = 'Drama';
code |title |did| date_prod|kind |len
-----+-------------+---+----------+----------+------
M_401|War and Peace|104|1967-02-12|Dramatic | 05:57
T_601|Yojimbo |106|1961-06-16|Dramatic | 01:50
DA101|Das Boot |110|1981-11-11|Dramatic | 02:29
-
-
-
-
-
-
</div>
<div class="diff rem">- Compatibility</div>
<div class="diff rem">-
-
-
-
-
- 1998-09-24
-
-
</div>
<div class="diff rem">- SQL92</div>
<div class="diff rem">-
- SQL92 defines a different syntax for positioned UPDATE statement:
-
- UPDATE table SET column = expression [, ...]
- WHERE CURRENT OF cursor
-
-
- where cursor
- identifies an open cursor.
-
-
-
-
+
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+
+
+ 1998-09-24
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ SQL92 defines a different syntax for positioned UPDATE statement:
+
+
+UPDATE table SET column = expression [, ...]
+ WHERE CURRENT OF cursor
+
+
+ where cursor
+ identifies an open cursor.
+
+
+
+
+
+
-
-
-
-VACUUM
-
-SQL - Language Statements
-
-
-
-VACUUM
-
-
-Clean and analyze a
Postgres database
-
-
-
-
-1998-10-04
-
-
-VACUUM [ VERBOSE ] [ ANALYZE ] [ table ]
-VACUUM [ VERBOSE ] ANALYZE [ table [ (column [, ...] ) ] ]
-
+
+
+
+ VACUUM
+
+ SQL - Language Statements
+
+
+
+ VACUUM
+
+
+ Clean and analyze a
Postgres database
+
+
+
+
+ 1998-10-04
+
+
+VACUUM [ VERBOSE ] [ ANALYZE ] [ table ]
+VACUUM [ VERBOSE ] ANALYZE [ ER">tBLE> [ (column [, ...] ) ] ]
+
+
+
+
+ 1998-10-04
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+ VERBOSE
+
+ Prints a detailed vacuum activity report for each table.
+
+
+
+
+ ANALYZE
+
+ Updates column statistics used by the optimizer to
+ determine the most efficient way to execute a query.
+ The statistics represent the disbursion of the data in each column.
+ This information is valuable when several execution paths are possible.
+
+
+
+
+ table
+
+ The name of a specific table to vacuum. Defaults to all tables.
+
+
+
+
+ column
+
+ The name of a specific column to analyze. Defaults to all columns.
+
+
+
+
+
+
+
+
+
+ 1998-10-04
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+
+VACUUM
+
+
+ The command has been accepted and the database is being cleaned.
+
+
+
-
-
- 1998-10-04
-
-
</div>
<div class="diff rem">- Inputs</div>
<div class="diff rem">-
-
-
-
-
- VERBOSE
-
-
- Prints a detailed vacuum activity report for each table.
-
-
-
-
-
- ANALYZE
-
-
- Updates column statistics used by the optimizer to
- determine the most efficient way to execute a query.
- The statistics represent the disbursion of the data in each column.
- This information is valuable when several execution paths are possible.
-
-
-
-
-
- table
-
-
- The name of a specific table to vacuum. Defaults to all tables.
-
-
-
-
-
- column
-
-
- The name of a specific column to analyze. Defaults to all columns.
-
-
-
-
-
-
+
+
+NOTICE: --Relation table--
+
+
+ The report header for table.
+
+
+
-
-
- 1998-10-04
-
-
</div>
<div class="diff rem">- Outputs</div>
<div class="diff rem">-
+
+
+NOTICE: Pages 98: Changed 25, Reapped 74, Empty 0, New 0;
+ Tup 1000: Vac 3000, Crash 0, UnUsed 0, MinLen 188, MaxLen 188;
+ Re-using: Free/Avail. Space 586952/586952; EndEmpty/Avail. Pages 0/74.
+ Elapsed 0/0 sec.
+
+
+ The analysis for table itself.
+
+
+
+
+
+
+NOTICE: Index index: Pages 28;
+ Tuples 1000: Deleted 3000. Elapsed 0/0 sec.
+
+
+ The analysis for an index on the target table.
+
+
+
+
+
+
+
-
-
-
- VACUUM
-
-
- The command has been accepted and the database is being cleaned.
-
-
-
-
-
-
- NOTICE: --Relation table--
-
-
- The report header for table.
-
-
-
+
+
+ 1998-10-04
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
+ VACUUM serves two purposes in
+
Postgres as both a means to reclaim storage and
+ also a means to collect information for the optimizer.
+
-
-
- NOTICE: Pages 98: Changed 25, Reapped 74, Empty 0, New 0;
- Tup 1000: Vac 3000, Crash 0, UnUsed 0, MinLen 188, MaxLen 188;
- Re-using: Free/Avail. Space 586952/586952; EndEmpty/Avail. Pages 0/74.
- Elapsed 0/0 sec.
-
-
- The analysis for table itself.
-
-
-
-
-
-
- NOTICE: Index index: Pages 28;
- Tuples 1000: Deleted 3000. Elapsed 0/0 sec.
-
-
- The analysis for an index on the target table.
-
-
-
-
-
-
-
+ VACUUM opens every class in the database,
+ cleans out records from rolled back transactions, and updates statistics in the
+ system catalogs. The statistics maintained include the number of
+ tuples and number of pages stored in all classes.
+
-
-
- 1998-10-04
-
-
</div>
<div class="diff rem">- Description</div>
<div class="diff rem">-
- VACUUM serves two purposes in
-
Postgres as both a means to reclaim storage and
- also a means to collect information for the optimizer.
-
- VACUUM opens every class in the database,
- cleans out records from rolled back transactions, and updates statistics in the
- system catalogs. The statistics maintained include the number of
- tuples and number of pages stored in all classes.
+ Running VACUUM
+ periodically will increase the speed of the database in processing user queries.
+
- Running VACUUM
- periodically will increase the speed of the database in processing user queries.
-
+
+
+ 1998-10-04
+
+
</div>
<div class="diff add">+ Notes</div>
<div class="diff add">+
+ The open database is the target for VACUUM.
+
+ We recommend that active production databases be cleaned nightly, in order
+ to keep statistics relatively current. The VACUUM
+ query may be executed at any time, however. In particular, after
+ copying a large class into
Postgres + or after deleting a large number of
+ records, it may be a good idea to issue a VACUUM
+ query. This will update the system catalogs with the results of all
+ recent changes, and allow the
Postgres + query optimizer to make better choices in planning user queries.
+
+ If the server crashes during a VACUUM command,
+ chances are it will leave a lock file hanging around.
+ Attempts to re-run the VACUUM command
+ result in an error message about the creation of a lock file. If you
+ are sure VACUUM is not running,
+ remove the pg_vlock file in your
+ database directory
+ (i.e. PGDATA/base/dbname/pg_vlock).
+
+
+
-
-
- 1998-10-04
-
-
</div>
<div class="diff rem">- Notes</div>
<div class="diff rem">-
- The open database is target for VACUUM.
-
- We recommend that active production databases be cleaned nightly, in order
- to keep statistics relatively current. The VACUUM
- query may be executed at any time, however. In particular, after
- copying a large class into
Postgres - or after deleting a large number of
- records, it may be a good idea to issue a VACUUM
- query. This will update the system catalogs with the results of all
- recent changes, and allow the
Postgres - query optimizer to make better choices in planning user queries.
-
- If the server crashes during a VACUUM command,
- chances are it will leave a lock file hanging around.
- Attempts to re-run the VACUUM command
- result in an error message about the creation of a lock file. If you
- are sure VACUUM is not running,
- remove the pg_vlock file in your
- database directory
- (i.e. PGDATA/base/dbname/pg_vlock).
-
-
-
-
+
+
</div>
<div class="diff add">+ Usage</div>
<div class="diff add">+
+ The following is an example from running VACUUM on a table
+ in the regression database:
-
-
</div>
<div class="diff rem">- Usage</div>
<div class="diff rem">-
- The following is an example from running VACUUM on a table
- in the regression database:
-
regression=> vacuum verbose analyze onek;
NOTICE: --Relation onek--
NOTICE: Pages 98: Changed 25, Reapped 74, Empty 0, New 0;
NOTICE: Index onek_unique2: Pages 19; Tuples 1000: Deleted 1000. Elapsed 0/0 sec.
NOTICE: Index onek_unique1: Pages 17; Tuples 1000: Deleted 1000. Elapsed 0/0 sec.
VACUUM
-
-
-
+
+
+
+
+
+
</div>
<div class="diff add">+ Compatibility</div>
<div class="diff add">+
+
+
+ 1998-10-04
+
+
</div>
<div class="diff add">+ SQL92</div>
<div class="diff add">+
+ There is no VACUUM statement in SQL92.
+
+
+
+
-
-
</div>
<div class="diff rem">- Compatibility</div>
<div class="diff rem">-
-
-
- 1998-10-04
-
-
</div>
<div class="diff rem">- SQL92</div>
<div class="diff rem">-
- There is no VACUUM statement in SQL92.
-
-
-
-
+
projects / postgresql.git / commitdiff