pg_reorg 1.1.7

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  1. Name
  2. Synopsis
  3. Description
  4. Examples
  5. Options
  6. Environment
  7. Restrictions
  8. Details
  9. Installations
  10. Requirements
  11. Releases
  12. See Also

Name

pg_reorg -- Reorganize tables in PostgreSQL databases without any locks.

Synopsis

pg_reorg [OPTIONS]

The following options can be specified in OPTIONS. See also "Options" for details.

Description

pg_reorg is an utility program to reorganize tables in PostgreSQL databases. Unlike clusterdb, it doesn't block any selections and updates during reorganization. You can choose one of the following methods to reorganize.

NOTICE:

Examples

Execute the following command to do online CLUSTER to all tables in test database.

$ pg_reorg test

Execute the following command to do online VACUUM FULL to foo table in test database.

$ pg_reorg --no-order --table foo -d test

Options

pg_reorg has the following command line options:

Reorg Options

Options to order rows. If not specified, pg_reorg do online CLUSTER using cluster indexes. Only one option can be specified. Options to specify target tables or databases.

-n
--no-order
Do online VACUUM FULL.
-o columns [,...]
--order-by=columns [,...]
Do online CLUSTER ordered by specified columns.
-t table
--table=table
Reorganize table only. If you don't specify this option, all tables in specified databases are reorganized.
-Z
--no-analyze
Do ANALYZE after reorganization. If you don't specify this option, ANALYZE is performed automatically after reorg.
-T seconds
--wait-timeout=seconds
pg_reorg needs to take an exclusive lock at the end of the reorganization. This setting controls how long it wait for acquiring the lock in seconds. If the lock cannot be taken even after the duration, pg_reorg forces to cancel conflicted queries. Also, if the server version is 8.4 or newer, pg_reorg forces to disconnect conflicted backends after twice time passed. The default is 60 seconds.
-Z
--no-analyze
Disable ANALYZE after the reorganization. If not specified, run ANALYZE after the reorganization.

Connection Options

Options to connect to servers. You cannot use --all and --dbname or --table together.

-a
--all
Reorganize all databases.
-d dbname
--dbname dbname
Specifies the name of the database to be reorganized. If this is not specified and -a (or --all) is not used, the database name is read from the environment variable PGDATABASE. If that is not set, the user name specified for the connection is used.
-h host
--host host
Specifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix domain socket.
-p port
--port port
Specifies the TCP port or local Unix domain socket file extension on which the server is listening for connections.
-U username
--username username
User name to connect as.
-w
--no-password
Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as a .pgpass file, the connection attempt will fail. This option can be useful in batch jobs and scripts where no user is present to enter a password.
-W
--password
Force the program to prompt for a password before connecting to a database.
This option is never essential, since the program will automatically prompt for a password if the server demands password authentication. However, vacuumdb will waste a connection attempt finding out that the server wants a password. In some cases it is worth typing -W to avoid the extra connection attempt.

Generic Options

-e
--echo
Echo commands sent to server.
-E
--elevel
Choose the output message level from DEBUG, INFO, NOTICE, WARNING, ERROR, LOG, FATAL, and PANIC. The default is INFO.
--help
Show usage of the program.
--version
Show the version number of the program.

Environment

PGDATABASE
PGHOST
PGPORT
PGUSER
Default connection parameters

This utility, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see Environment Variables).

Diagnostics

Error messages are reported when pg_reorg fails. The following list shows the cause of errors.

You need to cleanup by hand after fatal erros. To cleanup, execute $PGHOME/share/contrib/uninstall_pg_reorg.sql to the database where the error occured and then execute $PGHOME/share/contrib/pg_reorg.sql. (Do uninstall and reinstall.)

pg_reorg : reorg database "template1" ... skipped
pg_reorg is not installed in the database when --all option is specified.
Do register pg_reorg to the database.
ERROR: pg_reorg is not installed
pg_reorg is not installed in the database specified by --dbname.
Do register pg_reorg to the database.
ERROR: relation "table" has no primary key
The target table doesn't have PRIMARY KEY.
Define PRIMARY KEY to the table. (ALTER TABLE ADD PRIMARY KEY)
ERROR: relation "table" has no cluster key
The target table doesn't have CLUSTER KEY.
Define CLUSTER KEY to the table. (ALTER TABLE CLUSTER)
pg_reorg : query failed: ERROR: column "col" does not exist
The target table doesn't have columns specified by --order-by option.
Specify existing columns.
ERROR: permission denied for schema reorg
Permission error.
pg_reorg must be executed by superusers.
pg_reorg : query failed: ERROR: trigger "z_reorg_trigger" for relation "tbl" already exists
The target table already has a trigger named "z_reorg_trigger".
Delete or rename the trigger.
pg_reorg : trigger conflicted for tbl
The target table already has a trigger which follows by "z_reorg_trigger" in alphabetical order.
Delete or rename the trigger.

Restrictions

pg_reorg has the following restrictions. Be careful to avoid data corruptions.

Temp tables

pg_reorg cannot reorganize temp tables.

GiST indexes

pg_reorg cannot reorganize tables using GiST indexes.

DDL commands

You cannot do DDL commands except VACUUM and ANALYZE during pg_reorg. In many case pg_reorg would fail and rollback collectly, but there are some cases ending with data-corruption .

TRUNCATE
TRUNCATE is lost. Deleted rows still exist after pg_reorg.
CREATE INDEX
It causes index corruptions.
ALTER TABLE ... ADD COLUMN
It causes lost of data. Newly added columns are initialized with NULLs.
ALTER TABLE ... ALTER COLUMN TYPE
It causes data corruptions.
ALTER TABLE ... SET TABLESPACE
It causes data corruptions by wrong relfilenode.

Details

pg_reorg creates a work table in reorg schema and sorts rows in it. Then, it updates system catalog directly to swap the work table and the original one.

Installations

pg_reorg can be built with "make" on UNIX or Linux. pgxs build framework is used automatically. Before build, you might need to install postgres packages for developper (postgresql-devel, etc.) and add pg_config to your $PATH. 

$ cd pg_reorg
$ make
$ su
$ make install

You can also use Microsoft Visual C++ 2010 to build the program on Windows. There are project files in the msvc folder.

Start PostgreSQL and execute the script to register functions to your database.

$ pg_ctl start
$ psql -f $PGSHARE/contrib/pg_reorg.sql -d your_database

(NOTE: CREATE EXTENSION is not supported yet.)

Requirements

PostgreSQL version
PostgreSQL 8.2, 8.3, 8.4, 9.0, 9.1
OS
RHEL 5.2, Windows XP SP3
Disks
Requires amount of disks twice larger than target table and indexes. (If the total size of targets are 1GB, additional 2GB of disks are required.)

Releases

See Also

clusterdb, vacuumdb
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Portions Copyright (c) 2011, Itagaki Takahiro