EXECUTE SCRIPT — Execute SQL/DDL script
EXECUTE SCRIPT (options);
Executes a script containing arbitrary SQL statements on all nodes that are subscribed to a set at a common controlled point within the replication transaction stream.
The specified event origin must be the origin of the set.
The script file must not contain any START
or
COMMIT TRANSACTION
calls. (This changes
somewhat in PostgreSQL 8.0 once nested transactions, aka
savepoints, are supported) In addition, non-deterministic DML
statements (like updating a field with
CURRENT_TIMESTAMP
) must be avoided, since the
data changes done by the script are explicitly not
replicated.
SET ID = ival
The unique numeric ID number of the set affected by the script
FILENAME = '/path/to/file'
The name of the file containing the SQL script to execute. This might be a relative path, relative to the location of the slonik instance you are running, or, preferably, an absolute path on the system where slonik is to run.
The contents of the file are propagated as part of the event, so the file does not need to be accessible on any of the nodes.
EVENT NODE = ival
(Optional) The ID of the current origin of the set. Default value is 1.
EXECUTE ONLY ON = ival
(Optional) The ID of the only node to actually execute the script. This option causes the script to be propagated by all nodes but executed only by one. The default is to execute the script on all nodes that are subscribed to the set.
See also the warnings in Section 14, “Database Schema Changes (DDL)”.
Note that this is a locking operation, which means that it can get stuck behind other database activity.
At the start of this event, all tables in the specified set
are unlocked via the function
alterTableRestore(tab_id)
. After the SQL
script has run, they are returned to “replicating
state” using
alterTableForReplication(tab_id)
. This means
that all of these tables are locked by this slon
process for the duration of the SQL script
execution.
If a table's columns are modified, it is very important that the triggers be regenerated, otherwise they may be inappropriate for the new form of the table schema.
Note that if you need to make reference to the cluster
name, you can use the token @CLUSTERNAME@
; if
you need to make reference to the Slony-I namespace, you can use
the token @NAMESPACE@
; both will be expanded
into the appropriate replacement tokens.
It generally seems a bad idea to use quotes in DDL scripts. It appears preferable to handle that sort of thing “out of band.”
This uses schemadocddlscript( integer, text, integer ).