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Changes pg_trigger and extend pg_rewrite in order to allow triggers and

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rules to be defined with different, per session controllable, behaviors
for replication purposes.

This will allow replication systems like Slony-I and, as has been stated
on pgsql-hackers, other products to control the firing mechanism of
triggers and rewrite rules without modifying the system catalog directly.

The firing mechanisms are controlled by a new superuser-only GUC
variable, session_replication_role, together with a change to
pg_trigger.tgenabled and a new column pg_rewrite.ev_enabled. Both
columns are a single char data type now (tgenabled was a bool before).
The possible values in these attributes are:

     'O' - Trigger/Rule fires when session_replication_role is "origin"
           (default) or "local". This is the default behavior.

     'D' - Trigger/Rule is disabled and fires never

     'A' - Trigger/Rule fires always regardless of the setting of
           session_replication_role

     'R' - Trigger/Rule fires when session_replication_role is "replica"

The GUC variable can only be changed as long as the system does not have
any cached query plans. This will prevent changing the session role and
accidentally executing stored procedures or functions that have plans
cached that expand to the wrong query set due to differences in the rule
firing semantics.

The SQL syntax for changing a triggers/rules firing semantics is

     ALTER TABLE <tabname> <when> TRIGGER|RULE <name>;

     <when> ::= ENABLE | ENABLE ALWAYS | ENABLE REPLICA | DISABLE

psql's \d command as well as pg_dump are extended in a backward
compatible fashion.

Jan
This commit is contained in:
Jan Wieck
2007-03-19 23:38:32 +00:00
parent e927f8f14e
commit 0fe16500d3
24 changed files with 700 additions and 148 deletions
Download Patch File Download Diff File Expand all files Collapse all files

58
src/backend/parser/gram.y
View File

@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.582 2007/03/17 19:27:12 meskes Exp $
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.583 2007/03/19 23:38:29 wieck Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -365,7 +365,7 @@ static Node *makeXmlExpr(XmlExprOp op, char *name, List *named_args, List *args)
/* ordinary key words in alphabetical order */
%token <keyword> ABORT_P ABSOLUTE_P ACCESS ACTION ADD_P ADMIN AFTER
AGGREGATE ALL ALSO ALTER ANALYSE ANALYZE AND ANY ARRAY AS ASC
AGGREGATE ALL ALSO ALTER ALWAYS ANALYSE ANALYZE AND ANY ARRAY AS ASC
ASSERTION ASSIGNMENT ASYMMETRIC AT AUTHORIZATION
BACKWARD BEFORE BEGIN_P BETWEEN BIGINT BINARY BIT
@@ -422,8 +422,8 @@ static Node *makeXmlExpr(XmlExprOp op, char *name, List *named_args, List *args)
QUOTE
READ REAL REASSIGN RECHECK REFERENCES REINDEX RELATIVE_P RELEASE RENAME
REPEATABLE REPLACE RESET RESTART RESTRICT RETURNING RETURNS REVOKE RIGHT
ROLE ROLLBACK ROW ROWS RULE
REPEATABLE REPLACE REPLICA RESET RESTART RESTRICT RETURNING RETURNS REVOKE
RIGHT ROLE ROLLBACK ROW ROWS RULE
SAVEPOINT SCHEMA SCROLL SECOND_P SECURITY SELECT SEQUENCE
SERIALIZABLE SESSION SESSION_USER SET SETOF SHARE
@@ -1480,6 +1480,22 @@ alter_table_cmd:
n->name = $3;
$$ = (Node *)n;
}
/* ALTER TABLE <name> ENABLE ALWAYS TRIGGER <trig> */
| ENABLE_P ALWAYS TRIGGER name
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_EnableAlwaysTrig;
n->name = $4;
$$ = (Node *)n;
}
/* ALTER TABLE <name> ENABLE REPLICA TRIGGER <trig> */
| ENABLE_P REPLICA TRIGGER name
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_EnableReplicaTrig;
n->name = $4;
$$ = (Node *)n;
}
/* ALTER TABLE <name> ENABLE TRIGGER ALL */
| ENABLE_P TRIGGER ALL
{
@@ -1516,6 +1532,38 @@ alter_table_cmd:
n->subtype = AT_DisableTrigUser;
$$ = (Node *)n;
}
/* ALTER TABLE <name> ENABLE RULE <rule> */
| ENABLE_P RULE name
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_EnableRule;
n->name = $3;
$$ = (Node *)n;
}
/* ALTER TABLE <name> ENABLE ALWAYS RULE <rule> */
| ENABLE_P ALWAYS RULE name
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_EnableAlwaysRule;
n->name = $4;
$$ = (Node *)n;
}
/* ALTER TABLE <name> ENABLE REPLICA RULE <rule> */
| ENABLE_P REPLICA RULE name
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_EnableReplicaRule;
n->name = $4;
$$ = (Node *)n;
}
/* ALTER TABLE <name> DISABLE RULE <rule> */
| DISABLE_P RULE name
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_DisableRule;
n->name = $3;
$$ = (Node *)n;
}
/* ALTER TABLE <name> INHERIT <parent> */
| INHERIT qualified_name
{
@@ -8651,6 +8699,7 @@ unreserved_keyword:
| AGGREGATE
| ALSO
| ALTER
| ALWAYS
| ASSERTION
| ASSIGNMENT
| AT
@@ -8796,6 +8845,7 @@ unreserved_keyword:
| RENAME
| REPEATABLE
| REPLACE
| REPLICA
| RESET
| RESTART
| RESTRICT

4
src/backend/parser/keywords.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.184 2007/01/25 11:53:51 petere Exp $
* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.185 2007/03/19 23:38:29 wieck Exp $
*
*-------------------------------------------------------------------------
*/
@@ -42,6 +42,7 @@ static const ScanKeyword ScanKeywords[] = {
{"all", ALL},
{"also", ALSO},
{"alter", ALTER},
{"always", ALWAYS},
{"analyse", ANALYSE}, /* British spelling */
{"analyze", ANALYZE},
{"and", AND},
@@ -289,6 +290,7 @@ static const ScanKeyword ScanKeywords[] = {
{"rename", RENAME},
{"repeatable", REPEATABLE},
{"replace", REPLACE},
{"replica", REPLICA},
{"reset", RESET},
{"restart", RESTART},
{"restrict", RESTRICT},