postgresql/src/include/rewrite/prs2lock.h

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/*-------------------------------------------------------------------------
*
* prs2lock.h
* data structures for POSTGRES Rule System II (rewrite rules only)
*
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* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
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* src/include/rewrite/prs2lock.h
*
*-------------------------------------------------------------------------
*/
#ifndef PRS2LOCK_H
#define PRS2LOCK_H
#include "access/attnum.h"
#include "nodes/pg_list.h"
/*
* RewriteRule -
* holds an info for a rewrite rule
*
*/
typedef struct RewriteRule
{
Oid ruleId;
CmdType event;
Node *qual;
List *actions;
Changes pg_trigger and extend pg_rewrite in order to allow triggers and 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
2007-03-20 00:38:32 +01:00
char enabled;
bool isInstead;
} RewriteRule;
/*
* RuleLock -
* all rules that apply to a particular relation. Even though we only
* have the rewrite rule system left and these are not really "locks",
* the name is kept for historical reasons.
*/
typedef struct RuleLock
{
int numLocks;
RewriteRule **rules;
} RuleLock;
#endif /* REWRITE_H */