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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
113 lines
4.1 KiB
C
113 lines
4.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* pg_trigger.h
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* definition of the system "trigger" relation (pg_trigger)
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* along with the relation's initial contents.
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*
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*
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/catalog/pg_trigger.h,v 1.28 2007/03/19 23:38:31 wieck Exp $
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*
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* NOTES
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* the genbki.sh script reads this file and generates .bki
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* information from the DATA() statements.
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PG_TRIGGER_H
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#define PG_TRIGGER_H
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/* ----------------
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* postgres.h contains the system type definitions and the
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* CATALOG(), BKI_BOOTSTRAP and DATA() sugar words so this file
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* can be read by both genbki.sh and the C compiler.
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* ----------------
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*/
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/* ----------------
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* pg_trigger definition. cpp turns this into
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* typedef struct FormData_pg_trigger
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*
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* Note: when tgconstraint is nonzero, tgisconstraint must be true, and
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* tgconstrname, tgconstrrelid, tgdeferrable, tginitdeferred are redundant
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* with the referenced pg_constraint entry. The reason we keep these fields
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* is that we support "stand-alone" constraint triggers with no corresponding
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* pg_constraint entry.
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* ----------------
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*/
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#define TriggerRelationId 2620
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CATALOG(pg_trigger,2620)
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{
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Oid tgrelid; /* relation trigger is attached to */
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NameData tgname; /* trigger's name */
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Oid tgfoid; /* OID of function to be called */
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int2 tgtype; /* BEFORE/AFTER UPDATE/DELETE/INSERT
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* ROW/STATEMENT; see below */
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char tgenabled; /* trigger's firing configuration
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* WRT session_replication_role */
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bool tgisconstraint; /* trigger is a constraint trigger */
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NameData tgconstrname; /* constraint name */
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Oid tgconstrrelid; /* constraint's FROM table, if any */
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Oid tgconstraint; /* owning pg_constraint entry, if any */
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bool tgdeferrable; /* constraint trigger is deferrable */
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bool tginitdeferred; /* constraint trigger is deferred initially */
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int2 tgnargs; /* # of extra arguments in tgargs */
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/* VARIABLE LENGTH FIELDS: */
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int2vector tgattr; /* reserved for column-specific triggers */
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bytea tgargs; /* first\000second\000tgnargs\000 */
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} FormData_pg_trigger;
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/* ----------------
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* Form_pg_trigger corresponds to a pointer to a tuple with
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* the format of pg_trigger relation.
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* ----------------
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*/
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typedef FormData_pg_trigger *Form_pg_trigger;
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/* ----------------
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* compiler constants for pg_trigger
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* ----------------
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*/
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#define Natts_pg_trigger 14
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#define Anum_pg_trigger_tgrelid 1
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#define Anum_pg_trigger_tgname 2
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#define Anum_pg_trigger_tgfoid 3
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#define Anum_pg_trigger_tgtype 4
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#define Anum_pg_trigger_tgenabled 5
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#define Anum_pg_trigger_tgisconstraint 6
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#define Anum_pg_trigger_tgconstrname 7
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#define Anum_pg_trigger_tgconstrrelid 8
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#define Anum_pg_trigger_tgconstraint 9
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#define Anum_pg_trigger_tgdeferrable 10
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#define Anum_pg_trigger_tginitdeferred 11
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#define Anum_pg_trigger_tgnargs 12
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#define Anum_pg_trigger_tgattr 13
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#define Anum_pg_trigger_tgargs 14
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/* Bits within tgtype */
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#define TRIGGER_TYPE_ROW (1 << 0)
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#define TRIGGER_TYPE_BEFORE (1 << 1)
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#define TRIGGER_TYPE_INSERT (1 << 2)
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#define TRIGGER_TYPE_DELETE (1 << 3)
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#define TRIGGER_TYPE_UPDATE (1 << 4)
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/* Macros for manipulating tgtype */
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#define TRIGGER_CLEAR_TYPE(type) ((type) = 0)
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#define TRIGGER_SETT_ROW(type) ((type) |= TRIGGER_TYPE_ROW)
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#define TRIGGER_SETT_BEFORE(type) ((type) |= TRIGGER_TYPE_BEFORE)
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#define TRIGGER_SETT_INSERT(type) ((type) |= TRIGGER_TYPE_INSERT)
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#define TRIGGER_SETT_DELETE(type) ((type) |= TRIGGER_TYPE_DELETE)
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#define TRIGGER_SETT_UPDATE(type) ((type) |= TRIGGER_TYPE_UPDATE)
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#define TRIGGER_FOR_ROW(type) ((type) & TRIGGER_TYPE_ROW)
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#define TRIGGER_FOR_BEFORE(type) ((type) & TRIGGER_TYPE_BEFORE)
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#define TRIGGER_FOR_INSERT(type) ((type) & TRIGGER_TYPE_INSERT)
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#define TRIGGER_FOR_DELETE(type) ((type) & TRIGGER_TYPE_DELETE)
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#define TRIGGER_FOR_UPDATE(type) ((type) & TRIGGER_TYPE_UPDATE)
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#endif /* PG_TRIGGER_H */
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