tcn-1.patch

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File	+	−
src/backend/utils/adt/trigfuncs.c	167	1
src/include/catalog/pg_proc.h	2	0
src/include/utils/builtins.h	1	0

*** a/src/backend/utils/adt/trigfuncs.c
--- b/src/backend/utils/adt/trigfuncs.c
***************
*** 13,21 ****
   */
  #include "postgres.h"
  
! #include "access/htup.h"
  #include "commands/trigger.h"
  #include "utils/builtins.h"
  
  
  /*
--- 13,25 ----
   */
  #include "postgres.h"
  
! #include "executor/spi.h"
! #include "catalog/indexing.h"
! #include "commands/async.h"
  #include "commands/trigger.h"
  #include "utils/builtins.h"
+ #include "utils/fmgroids.h"
+ #include "utils/tqual.h"
  
  
  /*
***************
*** 93,95 **** suppress_redundant_updates_trigger(PG_FUNCTION_ARGS)
--- 97,261 ----
  
  	return PointerGetDatum(rettuple);
  }
+ 
+ 
+ /*
+  * Copy from s (for source) to r (for result), wrapping with q (quote)
+  * characters and doubling any quote characters found.
+  */
+ static char *
+ strcpy_quoted(char *r, const char *s, const char q)
+ {
+ 	*r++ = q;
+ 	while (*s)
+ 	{
+ 		if (*s == q)
+ 			*r++ = q;
+ 		*r++ = *s;
+ 		s++;
+ 	}
+ 	*r++ = q;
+ 	return r;
+ }
+ 
+ /*
+  * triggered_change_notification
+  *
+  * This trigger function will send a notification of data modification with
+  * primary key values.	The channel will be "tcn" unless the trigger is
+  * created with a parameter, in which case that parameter will be used.
+  */
+ Datum
+ triggered_change_notification(PG_FUNCTION_ARGS)
+ {
+ 	TriggerData *trigdata = (TriggerData *) fcinfo->context;
+ 	Trigger    *trigger;
+ 	int			nargs;
+ 	HeapTuple	trigtuple,
+ 				newtuple;
+ 	HeapTupleHeader trigheader,
+ 				newheader;
+ 	Relation	rel;
+ 	TupleDesc	tupdesc;
+ 	Relation	indexRelation;
+ 	ScanKeyData skey;
+ 	SysScanDesc scan;
+ 	HeapTuple	indexTuple;
+ 	char	   *channel;
+ 	char		operation;
+ 	char		payload[200];
+ 	char	   *p;
+ 	bool		foundPK;
+ 
+ 	/* make sure it's called as a trigger */
+ 	if (!CALLED_AS_TRIGGER(fcinfo))
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+ 		errmsg("triggered_change_notification: must be called as trigger")));
+ 
+ 	/* and that it's called after the change */
+ 	if (!TRIGGER_FIRED_AFTER(trigdata->tg_event))
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+ 				 errmsg("triggered_change_notification: must be called after the change")));
+ 
+ 	/* and that it's called for each row */
+ 	if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+ 				 errmsg("suppress_redundant_updates_trigger: must be called for each row")));
+ 
+ 	if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
+ 		operation = 'I';
+ 	else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
+ 		operation = 'U';
+ 	else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
+ 		operation = 'D';
+ 	else
+ 	{
+ 		elog(ERROR, "suppress_redundant_updates_trigger: trigger fired by unrecognized operation");
+ 		operation = 'X';		/* silence compiler warning */
+ 	}
+ 
+ 	trigger = trigdata->tg_trigger;
+ 	nargs = trigger->tgnargs;
+ 	if (nargs > 1)
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+ 				 errmsg("suppress_redundant_updates_trigger: must not be called with more than one parameter")));
+ 
+ 	if (nargs == 0)
+ 		channel = "tcn";
+ 	else
+ 		channel = trigger->tgargs[0];
+ 
+ 	/* get tuple data, set default result */
+ 	trigtuple = trigdata->tg_trigtuple;
+ 	newtuple = trigdata->tg_newtuple;
+ 
+ 	trigheader = trigtuple->t_data;
+ 	newheader = newtuple->t_data;
+ 
+ 	rel = trigdata->tg_relation;
+ 	tupdesc = rel->rd_att;
+ 
+ 	foundPK = false;
+ 
+ 	/* Prepare to scan pg_index for entries having indrelid = this rel. */
+ 	indexRelation = heap_open(IndexRelationId, AccessShareLock);
+ 	ScanKeyInit(&skey,
+ 				Anum_pg_index_indrelid,
+ 				BTEqualStrategyNumber, F_OIDEQ,
+ 				ObjectIdGetDatum(RelationGetRelid(rel)));
+ 
+ 	scan = systable_beginscan(indexRelation, IndexIndrelidIndexId, true,
+ 							  SnapshotNow, 1, &skey);
+ 
+ 	while (HeapTupleIsValid(indexTuple = systable_getnext(scan)))
+ 	{
+ 		Form_pg_index index = (Form_pg_index) GETSTRUCT(indexTuple);
+ 
+ 		/* we're only interested if it is the primary key */
+ 		if (index->indisprimary)
+ 		{
+ 			int			numatts = index->indnatts;
+ 
+ 			if (numatts > 0)
+ 			{
+ 				int			i;
+ 
+ 				foundPK = true;
+ 
+ 				p = strcpy_quoted(payload, SPI_getrelname(rel), '"');
+ 				*p++ = ',';
+ 				*p++ = operation;
+ 
+ 				for (i = 0; i < numatts; i++)
+ 				{
+ 					int			colno = index->indkey.values[i];
+ 
+ 					/* TODO: for UPDATE, check that the value wasn't updated? */
+ 
+ 					*p++ = ',';
+ 					p = strcpy_quoted(p, SPI_fname(tupdesc, colno), '"');
+ 					*p++ = '=';
+ 					p = strcpy_quoted(p, SPI_getvalue(trigtuple, tupdesc, colno), '\'');
+ 				}
+ 				*p = '\0';
+ 
+ 				Async_Notify(channel, payload);
+ 			}
+ 			break;
+ 		}
+ 	}
+ 
+ 	systable_endscan(scan);
+ 	heap_close(indexRelation, AccessShareLock);
+ 
+ 	if (!foundPK)
+ 		ereport(ERROR,
+ 				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+ 				 errmsg("triggered_change_notification: must be called on a table with a primary key")));
+ 
+ 	return PointerGetDatum(NULL);		/* after trigger; value doesn't matter */
+ }
*** a/src/include/catalog/pg_proc.h
--- b/src/include/catalog/pg_proc.h
***************
*** 1638,1643 **** DESCR("convert oid to int8");
--- 1638,1645 ----
  
  DATA(insert OID = 1291 (  suppress_redundant_updates_trigger	PGNSP PGUID 12 1 0 0 f f f t f v 0 0 2279 "" _null_ _null_ _null_ _null_ suppress_redundant_updates_trigger _null_ _null_ _null_ ));
  DESCR("trigger to suppress updates when new and old records match");
+ DATA(insert OID = 2650 (  triggered_change_notification	PGNSP PGUID 12 1 0 0 f f f t f v 0 0 2279 "" _null_ _null_ _null_ _null_ triggered_change_notification _null_ _null_ _null_ ));
+ DESCR("trigger function to send change notification with primary key in payload");
  
  DATA(insert OID = 1292 ( tideq			   PGNSP PGUID 12 1 0 0 f f f t f i 2 0 16 "27 27" _null_ _null_ _null_ _null_ tideq _null_ _null_ _null_ ));
  DESCR("equal");
*** a/src/include/utils/builtins.h
--- b/src/include/utils/builtins.h
***************
*** 959,964 **** extern Datum RI_FKey_setdefault_upd(PG_FUNCTION_ARGS);
--- 959,965 ----
  
  /* trigfuncs.c */
  extern Datum suppress_redundant_updates_trigger(PG_FUNCTION_ARGS);
+ extern Datum triggered_change_notification(PG_FUNCTION_ARGS);
  
  /* encoding support functions */
  extern Datum getdatabaseencoding(PG_FUNCTION_ARGS);