PostgreSQL Source Code git master
Functions | Variables
tcn.c File Reference
#include "postgres.h"
#include "access/htup_details.h"
#include "commands/async.h"
#include "commands/trigger.h"
#include "executor/spi.h"
#include "lib/stringinfo.h"
#include "utils/rel.h"
#include "utils/syscache.h"
Include dependency graph for tcn.c:

Go to the source code of this file.

Functions

static void strcpy_quoted (StringInfo r, const char *s, const char q)
 
 PG_FUNCTION_INFO_V1 (triggered_change_notification)
 
Datum triggered_change_notification (PG_FUNCTION_ARGS)
 

Variables

 PG_MODULE_MAGIC
 

Function Documentation

◆ PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1 ( triggered_change_notification  )

◆ strcpy_quoted()

static void strcpy_quoted ( StringInfo  r,
const char *  s,
const char  q 
)
static

Definition at line 33 of file tcn.c.

34{
35 appendStringInfoCharMacro(r, q);
36 while (*s)
37 {
38 if (*s == q)
39 appendStringInfoCharMacro(r, q);
40 appendStringInfoCharMacro(r, *s);
41 s++;
42 }
43 appendStringInfoCharMacro(r, q);
44}
appendStringInfoCharMacro
#define appendStringInfoCharMacro(str, ch)
Definition: stringinfo.h:231

References appendStringInfoCharMacro.

Referenced by triggered_change_notification().

◆ triggered_change_notification()

Datum triggered_change_notification ( PG_FUNCTION_ARGS  )

Definition at line 56 of file tcn.c.

57{
58 TriggerData *trigdata = (TriggerData *) fcinfo->context;
59 Trigger *trigger;
60 int nargs;
61 HeapTuple trigtuple;
62 Relation rel;
63 TupleDesc tupdesc;
64 char *channel;
65 char operation;
66 StringInfo payload = makeStringInfo();
67 bool foundPK;
68
69 List *indexoidlist;
70 ListCell *indexoidscan;
71
72 /* make sure it's called as a trigger */
73 if (!CALLED_AS_TRIGGER(fcinfo))
74 ereport(ERROR,
75 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
76 errmsg("triggered_change_notification: must be called as trigger")));
77
78 /* and that it's called after the change */
79 if (!TRIGGER_FIRED_AFTER(trigdata->tg_event))
80 ereport(ERROR,
81 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
82 errmsg("triggered_change_notification: must be called after the change")));
83
84 /* and that it's called for each row */
85 if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
86 ereport(ERROR,
87 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
88 errmsg("triggered_change_notification: must be called for each row")));
89
90 if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
91 operation = 'I';
92 else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
93 operation = 'U';
94 else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
95 operation = 'D';
96 else
97 {
98 elog(ERROR, "triggered_change_notification: trigger fired by unrecognized operation");
99 operation = 'X'; /* silence compiler warning */
100 }
101
102 trigger = trigdata->tg_trigger;
103 nargs = trigger->tgnargs;
104 if (nargs > 1)
105 ereport(ERROR,
106 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
107 errmsg("triggered_change_notification: must not be called with more than one parameter")));
108
109 if (nargs == 0)
110 channel = "tcn";
111 else
112 channel = trigger->tgargs[0];
113
114 /* get tuple data */
115 trigtuple = trigdata->tg_trigtuple;
116 rel = trigdata->tg_relation;
117 tupdesc = rel->rd_att;
118
119 foundPK = false;
120
121 /*
122 * Get the list of index OIDs for the table from the relcache, and look up
123 * each one in the pg_index syscache until we find one marked primary key
124 * (hopefully there isn't more than one such).
125 */
126 indexoidlist = RelationGetIndexList(rel);
127
128 foreach(indexoidscan, indexoidlist)
129 {
130 Oid indexoid = lfirst_oid(indexoidscan);
131 HeapTuple indexTuple;
132 Form_pg_index index;
133
134 indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
135 if (!HeapTupleIsValid(indexTuple)) /* should not happen */
136 elog(ERROR, "cache lookup failed for index %u", indexoid);
137 index = (Form_pg_index) GETSTRUCT(indexTuple);
138 /* we're only interested if it is the primary key and valid */
139 if (index->indisprimary && index->indisvalid)
140 {
141 int indnkeyatts = index->indnkeyatts;
142
143 if (indnkeyatts > 0)
144 {
145 int i;
146
147 foundPK = true;
148
149 strcpy_quoted(payload, RelationGetRelationName(rel), '"');
150 appendStringInfoCharMacro(payload, ',');
151 appendStringInfoCharMacro(payload, operation);
152
153 for (i = 0; i < indnkeyatts; i++)
154 {
155 int colno = index->indkey.values[i];
156 Form_pg_attribute attr = TupleDescAttr(tupdesc, colno - 1);
157
158 appendStringInfoCharMacro(payload, ',');
159 strcpy_quoted(payload, NameStr(attr->attname), '"');
160 appendStringInfoCharMacro(payload, '=');
161 strcpy_quoted(payload, SPI_getvalue(trigtuple, tupdesc, colno), '\'');
162 }
163
164 Async_Notify(channel, payload->data);
165 }
166 ReleaseSysCache(indexTuple);
167 break;
168 }
169 ReleaseSysCache(indexTuple);
170 }
171
172 list_free(indexoidlist);
173
174 if (!foundPK)
175 ereport(ERROR,
176 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
177 errmsg("triggered_change_notification: must be called on a table with a primary key")));
178
179 return PointerGetDatum(NULL); /* after trigger; value doesn't matter */
180}
Async_Notify
void Async_Notify(const char *channel, const char *payload)
Definition: async.c:591
NameStr
#define NameStr(name)
Definition: c.h:717
errcode
int errcode(int sqlerrcode)
Definition: elog.c:853
errmsg
int errmsg(const char *fmt,...)
Definition: elog.c:1070
ERROR
#define ERROR
Definition: elog.h:39
elog
#define elog(elevel,...)
Definition: elog.h:225
ereport
#define ereport(elevel,...)
Definition: elog.h:149
HeapTupleIsValid
#define HeapTupleIsValid(tuple)
Definition: htup.h:78
GETSTRUCT
static void * GETSTRUCT(const HeapTupleData *tuple)
Definition: htup_details.h:728
i
int i
Definition: isn.c:74
list_free
void list_free(List *list)
Definition: list.c:1546
Form_pg_attribute
FormData_pg_attribute * Form_pg_attribute
Definition: pg_attribute.h:200
Form_pg_index
FormData_pg_index * Form_pg_index
Definition: pg_index.h:70
lfirst_oid
#define lfirst_oid(lc)
Definition: pg_list.h:174
PointerGetDatum
static Datum PointerGetDatum(const void *X)
Definition: postgres.h:327
ObjectIdGetDatum
static Datum ObjectIdGetDatum(Oid X)
Definition: postgres.h:257
Oid
unsigned int Oid
Definition: postgres_ext.h:32
RelationGetRelationName
#define RelationGetRelationName(relation)
Definition: rel.h:547
RelationGetIndexList
List * RelationGetIndexList(Relation relation)
Definition: relcache.c:4764
SPI_getvalue
char * SPI_getvalue(HeapTuple tuple, TupleDesc tupdesc, int fnumber)
Definition: spi.c:1221
makeStringInfo
StringInfo makeStringInfo(void)
Definition: stringinfo.c:72
List
Definition: pg_list.h:54
RelationData::rd_att
TupleDesc rd_att
Definition: rel.h:112
TriggerData::tg_relation
Relation tg_relation
Definition: trigger.h:35
TriggerData::tg_event
TriggerEvent tg_event
Definition: trigger.h:34
TriggerData::tg_trigger
Trigger * tg_trigger
Definition: trigger.h:38
TriggerData::tg_trigtuple
HeapTuple tg_trigtuple
Definition: trigger.h:36
Trigger::tgnargs
int16 tgnargs
Definition: reltrigger.h:38
index
Definition: type.h:96
ReleaseSysCache
void ReleaseSysCache(HeapTuple tuple)
Definition: syscache.c:269
SearchSysCache1
HeapTuple SearchSysCache1(int cacheId, Datum key1)
Definition: syscache.c:221
strcpy_quoted
static void strcpy_quoted(StringInfo r, const char *s, const char q)
Definition: tcn.c:33
TRIGGER_FIRED_BY_DELETE
#define TRIGGER_FIRED_BY_DELETE(event)
Definition: trigger.h:113
CALLED_AS_TRIGGER
#define CALLED_AS_TRIGGER(fcinfo)
Definition: trigger.h:26
TRIGGER_FIRED_FOR_ROW
#define TRIGGER_FIRED_FOR_ROW(event)
Definition: trigger.h:122
TRIGGER_FIRED_AFTER
#define TRIGGER_FIRED_AFTER(event)
Definition: trigger.h:131
TRIGGER_FIRED_BY_INSERT
#define TRIGGER_FIRED_BY_INSERT(event)
Definition: trigger.h:110
TRIGGER_FIRED_BY_UPDATE
#define TRIGGER_FIRED_BY_UPDATE(event)
Definition: trigger.h:116
TupleDescAttr
static FormData_pg_attribute * TupleDescAttr(TupleDesc tupdesc, int i)
Definition: tupdesc.h:154

References appendStringInfoCharMacro, Async_Notify(), CALLED_AS_TRIGGER, elog, ereport, errcode(), errmsg(), ERROR, GETSTRUCT(), HeapTupleIsValid, i, lfirst_oid, list_free(), makeStringInfo(), NameStr, ObjectIdGetDatum(), PointerGetDatum(), RelationData::rd_att, RelationGetIndexList(), RelationGetRelationName, ReleaseSysCache(), SearchSysCache1(), SPI_getvalue(), strcpy_quoted(), TriggerData::tg_event, TriggerData::tg_relation, TriggerData::tg_trigger, TriggerData::tg_trigtuple, Trigger::tgnargs, TRIGGER_FIRED_AFTER, TRIGGER_FIRED_BY_DELETE, TRIGGER_FIRED_BY_INSERT, TRIGGER_FIRED_BY_UPDATE, TRIGGER_FIRED_FOR_ROW, and TupleDescAttr().

Variable Documentation

◆ PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 26 of file tcn.c.