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trigger.c
4632 lines (4120 loc) · 134 KB
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trigger.c
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/*-------------------------------------------------------------------------
*
* trigger.c
* PostgreSQL TRIGGERs support code.
*
* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/commands/trigger.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "commands/defrem.h"
#include "commands/trigger.h"
#include "executor/executor.h"
#include "executor/instrument.h"
#include "miscadmin.h"
#include "nodes/bitmapset.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/var.h"
#include "parser/parse_clause.h"
#include "parser/parse_collate.h"
#include "parser/parse_func.h"
#include "parser/parse_relation.h"
#include "parser/parsetree.h"
#include "pgstat.h"
#include "rewrite/rewriteManip.h"
#include "storage/bufmgr.h"
#include "tcop/utility.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/bytea.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
/* GUC variables */
int SessionReplicationRole = SESSION_REPLICATION_ROLE_ORIGIN;
#define GetModifiedColumns(relinfo, estate) \
(rt_fetch((relinfo)->ri_RangeTableIndex, (estate)->es_range_table)->modifiedCols)
/* Local function prototypes */
static void ConvertTriggerToFK(CreateTrigStmt *stmt, Oid funcoid);
static void SetTriggerFlags(TriggerDesc *trigdesc, Trigger *trigger);
static HeapTuple GetTupleForTrigger(EState *estate,
EPQState *epqstate,
ResultRelInfo *relinfo,
ItemPointer tid,
TupleTableSlot **newSlot);
static bool TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
Trigger *trigger, TriggerEvent event,
Bitmapset *modifiedCols,
HeapTuple oldtup, HeapTuple newtup);
static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
int tgindx,
FmgrInfo *finfo,
Instrumentation *instr,
MemoryContext per_tuple_context);
static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
int event, bool row_trigger,
HeapTuple oldtup, HeapTuple newtup,
List *recheckIndexes, Bitmapset *modifiedCols);
/*
* Create a trigger. Returns the OID of the created trigger.
*
* queryString is the source text of the CREATE TRIGGER command.
* This must be supplied if a whenClause is specified, else it can be NULL.
*
* constraintOid, if nonzero, says that this trigger is being created
* internally to implement that constraint. A suitable pg_depend entry will
* be made to link the trigger to that constraint. constraintOid is zero when
* executing a user-entered CREATE TRIGGER command. (For CREATE CONSTRAINT
* TRIGGER, we build a pg_constraint entry internally.)
*
* indexOid, if nonzero, is the OID of an index associated with the constraint.
* We do nothing with this except store it into pg_trigger.tgconstrindid.
*
* If isInternal is true then this is an internally-generated trigger.
* This argument sets the tgisinternal field of the pg_trigger entry, and
* if TRUE causes us to modify the given trigger name to ensure uniqueness.
*
* When isInternal is not true we require ACL_TRIGGER permissions on the
* relation. For internal triggers the caller must apply any required
* permission checks.
*
* Note: can return InvalidOid if we decided to not create a trigger at all,
* but a foreign-key constraint. This is a kluge for backwards compatibility.
*/
Oid
CreateTrigger(CreateTrigStmt *stmt, const char *queryString,
Oid constraintOid, Oid indexOid,
bool isInternal)
{
int16 tgtype;
int ncolumns;
int2 *columns;
int2vector *tgattr;
Node *whenClause;
List *whenRtable;
char *qual;
Datum values[Natts_pg_trigger];
bool nulls[Natts_pg_trigger];
Relation rel;
AclResult aclresult;
Relation tgrel;
SysScanDesc tgscan;
ScanKeyData key;
Relation pgrel;
HeapTuple tuple;
Oid fargtypes[1]; /* dummy */
Oid funcoid;
Oid funcrettype;
Oid trigoid;
char internaltrigname[NAMEDATALEN];
char *trigname;
Oid constrrelid = InvalidOid;
ObjectAddress myself,
referenced;
rel = heap_openrv(stmt->relation, AccessExclusiveLock);
/*
* Triggers must be on tables or views, and there are additional
* relation-type-specific restrictions.
*/
if (rel->rd_rel->relkind == RELKIND_RELATION)
{
/* Tables can't have INSTEAD OF triggers */
if (stmt->timing != TRIGGER_TYPE_BEFORE &&
stmt->timing != TRIGGER_TYPE_AFTER)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a table",
RelationGetRelationName(rel)),
errdetail("Tables cannot have INSTEAD OF triggers.")));
}
else if (rel->rd_rel->relkind == RELKIND_VIEW)
{
/*
* Views can have INSTEAD OF triggers (which we check below are
* row-level), or statement-level BEFORE/AFTER triggers.
*/
if (stmt->timing != TRIGGER_TYPE_INSTEAD && stmt->row)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a view",
RelationGetRelationName(rel)),
errdetail("Views cannot have row-level BEFORE or AFTER triggers.")));
/* Disallow TRUNCATE triggers on VIEWs */
if (TRIGGER_FOR_TRUNCATE(stmt->events))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a view",
RelationGetRelationName(rel)),
errdetail("Views cannot have TRUNCATE triggers.")));
}
else
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or view",
RelationGetRelationName(rel))));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
if (stmt->isconstraint && stmt->constrrel != NULL)
{
/*
* We must take a lock on the target relation to protect against
* concurrent drop. It's not clear that AccessShareLock is strong
* enough, but we certainly need at least that much... otherwise,
* we might end up creating a pg_constraint entry referencing a
* nonexistent table.
*/
constrrelid = RangeVarGetRelid(stmt->constrrel, AccessShareLock, false,
false);
}
/* permission checks */
if (!isInternal)
{
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_TRIGGER);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel));
if (OidIsValid(constrrelid))
{
aclresult = pg_class_aclcheck(constrrelid, GetUserId(),
ACL_TRIGGER);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
get_rel_name(constrrelid));
}
}
/* Compute tgtype */
TRIGGER_CLEAR_TYPE(tgtype);
if (stmt->row)
TRIGGER_SETT_ROW(tgtype);
tgtype |= stmt->timing;
tgtype |= stmt->events;
/* Disallow ROW-level TRUNCATE triggers */
if (TRIGGER_FOR_ROW(tgtype) && TRIGGER_FOR_TRUNCATE(tgtype))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("TRUNCATE FOR EACH ROW triggers are not supported")));
/* INSTEAD triggers must be row-level, and can't have WHEN or columns */
if (TRIGGER_FOR_INSTEAD(tgtype))
{
if (!TRIGGER_FOR_ROW(tgtype))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("INSTEAD OF triggers must be FOR EACH ROW")));
if (stmt->whenClause)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("INSTEAD OF triggers cannot have WHEN conditions")));
if (stmt->columns != NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("INSTEAD OF triggers cannot have column lists")));
}
/*
* Parse the WHEN clause, if any
*/
if (stmt->whenClause)
{
ParseState *pstate;
RangeTblEntry *rte;
List *varList;
ListCell *lc;
/* Set up a pstate to parse with */
pstate = make_parsestate(NULL);
pstate->p_sourcetext = queryString;
/*
* Set up RTEs for OLD and NEW references.
*
* 'OLD' must always have varno equal to 1 and 'NEW' equal to 2.
*/
rte = addRangeTableEntryForRelation(pstate, rel,
makeAlias("old", NIL),
false, false);
addRTEtoQuery(pstate, rte, false, true, true);
rte = addRangeTableEntryForRelation(pstate, rel,
makeAlias("new", NIL),
false, false);
addRTEtoQuery(pstate, rte, false, true, true);
/* Transform expression. Copy to be sure we don't modify original */
whenClause = transformWhereClause(pstate,
copyObject(stmt->whenClause),
"WHEN");
/* we have to fix its collations too */
assign_expr_collations(pstate, whenClause);
/*
* No subplans or aggregates, please
*/
if (pstate->p_hasSubLinks)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use subquery in trigger WHEN condition")));
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in trigger WHEN condition")));
if (pstate->p_hasWindowFuncs)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("cannot use window function in trigger WHEN condition")));
/*
* Check for disallowed references to OLD/NEW.
*
* NB: pull_var_clause is okay here only because we don't allow
* subselects in WHEN clauses; it would fail to examine the contents
* of subselects.
*/
varList = pull_var_clause(whenClause,
PVC_REJECT_AGGREGATES,
PVC_REJECT_PLACEHOLDERS);
foreach(lc, varList)
{
Var *var = (Var *) lfirst(lc);
switch (var->varno)
{
case PRS2_OLD_VARNO:
if (!TRIGGER_FOR_ROW(tgtype))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("statement trigger's WHEN condition cannot reference column values"),
parser_errposition(pstate, var->location)));
if (TRIGGER_FOR_INSERT(tgtype))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("INSERT trigger's WHEN condition cannot reference OLD values"),
parser_errposition(pstate, var->location)));
/* system columns are okay here */
break;
case PRS2_NEW_VARNO:
if (!TRIGGER_FOR_ROW(tgtype))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("statement trigger's WHEN condition cannot reference column values"),
parser_errposition(pstate, var->location)));
if (TRIGGER_FOR_DELETE(tgtype))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("DELETE trigger's WHEN condition cannot reference NEW values"),
parser_errposition(pstate, var->location)));
if (var->varattno < 0 && TRIGGER_FOR_BEFORE(tgtype))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("BEFORE trigger's WHEN condition cannot reference NEW system columns"),
parser_errposition(pstate, var->location)));
break;
default:
/* can't happen without add_missing_from, so just elog */
elog(ERROR, "trigger WHEN condition cannot contain references to other relations");
break;
}
}
/* we'll need the rtable for recordDependencyOnExpr */
whenRtable = pstate->p_rtable;
qual = nodeToString(whenClause);
free_parsestate(pstate);
}
else
{
whenClause = NULL;
whenRtable = NIL;
qual = NULL;
}
/*
* Find and validate the trigger function.
*/
funcoid = LookupFuncName(stmt->funcname, 0, fargtypes, false);
funcrettype = get_func_rettype(funcoid);
if (funcrettype != TRIGGEROID)
{
/*
* We allow OPAQUE just so we can load old dump files. When we see a
* trigger function declared OPAQUE, change it to TRIGGER.
*/
if (funcrettype == OPAQUEOID)
{
ereport(WARNING,
(errmsg("changing return type of function %s from \"opaque\" to \"trigger\"",
NameListToString(stmt->funcname))));
SetFunctionReturnType(funcoid, TRIGGEROID);
}
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("function %s must return type \"trigger\"",
NameListToString(stmt->funcname))));
}
/*
* If the command is a user-entered CREATE CONSTRAINT TRIGGER command that
* references one of the built-in RI_FKey trigger functions, assume it is
* from a dump of a pre-7.3 foreign key constraint, and take steps to
* convert this legacy representation into a regular foreign key
* constraint. Ugly, but necessary for loading old dump files.
*/
if (stmt->isconstraint && !isInternal &&
list_length(stmt->args) >= 6 &&
(list_length(stmt->args) % 2) == 0 &&
RI_FKey_trigger_type(funcoid) != RI_TRIGGER_NONE)
{
/* Keep lock on target rel until end of xact */
heap_close(rel, NoLock);
ConvertTriggerToFK(stmt, funcoid);
return InvalidOid;
}
/*
* If it's a user-entered CREATE CONSTRAINT TRIGGER command, make a
* corresponding pg_constraint entry.
*/
if (stmt->isconstraint && !OidIsValid(constraintOid))
{
/* Internal callers should have made their own constraints */
Assert(!isInternal);
constraintOid = CreateConstraintEntry(stmt->trigname,
RelationGetNamespace(rel),
CONSTRAINT_TRIGGER,
stmt->deferrable,
stmt->initdeferred,
true,
RelationGetRelid(rel),
NULL, /* no conkey */
0,
InvalidOid, /* no domain */
InvalidOid, /* no index */
InvalidOid, /* no foreign key */
NULL,
NULL,
NULL,
NULL,
0,
' ',
' ',
' ',
NULL, /* no exclusion */
NULL, /* no check constraint */
NULL,
NULL,
true, /* islocal */
0); /* inhcount */
}
/*
* Generate the trigger's OID now, so that we can use it in the name if
* needed.
*/
tgrel = heap_open(TriggerRelationId, RowExclusiveLock);
trigoid = GetNewOid(tgrel);
/*
* If trigger is internally generated, modify the provided trigger name to
* ensure uniqueness by appending the trigger OID. (Callers will usually
* supply a simple constant trigger name in these cases.)
*/
if (isInternal)
{
snprintf(internaltrigname, sizeof(internaltrigname),
"%s_%u", stmt->trigname, trigoid);
trigname = internaltrigname;
}
else
{
/* user-defined trigger; use the specified trigger name as-is */
trigname = stmt->trigname;
}
/*
* Scan pg_trigger for existing triggers on relation. We do this only to
* give a nice error message if there's already a trigger of the same
* name. (The unique index on tgrelid/tgname would complain anyway.) We
* can skip this for internally generated triggers, since the name
* modification above should be sufficient.
*
* NOTE that this is cool only because we have AccessExclusiveLock on
* the relation, so the trigger set won't be changing underneath us.
*/
if (!isInternal)
{
ScanKeyInit(&key,
Anum_pg_trigger_tgrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
if (namestrcmp(&(pg_trigger->tgname), trigname) == 0)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("trigger \"%s\" for relation \"%s\" already exists",
trigname, stmt->relation->relname)));
}
systable_endscan(tgscan);
}
/*
* Build the new pg_trigger tuple.
*/
memset(nulls, false, sizeof(nulls));
values[Anum_pg_trigger_tgrelid - 1] = ObjectIdGetDatum(RelationGetRelid(rel));
values[Anum_pg_trigger_tgname - 1] = DirectFunctionCall1(namein,
CStringGetDatum(trigname));
values[Anum_pg_trigger_tgfoid - 1] = ObjectIdGetDatum(funcoid);
values[Anum_pg_trigger_tgtype - 1] = Int16GetDatum(tgtype);
values[Anum_pg_trigger_tgenabled - 1] = CharGetDatum(TRIGGER_FIRES_ON_ORIGIN);
values[Anum_pg_trigger_tgisinternal - 1] = BoolGetDatum(isInternal);
values[Anum_pg_trigger_tgconstrrelid - 1] = ObjectIdGetDatum(constrrelid);
values[Anum_pg_trigger_tgconstrindid - 1] = ObjectIdGetDatum(indexOid);
values[Anum_pg_trigger_tgconstraint - 1] = ObjectIdGetDatum(constraintOid);
values[Anum_pg_trigger_tgdeferrable - 1] = BoolGetDatum(stmt->deferrable);
values[Anum_pg_trigger_tginitdeferred - 1] = BoolGetDatum(stmt->initdeferred);
if (stmt->args)
{
ListCell *le;
char *args;
int16 nargs = list_length(stmt->args);
int len = 0;
foreach(le, stmt->args)
{
char *ar = strVal(lfirst(le));
len += strlen(ar) + 4;
for (; *ar; ar++)
{
if (*ar == '\\')
len++;
}
}
args = (char *) palloc(len + 1);
args[0] = '\0';
foreach(le, stmt->args)
{
char *s = strVal(lfirst(le));
char *d = args + strlen(args);
while (*s)
{
if (*s == '\\')
*d++ = '\\';
*d++ = *s++;
}
strcpy(d, "\\000");
}
values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum(nargs);
values[Anum_pg_trigger_tgargs - 1] = DirectFunctionCall1(byteain,
CStringGetDatum(args));
}
else
{
values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum(0);
values[Anum_pg_trigger_tgargs - 1] = DirectFunctionCall1(byteain,
CStringGetDatum(""));
}
/* build column number array if it's a column-specific trigger */
ncolumns = list_length(stmt->columns);
if (ncolumns == 0)
columns = NULL;
else
{
ListCell *cell;
int i = 0;
columns = (int2 *) palloc(ncolumns * sizeof(int2));
foreach(cell, stmt->columns)
{
char *name = strVal(lfirst(cell));
int2 attnum;
int j;
/* Lookup column name. System columns are not allowed */
attnum = attnameAttNum(rel, name, false);
if (attnum == InvalidAttrNumber)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
name, RelationGetRelationName(rel))));
/* Check for duplicates */
for (j = i - 1; j >= 0; j--)
{
if (columns[j] == attnum)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" specified more than once",
name)));
}
columns[i++] = attnum;
}
}
tgattr = buildint2vector(columns, ncolumns);
values[Anum_pg_trigger_tgattr - 1] = PointerGetDatum(tgattr);
/* set tgqual if trigger has WHEN clause */
if (qual)
values[Anum_pg_trigger_tgqual - 1] = CStringGetTextDatum(qual);
else
nulls[Anum_pg_trigger_tgqual - 1] = true;
tuple = heap_form_tuple(tgrel->rd_att, values, nulls);
/* force tuple to have the desired OID */
HeapTupleSetOid(tuple, trigoid);
/*
* Insert tuple into pg_trigger.
*/
simple_heap_insert(tgrel, tuple);
CatalogUpdateIndexes(tgrel, tuple);
heap_freetuple(tuple);
heap_close(tgrel, RowExclusiveLock);
pfree(DatumGetPointer(values[Anum_pg_trigger_tgname - 1]));
pfree(DatumGetPointer(values[Anum_pg_trigger_tgargs - 1]));
pfree(DatumGetPointer(values[Anum_pg_trigger_tgattr - 1]));
/*
* Update relation's pg_class entry. Crucial side-effect: other backends
* (and this one too!) are sent SI message to make them rebuild relcache
* entries.
*/
pgrel = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy1(RELOID,
ObjectIdGetDatum(RelationGetRelid(rel)));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u",
RelationGetRelid(rel));
((Form_pg_class) GETSTRUCT(tuple))->relhastriggers = true;
simple_heap_update(pgrel, &tuple->t_self, tuple);
CatalogUpdateIndexes(pgrel, tuple);
heap_freetuple(tuple);
heap_close(pgrel, RowExclusiveLock);
/*
* We used to try to update the rel's relcache entry here, but that's
* fairly pointless since it will happen as a byproduct of the upcoming
* CommandCounterIncrement...
*/
/*
* Record dependencies for trigger. Always place a normal dependency on
* the function.
*/
myself.classId = TriggerRelationId;
myself.objectId = trigoid;
myself.objectSubId = 0;
referenced.classId = ProcedureRelationId;
referenced.objectId = funcoid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
if (isInternal && OidIsValid(constraintOid))
{
/*
* Internally-generated trigger for a constraint, so make it an
* internal dependency of the constraint. We can skip depending on
* the relation(s), as there'll be an indirect dependency via the
* constraint.
*/
referenced.classId = ConstraintRelationId;
referenced.objectId = constraintOid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_INTERNAL);
}
else
{
/*
* User CREATE TRIGGER, so place dependencies. We make trigger be
* auto-dropped if its relation is dropped or if the FK relation is
* dropped. (Auto drop is compatible with our pre-7.3 behavior.)
*/
referenced.classId = RelationRelationId;
referenced.objectId = RelationGetRelid(rel);
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
if (OidIsValid(constrrelid))
{
referenced.classId = RelationRelationId;
referenced.objectId = constrrelid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
}
/* Not possible to have an index dependency in this case */
Assert(!OidIsValid(indexOid));
/*
* If it's a user-specified constraint trigger, make the constraint
* internally dependent on the trigger instead of vice versa.
*/
if (OidIsValid(constraintOid))
{
referenced.classId = ConstraintRelationId;
referenced.objectId = constraintOid;
referenced.objectSubId = 0;
recordDependencyOn(&referenced, &myself, DEPENDENCY_INTERNAL);
}
}
/* If column-specific trigger, add normal dependencies on columns */
if (columns != NULL)
{
int i;
referenced.classId = RelationRelationId;
referenced.objectId = RelationGetRelid(rel);
for (i = 0; i < ncolumns; i++)
{
referenced.objectSubId = columns[i];
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
}
}
/*
* If it has a WHEN clause, add dependencies on objects mentioned in the
* expression (eg, functions, as well as any columns used).
*/
if (whenClause != NULL)
recordDependencyOnExpr(&myself, whenClause, whenRtable,
DEPENDENCY_NORMAL);
/* Post creation hook for new trigger */
InvokeObjectAccessHook(OAT_POST_CREATE,
TriggerRelationId, trigoid, 0);
/* Keep lock on target rel until end of xact */
heap_close(rel, NoLock);
return trigoid;
}
/*
* Convert legacy (pre-7.3) CREATE CONSTRAINT TRIGGER commands into
* full-fledged foreign key constraints.
*
* The conversion is complex because a pre-7.3 foreign key involved three
* separate triggers, which were reported separately in dumps. While the
* single trigger on the referencing table adds no new information, we need
* to know the trigger functions of both of the triggers on the referenced
* table to build the constraint declaration. Also, due to lack of proper
* dependency checking pre-7.3, it is possible that the source database had
* an incomplete set of triggers resulting in an only partially enforced
* FK constraint. (This would happen if one of the tables had been dropped
* and re-created, but only if the DB had been affected by a 7.0 pg_dump bug
* that caused loss of tgconstrrelid information.) We choose to translate to
* an FK constraint only when we've seen all three triggers of a set. This is
* implemented by storing unmatched items in a list in TopMemoryContext.
* We match triggers together by comparing the trigger arguments (which
* include constraint name, table and column names, so should be good enough).
*/
typedef struct
{
List *args; /* list of (T_String) Values or NIL */
Oid funcoids[3]; /* OIDs of trigger functions */
/* The three function OIDs are stored in the order update, delete, child */
} OldTriggerInfo;
static void
ConvertTriggerToFK(CreateTrigStmt *stmt, Oid funcoid)
{
static List *info_list = NIL;
static const char *const funcdescr[3] = {
gettext_noop("Found referenced table's UPDATE trigger."),
gettext_noop("Found referenced table's DELETE trigger."),
gettext_noop("Found referencing table's trigger.")
};
char *constr_name;
char *fk_table_name;
char *pk_table_name;
char fk_matchtype = FKCONSTR_MATCH_UNSPECIFIED;
List *fk_attrs = NIL;
List *pk_attrs = NIL;
StringInfoData buf;
int funcnum;
OldTriggerInfo *info = NULL;
ListCell *l;
int i;
/* Parse out the trigger arguments */
constr_name = strVal(linitial(stmt->args));
fk_table_name = strVal(lsecond(stmt->args));
pk_table_name = strVal(lthird(stmt->args));
i = 0;
foreach(l, stmt->args)
{
Value *arg = (Value *) lfirst(l);
i++;
if (i < 4) /* skip constraint and table names */
continue;
if (i == 4) /* handle match type */
{
if (strcmp(strVal(arg), "FULL") == 0)
fk_matchtype = FKCONSTR_MATCH_FULL;
else
fk_matchtype = FKCONSTR_MATCH_UNSPECIFIED;
continue;
}
if (i % 2)
fk_attrs = lappend(fk_attrs, arg);
else
pk_attrs = lappend(pk_attrs, arg);
}
/* Prepare description of constraint for use in messages */
initStringInfo(&buf);
appendStringInfo(&buf, "FOREIGN KEY %s(",
quote_identifier(fk_table_name));
i = 0;
foreach(l, fk_attrs)
{
Value *arg = (Value *) lfirst(l);
if (i++ > 0)
appendStringInfoChar(&buf, ',');
appendStringInfoString(&buf, quote_identifier(strVal(arg)));
}
appendStringInfo(&buf, ") REFERENCES %s(",
quote_identifier(pk_table_name));
i = 0;
foreach(l, pk_attrs)
{
Value *arg = (Value *) lfirst(l);
if (i++ > 0)
appendStringInfoChar(&buf, ',');
appendStringInfoString(&buf, quote_identifier(strVal(arg)));
}
appendStringInfoChar(&buf, ')');
/* Identify class of trigger --- update, delete, or referencing-table */
switch (funcoid)
{
case F_RI_FKEY_CASCADE_UPD:
case F_RI_FKEY_RESTRICT_UPD:
case F_RI_FKEY_SETNULL_UPD:
case F_RI_FKEY_SETDEFAULT_UPD:
case F_RI_FKEY_NOACTION_UPD:
funcnum = 0;
break;
case F_RI_FKEY_CASCADE_DEL:
case F_RI_FKEY_RESTRICT_DEL:
case F_RI_FKEY_SETNULL_DEL:
case F_RI_FKEY_SETDEFAULT_DEL:
case F_RI_FKEY_NOACTION_DEL:
funcnum = 1;
break;
default:
funcnum = 2;
break;
}
/* See if we have a match to this trigger */
foreach(l, info_list)
{
info = (OldTriggerInfo *) lfirst(l);
if (info->funcoids[funcnum] == InvalidOid &&
equal(info->args, stmt->args))
{
info->funcoids[funcnum] = funcoid;
break;
}
}
if (l == NULL)
{
/* First trigger of set, so create a new list entry */
MemoryContext oldContext;
ereport(NOTICE,
(errmsg("ignoring incomplete trigger group for constraint \"%s\" %s",
constr_name, buf.data),
errdetail("%s", _(funcdescr[funcnum]))));
oldContext = MemoryContextSwitchTo(TopMemoryContext);
info = (OldTriggerInfo *) palloc0(sizeof(OldTriggerInfo));
info->args = copyObject(stmt->args);
info->funcoids[funcnum] = funcoid;
info_list = lappend(info_list, info);
MemoryContextSwitchTo(oldContext);
}
else if (info->funcoids[0] == InvalidOid ||
info->funcoids[1] == InvalidOid ||
info->funcoids[2] == InvalidOid)
{
/* Second trigger of set */
ereport(NOTICE,
(errmsg("ignoring incomplete trigger group for constraint \"%s\" %s",
constr_name, buf.data),
errdetail("%s", _(funcdescr[funcnum]))));
}
else
{
/* OK, we have a set, so make the FK constraint ALTER TABLE cmd */
AlterTableStmt *atstmt = makeNode(AlterTableStmt);
AlterTableCmd *atcmd = makeNode(AlterTableCmd);
Constraint *fkcon = makeNode(Constraint);
ereport(NOTICE,
(errmsg("converting trigger group into constraint \"%s\" %s",
constr_name, buf.data),
errdetail("%s", _(funcdescr[funcnum]))));
fkcon->contype = CONSTR_FOREIGN;
fkcon->location = -1;
if (funcnum == 2)
{
/* This trigger is on the FK table */
atstmt->relation = stmt->relation;
if (stmt->constrrel)
fkcon->pktable = stmt->constrrel;
else
{
/* Work around ancient pg_dump bug that omitted constrrel */
fkcon->pktable = makeRangeVar(NULL, pk_table_name, -1);
}
}
else
{
/* This trigger is on the PK table */
fkcon->pktable = stmt->relation;
if (stmt->constrrel)
atstmt->relation = stmt->constrrel;
else
{
/* Work around ancient pg_dump bug that omitted constrrel */
atstmt->relation = makeRangeVar(NULL, fk_table_name, -1);
}
}
atstmt->cmds = list_make1(atcmd);
atstmt->relkind = OBJECT_TABLE;
atcmd->subtype = AT_AddConstraint;
atcmd->def = (Node *) fkcon;
if (strcmp(constr_name, "<unnamed>") == 0)
fkcon->conname = NULL;
else
fkcon->conname = constr_name;
fkcon->fk_attrs = fk_attrs;
fkcon->pk_attrs = pk_attrs;
fkcon->fk_matchtype = fk_matchtype;
switch (info->funcoids[0])
{
case F_RI_FKEY_NOACTION_UPD:
fkcon->fk_upd_action = FKCONSTR_ACTION_NOACTION;
break;
case F_RI_FKEY_CASCADE_UPD:
fkcon->fk_upd_action = FKCONSTR_ACTION_CASCADE;
break;
case F_RI_FKEY_RESTRICT_UPD:
fkcon->fk_upd_action = FKCONSTR_ACTION_RESTRICT;
break;
case F_RI_FKEY_SETNULL_UPD:
fkcon->fk_upd_action = FKCONSTR_ACTION_SETNULL;
break;
case F_RI_FKEY_SETDEFAULT_UPD:
fkcon->fk_upd_action = FKCONSTR_ACTION_SETDEFAULT;
break;
default:
/* can't get here because of earlier checks */
elog(ERROR, "confused about RI update function");
}
switch (info->funcoids[1])
{
case F_RI_FKEY_NOACTION_DEL:
fkcon->fk_del_action = FKCONSTR_ACTION_NOACTION;
break;
case F_RI_FKEY_CASCADE_DEL:
fkcon->fk_del_action = FKCONSTR_ACTION_CASCADE;
break;
case F_RI_FKEY_RESTRICT_DEL: