Remove unnecessary opening of other relation in RI_FKey_keyequal_upd_pk

and RI_FKey_keyequal_upd_fk, as well as no-longer-needed calls of
ri_BuildQueryKeyFull.  Aside from saving a few cycles, this avoids needless
deadlock risks when an update is not changing the columns that participate
in an RI constraint.  Per a gripe from Alexey Nalbat.

Back-patch to 8.3.  Earlier releases did have a need to open the other
relation due to the way in which they retrieved information about the RI
constraint, so this problem unfortunately can't easily be improved pre-8.3.

Tom Lane and Stephan Szabo

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 66df8e1b8393a6123dcc57cc4ed3e47cbfc33b49..65f541057ba9b9d38649acebdcf8d6a79343589e 100644 (file)
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -15,7 +15,7 @@
  *
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.103 2008/02/07 22:58:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.104 2008/02/18 23:00:32 tgl Exp $
  *
  * ----------
  */
@@ -67,13 +67,12 @@
 #define RI_PLAN_RESTRICT_UPD_CHECKREF  8
 #define RI_PLAN_SETNULL_DEL_DOUPDATE   9
 #define RI_PLAN_SETNULL_UPD_DOUPDATE   10
-#define RI_PLAN_KEYEQUAL_UPD           11
 
 #define MAX_QUOTED_NAME_LEN  (NAMEDATALEN*2+3)
 #define MAX_QUOTED_REL_NAME_LEN  (MAX_QUOTED_NAME_LEN*2)
 
 #define RIAttName(rel, attnum) NameStr(*attnumAttName(rel, attnum))
-#define RIAttType(rel, attnum) SPI_gettypeid(RelationGetDescr(rel), attnum)
+#define RIAttType(rel, attnum) attnumTypeId(rel, attnum)
 
 #define RI_TRIGTYPE_INSERT 1
 #define RI_TRIGTYPE_UPDATE 2
@@ -2516,8 +2515,6 @@ RI_FKey_keyequal_upd_pk(Trigger *trigger, Relation pk_rel,
                        HeapTuple old_row, HeapTuple new_row)
 {
    RI_ConstraintInfo riinfo;
-   Relation    fk_rel;
-   RI_QueryKey qkey;
 
    /*
     * Get arguments.
@@ -2530,18 +2527,11 @@ RI_FKey_keyequal_upd_pk(Trigger *trigger, Relation pk_rel,
    if (riinfo.nkeys == 0)
        return true;
 
-   fk_rel = heap_open(riinfo.fk_relid, AccessShareLock);
-
    switch (riinfo.confmatchtype)
    {
        case FKCONSTR_MATCH_UNSPECIFIED:
        case FKCONSTR_MATCH_FULL:
-           ri_BuildQueryKeyFull(&qkey, &riinfo,
-                                RI_PLAN_KEYEQUAL_UPD);
-
-           heap_close(fk_rel, AccessShareLock);
-
-           /* Return if key's are equal */
+           /* Return true if keys are equal */
            return ri_KeysEqual(pk_rel, old_row, new_row, &riinfo, true);
 
            /* Handle MATCH PARTIAL set null delete. */
@@ -2570,8 +2560,6 @@ RI_FKey_keyequal_upd_fk(Trigger *trigger, Relation fk_rel,
                        HeapTuple old_row, HeapTuple new_row)
 {
    RI_ConstraintInfo riinfo;
-   Relation    pk_rel;
-   RI_QueryKey qkey;
 
    /*
     * Get arguments.
@@ -2584,17 +2572,11 @@ RI_FKey_keyequal_upd_fk(Trigger *trigger, Relation fk_rel,
    if (riinfo.nkeys == 0)
        return true;
 
-   pk_rel = heap_open(riinfo.pk_relid, AccessShareLock);
-
    switch (riinfo.confmatchtype)
    {
        case FKCONSTR_MATCH_UNSPECIFIED:
        case FKCONSTR_MATCH_FULL:
-           ri_BuildQueryKeyFull(&qkey, &riinfo,
-                                RI_PLAN_KEYEQUAL_UPD);
-           heap_close(pk_rel, AccessShareLock);
-
-           /* Return if key's are equal */
+           /* Return true if keys are equal */
            return ri_KeysEqual(fk_rel, old_row, new_row, &riinfo, false);
 
            /* Handle MATCH PARTIAL set null delete. */