refactor: Move some code that updates pg_constraint to a separate function

This extracts common/duplicate code for different ALTER CONSTRAINT
variants into a common function.  We plan to add more variants that
would use the same code.

Author: Amul Sul <amul.sul@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/CAAJ_b962c5AcYW9KUt_R_ER5qs3fUGbe4az-SP-vuwPS-w-AGA@mail.gmail.com

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4974536e084e49a3c4065b0cf00c3fa819b39a38..778e956b1ffa3730fd7ba09bf40852c2bead886c 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -402,6 +402,8 @@ static void ATExecAlterChildConstr(List **wqueue, ATAlterConstraint *cmdcon,
                                   Relation conrel, Relation tgrel, Relation rel,
                                   HeapTuple contuple, bool recurse, List **otherrelids,
                                   LOCKMODE lockmode);
+static void AlterConstrUpdateConstraintEntry(ATAlterConstraint *cmdcon, Relation conrel,
+                                            HeapTuple contuple);
 static ObjectAddress ATExecValidateConstraint(List **wqueue,
                                              Relation rel, char *constrName,
                                              bool recurse, bool recursing, LOCKMODE lockmode);
@@ -12093,23 +12095,9 @@ ATExecAlterConstraintInternal(List **wqueue, ATAlterConstraint *cmdcon,
        (currcon->condeferrable != cmdcon->deferrable ||
         currcon->condeferred != cmdcon->initdeferred))
    {
-       HeapTuple   copyTuple;
-       Form_pg_constraint copy_con;
-
-       copyTuple = heap_copytuple(contuple);
-       copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
-       copy_con->condeferrable = cmdcon->deferrable;
-       copy_con->condeferred = cmdcon->initdeferred;
-       CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
-
-       InvokeObjectPostAlterHook(ConstraintRelationId, currcon->oid, 0);
-
-       heap_freetuple(copyTuple);
+       AlterConstrUpdateConstraintEntry(cmdcon, conrel, contuple);
        changed = true;
 
-       /* Make new constraint flags visible to others */
-       CacheInvalidateRelcache(rel);
-
        /*
         * Now we need to update the multiple entries in pg_trigger that
         * implement the constraint.
@@ -12140,27 +12128,14 @@ ATExecAlterConstraintInternal(List **wqueue, ATAlterConstraint *cmdcon,
        AttrNumber  colNum;
        char       *colName;
        List       *children;
-       HeapTuple   copyTuple;
-       Form_pg_constraint copy_con;
 
        /* The current implementation only works for NOT NULL constraints */
        Assert(currcon->contype == CONSTRAINT_NOTNULL);
 
-       copyTuple = heap_copytuple(contuple);
-       copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
-       copy_con->connoinherit = cmdcon->noinherit;
-
-       CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
-
-       InvokeObjectPostAlterHook(ConstraintRelationId, currcon->oid, 0);
-
+       AlterConstrUpdateConstraintEntry(cmdcon, conrel, contuple);
        CommandCounterIncrement();
-       heap_freetuple(copyTuple);
        changed = true;
 
-       /* Make new constraint flags visible to others */
-       CacheInvalidateRelcache(rel);
-
        /* Fetch the column number and name */
        colNum = extractNotNullColumn(contuple);
        colName = get_attname(currcon->conrelid, colNum, false);
@@ -12320,6 +12295,39 @@ ATExecAlterChildConstr(List **wqueue, ATAlterConstraint *cmdcon,
    systable_endscan(pscan);
 }
 
+/*
+ * Update the constraint entry for the given ATAlterConstraint command, and
+ * invoke the appropriate hooks.
+ */
+static void
+AlterConstrUpdateConstraintEntry(ATAlterConstraint *cmdcon, Relation conrel,
+                                HeapTuple contuple)
+{
+   HeapTuple   copyTuple;
+   Form_pg_constraint copy_con;
+
+   Assert(cmdcon->alterDeferrability || cmdcon->alterInheritability);
+
+   copyTuple = heap_copytuple(contuple);
+   copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
+
+   if (cmdcon->alterDeferrability)
+   {
+       copy_con->condeferrable = cmdcon->deferrable;
+       copy_con->condeferred = cmdcon->initdeferred;
+   }
+   if (cmdcon->alterInheritability)
+       copy_con->connoinherit = cmdcon->noinherit;
+
+   CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
+   InvokeObjectPostAlterHook(ConstraintRelationId, copy_con->oid, 0);
+
+   /* Make new constraint flags visible to others */
+   CacheInvalidateRelcacheByRelid(copy_con->conrelid);
+
+   heap_freetuple(copyTuple);
+}
+
 /*
  * ALTER TABLE VALIDATE CONSTRAINT
  *