Small code simplification

Apply the same code simplification to ATExecAddColumn as was done in
7ff9afbbd: apply GETSTRUCT() once instead of doing it repeatedly in
the same function.

Author: Tender Wang
Discussion: https://postgr.es/m/CAHewXNkO9+U437jvKT14s0MCu6Qpf6G-p2mZK5J9mAi4cHDgpQ@mail.gmail.com

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index dfba5f357b8450212538ed955db0c30fb3d34481..13bb8811204323a9d0a52e0e7db0b08efeb2e1f6 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -7028,6 +7028,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
        Relation        pgclass,
                                attrdesc;
        HeapTuple       reltup;
+       Form_pg_class relform;
        Form_pg_attribute attribute;
        int                     newattnum;
        char            relkind;
@@ -7161,10 +7162,11 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
        reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(myrelid));
        if (!HeapTupleIsValid(reltup))
                elog(ERROR, "cache lookup failed for relation %u", myrelid);
-       relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind;
+       relform = (Form_pg_class) GETSTRUCT(reltup);
+       relkind = relform->relkind;
 
        /* Determine the new attribute's number */
-       newattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts + 1;
+       newattnum = relform->relnatts + 1;
        if (newattnum > MaxHeapAttributeNumber)
                ereport(ERROR,
                                (errcode(ERRCODE_TOO_MANY_COLUMNS),
@@ -7193,7 +7195,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
        /*
         * Update pg_class tuple as appropriate
         */
-       ((Form_pg_class) GETSTRUCT(reltup))->relnatts = newattnum;
+       relform->relnatts = newattnum;
 
        CatalogTupleUpdate(pgclass, &reltup->t_self, reltup);