ADD/DROPS inherits - Mailing list pgsql-patches

From Greg Stark
Subject ADD/DROPS inherits
Date
Msg-id 87slmadpfn.fsf@stark.xeocode.com
Whole thread Raw
Responses Re: ADD/DROPS inherits  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-patches
I couldn't figure out how to make use of the predigested constraints in the
relcache, so I continued on the tack I was on. I just stuf the entire
HeapTuple in a list and decompiled the constraint source only if I find a
constraint with a matching name.

Points I'm uncertain about:

. I throw an elog() error if there's a null conbin for a CHECK constraint. Is
  it possible for a valid CHECK constraint structure to have a null conbin?

. Memory management. Do I need the heap_copytuple or is that unnecessary?
  Would it be ok to simply store the actual HeapTuples as the scan proceeds?

. Locking -- all of it :)

I added some basic (very basic) regression tests and documentation. Did I find
the right places? Is that enough or should I add more?


Index: doc/src/sgml/ref/alter_table.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v
retrieving revision 1.84
diff -u -p -c -r1.84 alter_table.sgml
cvs diff: conflicting specifications of output style
*** doc/src/sgml/ref/alter_table.sgml    12 Feb 2006 19:11:00 -0000    1.84
--- doc/src/sgml/ref/alter_table.sgml    12 Jun 2006 21:30:54 -0000
*************** where <replaceable class="PARAMETER">act
*** 46,51 ****
--- 46,53 ----
      CLUSTER ON <replaceable class="PARAMETER">index_name</replaceable>
      SET WITHOUT CLUSTER
      SET WITHOUT OIDS
+     INHERIT <replaceable class="PARAMETER">parent_table</replaceable>
+     NO INHERIT <replaceable class="PARAMETER">parent_table</replaceable>
      OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
      SET TABLESPACE <replaceable class="PARAMETER">new_tablespace</replaceable>
  </synopsis>
*************** where <replaceable class="PARAMETER">act
*** 250,255 ****
--- 252,303 ----
     </varlistentry>

     <varlistentry>
+     <term><literal>INHERIT <replaceable class="PARAMETER">parent_table</replaceable></literal></term>
+     <listitem>
+      <para>
+
+       This form adds a new parent table to the table. This won't add new
+       columns to the child table, instead all columns of the parent table must
+       already exist in the child table. They must have matching data types,
+       and if they have <literal>NOT NULL</literal> constraints in the parent
+       then they must also have <literal>NOT NULL</literal> constraints in the
+       child.
+
+       </para>
+       <para>
+
+       There must also be matching table constraints for all
+       <literal>CHECK</literal> table constraints of the parent. Currently
+       <literal>UNIQUE</literal>, <literal>PRIMARY KEY</literal>, and
+       <literal>FOREIGN KEY</literal> constraints are ignored however this may
+       change in the future.
+
+       </para>
+       <para>
+
+       The easiest way to create a suitable table is to create a table using
+       <literal>INHERITS</literal> and then remove it via <literal>NO
+       INHERIT</literal>. Alternatively create a table using
+       <literal>LIKE</literal> however note that <literal>LIKE</literal> does
+       not create the necessary constraints.
+
+      </para>
+
+     </listitem>
+    </varlistentry>
+
+    <varlistentry>
+     <term><literal>NO INHERIT <replaceable class="PARAMETER">parent_table</replaceable></literal></term>
+     <listitem>
+      <para>
+      This form removes a parent table from the list of parents of the table.
+      Queries against the parent table will no longer include records drawn
+      from the target table.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry>
      <term><literal>OWNER</literal></term>
      <listitem>
       <para>
Index: src/backend/commands/tablecmds.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/commands/tablecmds.c,v
retrieving revision 1.184
diff -u -p -c -r1.184 tablecmds.c
cvs diff: conflicting specifications of output style
*** src/backend/commands/tablecmds.c    10 May 2006 23:18:39 -0000    1.184
--- src/backend/commands/tablecmds.c    12 Jun 2006 21:30:54 -0000
*************** typedef struct NewColumnValue
*** 159,166 ****
--- 159,168 ----
  static void truncate_check_rel(Relation rel);
  static List *MergeAttributes(List *schema, List *supers, bool istemp,
                  List **supOids, List **supconstr, int *supOidCount);
+ static void MergeAttributesIntoExisting(Relation rel, Relation relation);
  static bool change_varattnos_of_a_node(Node *node, const AttrNumber *newattno);
  static void StoreCatalogInheritance(Oid relationId, List *supers);
+ static void StoreCatalogInheritance1(Oid relationId, Oid parentOid, int16 seqNumber, Relation catalogRelation);
  static int    findAttrByName(const char *attributeName, List *schema);
  static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
  static bool needs_toast_table(Relation rel);
*************** static void ATPrepSetTableSpace(AlteredT
*** 246,251 ****
--- 248,255 ----
  static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace);
  static void ATExecEnableDisableTrigger(Relation rel, char *trigname,
                             bool enable, bool skip_system);
+ static void ATExecAddInherits(Relation rel, RangeVar *parent);
+ static void ATExecDropInherits(Relation rel, RangeVar *parent);
  static void copy_relation_data(Relation rel, SMgrRelation dst);
  static void update_ri_trigger_args(Oid relid,
                         const char *oldname,
*************** static void
*** 1156,1165 ****
  StoreCatalogInheritance(Oid relationId, List *supers)
  {
      Relation    relation;
-     TupleDesc    desc;
      int16        seqNumber;
      ListCell   *entry;
-     HeapTuple    tuple;

      /*
       * sanity checks
--- 1160,1167 ----
*************** StoreCatalogInheritance(Oid relationId,
*** 1179,1194 ****
       * anymore, there's no need to look for indirect ancestors.)
       */
      relation = heap_open(InheritsRelationId, RowExclusiveLock);
-     desc = RelationGetDescr(relation);

      seqNumber = 1;
      foreach(entry, supers)
      {
!         Oid            parentOid = lfirst_oid(entry);
          Datum        datum[Natts_pg_inherits];
          char        nullarr[Natts_pg_inherits];
          ObjectAddress childobject,
                      parentobject;

          datum[0] = ObjectIdGetDatum(relationId);        /* inhrel */
          datum[1] = ObjectIdGetDatum(parentOid); /* inhparent */
--- 1181,1206 ----
       * anymore, there's no need to look for indirect ancestors.)
       */
      relation = heap_open(InheritsRelationId, RowExclusiveLock);

      seqNumber = 1;
      foreach(entry, supers)
      {
!         StoreCatalogInheritance1(relationId, lfirst_oid(entry), seqNumber, relation);
!         seqNumber += 1;
!     }
!
!     heap_close(relation, RowExclusiveLock);
! }
!
! static void
! StoreCatalogInheritance1(Oid relationId, Oid parentOid, int16 seqNumber, Relation relation)
! {
          Datum        datum[Natts_pg_inherits];
          char        nullarr[Natts_pg_inherits];
          ObjectAddress childobject,
                      parentobject;
+         HeapTuple    tuple;
+         TupleDesc desc = RelationGetDescr(relation);

          datum[0] = ObjectIdGetDatum(relationId);        /* inhrel */
          datum[1] = ObjectIdGetDatum(parentOid); /* inhparent */
*************** StoreCatalogInheritance(Oid relationId,
*** 1223,1232 ****
           */
          setRelhassubclassInRelation(parentOid, true);

-         seqNumber += 1;
-     }
-
-     heap_close(relation, RowExclusiveLock);
  }

  /*
--- 1235,1240 ----
*************** ATPrepCmd(List **wqueue, Relation rel, A
*** 2053,2058 ****
--- 2061,2068 ----
          case AT_DisableTrig:    /* DISABLE TRIGGER variants */
          case AT_DisableTrigAll:
          case AT_DisableTrigUser:
+         case AT_AddInherits:
+         case AT_DropInherits:
              ATSimplePermissions(rel, false);
              /* These commands never recurse */
              /* No command-specific prep needed */
*************** ATExecCmd(AlteredTableInfo *tab, Relatio
*** 2233,2238 ****
--- 2243,2254 ----
          case AT_DisableTrigUser:        /* DISABLE TRIGGER USER */
              ATExecEnableDisableTrigger(rel, NULL, false, true);
              break;
+         case AT_DropInherits:
+             ATExecDropInherits(rel, cmd->parent);
+             break;
+         case AT_AddInherits:
+             ATExecAddInherits(rel, cmd->parent);
+             break;
          default:                /* oops */
              elog(ERROR, "unrecognized alter table type: %d",
                   (int) cmd->subtype);
*************** ATExecEnableDisableTrigger(Relation rel,
*** 5880,5885 ****
--- 5896,6294 ----
      EnableDisableTrigger(rel, trigname, enable, skip_system);
  }

+ static char *
+ decompile_conbin(HeapTuple contuple, TupleDesc tupledesc)
+ {
+     Form_pg_constraint con = (Form_pg_constraint)(GETSTRUCT(contuple));
+     bool isnull;
+     Datum d;
+
+     d = fastgetattr(contuple, Anum_pg_constraint_conbin, tupledesc, &isnull);
+     if (isnull)
+         elog(ERROR, "conbin is null for constraint \"%s\"", NameStr(con->conname));
+     d = DirectFunctionCall2(pg_get_expr, d, ObjectIdGetDatum(con->conrelid));
+     return DatumGetCString(DirectFunctionCall1(textout,d));
+ }
+
+
+ static void
+ ATExecAddInherits(Relation rel, RangeVar *parent)
+ {
+     Relation     relation, catalogRelation;
+     SysScanDesc scan;
+     ScanKeyData key;
+     HeapTuple     inheritsTuple, constraintTuple;
+     int4         inhseqno;
+     ListCell       *elem;
+     List         *children, *constraints;
+     TupleDesc       tupleDesc;
+
+     relation = heap_openrv(parent, AccessShareLock); /* XXX is this enough locking? */
+     if (relation->rd_rel->relkind != RELKIND_RELATION)
+         ereport(ERROR,
+                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+                  errmsg("inherited relation \"%s\" is not a table",
+                         parent->relname)));
+
+
+     /* Permanent rels cannot inherit from temporary ones */
+     if (!rel->rd_istemp && isTempNamespace(RelationGetNamespace(relation)))
+         ereport(ERROR,
+                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+                  errmsg("cannot inherit from temporary relation \"%s\"",
+                         parent->relname)));
+
+     if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
+         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
+                        RelationGetRelationName(relation));
+
+     /* If parent has OIDs then all children must have OIDs */
+     if (relation->rd_rel->relhasoids && !rel->rd_rel->relhasoids)
+         ereport(ERROR,
+                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+                  errmsg("table \"%s\" without OIDs cannot inherit from table \"%s\" with OIDs",
+                         RelationGetRelationName(rel), parent->relname)));
+
+     /*
+      * Reject duplications in the list of parents. -- this is the same check as
+      * when creating a table, but maybe we should check for the parent anywhere
+      * higher in the inheritance structure?
+      */
+     catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
+     ScanKeyInit(&key,
+                 Anum_pg_inherits_inhrelid,
+                 BTEqualStrategyNumber, F_OIDEQ,
+                 ObjectIdGetDatum(RelationGetRelid(rel)));
+     scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId, true, SnapshotNow, 1, &key);
+     inhseqno = 0; /* inhseqno sequences are supposed to start at 1 */
+     while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
+     {
+         Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inheritsTuple);
+         if (inh->inhparent == RelationGetRelid(relation))
+             ereport(ERROR,
+                     (errcode(ERRCODE_DUPLICATE_TABLE),
+                      errmsg("inherited relation \"%s\" duplicated",
+                             parent->relname)));
+         /* Accumulate the max seqno -- BUT if we spot a hole use it instead
+          * This means if you DROP and ADD the same parent the order will be maintained
+          * which will mean pg_dump won't gratuitously reorder your columns.
+          */
+         if (inh->inhseqno == inhseqno+1)
+             inhseqno = inh->inhseqno;
+     }
+     systable_endscan(scan);
+     heap_close(catalogRelation, RowExclusiveLock);
+
+     /* Get children because we have to manually recurse and also because we
+      * have to check for recursive inheritance graphs */
+
+     /* this routine is actually in the planner */
+     children = find_all_inheritors(RelationGetRelid(rel));
+
+     if (list_member_oid(children, RelationGetRelid(relation)))
+         ereport(ERROR,
+                 (errcode(ERRCODE_DUPLICATE_TABLE),
+                  errmsg("circular inheritance structure found, \"%s\" is already a child of \"%s\"",
+                         parent->relname, RelationGetRelationName(rel))));
+
+     foreach(elem, children)
+         {
+             Oid            childrelid = lfirst_oid(elem);
+             Relation    childrel;
+
+             childrel = relation_open(childrelid, AccessExclusiveLock);
+             MergeAttributesIntoExisting(childrel, relation);
+             relation_close(childrel, NoLock);
+         }
+
+
+
+     /* Now check the constraints
+      *
+      * Currently only check constraints are copied when making children so only
+      * check those -- foreign key constraints can and probably ought to be
+      * added but unique/primary key are a whole other ball of wax
+      */
+
+     /* XXX this is O(n^2) which may be issue with tables with many constraints. As
+      * long as tables usually have more like 10 constraints it shouldn't be an
+      * issue. even 100 constraints shouldn't be the end of the world.
+      */
+
+     /* First gather up the child's constraint definitions */
+     catalogRelation = heap_open(ConstraintRelationId, AccessShareLock);
+     tupleDesc = RelationGetDescr(catalogRelation);
+
+     ScanKeyInit(&key,
+                 Anum_pg_constraint_conrelid,
+                 BTEqualStrategyNumber, F_OIDEQ,
+                 ObjectIdGetDatum(RelationGetRelid(rel)));
+     scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId, true, SnapshotNow, 1, &key);
+     constraints = NIL;
+     while (HeapTupleIsValid(constraintTuple = systable_getnext(scan))) {
+         Form_pg_constraint con = (Form_pg_constraint)(GETSTRUCT(constraintTuple));
+         if (con->contype != CONSTRAINT_CHECK)
+             continue;
+         constraints = lappend(constraints, heap_copytuple(constraintTuple)); /* XXX Do I need the copytuple here? */
+     }
+     systable_endscan(scan);
+
+     /* Then loop through the parent's constraints */
+     ScanKeyInit(&key,
+                 Anum_pg_constraint_conrelid,
+                 BTEqualStrategyNumber, F_OIDEQ,
+                 ObjectIdGetDatum(RelationGetRelid(relation)));
+     scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId, true, SnapshotNow, 1, &key);
+     while (HeapTupleIsValid(constraintTuple = systable_getnext(scan))) {
+         bool found = 0;
+         Form_pg_constraint parent_con = (Form_pg_constraint)(GETSTRUCT(constraintTuple));
+         if (parent_con->contype != CONSTRAINT_CHECK)
+             continue;
+
+         foreach(elem, constraints) {
+             HeapTuple child_contuple = lfirst(elem);
+             Form_pg_constraint            child_con = (Form_pg_constraint)(GETSTRUCT(child_contuple));
+
+             if (strcmp(NameStr(parent_con->conname),
+                        NameStr(child_con->conname)))
+                 continue;
+
+             if (parent_con->condeferrable != child_con->condeferrable ||
+                 parent_con->condeferred != child_con->condeferred ||
+                 parent_con->contypid != child_con->contypid ||
+                 strcmp(decompile_conbin(constraintTuple, tupleDesc),
+                        decompile_conbin(child_contuple, tupleDesc))
+                 )
+                 ereport(ERROR,
+                         (errcode(ERRCODE_DATATYPE_MISMATCH),
+                          errmsg("constraint definition for CHECK constraint \"%s\" doesn't match",
+                                 NameStr(parent_con->conname))));
+
+             found = 1;
+             break;
+         }
+         if (!found)
+             ereport(ERROR,
+                     (errcode(ERRCODE_DATATYPE_MISMATCH),
+                      errmsg("child table missing constraint matching parent table constraint \"%s\"",
+                             NameStr(parent_con->conname))));
+
+     }
+     systable_endscan(scan);
+     heap_close(catalogRelation, AccessShareLock);
+
+     catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
+     StoreCatalogInheritance1(RelationGetRelid(rel), RelationGetRelid(relation), inhseqno+1, catalogRelation);
+     heap_close(catalogRelation, RowExclusiveLock);
+
+     heap_close(relation, AccessShareLock);
+ }
+
+ static void
+ MergeAttributesIntoExisting(Relation rel, Relation relation)
+ {
+     Relation     attrdesc;
+     AttrNumber    parent_attno, child_attno;
+     TupleDesc    tupleDesc;
+     TupleConstr *constr;
+     HeapTuple     tuple;
+
+     child_attno = RelationGetNumberOfAttributes(rel);
+
+     tupleDesc = RelationGetDescr(relation);
+     constr = tupleDesc->constr;
+
+     for (parent_attno = 1; parent_attno <= tupleDesc->natts;
+          parent_attno++)
+     {
+         Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
+         char       *attributeName = NameStr(attribute->attname);
+
+         /* Ignore dropped columns in the parent. */
+         if (attribute->attisdropped)
+             continue;
+
+         /* Does it conflict with an existing column? */
+         attrdesc = heap_open(AttributeRelationId, RowExclusiveLock);
+
+         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), attributeName);
+         if (HeapTupleIsValid(tuple)) {
+             /*
+              * Yes, try to merge the two column definitions. They must
+              * have the same type and typmod.
+              */
+             Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
+             if (attribute->atttypid  != childatt->atttypid ||
+                 attribute->atttypmod != childatt->atttypmod ||
+                 (attribute->attnotnull && !childatt->attnotnull))
+                 ereport(ERROR,
+                         (errcode(ERRCODE_DATATYPE_MISMATCH),
+                          errmsg("child table \"%s\" has different type for column \"%s\"",
+                                 RelationGetRelationName(rel), NameStr(attribute->attname))));
+
+             childatt->attinhcount++;
+             simple_heap_update(attrdesc, &tuple->t_self, tuple);
+             CatalogUpdateIndexes(attrdesc, tuple); /* XXX strength reduce openindexes to outside loop? */
+             heap_freetuple(tuple);
+
+             /* We don't touch default at all since we're not making any other
+              * DDL changes to the child */
+
+         } else {
+             /*
+              * No, create a new inherited column
+              *
+              * Creating inherited columns in this case seems to be unpopular.
+              * In the common use case of partitioned tables it's a foot-gun.
+              */
+             ereport(ERROR,
+                     (errcode(ERRCODE_DATATYPE_MISMATCH),
+                      errmsg("child table missing column \"%s\"",
+                             NameStr(attribute->attname))));
+         }
+         heap_close(attrdesc, RowExclusiveLock);
+     }
+
+ }
+
+ static void
+ ATExecDropInherits(Relation rel, RangeVar *parent)
+ {
+
+
+     Relation    catalogRelation;
+     SysScanDesc scan;
+     ScanKeyData key[2];
+     HeapTuple    inheritsTuple, attributeTuple, depTuple;
+     Oid            inhparent;
+     Oid            dropparent;
+     int         found = 0;
+
+     /* Get the OID of parent -- if no schema is specified use the regular
+      * search path and only drop the one table that's found. We could try to be
+      * clever and look at each parent and see if it matches but that would be
+      * inconsistent with other operations I think. */
+
+     Assert(rel);
+     Assert(parent);
+
+     dropparent = RangeVarGetRelid(parent, false);
+
+     /* Search through the direct parents of rel looking for dropparent oid */
+
+     catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
+     ScanKeyInit(key,
+                 Anum_pg_inherits_inhrelid,
+                 BTEqualStrategyNumber, F_OIDEQ,
+                 ObjectIdGetDatum(RelationGetRelid(rel)));
+     scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId, true, SnapshotNow, 1, key);
+     while (!found && HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
+     {
+         inhparent = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhparent;
+         if (inhparent == dropparent) {
+             simple_heap_delete(catalogRelation, &inheritsTuple->t_self);
+             found = 1;
+         }
+     }
+     systable_endscan(scan);
+     heap_close(catalogRelation, RowExclusiveLock);
+
+
+     if (!found) {
+         /* would it be better to look up the actual schema of dropparent and
+          * make the error message explicitly name the qualified name it's
+          * trying to drop ?*/
+         if (parent->schemaname)
+             ereport(ERROR,
+                     (errcode(ERRCODE_UNDEFINED_TABLE),
+                      errmsg("relation \"%s.%s\" is not a parent of relation \"%s\"",
+                             parent->schemaname, parent->relname, RelationGetRelationName(rel))));
+         else
+             ereport(ERROR,
+                     (errcode(ERRCODE_UNDEFINED_TABLE),
+                      errmsg("relation \"%s\" is not a parent of relation \"%s\"",
+                             parent->relname, RelationGetRelationName(rel))));
+     }
+
+     /* Search through columns looking for matching columns from parent table */
+
+     catalogRelation = heap_open(AttributeRelationId, RowExclusiveLock);
+     ScanKeyInit(key,
+                 Anum_pg_attribute_attrelid,
+                 BTEqualStrategyNumber, F_OIDEQ,
+                 ObjectIdGetDatum(RelationGetRelid(rel)));
+     scan = systable_beginscan(catalogRelation, AttributeRelidNumIndexId, true, SnapshotNow, 1, key);
+     while (HeapTupleIsValid(attributeTuple = systable_getnext(scan))) {
+         Form_pg_attribute att = ((Form_pg_attribute)GETSTRUCT(attributeTuple));
+         /* Not an inherited column at all
+          * (do NOT use islocal for this test--it can be true for inherited columns)
+          */
+         if (att->attinhcount == 0)
+             continue;
+         if (att->attisdropped) /* XXX Is this right? */
+             continue;
+         if (SearchSysCacheExistsAttName(dropparent, NameStr(att->attname))) {
+             /* Decrement inhcount and possibly set islocal to 1 */
+             HeapTuple copyTuple = heap_copytuple(attributeTuple);
+             Form_pg_attribute copy_att = ((Form_pg_attribute)GETSTRUCT(copyTuple));
+
+             copy_att->attinhcount--;
+             if (copy_att->attinhcount == 0)
+                 copy_att->attislocal = 1;
+
+             simple_heap_update(catalogRelation, ©Tuple->t_self, copyTuple);
+             /* XXX "Avoid using it for multiple tuples, since opening the
+              * indexes and building the index info structures is moderately
+              * expensive." Perhaps this can be moved outside the loop or else
+              * at least the CatalogOpenIndexes/CatalogCloseIndexes moved
+              * outside the loop but when I try that it seg faults?!*/
+             CatalogUpdateIndexes(catalogRelation, copyTuple);
+             heap_freetuple(copyTuple);
+         }
+     }
+     systable_endscan(scan);
+     heap_close(catalogRelation, RowExclusiveLock);
+
+
+     /* Drop the dependency
+      *
+      * There's no convenient way to do this, so go trawling through pg_depend
+      */
+
+     catalogRelation = heap_open(DependRelationId, RowExclusiveLock);
+
+     ScanKeyInit(&key[0],
+                 Anum_pg_depend_classid,
+                 BTEqualStrategyNumber, F_OIDEQ,
+                 RelationRelationId);
+     ScanKeyInit(&key[1],
+                 Anum_pg_depend_objid,
+                 BTEqualStrategyNumber, F_OIDEQ,
+                 ObjectIdGetDatum(RelationGetRelid(rel)));
+
+     scan = systable_beginscan(catalogRelation, DependDependerIndexId, true,
+                               SnapshotNow, 2, key);
+
+     while (HeapTupleIsValid(depTuple = systable_getnext(scan))) {
+         Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(depTuple);
+
+         if (dep->refclassid == RelationRelationId &&
+             dep->refobjid == dropparent &&
+             dep->deptype == DEPENDENCY_NORMAL) {
+
+             /* Only delete a single dependency -- there shouldn't be more but just in case... */
+             simple_heap_delete(catalogRelation, &depTuple->t_self);
+
+             break;
+         }
+     }
+     systable_endscan(scan);
+
+     heap_close(catalogRelation, RowExclusiveLock);
+ }
+
+
+
  /*
   * ALTER TABLE CREATE TOAST TABLE
   *
Index: src/backend/nodes/copyfuncs.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v
retrieving revision 1.335
diff -u -p -c -r1.335 copyfuncs.c
cvs diff: conflicting specifications of output style
*** src/backend/nodes/copyfuncs.c    30 Apr 2006 18:30:38 -0000    1.335
--- src/backend/nodes/copyfuncs.c    12 Jun 2006 21:30:54 -0000
*************** _copyAlterTableCmd(AlterTableCmd *from)
*** 1799,1804 ****
--- 1799,1805 ----
      COPY_SCALAR_FIELD(subtype);
      COPY_STRING_FIELD(name);
      COPY_NODE_FIELD(def);
+     COPY_NODE_FIELD(parent);
      COPY_NODE_FIELD(transform);
      COPY_SCALAR_FIELD(behavior);

Index: src/backend/parser/gram.y
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/parser/gram.y,v
retrieving revision 2.545
diff -u -p -c -r2.545 gram.y
cvs diff: conflicting specifications of output style
*** src/backend/parser/gram.y    27 May 2006 17:38:45 -0000    2.545
--- src/backend/parser/gram.y    12 Jun 2006 21:30:57 -0000
*************** alter_table_cmd:
*** 1514,1519 ****
--- 1514,1535 ----
                      n->subtype = AT_DisableTrigUser;
                      $$ = (Node *)n;
                  }
+             /* ALTER TABLE <name> ALTER INHERITS ADD <parent> */
+             | INHERIT qualified_name
+                 {
+                     AlterTableCmd *n = makeNode(AlterTableCmd);
+                     n->subtype = AT_AddInherits;
+                     n->parent = $2;
+                     $$ = (Node *)n;
+                 }
+             /* ALTER TABLE <name> alter INHERITS DROP <parent> */
+             | NO INHERIT qualified_name
+                 {
+                     AlterTableCmd *n = makeNode(AlterTableCmd);
+                     n->subtype = AT_DropInherits;
+                     n->parent = $3;
+                     $$ = (Node *)n;
+                 }
              | alter_rel_cmd
                  {
                      $$ = $1;
Index: src/include/nodes/parsenodes.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/include/nodes/parsenodes.h,v
retrieving revision 1.310
diff -u -p -c -r1.310 parsenodes.h
cvs diff: conflicting specifications of output style
*** src/include/nodes/parsenodes.h    30 Apr 2006 18:30:40 -0000    1.310
--- src/include/nodes/parsenodes.h    12 Jun 2006 21:31:06 -0000
*************** typedef enum AlterTableType
*** 874,880 ****
      AT_EnableTrigAll,            /* ENABLE TRIGGER ALL */
      AT_DisableTrigAll,            /* DISABLE TRIGGER ALL */
      AT_EnableTrigUser,            /* ENABLE TRIGGER USER */
!     AT_DisableTrigUser            /* DISABLE TRIGGER USER */
  } AlterTableType;

  typedef struct AlterTableCmd    /* one subcommand of an ALTER TABLE */
--- 874,882 ----
      AT_EnableTrigAll,            /* ENABLE TRIGGER ALL */
      AT_DisableTrigAll,            /* DISABLE TRIGGER ALL */
      AT_EnableTrigUser,            /* ENABLE TRIGGER USER */
!     AT_DisableTrigUser,            /* DISABLE TRIGGER USER */
!     AT_AddInherits,                /* ADD INHERITS parent */
!     AT_DropInherits                /* DROP INHERITS parent */
  } AlterTableType;

  typedef struct AlterTableCmd    /* one subcommand of an ALTER TABLE */
*************** typedef struct AlterTableCmd    /* one subc
*** 883,888 ****
--- 885,891 ----
      AlterTableType subtype;        /* Type of table alteration to apply */
      char       *name;            /* column, constraint, or trigger to act on,
                                   * or new owner or tablespace */
+     RangeVar   *parent;            /* Parent table for add/drop inherits */
      Node       *def;            /* definition of new column, column type,
                                   * index, or constraint */
      Node       *transform;        /* transformation expr for ALTER TYPE */
Index: src/test/regress/expected/alter_table.out
===================================================================
RCS file: /projects/cvsroot/pgsql/src/test/regress/expected/alter_table.out,v
retrieving revision 1.94
diff -u -p -c -r1.94 alter_table.out
cvs diff: conflicting specifications of output style
*** src/test/regress/expected/alter_table.out    23 Mar 2006 00:19:30 -0000    1.94
--- src/test/regress/expected/alter_table.out    12 Jun 2006 21:31:12 -0000
*************** insert into atacc3 (test2) values (3);
*** 306,311 ****
--- 306,361 ----
  drop table atacc3;
  drop table atacc2;
  drop table atacc1;
+ -- same things with one created with INHERIT
+ create table atacc1 (test int);
+ create table atacc2 (test2 int);
+ create table atacc3 (test3 int) inherits (atacc1, atacc2);
+ alter table atacc3 no inherit atacc2;
+ -- fail
+ alter table atacc3 no inherit atacc2;
+ ERROR:  relation "atacc2" is not a parent of relation "atacc3"
+ -- make sure it really isn't a child
+ insert into atacc3 (test2) values (3);
+ select test2 from atacc2;
+  test2
+ -------
+ (0 rows)
+
+ -- fail due to missing constraint
+ alter table atacc2 add constraint foo check (test2>0);
+ alter table atacc3 inherit atacc2;
+ ERROR:  child table missing constraint matching parent table constraint "foo"
+ -- fail due to missing column
+ alter table atacc3 rename test2 to testx;
+ alter table atacc3 inherit atacc2;
+ ERROR:  child table missing column "test2"
+ -- fail due to mismatched data type
+ alter table atacc3 add test2 bool;
+ alter table atacc3 add inherit atacc2;
+ alter table atacc3 drop test2;
+ -- succeed
+ alter table atacc3 add test2 int;
+ update atacc3 set test2 = 4 where test2 is null;
+ alter table atacc3 add constraint foo check (test2>0);
+ alter table atacc3 inherit atacc2;
+ -- fail due to duplicates and circular inheritance
+ alter table atacc3 inherit atacc2;
+ ERROR:  inherited relation "atacc2" duplicated
+ alter table atacc2 inherit atacc3;
+ ERROR:  circular inheritance structure found, "atacc3" is already a child of "atacc2"
+ alter table atacc2 inherit atacc2;
+ ERROR:  circular inheritance structure found, "atacc2" is already a child of "atacc2"
+ -- test that we really are a child now (should see 4 not 3 and cascade should go through)
+ select test2 from atacc2;
+  test2
+ -------
+      4
+ (1 row)
+
+ drop table atacc2 cascade;
+ NOTICE:  drop cascades to table atacc3
+ NOTICE:  drop cascades to constraint foo on table atacc3
+ drop table atacc1;
  -- let's try only to add only to the parent
  create table atacc1 (test int);
  create table atacc2 (test2 int);
Index: src/test/regress/sql/alter_table.sql
===================================================================
RCS file: /projects/cvsroot/pgsql/src/test/regress/sql/alter_table.sql,v
retrieving revision 1.54
diff -u -p -c -r1.54 alter_table.sql
cvs diff: conflicting specifications of output style
*** src/test/regress/sql/alter_table.sql    12 Feb 2006 19:11:01 -0000    1.54
--- src/test/regress/sql/alter_table.sql    12 Jun 2006 21:31:12 -0000
*************** drop table atacc3;
*** 336,341 ****
--- 336,375 ----
  drop table atacc2;
  drop table atacc1;

+ -- same things with one created with INHERIT
+ create table atacc1 (test int);
+ create table atacc2 (test2 int);
+ create table atacc3 (test3 int) inherits (atacc1, atacc2);
+ alter table atacc3 no inherit atacc2;
+ -- fail
+ alter table atacc3 no inherit atacc2;
+ -- make sure it really isn't a child
+ insert into atacc3 (test2) values (3);
+ select test2 from atacc2;
+ -- fail due to missing constraint
+ alter table atacc2 add constraint foo check (test2>0);
+ alter table atacc3 inherit atacc2;
+ -- fail due to missing column
+ alter table atacc3 rename test2 to testx;
+ alter table atacc3 inherit atacc2;
+ -- fail due to mismatched data type
+ alter table atacc3 add test2 bool;
+ alter table atacc3 add inherit atacc2;
+ alter table atacc3 drop test2;
+ -- succeed
+ alter table atacc3 add test2 int;
+ update atacc3 set test2 = 4 where test2 is null;
+ alter table atacc3 add constraint foo check (test2>0);
+ alter table atacc3 inherit atacc2;
+ -- fail due to duplicates and circular inheritance
+ alter table atacc3 inherit atacc2;
+ alter table atacc2 inherit atacc3;
+ alter table atacc2 inherit atacc2;
+ -- test that we really are a child now (should see 4 not 3 and cascade should go through)
+ select test2 from atacc2;
+ drop table atacc2 cascade;
+ drop table atacc1;
+
  -- let's try only to add only to the parent

  create table atacc1 (test int);


--
greg

pgsql-patches by date:

Previous
From: Alvaro Herrera
Date:
Subject: Re: Non-transactional pg_class, try 2
Next
From: Simon Riggs
Date:
Subject: Re: Non-transactional pg_class, try 2