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Add support for not-null constraints on virtual generated columns

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This was left out of the original patch for virtual generated columns
(commit 83ea6c5402).

This just involves a bit of extra work in the executor to expand the
generation expressions and run a "IS NOT NULL" test against them.

There is also a bit of work to make sure that not-null constraints are
checked during a table rewrite.

Author: jian he <jian.universality@gmail.com>
Reviewed-by: Xuneng Zhou <xunengzhou@gmail.com>
Reviewed-by: Navneet Kumar <thanit3111@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/CACJufxHArQysbDkWFmvK+D1TPHQWWTxWN15cMuUaTYX3xhQXgg@mail.gmail.com
This commit is contained in:
Peter Eisentraut
2025-03-28 13:53:37 +01:00
parent 747ddd38cb
commit cdc168ad4b
9 changed files with 363 additions and 122 deletions
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222
src/backend/executor/execMain.c
View File

@ -92,6 +92,9 @@ static bool ExecCheckPermissionsModified(Oid relOid, Oid userid,
AclMode requiredPerms);
static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt);
static void EvalPlanQualStart(EPQState *epqstate, Plan *planTree);
static void ReportNotNullViolationError(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
EState *estate, int attnum);
/* end of local decls */
@ -1372,6 +1375,7 @@ InitResultRelInfo(ResultRelInfo *resultRelInfo,
resultRelInfo->ri_FdwState = NULL;
resultRelInfo->ri_usesFdwDirectModify = false;
resultRelInfo->ri_CheckConstraintExprs = NULL;
resultRelInfo->ri_GenVirtualNotNullConstraintExprs = NULL;
resultRelInfo->ri_GeneratedExprsI = NULL;
resultRelInfo->ri_GeneratedExprsU = NULL;
resultRelInfo->ri_projectReturning = NULL;
@ -1842,7 +1846,7 @@ ExecutePlan(QueryDesc *queryDesc,
/*
* ExecRelCheck --- check that tuple meets constraints for result relation
* ExecRelCheck --- check that tuple meets check constraints for result relation
*
* Returns NULL if OK, else name of failed check constraint
*/
@ -2056,11 +2060,15 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
TupleDesc tupdesc = RelationGetDescr(rel);
TupleConstr *constr = tupdesc->constr;
Bitmapset *modifiedCols;
List *notnull_virtual_attrs = NIL;
Assert(constr); /* we should not be called otherwise */
/*
* Verify not-null constraints.
*
* Not-null constraints on virtual generated columns are collected and
* checked separately below.
*/
if (constr->has_not_null)
{
@ -2068,61 +2076,26 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
{
Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
if (att->attnotnull && slot_attisnull(slot, attnum))
{
char *val_desc;
Relation orig_rel = rel;
TupleDesc orig_tupdesc = RelationGetDescr(rel);
/*
* If the tuple has been routed, it's been converted to the
* partition's rowtype, which might differ from the root
* table's. We must convert it back to the root table's
* rowtype so that val_desc shown error message matches the
* input tuple.
*/
if (resultRelInfo->ri_RootResultRelInfo)
{
ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo;
AttrMap *map;
tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
/* a reverse map */
map = build_attrmap_by_name_if_req(orig_tupdesc,
tupdesc,
false);
/*
* Partition-specific slot's tupdesc can't be changed, so
* allocate a new one.
*/
if (map != NULL)
slot = execute_attr_map_slot(map, slot,
MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
ExecGetUpdatedCols(rootrel, estate));
rel = rootrel->ri_RelationDesc;
}
else
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
slot,
tupdesc,
modifiedCols,
64);
ereport(ERROR,
errcode(ERRCODE_NOT_NULL_VIOLATION),
errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint",
NameStr(att->attname),
RelationGetRelationName(orig_rel)),
val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
errtablecol(orig_rel, attnum));
}
if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
notnull_virtual_attrs = lappend_int(notnull_virtual_attrs, attnum);
else if (att->attnotnull && slot_attisnull(slot, attnum))
ReportNotNullViolationError(resultRelInfo, slot, estate, attnum);
}
}
/*
* Verify not-null constraints on virtual generated column, if any.
*/
if (notnull_virtual_attrs)
{
AttrNumber attnum;
attnum = ExecRelGenVirtualNotNull(resultRelInfo, slot, estate,
notnull_virtual_attrs);
if (attnum != InvalidAttrNumber)
ReportNotNullViolationError(resultRelInfo, slot, estate, attnum);
}
/*
* Verify check constraints.
*/
@ -2135,7 +2108,12 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
char *val_desc;
Relation orig_rel = rel;
/* See the comment above. */
/*
* If the tuple has been routed, it's been converted to the
* partition's rowtype, which might differ from the root table's.
* We must convert it back to the root table's rowtype so that
* val_desc shown error message matches the input tuple.
*/
if (resultRelInfo->ri_RootResultRelInfo)
{
ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo;
@ -2177,6 +2155,142 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
}
}
/*
* Verify not-null constraints on virtual generated columns of the given
* tuple slot.
*
* Return value of InvalidAttrNumber means all not-null constraints on virtual
* generated columns are satisfied. A return value > 0 means a not-null
* violation happened for that attribute.
*
* notnull_virtual_attrs is the list of the attnums of virtual generated column with
* not-null constraints.
*/
AttrNumber
ExecRelGenVirtualNotNull(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
EState *estate, List *notnull_virtual_attrs)
{
Relation rel = resultRelInfo->ri_RelationDesc;
ExprContext *econtext;
MemoryContext oldContext;
/*
* We implement this by building a NullTest node for each virtual
* generated column, which we cache in resultRelInfo, and running those
* through ExecCheck().
*/
if (resultRelInfo->ri_GenVirtualNotNullConstraintExprs == NULL)
{
oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
resultRelInfo->ri_GenVirtualNotNullConstraintExprs =
palloc0_array(ExprState *, list_length(notnull_virtual_attrs));
foreach_int(attnum, notnull_virtual_attrs)
{
int i = foreach_current_index(attnum);
NullTest *nnulltest;
/* "generated_expression IS NOT NULL" check. */
nnulltest = makeNode(NullTest);
nnulltest->arg = (Expr *) build_generation_expression(rel, attnum);
nnulltest->nulltesttype = IS_NOT_NULL;
nnulltest->argisrow = false;
nnulltest->location = -1;
resultRelInfo->ri_GenVirtualNotNullConstraintExprs[i] =
ExecPrepareExpr((Expr *) nnulltest, estate);
}
MemoryContextSwitchTo(oldContext);
}
/*
* We will use the EState's per-tuple context for evaluating virtual
* generated column not null constraint expressions (creating it if it's
* not already there).
*/
econtext = GetPerTupleExprContext(estate);
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;
/* And evaluate the check constraints for virtual generated column */
foreach_int(attnum, notnull_virtual_attrs)
{
int i = foreach_current_index(attnum);
ExprState *exprstate = resultRelInfo->ri_GenVirtualNotNullConstraintExprs[i];
Assert(exprstate != NULL);
if (!ExecCheck(exprstate, econtext))
return attnum;
}
/* InvalidAttrNumber result means no error */
return InvalidAttrNumber;
}
/*
* Report a violation of a not-null constraint that was already detected.
*/
static void
ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
EState *estate, int attnum)
{
Bitmapset *modifiedCols;
char *val_desc;
Relation rel = resultRelInfo->ri_RelationDesc;
Relation orig_rel = rel;
TupleDesc tupdesc = RelationGetDescr(rel);
TupleDesc orig_tupdesc = RelationGetDescr(rel);
Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1);
Assert(attnum > 0);
/*
* If the tuple has been routed, it's been converted to the partition's
* rowtype, which might differ from the root table's. We must convert it
* back to the root table's rowtype so that val_desc shown error message
* matches the input tuple.
*/
if (resultRelInfo->ri_RootResultRelInfo)
{
ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo;
AttrMap *map;
tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
/* a reverse map */
map = build_attrmap_by_name_if_req(orig_tupdesc,
tupdesc,
false);
/*
* Partition-specific slot's tupdesc can't be changed, so allocate a
* new one.
*/
if (map != NULL)
slot = execute_attr_map_slot(map, slot,
MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
ExecGetUpdatedCols(rootrel, estate));
rel = rootrel->ri_RelationDesc;
}
else
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
slot,
tupdesc,
modifiedCols,
64);
ereport(ERROR,
errcode(ERRCODE_NOT_NULL_VIOLATION),
errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint",
NameStr(att->attname),
RelationGetRelationName(orig_rel)),
val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
errtablecol(orig_rel, attnum));
}
/*
* ExecWithCheckOptions -- check that tuple satisfies any WITH CHECK OPTIONs
* of the specified kind.