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synced 2024-12-09 08:10:09 +08:00
Refactor validation of new partitions a little bit.
Move some logic that is currently in ATExecAttachPartition to separate functions to facilitate future code reuse. Ashutosh Bapat and Jeevan Ladhe Discussion: http://postgr.es/m/CA+Tgmobbnamyvii0pRdg9pp_jLHSUvq7u5SiRrVV0tEFFU58Tg@mail.gmail.com
This commit is contained in:
Robert Haas
parent
1e56883a52
commit
ecfe59e50f
@ -473,6 +473,11 @@ static void CreateInheritance(Relation child_rel, Relation parent_rel);
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static void RemoveInheritance(Relation child_rel, Relation parent_rel);
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static ObjectAddress ATExecAttachPartition(List **wqueue, Relation rel,
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PartitionCmd *cmd);
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static bool PartConstraintImpliedByRelConstraint(Relation scanrel,
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List *partConstraint);
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static void ValidatePartitionConstraints(List **wqueue, Relation scanrel,
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List *scanrel_children,
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List *partConstraint);
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static ObjectAddress ATExecDetachPartition(Relation rel, RangeVar *name);
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@ -13424,6 +13429,169 @@ ComputePartitionAttrs(Relation rel, List *partParams, AttrNumber *partattrs,
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}
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}
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/*
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* PartConstraintImpliedByRelConstraint
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* Does scanrel's existing constraints imply the partition constraint?
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*
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* Existing constraints includes its check constraints and column-level
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* NOT NULL constraints and partConstraint describes the partition constraint.
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*/
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static bool
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PartConstraintImpliedByRelConstraint(Relation scanrel,
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List *partConstraint)
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{
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List *existConstraint = NIL;
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TupleConstr *constr = RelationGetDescr(scanrel)->constr;
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int num_check,
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i;
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if (constr && constr->has_not_null)
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{
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int natts = scanrel->rd_att->natts;
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for (i = 1; i <= natts; i++)
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{
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Form_pg_attribute att = scanrel->rd_att->attrs[i - 1];
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if (att->attnotnull && !att->attisdropped)
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{
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NullTest *ntest = makeNode(NullTest);
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ntest->arg = (Expr *) makeVar(1,
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i,
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att->atttypid,
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att->atttypmod,
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att->attcollation,
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0);
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ntest->nulltesttype = IS_NOT_NULL;
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/*
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* argisrow=false is correct even for a composite column,
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* because attnotnull does not represent a SQL-spec IS NOT
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* NULL test in such a case, just IS DISTINCT FROM NULL.
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*/
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ntest->argisrow = false;
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ntest->location = -1;
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existConstraint = lappend(existConstraint, ntest);
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}
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}
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}
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num_check = (constr != NULL) ? constr->num_check : 0;
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for (i = 0; i < num_check; i++)
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{
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Node *cexpr;
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/*
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* If this constraint hasn't been fully validated yet, we must ignore
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* it here.
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*/
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if (!constr->check[i].ccvalid)
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continue;
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cexpr = stringToNode(constr->check[i].ccbin);
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/*
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* Run each expression through const-simplification and
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* canonicalization. It is necessary, because we will be comparing it
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* to similarly-processed partition constraint expressions, and may
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* fail to detect valid matches without this.
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*/
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cexpr = eval_const_expressions(NULL, cexpr);
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cexpr = (Node *) canonicalize_qual((Expr *) cexpr);
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existConstraint = list_concat(existConstraint,
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make_ands_implicit((Expr *) cexpr));
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}
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if (existConstraint != NIL)
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existConstraint = list_make1(make_ands_explicit(existConstraint));
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/* And away we go ... */
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return predicate_implied_by(partConstraint, existConstraint, true);
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}
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/*
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* ValidatePartitionConstraints
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*
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* Check whether all rows in the given table obey the given partition
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* constraint; if so, it can be attached as a partition. We do this by
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* scanning the table (or all of its leaf partitions) row by row, except when
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* the existing constraints are sufficient to prove that the new partitioning
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* constraint must already hold.
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*/
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static void
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ValidatePartitionConstraints(List **wqueue, Relation scanrel,
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List *scanrel_children,
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List *partConstraint)
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{
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bool found_whole_row;
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ListCell *lc;
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if (partConstraint == NIL)
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return;
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/*
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* Based on the table's existing constraints, determine if we can skip
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* scanning the table to validate the partition constraint.
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*/
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if (PartConstraintImpliedByRelConstraint(scanrel, partConstraint))
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{
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ereport(INFO,
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(errmsg("partition constraint for table \"%s\" is implied by existing constraints",
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RelationGetRelationName(scanrel))));
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return;
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}
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/* Constraints proved insufficient, so we need to scan the table. */
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foreach(lc, scanrel_children)
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{
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AlteredTableInfo *tab;
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Oid part_relid = lfirst_oid(lc);
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Relation part_rel;
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List *my_partconstr = partConstraint;
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/* Lock already taken */
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if (part_relid != RelationGetRelid(scanrel))
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part_rel = heap_open(part_relid, NoLock);
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else
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part_rel = scanrel;
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/*
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* Skip if the partition is itself a partitioned table. We can only
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* ever scan RELKIND_RELATION relations.
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*/
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if (part_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
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{
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if (part_rel != scanrel)
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heap_close(part_rel, NoLock);
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continue;
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}
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if (part_rel != scanrel)
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{
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/*
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* Adjust the constraint for scanrel so that it matches this
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* partition's attribute numbers.
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*/
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my_partconstr = map_partition_varattnos(my_partconstr, 1,
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part_rel, scanrel,
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&found_whole_row);
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/* There can never be a whole-row reference here */
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if (found_whole_row)
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elog(ERROR, "unexpected whole-row reference found in partition key");
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}
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/* Grab a work queue entry. */
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tab = ATGetQueueEntry(wqueue, part_rel);
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tab->partition_constraint = (Expr *) linitial(my_partconstr);
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/* keep our lock until commit */
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if (part_rel != scanrel)
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heap_close(part_rel, NoLock);
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}
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}
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/*
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* ALTER TABLE <name> ATTACH PARTITION <partition-name> FOR VALUES
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*
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@ -13435,15 +13603,12 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
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Relation attachrel,
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catalog;
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List *attachrel_children;
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TupleConstr *attachrel_constr;
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List *partConstraint,
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*existConstraint;
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List *partConstraint;
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SysScanDesc scan;
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ScanKeyData skey;
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AttrNumber attno;
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int natts;
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TupleDesc tupleDesc;
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bool skip_validate = false;
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ObjectAddress address;
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const char *trigger_name;
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bool found_whole_row;
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@ -13637,148 +13802,9 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
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if (found_whole_row)
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elog(ERROR, "unexpected whole-row reference found in partition key");
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/*
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* Check if we can do away with having to scan the table being attached to
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* validate the partition constraint, by *proving* that the existing
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* constraints of the table *imply* the partition predicate. We include
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* the table's check constraints and NOT NULL constraints in the list of
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* clauses passed to predicate_implied_by().
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*
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* There is a case in which we cannot rely on just the result of the
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* proof.
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*/
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attachrel_constr = tupleDesc->constr;
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existConstraint = NIL;
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if (attachrel_constr != NULL)
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{
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int num_check = attachrel_constr->num_check;
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int i;
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if (attachrel_constr->has_not_null)
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{
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int natts = attachrel->rd_att->natts;
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for (i = 1; i <= natts; i++)
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{
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Form_pg_attribute att = attachrel->rd_att->attrs[i - 1];
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if (att->attnotnull && !att->attisdropped)
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{
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NullTest *ntest = makeNode(NullTest);
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ntest->arg = (Expr *) makeVar(1,
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i,
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att->atttypid,
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att->atttypmod,
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att->attcollation,
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0);
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ntest->nulltesttype = IS_NOT_NULL;
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/*
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* argisrow=false is correct even for a composite column,
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* because attnotnull does not represent a SQL-spec IS NOT
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* NULL test in such a case, just IS DISTINCT FROM NULL.
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*/
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ntest->argisrow = false;
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ntest->location = -1;
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existConstraint = lappend(existConstraint, ntest);
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}
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}
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}
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for (i = 0; i < num_check; i++)
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{
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Node *cexpr;
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/*
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* If this constraint hasn't been fully validated yet, we must
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* ignore it here.
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*/
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if (!attachrel_constr->check[i].ccvalid)
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continue;
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cexpr = stringToNode(attachrel_constr->check[i].ccbin);
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/*
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* Run each expression through const-simplification and
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* canonicalization. It is necessary, because we will be
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* comparing it to similarly-processed qual clauses, and may fail
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* to detect valid matches without this.
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*/
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cexpr = eval_const_expressions(NULL, cexpr);
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cexpr = (Node *) canonicalize_qual((Expr *) cexpr);
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existConstraint = list_concat(existConstraint,
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make_ands_implicit((Expr *) cexpr));
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}
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existConstraint = list_make1(make_ands_explicit(existConstraint));
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/* And away we go ... */
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if (predicate_implied_by(partConstraint, existConstraint, true))
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skip_validate = true;
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}
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if (skip_validate)
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{
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/* No need to scan the table after all. */
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ereport(INFO,
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(errmsg("partition constraint for table \"%s\" is implied by existing constraints",
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RelationGetRelationName(attachrel))));
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}
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else
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{
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/* Constraints proved insufficient, so we need to scan the table. */
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ListCell *lc;
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foreach(lc, attachrel_children)
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{
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AlteredTableInfo *tab;
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Oid part_relid = lfirst_oid(lc);
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Relation part_rel;
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List *my_partconstr = partConstraint;
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/* Lock already taken */
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if (part_relid != RelationGetRelid(attachrel))
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part_rel = heap_open(part_relid, NoLock);
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else
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part_rel = attachrel;
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/*
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* Skip if the partition is itself a partitioned table. We can
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* only ever scan RELKIND_RELATION relations.
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*/
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if (part_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
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{
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if (part_rel != attachrel)
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heap_close(part_rel, NoLock);
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continue;
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}
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if (part_rel != attachrel)
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{
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/*
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* Adjust the constraint that we constructed above for
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* attachRel so that it matches this partition's attribute
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* numbers.
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*/
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my_partconstr = map_partition_varattnos(my_partconstr, 1,
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part_rel, attachrel,
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&found_whole_row);
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/* There can never be a whole-row reference here */
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if (found_whole_row)
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elog(ERROR, "unexpected whole-row reference found in partition key");
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}
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/* Grab a work queue entry. */
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tab = ATGetQueueEntry(wqueue, part_rel);
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tab->partition_constraint = (Expr *) linitial(my_partconstr);
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/* keep our lock until commit */
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if (part_rel != attachrel)
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heap_close(part_rel, NoLock);
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}
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}
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/* Validate partition constraints against the table being attached. */
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ValidatePartitionConstraints(wqueue, attachrel, attachrel_children,
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partConstraint);
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ObjectAddressSet(address, RelationRelationId, RelationGetRelid(attachrel));
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