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Move inheritance expansion code into its own file
This commit moves expand_inherited_tables and underlings from
optimizer/prep/prepunionc.c to optimizer/utils/inherit.c.
Also, all of the AppendRelInfo-based expression manipulation routines
are moved to optimizer/utils/appendinfo.c.
No functional code changes. One exception is the introduction of
make_append_rel_info, but that's still just moving around code.
Also, stop including <limits.h> in prepunion.c, which no longer needs
it since 3fc6e2d7f5. I (Álvaro) noticed this because Amit was copying
that to inherit.c, which likewise doesn't need it.
Author: Amit Langote
Discussion: https://postgr.es/m/3be67028-a00a-502c-199a-da00eec8fb6e@lab.ntt.co.jp
This commit is contained in:
Alvaro Herrera
439
src/backend/optimizer/util/inherit.c
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439
src/backend/optimizer/util/inherit.c
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@ -0,0 +1,439 @@
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/*-------------------------------------------------------------------------
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*
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* inherit.c
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* Routines to process child relations in inheritance trees
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*
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* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/backend/optimizer/path/inherit.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/heapam.h"
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#include "catalog/partition.h"
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#include "catalog/pg_inherits.h"
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#include "miscadmin.h"
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#include "optimizer/appendinfo.h"
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#include "optimizer/inherit.h"
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#include "optimizer/planner.h"
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#include "optimizer/prep.h"
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#include "utils/rel.h"
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static void expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte,
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Index rti);
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static void expand_partitioned_rtentry(PlannerInfo *root,
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RangeTblEntry *parentrte,
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Index parentRTindex, Relation parentrel,
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PlanRowMark *top_parentrc, LOCKMODE lockmode,
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List **appinfos);
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static void expand_single_inheritance_child(PlannerInfo *root,
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RangeTblEntry *parentrte,
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Index parentRTindex, Relation parentrel,
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PlanRowMark *top_parentrc, Relation childrel,
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List **appinfos, RangeTblEntry **childrte_p,
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Index *childRTindex_p);
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/*
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* expand_inherited_tables
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* Expand each rangetable entry that represents an inheritance set
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* into an "append relation". At the conclusion of this process,
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* the "inh" flag is set in all and only those RTEs that are append
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* relation parents.
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*/
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void
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expand_inherited_tables(PlannerInfo *root)
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{
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Index nrtes;
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Index rti;
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ListCell *rl;
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/*
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* expand_inherited_rtentry may add RTEs to parse->rtable. The function is
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* expected to recursively handle any RTEs that it creates with inh=true.
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* So just scan as far as the original end of the rtable list.
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*/
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nrtes = list_length(root->parse->rtable);
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rl = list_head(root->parse->rtable);
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for (rti = 1; rti <= nrtes; rti++)
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{
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RangeTblEntry *rte = (RangeTblEntry *) lfirst(rl);
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expand_inherited_rtentry(root, rte, rti);
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rl = lnext(rl);
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}
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}
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/*
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* expand_inherited_rtentry
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* Check whether a rangetable entry represents an inheritance set.
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* If so, add entries for all the child tables to the query's
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* rangetable, and build AppendRelInfo nodes for all the child tables
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* and add them to root->append_rel_list. If not, clear the entry's
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* "inh" flag to prevent later code from looking for AppendRelInfos.
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*
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* Note that the original RTE is considered to represent the whole
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* inheritance set. The first of the generated RTEs is an RTE for the same
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* table, but with inh = false, to represent the parent table in its role
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* as a simple member of the inheritance set.
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*
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* A childless table is never considered to be an inheritance set. For
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* regular inheritance, a parent RTE must always have at least two associated
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* AppendRelInfos: one corresponding to the parent table as a simple member of
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* inheritance set and one or more corresponding to the actual children.
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* Since a partitioned table is not scanned, it might have only one associated
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* AppendRelInfo.
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*/
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static void
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expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
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{
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Oid parentOID;
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PlanRowMark *oldrc;
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Relation oldrelation;
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LOCKMODE lockmode;
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List *inhOIDs;
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ListCell *l;
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/* Does RT entry allow inheritance? */
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if (!rte->inh)
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return;
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/* Ignore any already-expanded UNION ALL nodes */
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if (rte->rtekind != RTE_RELATION)
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{
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Assert(rte->rtekind == RTE_SUBQUERY);
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return;
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}
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/* Fast path for common case of childless table */
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parentOID = rte->relid;
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if (!has_subclass(parentOID))
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{
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/* Clear flag before returning */
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rte->inh = false;
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return;
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}
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/*
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* The rewriter should already have obtained an appropriate lock on each
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* relation named in the query. However, for each child relation we add
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* to the query, we must obtain an appropriate lock, because this will be
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* the first use of those relations in the parse/rewrite/plan pipeline.
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* Child rels should use the same lockmode as their parent.
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*/
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lockmode = rte->rellockmode;
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/* Scan for all members of inheritance set, acquire needed locks */
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inhOIDs = find_all_inheritors(parentOID, lockmode, NULL);
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/*
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* Check that there's at least one descendant, else treat as no-child
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* case. This could happen despite above has_subclass() check, if table
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* once had a child but no longer does.
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*/
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if (list_length(inhOIDs) < 2)
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{
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/* Clear flag before returning */
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rte->inh = false;
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return;
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}
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/*
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* If parent relation is selected FOR UPDATE/SHARE, we need to mark its
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* PlanRowMark as isParent = true, and generate a new PlanRowMark for each
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* child.
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*/
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oldrc = get_plan_rowmark(root->rowMarks, rti);
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if (oldrc)
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oldrc->isParent = true;
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/*
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* Must open the parent relation to examine its tupdesc. We need not lock
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* it; we assume the rewriter already did.
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*/
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oldrelation = heap_open(parentOID, NoLock);
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/* Scan the inheritance set and expand it */
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if (RelationGetPartitionDesc(oldrelation) != NULL)
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{
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Assert(rte->relkind == RELKIND_PARTITIONED_TABLE);
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/*
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* If this table has partitions, recursively expand them in the order
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* in which they appear in the PartitionDesc. While at it, also
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* extract the partition key columns of all the partitioned tables.
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*/
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expand_partitioned_rtentry(root, rte, rti, oldrelation, oldrc,
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lockmode, &root->append_rel_list);
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}
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else
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{
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List *appinfos = NIL;
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RangeTblEntry *childrte;
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Index childRTindex;
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/*
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* This table has no partitions. Expand any plain inheritance
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* children in the order the OIDs were returned by
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* find_all_inheritors.
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*/
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foreach(l, inhOIDs)
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{
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Oid childOID = lfirst_oid(l);
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Relation newrelation;
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/* Open rel if needed; we already have required locks */
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if (childOID != parentOID)
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newrelation = heap_open(childOID, NoLock);
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else
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newrelation = oldrelation;
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/*
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* It is possible that the parent table has children that are temp
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* tables of other backends. We cannot safely access such tables
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* (because of buffering issues), and the best thing to do seems
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* to be to silently ignore them.
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*/
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if (childOID != parentOID && RELATION_IS_OTHER_TEMP(newrelation))
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{
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heap_close(newrelation, lockmode);
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continue;
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}
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expand_single_inheritance_child(root, rte, rti, oldrelation, oldrc,
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newrelation,
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&appinfos, &childrte,
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&childRTindex);
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/* Close child relations, but keep locks */
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if (childOID != parentOID)
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heap_close(newrelation, NoLock);
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}
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/*
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* If all the children were temp tables, pretend it's a
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* non-inheritance situation; we don't need Append node in that case.
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* The duplicate RTE we added for the parent table is harmless, so we
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* don't bother to get rid of it; ditto for the useless PlanRowMark
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* node.
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*/
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if (list_length(appinfos) < 2)
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rte->inh = false;
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else
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root->append_rel_list = list_concat(root->append_rel_list,
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appinfos);
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}
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heap_close(oldrelation, NoLock);
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}
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/*
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* expand_partitioned_rtentry
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* Recursively expand an RTE for a partitioned table.
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*/
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static void
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expand_partitioned_rtentry(PlannerInfo *root, RangeTblEntry *parentrte,
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Index parentRTindex, Relation parentrel,
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PlanRowMark *top_parentrc, LOCKMODE lockmode,
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List **appinfos)
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{
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int i;
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RangeTblEntry *childrte;
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Index childRTindex;
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PartitionDesc partdesc = RelationGetPartitionDesc(parentrel);
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check_stack_depth();
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/* A partitioned table should always have a partition descriptor. */
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Assert(partdesc);
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Assert(parentrte->inh);
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/*
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* Note down whether any partition key cols are being updated. Though it's
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* the root partitioned table's updatedCols we are interested in, we
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* instead use parentrte to get the updatedCols. This is convenient
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* because parentrte already has the root partrel's updatedCols translated
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* to match the attribute ordering of parentrel.
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*/
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if (!root->partColsUpdated)
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root->partColsUpdated =
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has_partition_attrs(parentrel, parentrte->updatedCols, NULL);
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/* First expand the partitioned table itself. */
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expand_single_inheritance_child(root, parentrte, parentRTindex, parentrel,
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top_parentrc, parentrel,
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appinfos, &childrte, &childRTindex);
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/*
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* If the partitioned table has no partitions, treat this as the
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* non-inheritance case.
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*/
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if (partdesc->nparts == 0)
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{
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parentrte->inh = false;
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return;
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}
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for (i = 0; i < partdesc->nparts; i++)
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{
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Oid childOID = partdesc->oids[i];
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Relation childrel;
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/* Open rel; we already have required locks */
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childrel = heap_open(childOID, NoLock);
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/*
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* Temporary partitions belonging to other sessions should have been
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* disallowed at definition, but for paranoia's sake, let's double
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* check.
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*/
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if (RELATION_IS_OTHER_TEMP(childrel))
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elog(ERROR, "temporary relation from another session found as partition");
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expand_single_inheritance_child(root, parentrte, parentRTindex,
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parentrel, top_parentrc, childrel,
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appinfos, &childrte, &childRTindex);
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/* If this child is itself partitioned, recurse */
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if (childrel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
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expand_partitioned_rtentry(root, childrte, childRTindex,
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childrel, top_parentrc, lockmode,
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appinfos);
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/* Close child relation, but keep locks */
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heap_close(childrel, NoLock);
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}
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}
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/*
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* expand_single_inheritance_child
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* Build a RangeTblEntry and an AppendRelInfo, if appropriate, plus
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* maybe a PlanRowMark.
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*
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* We now expand the partition hierarchy level by level, creating a
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* corresponding hierarchy of AppendRelInfos and RelOptInfos, where each
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* partitioned descendant acts as a parent of its immediate partitions.
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* (This is a difference from what older versions of PostgreSQL did and what
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* is still done in the case of table inheritance for unpartitioned tables,
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* where the hierarchy is flattened during RTE expansion.)
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*
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* PlanRowMarks still carry the top-parent's RTI, and the top-parent's
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* allMarkTypes field still accumulates values from all descendents.
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*
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* "parentrte" and "parentRTindex" are immediate parent's RTE and
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* RTI. "top_parentrc" is top parent's PlanRowMark.
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*
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* The child RangeTblEntry and its RTI are returned in "childrte_p" and
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* "childRTindex_p" resp.
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*/
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static void
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expand_single_inheritance_child(PlannerInfo *root, RangeTblEntry *parentrte,
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Index parentRTindex, Relation parentrel,
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PlanRowMark *top_parentrc, Relation childrel,
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List **appinfos, RangeTblEntry **childrte_p,
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Index *childRTindex_p)
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{
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Query *parse = root->parse;
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Oid parentOID = RelationGetRelid(parentrel);
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Oid childOID = RelationGetRelid(childrel);
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RangeTblEntry *childrte;
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Index childRTindex;
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AppendRelInfo *appinfo;
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/*
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* Build an RTE for the child, and attach to query's rangetable list. We
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* copy most fields of the parent's RTE, but replace relation OID and
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* relkind, and set inh = false. Also, set requiredPerms to zero since
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* all required permissions checks are done on the original RTE. Likewise,
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* set the child's securityQuals to empty, because we only want to apply
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* the parent's RLS conditions regardless of what RLS properties
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* individual children may have. (This is an intentional choice to make
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* inherited RLS work like regular permissions checks.) The parent
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* securityQuals will be propagated to children along with other base
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* restriction clauses, so we don't need to do it here.
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*/
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childrte = copyObject(parentrte);
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*childrte_p = childrte;
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childrte->relid = childOID;
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childrte->relkind = childrel->rd_rel->relkind;
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/* A partitioned child will need to be expanded further. */
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if (childOID != parentOID &&
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childrte->relkind == RELKIND_PARTITIONED_TABLE)
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childrte->inh = true;
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else
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childrte->inh = false;
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childrte->requiredPerms = 0;
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childrte->securityQuals = NIL;
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parse->rtable = lappend(parse->rtable, childrte);
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childRTindex = list_length(parse->rtable);
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*childRTindex_p = childRTindex;
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/*
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* We need an AppendRelInfo if paths will be built for the child RTE. If
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* childrte->inh is true, then we'll always need to generate append paths
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* for it. If childrte->inh is false, we must scan it if it's not a
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* partitioned table; but if it is a partitioned table, then it never has
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* any data of its own and need not be scanned.
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*/
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if (childrte->relkind != RELKIND_PARTITIONED_TABLE || childrte->inh)
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{
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appinfo = make_append_rel_info(parentrel, childrel,
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parentRTindex, childRTindex);
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*appinfos = lappend(*appinfos, appinfo);
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/*
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* Translate the column permissions bitmaps to the child's attnums (we
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* have to build the translated_vars list before we can do this). But
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* if this is the parent table, leave copyObject's result alone.
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*
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* Note: we need to do this even though the executor won't run any
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* permissions checks on the child RTE. The insertedCols/updatedCols
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* bitmaps may be examined for trigger-firing purposes.
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*/
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if (childOID != parentOID)
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{
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childrte->selectedCols = translate_col_privs(parentrte->selectedCols,
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appinfo->translated_vars);
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childrte->insertedCols = translate_col_privs(parentrte->insertedCols,
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appinfo->translated_vars);
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childrte->updatedCols = translate_col_privs(parentrte->updatedCols,
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appinfo->translated_vars);
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}
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}
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/*
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* Build a PlanRowMark if parent is marked FOR UPDATE/SHARE.
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*/
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if (top_parentrc)
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{
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PlanRowMark *childrc = makeNode(PlanRowMark);
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childrc->rti = childRTindex;
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childrc->prti = top_parentrc->rti;
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childrc->rowmarkId = top_parentrc->rowmarkId;
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/* Reselect rowmark type, because relkind might not match parent */
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childrc->markType = select_rowmark_type(childrte,
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top_parentrc->strength);
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childrc->allMarkTypes = (1 << childrc->markType);
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childrc->strength = top_parentrc->strength;
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childrc->waitPolicy = top_parentrc->waitPolicy;
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/*
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* We mark RowMarks for partitioned child tables as parent RowMarks so
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* that the executor ignores them (except their existence means that
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* the child tables be locked using appropriate mode).
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*/
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childrc->isParent = (childrte->relkind == RELKIND_PARTITIONED_TABLE);
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/* Include child's rowmark type in top parent's allMarkTypes */
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top_parentrc->allMarkTypes |= childrc->allMarkTypes;
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root->rowMarks = lappend(root->rowMarks, childrc);
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}
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}
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