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https://github.com/postgres/postgres.git
synced 2025-06-29 10:41:53 +03:00
Fix performance problems with pg_index lookups (see, for example,
discussion of 5/19/00). pg_index is now searched for indexes of a relation using an indexscan. Moreover, this is done once and cached in the relcache entry for the relation, in the form of a list of OIDs for the indexes. This list is used by the parser and executor to drive lookups in the pg_index syscache when they want to know the properties of the indexes. Net result: index information will be fully cached for repetitive operations such as inserts.
This commit is contained in:
Tom Lane
@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/executor/execUtils.c,v 1.59 2000/06/15 04:09:52 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/executor/execUtils.c,v 1.60 2000/06/17 21:48:49 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -53,6 +53,8 @@
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#include "miscadmin.h"
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#include "utils/builtins.h"
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#include "utils/fmgroids.h"
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#include "utils/relcache.h"
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#include "utils/syscache.h"
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static void ExecGetIndexKeyInfo(Form_pg_index indexTuple, int *numAttsOutP,
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AttrNumber **attsOutP, FuncIndexInfoPtr fInfoP);
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@ -657,7 +659,7 @@ ExecGetIndexKeyInfo(Form_pg_index indexTuple,
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* check parameters
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* ----------------
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*/
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if (numAttsOutP == NULL && attsOutP == NULL)
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if (numAttsOutP == NULL || attsOutP == NULL)
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{
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elog(DEBUG, "ExecGetIndexKeyInfo: %s",
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"invalid parameters: numAttsOutP and attsOutP must be non-NULL");
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@ -724,115 +726,112 @@ ExecGetIndexKeyInfo(Form_pg_index indexTuple,
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/* ----------------------------------------------------------------
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* ExecOpenIndices
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*
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* Here we scan the pg_index relation to find indices
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* associated with a given heap relation oid. Since we
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* don't know in advance how many indices we have, we
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* form lists containing the information we need from
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* pg_index and then process these lists.
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* Find the indices associated with a result relation, open them,
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* and save information about them in the result RelationInfo.
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*
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* Note: much of this code duplicates effort done by
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* the IndexCatalogInformation function in plancat.c
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* because IndexCatalogInformation is poorly written.
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* At entry, caller has already opened and locked
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* resultRelationInfo->ri_RelationDesc.
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*
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* It would be much better if the functionality provided
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* by this function and IndexCatalogInformation was
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* in the form of a small set of orthogonal routines..
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* If you are trying to understand this, I suggest you
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* look at the code to IndexCatalogInformation and
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* FormIndexTuple.. -cim 9/27/89
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* This used to be horribly ugly code, and slow too because it
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* did a sequential scan of pg_index. Now we rely on the relcache
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* to cache a list of the OIDs of the indices associated with any
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* specific relation, and we use the pg_index syscache to get the
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* entries we need from pg_index.
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* ----------------------------------------------------------------
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*/
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void
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ExecOpenIndices(Oid resultRelationOid,
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RelationInfo *resultRelationInfo)
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ExecOpenIndices(RelationInfo *resultRelationInfo)
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{
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Relation indexRd;
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HeapScanDesc indexSd;
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ScanKeyData key;
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HeapTuple tuple;
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Form_pg_index indexStruct;
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Oid indexOid;
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List *oidList;
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List *nkeyList;
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List *keyList;
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List *fiList;
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char *predString;
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List *predList;
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List *indexoid;
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List *numkeys;
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List *indexkeys;
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List *indexfuncs;
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List *indexpreds;
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int len;
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Relation resultRelation = resultRelationInfo->ri_RelationDesc;
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List *indexoidlist,
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*indexoidscan;
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int len,
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i;
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RelationPtr relationDescs;
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IndexInfo **indexInfoArray;
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FuncIndexInfoPtr fInfoP;
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int numKeyAtts;
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AttrNumber *indexKeyAtts;
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PredInfo *predicate;
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int i;
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resultRelationInfo->ri_NumIndices = 0;
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if (!RelationGetForm(resultRelationInfo->ri_RelationDesc)->relhasindex)
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/* checks for disabled indexes */
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if (! RelationGetForm(resultRelation)->relhasindex)
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return;
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if (IsIgnoringSystemIndexes() &&
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IsSystemRelationName(RelationGetRelationName(resultRelationInfo->ri_RelationDesc)))
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IsSystemRelationName(RelationGetRelationName(resultRelation)))
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return;
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/* ----------------
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* open pg_index
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* ----------------
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*/
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indexRd = heap_openr(IndexRelationName, AccessShareLock);
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/* ----------------
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* form a scan key
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* Get cached list of index OIDs
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* ----------------
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*/
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ScanKeyEntryInitialize(&key, 0, Anum_pg_index_indrelid,
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F_OIDEQ,
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ObjectIdGetDatum(resultRelationOid));
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indexoidlist = RelationGetIndexList(resultRelation);
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len = length(indexoidlist);
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if (len == 0)
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return;
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/* ----------------
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* scan the index relation, looking for indices for our
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* result relation..
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* allocate space for result arrays
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* ----------------
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*/
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indexSd = heap_beginscan(indexRd, /* scan desc */
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false, /* scan backward flag */
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SnapshotNow, /* NOW snapshot */
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1, /* number scan keys */
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&key); /* scan keys */
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relationDescs = (RelationPtr) palloc(len * sizeof(Relation));
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indexInfoArray = (IndexInfo **) palloc(len * sizeof(IndexInfo *));
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oidList = NIL;
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nkeyList = NIL;
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keyList = NIL;
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fiList = NIL;
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predList = NIL;
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resultRelationInfo->ri_NumIndices = len;
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resultRelationInfo->ri_IndexRelationDescs = relationDescs;
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resultRelationInfo->ri_IndexRelationInfo = indexInfoArray;
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while (HeapTupleIsValid(tuple = heap_getnext(indexSd, 0)))
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/* ----------------
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* For each index, open the index relation and save pg_index info.
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* ----------------
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*/
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i = 0;
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foreach(indexoidscan, indexoidlist)
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{
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Oid indexOid = lfirsti(indexoidscan);
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Relation indexDesc;
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HeapTuple indexTuple;
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Form_pg_index indexStruct;
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int numKeyAtts;
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AttrNumber *indexKeyAtts;
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FuncIndexInfoPtr fInfoP;
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PredInfo *predicate;
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IndexInfo *ii;
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/* ----------------
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* For each index relation we find, extract the information
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* we need and store it in a list..
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* Open (and lock, if necessary) the index relation
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*
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* first get the oid of the index relation from the tuple
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* Hack for not btree and hash indices: they use relation
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* level exclusive locking on update (i.e. - they are not
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* ready for MVCC) and so we have to exclusively lock
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* indices here to prevent deadlocks if we will scan them
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* - index_beginscan places AccessShareLock, indices
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* update methods don't use locks at all. We release this
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* lock in ExecCloseIndices. Note, that hashes use page
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* level locking - i.e. are not deadlock-free, - let's
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* them be on their way -:)) vadim 03-12-1998
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* ----------------
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*/
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indexStruct = (Form_pg_index) GETSTRUCT(tuple);
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indexOid = indexStruct->indexrelid;
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indexDesc = index_open(indexOid);
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if (indexDesc->rd_rel->relam != BTREE_AM_OID &&
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indexDesc->rd_rel->relam != HASH_AM_OID)
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LockRelation(indexDesc, AccessExclusiveLock);
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/* ----------------
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* allocate space for functional index information.
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* Get the pg_index tuple for the index
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* ----------------
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*/
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indexTuple = SearchSysCacheTupleCopy(INDEXRELID,
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ObjectIdGetDatum(indexOid),
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0, 0, 0);
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if (!HeapTupleIsValid(indexTuple))
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elog(ERROR, "ExecOpenIndices: index %u not found", indexOid);
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indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
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/* ----------------
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* extract the index key information from the tuple
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* ----------------
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*/
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fInfoP = (FuncIndexInfoPtr) palloc(sizeof(*fInfoP));
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/* ----------------
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* next get the index key information from the tuple
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* ----------------
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*/
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ExecGetIndexKeyInfo(indexStruct,
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&numKeyAtts,
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&indexKeyAtts,
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@ -844,6 +843,8 @@ ExecOpenIndices(Oid resultRelationOid,
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*/
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if (VARSIZE(&indexStruct->indpred) != 0)
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{
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char *predString;
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predString = textout(&indexStruct->indpred);
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predicate = (PredInfo *) stringToNode(predString);
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pfree(predString);
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@ -851,152 +852,21 @@ ExecOpenIndices(Oid resultRelationOid,
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else
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predicate = NULL;
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/* ----------------
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* save the index information into lists
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* ----------------
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*/
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oidList = lconsi(indexOid, oidList);
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nkeyList = lconsi(numKeyAtts, nkeyList);
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keyList = lcons(indexKeyAtts, keyList);
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fiList = lcons(fInfoP, fiList);
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predList = lcons(predicate, predList);
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/* Save the index info */
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ii = makeNode(IndexInfo);
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ii->ii_NumKeyAttributes = numKeyAtts;
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ii->ii_KeyAttributeNumbers = indexKeyAtts;
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ii->ii_FuncIndexInfo = fInfoP;
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ii->ii_Predicate = (Node *) predicate;
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heap_freetuple(indexTuple);
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relationDescs[i] = indexDesc;
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indexInfoArray[i] = ii;
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i++;
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}
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/* ----------------
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* we have the info we need so close the pg_index relation..
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* ----------------
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*/
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heap_endscan(indexSd);
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heap_close(indexRd, AccessShareLock);
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/* ----------------
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* Now that we've collected the index information into three
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* lists, we open the index relations and store the descriptors
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* and the key information into arrays.
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* ----------------
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*/
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len = length(oidList);
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if (len > 0)
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{
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/* ----------------
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* allocate space for relation descs
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* ----------------
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*/
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CXT1_printf("ExecOpenIndices: context is %d\n", CurrentMemoryContext);
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relationDescs = (RelationPtr)
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palloc(len * sizeof(Relation));
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/* ----------------
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* initialize index info array
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* ----------------
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*/
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CXT1_printf("ExecOpenIndices: context is %d\n", CurrentMemoryContext);
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indexInfoArray = (IndexInfo **)
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palloc(len * sizeof(IndexInfo *));
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for (i = 0; i < len; i++)
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{
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IndexInfo *ii = makeNode(IndexInfo);
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ii->ii_NumKeyAttributes = 0;
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ii->ii_KeyAttributeNumbers = (AttrNumber *) NULL;
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ii->ii_FuncIndexInfo = (FuncIndexInfoPtr) NULL;
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ii->ii_Predicate = NULL;
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indexInfoArray[i] = ii;
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}
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/* ----------------
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* attempt to open each of the indices. If we succeed,
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* then store the index relation descriptor into the
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* relation descriptor array.
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* ----------------
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*/
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i = 0;
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foreach(indexoid, oidList)
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{
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Relation indexDesc;
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indexOid = lfirsti(indexoid);
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indexDesc = index_open(indexOid);
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if (indexDesc != NULL)
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{
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relationDescs[i++] = indexDesc;
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/*
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* Hack for not btree and hash indices: they use relation
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* level exclusive locking on update (i.e. - they are not
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* ready for MVCC) and so we have to exclusively lock
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* indices here to prevent deadlocks if we will scan them
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* - index_beginscan places AccessShareLock, indices
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* update methods don't use locks at all. We release this
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* lock in ExecCloseIndices. Note, that hashes use page
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* level locking - i.e. are not deadlock-free, - let's
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* them be on their way -:)) vadim 03-12-1998
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*/
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if (indexDesc->rd_rel->relam != BTREE_AM_OID &&
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indexDesc->rd_rel->relam != HASH_AM_OID)
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LockRelation(indexDesc, AccessExclusiveLock);
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}
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}
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/* ----------------
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* store the relation descriptor array and number of
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* descs into the result relation info.
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* ----------------
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*/
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resultRelationInfo->ri_NumIndices = i;
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resultRelationInfo->ri_IndexRelationDescs = relationDescs;
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/* ----------------
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* store the index key information collected in our
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* lists into the index info array
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* ----------------
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*/
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i = 0;
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foreach(numkeys, nkeyList)
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{
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numKeyAtts = lfirsti(numkeys);
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indexInfoArray[i++]->ii_NumKeyAttributes = numKeyAtts;
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}
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i = 0;
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foreach(indexkeys, keyList)
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{
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indexKeyAtts = (AttrNumber *) lfirst(indexkeys);
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indexInfoArray[i++]->ii_KeyAttributeNumbers = indexKeyAtts;
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}
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i = 0;
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foreach(indexfuncs, fiList)
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{
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FuncIndexInfoPtr fiP = (FuncIndexInfoPtr) lfirst(indexfuncs);
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indexInfoArray[i++]->ii_FuncIndexInfo = fiP;
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}
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i = 0;
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foreach(indexpreds, predList)
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indexInfoArray[i++]->ii_Predicate = lfirst(indexpreds);
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/* ----------------
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* store the index info array into relation info
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* ----------------
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*/
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resultRelationInfo->ri_IndexRelationInfo = indexInfoArray;
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}
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/* ----------------
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* All done, resultRelationInfo now contains complete information
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* on the indices associated with the result relation.
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* ----------------
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*/
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/* should free oidList, nkeyList and keyList here */
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/* OK - let's do it -jolly */
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freeList(oidList);
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freeList(nkeyList);
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freeList(keyList);
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freeList(fiList);
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freeList(predList);
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freeList(indexoidlist);
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}
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/* ----------------------------------------------------------------
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@ -1035,91 +905,6 @@ ExecCloseIndices(RelationInfo *resultRelationInfo)
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*/
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}
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/* ----------------------------------------------------------------
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* ExecFormIndexTuple
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*
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* Most of this code is cannabilized from DefaultBuild().
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* As said in the comments for ExecOpenIndices, most of
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* this functionality should be rearranged into a proper
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* set of routines..
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* ----------------------------------------------------------------
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*/
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#ifdef NOT_USED
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IndexTuple
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ExecFormIndexTuple(HeapTuple heapTuple,
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Relation heapRelation,
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Relation indexRelation,
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IndexInfo *indexInfo)
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{
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IndexTuple indexTuple;
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TupleDesc heapDescriptor;
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TupleDesc indexDescriptor;
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Datum *datum;
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char *nulls;
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int numberOfAttributes;
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AttrNumber *keyAttributeNumbers;
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FuncIndexInfoPtr fInfoP;
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/* ----------------
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* get information from index info structure
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* ----------------
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*/
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numberOfAttributes = indexInfo->ii_NumKeyAttributes;
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keyAttributeNumbers = indexInfo->ii_KeyAttributeNumbers;
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fInfoP = indexInfo->ii_FuncIndexInfo;
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/* ----------------
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* datum and null are arrays in which we collect the index attributes
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* when forming a new index tuple.
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* ----------------
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*/
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CXT1_printf("ExecFormIndexTuple: context is %d\n", CurrentMemoryContext);
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datum = (Datum *) palloc(numberOfAttributes * sizeof *datum);
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nulls = (char *) palloc(numberOfAttributes * sizeof *nulls);
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/* ----------------
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* get the tuple descriptors from the relations so we know
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* how to form the index tuples..
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* ----------------
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*/
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heapDescriptor = RelationGetDescr(heapRelation);
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indexDescriptor = RelationGetDescr(indexRelation);
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/* ----------------
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* FormIndexDatum fills in its datum and null parameters
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* with attribute information taken from the given heap tuple.
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* ----------------
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*/
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FormIndexDatum(numberOfAttributes, /* num attributes */
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keyAttributeNumbers, /* array of att nums to extract */
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heapTuple, /* tuple from base relation */
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heapDescriptor, /* heap tuple's descriptor */
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datum, /* return: array of attributes */
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nulls, /* return: array of char's */
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fInfoP); /* functional index information */
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indexTuple = index_formtuple(indexDescriptor,
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datum,
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nulls);
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/* ----------------
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* free temporary arrays
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*
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* XXX should store these in the IndexInfo instead of allocating
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* and freeing on every insertion, but efficency here is not
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* that important and FormIndexTuple is wasteful anyways..
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* -cim 9/27/89
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* ----------------
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*/
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pfree(nulls);
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pfree(datum);
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return indexTuple;
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}
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#endif
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/* ----------------------------------------------------------------
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* ExecInsertIndexTuples
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*
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Reference in New Issue
Block a user