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This reworks the reloption parsing and build of a couple of index AMs by creating new structures for each index AM's options. This split was already done for BRIN, GIN and GiST (which actually has a fillfactor parameter), but not for hash, B-tree and SPGiST which relied on StdRdOptions due to an overlap with the default option set. This saves a couple of bytes for rd_options in each relcache entry with indexes making use of relation options, and brings more consistency between all index AMs. While on it, add a couple of AssertMacro() calls to make sure that utility macros to grab values of reloptions are used with the expected index AM. Author: Nikolay Shaplov Reviewed-by: Amit Langote, Michael Paquier, Álvaro Herrera, Dent John Discussion: https://postgr.es/m/4127670.gFlpRb6XCm@x200m
2569 lines
78 KiB
C
2569 lines
78 KiB
C
/*-------------------------------------------------------------------------
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*
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* nbtutils.c
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* Utility code for Postgres btree implementation.
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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/access/nbtree/nbtutils.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 <time.h>
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#include "access/nbtree.h"
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#include "access/reloptions.h"
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#include "access/relscan.h"
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#include "commands/progress.h"
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#include "lib/qunique.h"
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#include "miscadmin.h"
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#include "utils/array.h"
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#include "utils/datum.h"
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#include "utils/lsyscache.h"
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#include "utils/memutils.h"
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#include "utils/rel.h"
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typedef struct BTSortArrayContext
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{
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FmgrInfo flinfo;
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Oid collation;
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bool reverse;
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} BTSortArrayContext;
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static Datum _bt_find_extreme_element(IndexScanDesc scan, ScanKey skey,
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StrategyNumber strat,
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Datum *elems, int nelems);
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static int _bt_sort_array_elements(IndexScanDesc scan, ScanKey skey,
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bool reverse,
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Datum *elems, int nelems);
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static int _bt_compare_array_elements(const void *a, const void *b, void *arg);
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static bool _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
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ScanKey leftarg, ScanKey rightarg,
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bool *result);
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static bool _bt_fix_scankey_strategy(ScanKey skey, int16 *indoption);
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static void _bt_mark_scankey_required(ScanKey skey);
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static bool _bt_check_rowcompare(ScanKey skey,
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IndexTuple tuple, int tupnatts, TupleDesc tupdesc,
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ScanDirection dir, bool *continuescan);
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static int _bt_keep_natts(Relation rel, IndexTuple lastleft,
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IndexTuple firstright, BTScanInsert itup_key);
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/*
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* _bt_mkscankey
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* Build an insertion scan key that contains comparison data from itup
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* as well as comparator routines appropriate to the key datatypes.
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*
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* When itup is a non-pivot tuple, the returned insertion scan key is
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* suitable for finding a place for it to go on the leaf level. Pivot
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* tuples can be used to re-find leaf page with matching high key, but
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* then caller needs to set scan key's pivotsearch field to true. This
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* allows caller to search for a leaf page with a matching high key,
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* which is usually to the left of the first leaf page a non-pivot match
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* might appear on.
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*
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* The result is intended for use with _bt_compare() and _bt_truncate().
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* Callers that don't need to fill out the insertion scankey arguments
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* (e.g. they use an ad-hoc comparison routine, or only need a scankey
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* for _bt_truncate()) can pass a NULL index tuple. The scankey will
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* be initialized as if an "all truncated" pivot tuple was passed
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* instead.
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*
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* Note that we may occasionally have to share lock the metapage to
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* determine whether or not the keys in the index are expected to be
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* unique (i.e. if this is a "heapkeyspace" index). We assume a
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* heapkeyspace index when caller passes a NULL tuple, allowing index
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* build callers to avoid accessing the non-existent metapage.
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*/
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BTScanInsert
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_bt_mkscankey(Relation rel, IndexTuple itup)
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{
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BTScanInsert key;
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ScanKey skey;
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TupleDesc itupdesc;
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int indnkeyatts;
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int16 *indoption;
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int tupnatts;
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int i;
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itupdesc = RelationGetDescr(rel);
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indnkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
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indoption = rel->rd_indoption;
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tupnatts = itup ? BTreeTupleGetNAtts(itup, rel) : 0;
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Assert(tupnatts <= IndexRelationGetNumberOfAttributes(rel));
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/*
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* We'll execute search using scan key constructed on key columns.
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* Truncated attributes and non-key attributes are omitted from the final
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* scan key.
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*/
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key = palloc(offsetof(BTScanInsertData, scankeys) +
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sizeof(ScanKeyData) * indnkeyatts);
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key->heapkeyspace = itup == NULL || _bt_heapkeyspace(rel);
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key->anynullkeys = false; /* initial assumption */
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key->nextkey = false;
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key->pivotsearch = false;
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key->keysz = Min(indnkeyatts, tupnatts);
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key->scantid = key->heapkeyspace && itup ?
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BTreeTupleGetHeapTID(itup) : NULL;
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skey = key->scankeys;
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for (i = 0; i < indnkeyatts; i++)
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{
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FmgrInfo *procinfo;
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Datum arg;
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bool null;
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int flags;
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/*
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* We can use the cached (default) support procs since no cross-type
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* comparison can be needed.
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*/
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procinfo = index_getprocinfo(rel, i + 1, BTORDER_PROC);
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/*
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* Key arguments built from truncated attributes (or when caller
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* provides no tuple) are defensively represented as NULL values. They
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* should never be used.
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*/
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if (i < tupnatts)
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arg = index_getattr(itup, i + 1, itupdesc, &null);
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else
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{
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arg = (Datum) 0;
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null = true;
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}
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flags = (null ? SK_ISNULL : 0) | (indoption[i] << SK_BT_INDOPTION_SHIFT);
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ScanKeyEntryInitializeWithInfo(&skey[i],
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flags,
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(AttrNumber) (i + 1),
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InvalidStrategy,
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InvalidOid,
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rel->rd_indcollation[i],
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procinfo,
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arg);
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/* Record if any key attribute is NULL (or truncated) */
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if (null)
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key->anynullkeys = true;
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}
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return key;
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}
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/*
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* free a retracement stack made by _bt_search.
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*/
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void
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_bt_freestack(BTStack stack)
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{
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BTStack ostack;
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while (stack != NULL)
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{
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ostack = stack;
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stack = stack->bts_parent;
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pfree(ostack);
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}
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}
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/*
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* _bt_preprocess_array_keys() -- Preprocess SK_SEARCHARRAY scan keys
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*
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* If there are any SK_SEARCHARRAY scan keys, deconstruct the array(s) and
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* set up BTArrayKeyInfo info for each one that is an equality-type key.
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* Prepare modified scan keys in so->arrayKeyData, which will hold the current
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* array elements during each primitive indexscan operation. For inequality
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* array keys, it's sufficient to find the extreme element value and replace
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* the whole array with that scalar value.
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*
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* Note: the reason we need so->arrayKeyData, rather than just scribbling
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* on scan->keyData, is that callers are permitted to call btrescan without
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* supplying a new set of scankey data.
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*/
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void
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_bt_preprocess_array_keys(IndexScanDesc scan)
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{
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BTScanOpaque so = (BTScanOpaque) scan->opaque;
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int numberOfKeys = scan->numberOfKeys;
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int16 *indoption = scan->indexRelation->rd_indoption;
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int numArrayKeys;
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ScanKey cur;
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int i;
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MemoryContext oldContext;
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/* Quick check to see if there are any array keys */
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numArrayKeys = 0;
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for (i = 0; i < numberOfKeys; i++)
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{
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cur = &scan->keyData[i];
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if (cur->sk_flags & SK_SEARCHARRAY)
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{
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numArrayKeys++;
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Assert(!(cur->sk_flags & (SK_ROW_HEADER | SK_SEARCHNULL | SK_SEARCHNOTNULL)));
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/* If any arrays are null as a whole, we can quit right now. */
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if (cur->sk_flags & SK_ISNULL)
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{
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so->numArrayKeys = -1;
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so->arrayKeyData = NULL;
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return;
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}
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}
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}
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/* Quit if nothing to do. */
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if (numArrayKeys == 0)
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{
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so->numArrayKeys = 0;
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so->arrayKeyData = NULL;
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return;
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}
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/*
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* Make a scan-lifespan context to hold array-associated data, or reset it
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* if we already have one from a previous rescan cycle.
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*/
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if (so->arrayContext == NULL)
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so->arrayContext = AllocSetContextCreate(CurrentMemoryContext,
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"BTree array context",
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ALLOCSET_SMALL_SIZES);
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else
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MemoryContextReset(so->arrayContext);
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oldContext = MemoryContextSwitchTo(so->arrayContext);
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/* Create modifiable copy of scan->keyData in the workspace context */
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so->arrayKeyData = (ScanKey) palloc(scan->numberOfKeys * sizeof(ScanKeyData));
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memcpy(so->arrayKeyData,
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scan->keyData,
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scan->numberOfKeys * sizeof(ScanKeyData));
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/* Allocate space for per-array data in the workspace context */
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so->arrayKeys = (BTArrayKeyInfo *) palloc0(numArrayKeys * sizeof(BTArrayKeyInfo));
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/* Now process each array key */
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numArrayKeys = 0;
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for (i = 0; i < numberOfKeys; i++)
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{
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ArrayType *arrayval;
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int16 elmlen;
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bool elmbyval;
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char elmalign;
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int num_elems;
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Datum *elem_values;
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bool *elem_nulls;
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int num_nonnulls;
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int j;
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cur = &so->arrayKeyData[i];
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if (!(cur->sk_flags & SK_SEARCHARRAY))
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continue;
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/*
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* First, deconstruct the array into elements. Anything allocated
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* here (including a possibly detoasted array value) is in the
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* workspace context.
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*/
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arrayval = DatumGetArrayTypeP(cur->sk_argument);
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/* We could cache this data, but not clear it's worth it */
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get_typlenbyvalalign(ARR_ELEMTYPE(arrayval),
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&elmlen, &elmbyval, &elmalign);
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deconstruct_array(arrayval,
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ARR_ELEMTYPE(arrayval),
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elmlen, elmbyval, elmalign,
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&elem_values, &elem_nulls, &num_elems);
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/*
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* Compress out any null elements. We can ignore them since we assume
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* all btree operators are strict.
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*/
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num_nonnulls = 0;
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for (j = 0; j < num_elems; j++)
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{
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if (!elem_nulls[j])
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elem_values[num_nonnulls++] = elem_values[j];
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}
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/* We could pfree(elem_nulls) now, but not worth the cycles */
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/* If there's no non-nulls, the scan qual is unsatisfiable */
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if (num_nonnulls == 0)
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{
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numArrayKeys = -1;
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break;
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}
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/*
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* If the comparison operator is not equality, then the array qual
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* degenerates to a simple comparison against the smallest or largest
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* non-null array element, as appropriate.
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*/
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switch (cur->sk_strategy)
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{
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case BTLessStrategyNumber:
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case BTLessEqualStrategyNumber:
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cur->sk_argument =
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_bt_find_extreme_element(scan, cur,
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BTGreaterStrategyNumber,
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elem_values, num_nonnulls);
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continue;
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case BTEqualStrategyNumber:
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/* proceed with rest of loop */
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break;
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case BTGreaterEqualStrategyNumber:
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case BTGreaterStrategyNumber:
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cur->sk_argument =
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_bt_find_extreme_element(scan, cur,
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BTLessStrategyNumber,
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elem_values, num_nonnulls);
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continue;
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default:
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elog(ERROR, "unrecognized StrategyNumber: %d",
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(int) cur->sk_strategy);
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break;
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}
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/*
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* Sort the non-null elements and eliminate any duplicates. We must
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* sort in the same ordering used by the index column, so that the
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* successive primitive indexscans produce data in index order.
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*/
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num_elems = _bt_sort_array_elements(scan, cur,
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(indoption[cur->sk_attno - 1] & INDOPTION_DESC) != 0,
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elem_values, num_nonnulls);
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/*
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* And set up the BTArrayKeyInfo data.
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*/
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so->arrayKeys[numArrayKeys].scan_key = i;
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so->arrayKeys[numArrayKeys].num_elems = num_elems;
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so->arrayKeys[numArrayKeys].elem_values = elem_values;
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numArrayKeys++;
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}
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so->numArrayKeys = numArrayKeys;
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MemoryContextSwitchTo(oldContext);
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}
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/*
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* _bt_find_extreme_element() -- get least or greatest array element
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*
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* scan and skey identify the index column, whose opfamily determines the
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* comparison semantics. strat should be BTLessStrategyNumber to get the
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* least element, or BTGreaterStrategyNumber to get the greatest.
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*/
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static Datum
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_bt_find_extreme_element(IndexScanDesc scan, ScanKey skey,
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StrategyNumber strat,
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Datum *elems, int nelems)
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{
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Relation rel = scan->indexRelation;
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Oid elemtype,
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cmp_op;
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RegProcedure cmp_proc;
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FmgrInfo flinfo;
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Datum result;
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int i;
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/*
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* Determine the nominal datatype of the array elements. We have to
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* support the convention that sk_subtype == InvalidOid means the opclass
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* input type; this is a hack to simplify life for ScanKeyInit().
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*/
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elemtype = skey->sk_subtype;
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if (elemtype == InvalidOid)
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elemtype = rel->rd_opcintype[skey->sk_attno - 1];
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/*
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* Look up the appropriate comparison operator in the opfamily.
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*
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* Note: it's possible that this would fail, if the opfamily is
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* incomplete, but it seems quite unlikely that an opfamily would omit
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* non-cross-type comparison operators for any datatype that it supports
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* at all.
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*/
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cmp_op = get_opfamily_member(rel->rd_opfamily[skey->sk_attno - 1],
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elemtype,
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elemtype,
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strat);
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if (!OidIsValid(cmp_op))
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elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
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strat, elemtype, elemtype,
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rel->rd_opfamily[skey->sk_attno - 1]);
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cmp_proc = get_opcode(cmp_op);
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if (!RegProcedureIsValid(cmp_proc))
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elog(ERROR, "missing oprcode for operator %u", cmp_op);
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fmgr_info(cmp_proc, &flinfo);
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Assert(nelems > 0);
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result = elems[0];
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for (i = 1; i < nelems; i++)
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{
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if (DatumGetBool(FunctionCall2Coll(&flinfo,
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skey->sk_collation,
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elems[i],
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result)))
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result = elems[i];
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}
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return result;
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}
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/*
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* _bt_sort_array_elements() -- sort and de-dup array elements
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*
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* The array elements are sorted in-place, and the new number of elements
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* after duplicate removal is returned.
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*
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* scan and skey identify the index column, whose opfamily determines the
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* comparison semantics. If reverse is true, we sort in descending order.
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*/
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static int
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_bt_sort_array_elements(IndexScanDesc scan, ScanKey skey,
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bool reverse,
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Datum *elems, int nelems)
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{
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Relation rel = scan->indexRelation;
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Oid elemtype;
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RegProcedure cmp_proc;
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BTSortArrayContext cxt;
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if (nelems <= 1)
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return nelems; /* no work to do */
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|
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/*
|
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* Determine the nominal datatype of the array elements. We have to
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* support the convention that sk_subtype == InvalidOid means the opclass
|
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* input type; this is a hack to simplify life for ScanKeyInit().
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*/
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elemtype = skey->sk_subtype;
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if (elemtype == InvalidOid)
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elemtype = rel->rd_opcintype[skey->sk_attno - 1];
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/*
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* Look up the appropriate comparison function in the opfamily.
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*
|
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* Note: it's possible that this would fail, if the opfamily is
|
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* incomplete, but it seems quite unlikely that an opfamily would omit
|
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* non-cross-type support functions for any datatype that it supports at
|
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* all.
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*/
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cmp_proc = get_opfamily_proc(rel->rd_opfamily[skey->sk_attno - 1],
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elemtype,
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elemtype,
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BTORDER_PROC);
|
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if (!RegProcedureIsValid(cmp_proc))
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elog(ERROR, "missing support function %d(%u,%u) in opfamily %u",
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BTORDER_PROC, elemtype, elemtype,
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rel->rd_opfamily[skey->sk_attno - 1]);
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/* Sort the array elements */
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fmgr_info(cmp_proc, &cxt.flinfo);
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cxt.collation = skey->sk_collation;
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cxt.reverse = reverse;
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qsort_arg((void *) elems, nelems, sizeof(Datum),
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_bt_compare_array_elements, (void *) &cxt);
|
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|
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/* Now scan the sorted elements and remove duplicates */
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return qunique_arg(elems, nelems, sizeof(Datum),
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_bt_compare_array_elements, &cxt);
|
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}
|
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|
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/*
|
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* qsort_arg comparator for sorting array elements
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*/
|
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static int
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_bt_compare_array_elements(const void *a, const void *b, void *arg)
|
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{
|
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Datum da = *((const Datum *) a);
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Datum db = *((const Datum *) b);
|
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BTSortArrayContext *cxt = (BTSortArrayContext *) arg;
|
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int32 compare;
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compare = DatumGetInt32(FunctionCall2Coll(&cxt->flinfo,
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cxt->collation,
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da, db));
|
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if (cxt->reverse)
|
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INVERT_COMPARE_RESULT(compare);
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return compare;
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}
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|
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/*
|
|
* _bt_start_array_keys() -- Initialize array keys at start of a scan
|
|
*
|
|
* Set up the cur_elem counters and fill in the first sk_argument value for
|
|
* each array scankey. We can't do this until we know the scan direction.
|
|
*/
|
|
void
|
|
_bt_start_array_keys(IndexScanDesc scan, ScanDirection dir)
|
|
{
|
|
BTScanOpaque so = (BTScanOpaque) scan->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < so->numArrayKeys; i++)
|
|
{
|
|
BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
|
|
ScanKey skey = &so->arrayKeyData[curArrayKey->scan_key];
|
|
|
|
Assert(curArrayKey->num_elems > 0);
|
|
if (ScanDirectionIsBackward(dir))
|
|
curArrayKey->cur_elem = curArrayKey->num_elems - 1;
|
|
else
|
|
curArrayKey->cur_elem = 0;
|
|
skey->sk_argument = curArrayKey->elem_values[curArrayKey->cur_elem];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* _bt_advance_array_keys() -- Advance to next set of array elements
|
|
*
|
|
* Returns true if there is another set of values to consider, false if not.
|
|
* On true result, the scankeys are initialized with the next set of values.
|
|
*/
|
|
bool
|
|
_bt_advance_array_keys(IndexScanDesc scan, ScanDirection dir)
|
|
{
|
|
BTScanOpaque so = (BTScanOpaque) scan->opaque;
|
|
bool found = false;
|
|
int i;
|
|
|
|
/*
|
|
* We must advance the last array key most quickly, since it will
|
|
* correspond to the lowest-order index column among the available
|
|
* qualifications. This is necessary to ensure correct ordering of output
|
|
* when there are multiple array keys.
|
|
*/
|
|
for (i = so->numArrayKeys - 1; i >= 0; i--)
|
|
{
|
|
BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
|
|
ScanKey skey = &so->arrayKeyData[curArrayKey->scan_key];
|
|
int cur_elem = curArrayKey->cur_elem;
|
|
int num_elems = curArrayKey->num_elems;
|
|
|
|
if (ScanDirectionIsBackward(dir))
|
|
{
|
|
if (--cur_elem < 0)
|
|
{
|
|
cur_elem = num_elems - 1;
|
|
found = false; /* need to advance next array key */
|
|
}
|
|
else
|
|
found = true;
|
|
}
|
|
else
|
|
{
|
|
if (++cur_elem >= num_elems)
|
|
{
|
|
cur_elem = 0;
|
|
found = false; /* need to advance next array key */
|
|
}
|
|
else
|
|
found = true;
|
|
}
|
|
|
|
curArrayKey->cur_elem = cur_elem;
|
|
skey->sk_argument = curArrayKey->elem_values[cur_elem];
|
|
if (found)
|
|
break;
|
|
}
|
|
|
|
/* advance parallel scan */
|
|
if (scan->parallel_scan != NULL)
|
|
_bt_parallel_advance_array_keys(scan);
|
|
|
|
return found;
|
|
}
|
|
|
|
/*
|
|
* _bt_mark_array_keys() -- Handle array keys during btmarkpos
|
|
*
|
|
* Save the current state of the array keys as the "mark" position.
|
|
*/
|
|
void
|
|
_bt_mark_array_keys(IndexScanDesc scan)
|
|
{
|
|
BTScanOpaque so = (BTScanOpaque) scan->opaque;
|
|
int i;
|
|
|
|
for (i = 0; i < so->numArrayKeys; i++)
|
|
{
|
|
BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
|
|
|
|
curArrayKey->mark_elem = curArrayKey->cur_elem;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* _bt_restore_array_keys() -- Handle array keys during btrestrpos
|
|
*
|
|
* Restore the array keys to where they were when the mark was set.
|
|
*/
|
|
void
|
|
_bt_restore_array_keys(IndexScanDesc scan)
|
|
{
|
|
BTScanOpaque so = (BTScanOpaque) scan->opaque;
|
|
bool changed = false;
|
|
int i;
|
|
|
|
/* Restore each array key to its position when the mark was set */
|
|
for (i = 0; i < so->numArrayKeys; i++)
|
|
{
|
|
BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
|
|
ScanKey skey = &so->arrayKeyData[curArrayKey->scan_key];
|
|
int mark_elem = curArrayKey->mark_elem;
|
|
|
|
if (curArrayKey->cur_elem != mark_elem)
|
|
{
|
|
curArrayKey->cur_elem = mark_elem;
|
|
skey->sk_argument = curArrayKey->elem_values[mark_elem];
|
|
changed = true;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we changed any keys, we must redo _bt_preprocess_keys. That might
|
|
* sound like overkill, but in cases with multiple keys per index column
|
|
* it seems necessary to do the full set of pushups.
|
|
*/
|
|
if (changed)
|
|
{
|
|
_bt_preprocess_keys(scan);
|
|
/* The mark should have been set on a consistent set of keys... */
|
|
Assert(so->qual_ok);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* _bt_preprocess_keys() -- Preprocess scan keys
|
|
*
|
|
* The given search-type keys (in scan->keyData[] or so->arrayKeyData[])
|
|
* are copied to so->keyData[] with possible transformation.
|
|
* scan->numberOfKeys is the number of input keys, so->numberOfKeys gets
|
|
* the number of output keys (possibly less, never greater).
|
|
*
|
|
* The output keys are marked with additional sk_flags bits beyond the
|
|
* system-standard bits supplied by the caller. The DESC and NULLS_FIRST
|
|
* indoption bits for the relevant index attribute are copied into the flags.
|
|
* Also, for a DESC column, we commute (flip) all the sk_strategy numbers
|
|
* so that the index sorts in the desired direction.
|
|
*
|
|
* One key purpose of this routine is to discover which scan keys must be
|
|
* satisfied to continue the scan. It also attempts to eliminate redundant
|
|
* keys and detect contradictory keys. (If the index opfamily provides
|
|
* incomplete sets of cross-type operators, we may fail to detect redundant
|
|
* or contradictory keys, but we can survive that.)
|
|
*
|
|
* The output keys must be sorted by index attribute. Presently we expect
|
|
* (but verify) that the input keys are already so sorted --- this is done
|
|
* by match_clauses_to_index() in indxpath.c. Some reordering of the keys
|
|
* within each attribute may be done as a byproduct of the processing here,
|
|
* but no other code depends on that.
|
|
*
|
|
* The output keys are marked with flags SK_BT_REQFWD and/or SK_BT_REQBKWD
|
|
* if they must be satisfied in order to continue the scan forward or backward
|
|
* respectively. _bt_checkkeys uses these flags. For example, if the quals
|
|
* are "x = 1 AND y < 4 AND z < 5", then _bt_checkkeys will reject a tuple
|
|
* (1,2,7), but we must continue the scan in case there are tuples (1,3,z).
|
|
* But once we reach tuples like (1,4,z) we can stop scanning because no
|
|
* later tuples could match. This is reflected by marking the x and y keys,
|
|
* but not the z key, with SK_BT_REQFWD. In general, the keys for leading
|
|
* attributes with "=" keys are marked both SK_BT_REQFWD and SK_BT_REQBKWD.
|
|
* For the first attribute without an "=" key, any "<" and "<=" keys are
|
|
* marked SK_BT_REQFWD while any ">" and ">=" keys are marked SK_BT_REQBKWD.
|
|
* This can be seen to be correct by considering the above example. Note
|
|
* in particular that if there are no keys for a given attribute, the keys for
|
|
* subsequent attributes can never be required; for instance "WHERE y = 4"
|
|
* requires a full-index scan.
|
|
*
|
|
* If possible, redundant keys are eliminated: we keep only the tightest
|
|
* >/>= bound and the tightest </<= bound, and if there's an = key then
|
|
* that's the only one returned. (So, we return either a single = key,
|
|
* or one or two boundary-condition keys for each attr.) However, if we
|
|
* cannot compare two keys for lack of a suitable cross-type operator,
|
|
* we cannot eliminate either. If there are two such keys of the same
|
|
* operator strategy, the second one is just pushed into the output array
|
|
* without further processing here. We may also emit both >/>= or both
|
|
* </<= keys if we can't compare them. The logic about required keys still
|
|
* works if we don't eliminate redundant keys.
|
|
*
|
|
* Note that one reason we need direction-sensitive required-key flags is
|
|
* precisely that we may not be able to eliminate redundant keys. Suppose
|
|
* we have "x > 4::int AND x > 10::bigint", and we are unable to determine
|
|
* which key is more restrictive for lack of a suitable cross-type operator.
|
|
* _bt_first will arbitrarily pick one of the keys to do the initial
|
|
* positioning with. If it picks x > 4, then the x > 10 condition will fail
|
|
* until we reach index entries > 10; but we can't stop the scan just because
|
|
* x > 10 is failing. On the other hand, if we are scanning backwards, then
|
|
* failure of either key is indeed enough to stop the scan. (In general, when
|
|
* inequality keys are present, the initial-positioning code only promises to
|
|
* position before the first possible match, not exactly at the first match,
|
|
* for a forward scan; or after the last match for a backward scan.)
|
|
*
|
|
* As a byproduct of this work, we can detect contradictory quals such
|
|
* as "x = 1 AND x > 2". If we see that, we return so->qual_ok = false,
|
|
* indicating the scan need not be run at all since no tuples can match.
|
|
* (In this case we do not bother completing the output key array!)
|
|
* Again, missing cross-type operators might cause us to fail to prove the
|
|
* quals contradictory when they really are, but the scan will work correctly.
|
|
*
|
|
* Row comparison keys are currently also treated without any smarts:
|
|
* we just transfer them into the preprocessed array without any
|
|
* editorialization. We can treat them the same as an ordinary inequality
|
|
* comparison on the row's first index column, for the purposes of the logic
|
|
* about required keys.
|
|
*
|
|
* Note: the reason we have to copy the preprocessed scan keys into private
|
|
* storage is that we are modifying the array based on comparisons of the
|
|
* key argument values, which could change on a rescan or after moving to
|
|
* new elements of array keys. Therefore we can't overwrite the source data.
|
|
*/
|
|
void
|
|
_bt_preprocess_keys(IndexScanDesc scan)
|
|
{
|
|
BTScanOpaque so = (BTScanOpaque) scan->opaque;
|
|
int numberOfKeys = scan->numberOfKeys;
|
|
int16 *indoption = scan->indexRelation->rd_indoption;
|
|
int new_numberOfKeys;
|
|
int numberOfEqualCols;
|
|
ScanKey inkeys;
|
|
ScanKey outkeys;
|
|
ScanKey cur;
|
|
ScanKey xform[BTMaxStrategyNumber];
|
|
bool test_result;
|
|
int i,
|
|
j;
|
|
AttrNumber attno;
|
|
|
|
/* initialize result variables */
|
|
so->qual_ok = true;
|
|
so->numberOfKeys = 0;
|
|
|
|
if (numberOfKeys < 1)
|
|
return; /* done if qual-less scan */
|
|
|
|
/*
|
|
* Read so->arrayKeyData if array keys are present, else scan->keyData
|
|
*/
|
|
if (so->arrayKeyData != NULL)
|
|
inkeys = so->arrayKeyData;
|
|
else
|
|
inkeys = scan->keyData;
|
|
|
|
outkeys = so->keyData;
|
|
cur = &inkeys[0];
|
|
/* we check that input keys are correctly ordered */
|
|
if (cur->sk_attno < 1)
|
|
elog(ERROR, "btree index keys must be ordered by attribute");
|
|
|
|
/* We can short-circuit most of the work if there's just one key */
|
|
if (numberOfKeys == 1)
|
|
{
|
|
/* Apply indoption to scankey (might change sk_strategy!) */
|
|
if (!_bt_fix_scankey_strategy(cur, indoption))
|
|
so->qual_ok = false;
|
|
memcpy(outkeys, cur, sizeof(ScanKeyData));
|
|
so->numberOfKeys = 1;
|
|
/* We can mark the qual as required if it's for first index col */
|
|
if (cur->sk_attno == 1)
|
|
_bt_mark_scankey_required(outkeys);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Otherwise, do the full set of pushups.
|
|
*/
|
|
new_numberOfKeys = 0;
|
|
numberOfEqualCols = 0;
|
|
|
|
/*
|
|
* Initialize for processing of keys for attr 1.
|
|
*
|
|
* xform[i] points to the currently best scan key of strategy type i+1; it
|
|
* is NULL if we haven't yet found such a key for this attr.
|
|
*/
|
|
attno = 1;
|
|
memset(xform, 0, sizeof(xform));
|
|
|
|
/*
|
|
* Loop iterates from 0 to numberOfKeys inclusive; we use the last pass to
|
|
* handle after-last-key processing. Actual exit from the loop is at the
|
|
* "break" statement below.
|
|
*/
|
|
for (i = 0;; cur++, i++)
|
|
{
|
|
if (i < numberOfKeys)
|
|
{
|
|
/* Apply indoption to scankey (might change sk_strategy!) */
|
|
if (!_bt_fix_scankey_strategy(cur, indoption))
|
|
{
|
|
/* NULL can't be matched, so give up */
|
|
so->qual_ok = false;
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we are at the end of the keys for a particular attr, finish up
|
|
* processing and emit the cleaned-up keys.
|
|
*/
|
|
if (i == numberOfKeys || cur->sk_attno != attno)
|
|
{
|
|
int priorNumberOfEqualCols = numberOfEqualCols;
|
|
|
|
/* check input keys are correctly ordered */
|
|
if (i < numberOfKeys && cur->sk_attno < attno)
|
|
elog(ERROR, "btree index keys must be ordered by attribute");
|
|
|
|
/*
|
|
* If = has been specified, all other keys can be eliminated as
|
|
* redundant. If we have a case like key = 1 AND key > 2, we can
|
|
* set qual_ok to false and abandon further processing.
|
|
*
|
|
* We also have to deal with the case of "key IS NULL", which is
|
|
* unsatisfiable in combination with any other index condition. By
|
|
* the time we get here, that's been classified as an equality
|
|
* check, and we've rejected any combination of it with a regular
|
|
* equality condition; but not with other types of conditions.
|
|
*/
|
|
if (xform[BTEqualStrategyNumber - 1])
|
|
{
|
|
ScanKey eq = xform[BTEqualStrategyNumber - 1];
|
|
|
|
for (j = BTMaxStrategyNumber; --j >= 0;)
|
|
{
|
|
ScanKey chk = xform[j];
|
|
|
|
if (!chk || j == (BTEqualStrategyNumber - 1))
|
|
continue;
|
|
|
|
if (eq->sk_flags & SK_SEARCHNULL)
|
|
{
|
|
/* IS NULL is contradictory to anything else */
|
|
so->qual_ok = false;
|
|
return;
|
|
}
|
|
|
|
if (_bt_compare_scankey_args(scan, chk, eq, chk,
|
|
&test_result))
|
|
{
|
|
if (!test_result)
|
|
{
|
|
/* keys proven mutually contradictory */
|
|
so->qual_ok = false;
|
|
return;
|
|
}
|
|
/* else discard the redundant non-equality key */
|
|
xform[j] = NULL;
|
|
}
|
|
/* else, cannot determine redundancy, keep both keys */
|
|
}
|
|
/* track number of attrs for which we have "=" keys */
|
|
numberOfEqualCols++;
|
|
}
|
|
|
|
/* try to keep only one of <, <= */
|
|
if (xform[BTLessStrategyNumber - 1]
|
|
&& xform[BTLessEqualStrategyNumber - 1])
|
|
{
|
|
ScanKey lt = xform[BTLessStrategyNumber - 1];
|
|
ScanKey le = xform[BTLessEqualStrategyNumber - 1];
|
|
|
|
if (_bt_compare_scankey_args(scan, le, lt, le,
|
|
&test_result))
|
|
{
|
|
if (test_result)
|
|
xform[BTLessEqualStrategyNumber - 1] = NULL;
|
|
else
|
|
xform[BTLessStrategyNumber - 1] = NULL;
|
|
}
|
|
}
|
|
|
|
/* try to keep only one of >, >= */
|
|
if (xform[BTGreaterStrategyNumber - 1]
|
|
&& xform[BTGreaterEqualStrategyNumber - 1])
|
|
{
|
|
ScanKey gt = xform[BTGreaterStrategyNumber - 1];
|
|
ScanKey ge = xform[BTGreaterEqualStrategyNumber - 1];
|
|
|
|
if (_bt_compare_scankey_args(scan, ge, gt, ge,
|
|
&test_result))
|
|
{
|
|
if (test_result)
|
|
xform[BTGreaterEqualStrategyNumber - 1] = NULL;
|
|
else
|
|
xform[BTGreaterStrategyNumber - 1] = NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Emit the cleaned-up keys into the outkeys[] array, and then
|
|
* mark them if they are required. They are required (possibly
|
|
* only in one direction) if all attrs before this one had "=".
|
|
*/
|
|
for (j = BTMaxStrategyNumber; --j >= 0;)
|
|
{
|
|
if (xform[j])
|
|
{
|
|
ScanKey outkey = &outkeys[new_numberOfKeys++];
|
|
|
|
memcpy(outkey, xform[j], sizeof(ScanKeyData));
|
|
if (priorNumberOfEqualCols == attno - 1)
|
|
_bt_mark_scankey_required(outkey);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Exit loop here if done.
|
|
*/
|
|
if (i == numberOfKeys)
|
|
break;
|
|
|
|
/* Re-initialize for new attno */
|
|
attno = cur->sk_attno;
|
|
memset(xform, 0, sizeof(xform));
|
|
}
|
|
|
|
/* check strategy this key's operator corresponds to */
|
|
j = cur->sk_strategy - 1;
|
|
|
|
/* if row comparison, push it directly to the output array */
|
|
if (cur->sk_flags & SK_ROW_HEADER)
|
|
{
|
|
ScanKey outkey = &outkeys[new_numberOfKeys++];
|
|
|
|
memcpy(outkey, cur, sizeof(ScanKeyData));
|
|
if (numberOfEqualCols == attno - 1)
|
|
_bt_mark_scankey_required(outkey);
|
|
|
|
/*
|
|
* We don't support RowCompare using equality; such a qual would
|
|
* mess up the numberOfEqualCols tracking.
|
|
*/
|
|
Assert(j != (BTEqualStrategyNumber - 1));
|
|
continue;
|
|
}
|
|
|
|
/* have we seen one of these before? */
|
|
if (xform[j] == NULL)
|
|
{
|
|
/* nope, so remember this scankey */
|
|
xform[j] = cur;
|
|
}
|
|
else
|
|
{
|
|
/* yup, keep only the more restrictive key */
|
|
if (_bt_compare_scankey_args(scan, cur, cur, xform[j],
|
|
&test_result))
|
|
{
|
|
if (test_result)
|
|
xform[j] = cur;
|
|
else if (j == (BTEqualStrategyNumber - 1))
|
|
{
|
|
/* key == a && key == b, but a != b */
|
|
so->qual_ok = false;
|
|
return;
|
|
}
|
|
/* else old key is more restrictive, keep it */
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* We can't determine which key is more restrictive. Keep the
|
|
* previous one in xform[j] and push this one directly to the
|
|
* output array.
|
|
*/
|
|
ScanKey outkey = &outkeys[new_numberOfKeys++];
|
|
|
|
memcpy(outkey, cur, sizeof(ScanKeyData));
|
|
if (numberOfEqualCols == attno - 1)
|
|
_bt_mark_scankey_required(outkey);
|
|
}
|
|
}
|
|
}
|
|
|
|
so->numberOfKeys = new_numberOfKeys;
|
|
}
|
|
|
|
/*
|
|
* Compare two scankey values using a specified operator.
|
|
*
|
|
* The test we want to perform is logically "leftarg op rightarg", where
|
|
* leftarg and rightarg are the sk_argument values in those ScanKeys, and
|
|
* the comparison operator is the one in the op ScanKey. However, in
|
|
* cross-data-type situations we may need to look up the correct operator in
|
|
* the index's opfamily: it is the one having amopstrategy = op->sk_strategy
|
|
* and amoplefttype/amoprighttype equal to the two argument datatypes.
|
|
*
|
|
* If the opfamily doesn't supply a complete set of cross-type operators we
|
|
* may not be able to make the comparison. If we can make the comparison
|
|
* we store the operator result in *result and return true. We return false
|
|
* if the comparison could not be made.
|
|
*
|
|
* Note: op always points at the same ScanKey as either leftarg or rightarg.
|
|
* Since we don't scribble on the scankeys, this aliasing should cause no
|
|
* trouble.
|
|
*
|
|
* Note: this routine needs to be insensitive to any DESC option applied
|
|
* to the index column. For example, "x < 4" is a tighter constraint than
|
|
* "x < 5" regardless of which way the index is sorted.
|
|
*/
|
|
static bool
|
|
_bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
|
|
ScanKey leftarg, ScanKey rightarg,
|
|
bool *result)
|
|
{
|
|
Relation rel = scan->indexRelation;
|
|
Oid lefttype,
|
|
righttype,
|
|
optype,
|
|
opcintype,
|
|
cmp_op;
|
|
StrategyNumber strat;
|
|
|
|
/*
|
|
* First, deal with cases where one or both args are NULL. This should
|
|
* only happen when the scankeys represent IS NULL/NOT NULL conditions.
|
|
*/
|
|
if ((leftarg->sk_flags | rightarg->sk_flags) & SK_ISNULL)
|
|
{
|
|
bool leftnull,
|
|
rightnull;
|
|
|
|
if (leftarg->sk_flags & SK_ISNULL)
|
|
{
|
|
Assert(leftarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
|
|
leftnull = true;
|
|
}
|
|
else
|
|
leftnull = false;
|
|
if (rightarg->sk_flags & SK_ISNULL)
|
|
{
|
|
Assert(rightarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
|
|
rightnull = true;
|
|
}
|
|
else
|
|
rightnull = false;
|
|
|
|
/*
|
|
* We treat NULL as either greater than or less than all other values.
|
|
* Since true > false, the tests below work correctly for NULLS LAST
|
|
* logic. If the index is NULLS FIRST, we need to flip the strategy.
|
|
*/
|
|
strat = op->sk_strategy;
|
|
if (op->sk_flags & SK_BT_NULLS_FIRST)
|
|
strat = BTCommuteStrategyNumber(strat);
|
|
|
|
switch (strat)
|
|
{
|
|
case BTLessStrategyNumber:
|
|
*result = (leftnull < rightnull);
|
|
break;
|
|
case BTLessEqualStrategyNumber:
|
|
*result = (leftnull <= rightnull);
|
|
break;
|
|
case BTEqualStrategyNumber:
|
|
*result = (leftnull == rightnull);
|
|
break;
|
|
case BTGreaterEqualStrategyNumber:
|
|
*result = (leftnull >= rightnull);
|
|
break;
|
|
case BTGreaterStrategyNumber:
|
|
*result = (leftnull > rightnull);
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized StrategyNumber: %d", (int) strat);
|
|
*result = false; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* The opfamily we need to worry about is identified by the index column.
|
|
*/
|
|
Assert(leftarg->sk_attno == rightarg->sk_attno);
|
|
|
|
opcintype = rel->rd_opcintype[leftarg->sk_attno - 1];
|
|
|
|
/*
|
|
* Determine the actual datatypes of the ScanKey arguments. We have to
|
|
* support the convention that sk_subtype == InvalidOid means the opclass
|
|
* input type; this is a hack to simplify life for ScanKeyInit().
|
|
*/
|
|
lefttype = leftarg->sk_subtype;
|
|
if (lefttype == InvalidOid)
|
|
lefttype = opcintype;
|
|
righttype = rightarg->sk_subtype;
|
|
if (righttype == InvalidOid)
|
|
righttype = opcintype;
|
|
optype = op->sk_subtype;
|
|
if (optype == InvalidOid)
|
|
optype = opcintype;
|
|
|
|
/*
|
|
* If leftarg and rightarg match the types expected for the "op" scankey,
|
|
* we can use its already-looked-up comparison function.
|
|
*/
|
|
if (lefttype == opcintype && righttype == optype)
|
|
{
|
|
*result = DatumGetBool(FunctionCall2Coll(&op->sk_func,
|
|
op->sk_collation,
|
|
leftarg->sk_argument,
|
|
rightarg->sk_argument));
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Otherwise, we need to go to the syscache to find the appropriate
|
|
* operator. (This cannot result in infinite recursion, since no
|
|
* indexscan initiated by syscache lookup will use cross-data-type
|
|
* operators.)
|
|
*
|
|
* If the sk_strategy was flipped by _bt_fix_scankey_strategy, we have to
|
|
* un-flip it to get the correct opfamily member.
|
|
*/
|
|
strat = op->sk_strategy;
|
|
if (op->sk_flags & SK_BT_DESC)
|
|
strat = BTCommuteStrategyNumber(strat);
|
|
|
|
cmp_op = get_opfamily_member(rel->rd_opfamily[leftarg->sk_attno - 1],
|
|
lefttype,
|
|
righttype,
|
|
strat);
|
|
if (OidIsValid(cmp_op))
|
|
{
|
|
RegProcedure cmp_proc = get_opcode(cmp_op);
|
|
|
|
if (RegProcedureIsValid(cmp_proc))
|
|
{
|
|
*result = DatumGetBool(OidFunctionCall2Coll(cmp_proc,
|
|
op->sk_collation,
|
|
leftarg->sk_argument,
|
|
rightarg->sk_argument));
|
|
return true;
|
|
}
|
|
}
|
|
|
|
/* Can't make the comparison */
|
|
*result = false; /* suppress compiler warnings */
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Adjust a scankey's strategy and flags setting as needed for indoptions.
|
|
*
|
|
* We copy the appropriate indoption value into the scankey sk_flags
|
|
* (shifting to avoid clobbering system-defined flag bits). Also, if
|
|
* the DESC option is set, commute (flip) the operator strategy number.
|
|
*
|
|
* A secondary purpose is to check for IS NULL/NOT NULL scankeys and set up
|
|
* the strategy field correctly for them.
|
|
*
|
|
* Lastly, for ordinary scankeys (not IS NULL/NOT NULL), we check for a
|
|
* NULL comparison value. Since all btree operators are assumed strict,
|
|
* a NULL means that the qual cannot be satisfied. We return true if the
|
|
* comparison value isn't NULL, or false if the scan should be abandoned.
|
|
*
|
|
* This function is applied to the *input* scankey structure; therefore
|
|
* on a rescan we will be looking at already-processed scankeys. Hence
|
|
* we have to be careful not to re-commute the strategy if we already did it.
|
|
* It's a bit ugly to modify the caller's copy of the scankey but in practice
|
|
* there shouldn't be any problem, since the index's indoptions are certainly
|
|
* not going to change while the scankey survives.
|
|
*/
|
|
static bool
|
|
_bt_fix_scankey_strategy(ScanKey skey, int16 *indoption)
|
|
{
|
|
int addflags;
|
|
|
|
addflags = indoption[skey->sk_attno - 1] << SK_BT_INDOPTION_SHIFT;
|
|
|
|
/*
|
|
* We treat all btree operators as strict (even if they're not so marked
|
|
* in pg_proc). This means that it is impossible for an operator condition
|
|
* with a NULL comparison constant to succeed, and we can reject it right
|
|
* away.
|
|
*
|
|
* However, we now also support "x IS NULL" clauses as search conditions,
|
|
* so in that case keep going. The planner has not filled in any
|
|
* particular strategy in this case, so set it to BTEqualStrategyNumber
|
|
* --- we can treat IS NULL as an equality operator for purposes of search
|
|
* strategy.
|
|
*
|
|
* Likewise, "x IS NOT NULL" is supported. We treat that as either "less
|
|
* than NULL" in a NULLS LAST index, or "greater than NULL" in a NULLS
|
|
* FIRST index.
|
|
*
|
|
* Note: someday we might have to fill in sk_collation from the index
|
|
* column's collation. At the moment this is a non-issue because we'll
|
|
* never actually call the comparison operator on a NULL.
|
|
*/
|
|
if (skey->sk_flags & SK_ISNULL)
|
|
{
|
|
/* SK_ISNULL shouldn't be set in a row header scankey */
|
|
Assert(!(skey->sk_flags & SK_ROW_HEADER));
|
|
|
|
/* Set indoption flags in scankey (might be done already) */
|
|
skey->sk_flags |= addflags;
|
|
|
|
/* Set correct strategy for IS NULL or NOT NULL search */
|
|
if (skey->sk_flags & SK_SEARCHNULL)
|
|
{
|
|
skey->sk_strategy = BTEqualStrategyNumber;
|
|
skey->sk_subtype = InvalidOid;
|
|
skey->sk_collation = InvalidOid;
|
|
}
|
|
else if (skey->sk_flags & SK_SEARCHNOTNULL)
|
|
{
|
|
if (skey->sk_flags & SK_BT_NULLS_FIRST)
|
|
skey->sk_strategy = BTGreaterStrategyNumber;
|
|
else
|
|
skey->sk_strategy = BTLessStrategyNumber;
|
|
skey->sk_subtype = InvalidOid;
|
|
skey->sk_collation = InvalidOid;
|
|
}
|
|
else
|
|
{
|
|
/* regular qual, so it cannot be satisfied */
|
|
return false;
|
|
}
|
|
|
|
/* Needn't do the rest */
|
|
return true;
|
|
}
|
|
|
|
/* Adjust strategy for DESC, if we didn't already */
|
|
if ((addflags & SK_BT_DESC) && !(skey->sk_flags & SK_BT_DESC))
|
|
skey->sk_strategy = BTCommuteStrategyNumber(skey->sk_strategy);
|
|
skey->sk_flags |= addflags;
|
|
|
|
/* If it's a row header, fix row member flags and strategies similarly */
|
|
if (skey->sk_flags & SK_ROW_HEADER)
|
|
{
|
|
ScanKey subkey = (ScanKey) DatumGetPointer(skey->sk_argument);
|
|
|
|
for (;;)
|
|
{
|
|
Assert(subkey->sk_flags & SK_ROW_MEMBER);
|
|
addflags = indoption[subkey->sk_attno - 1] << SK_BT_INDOPTION_SHIFT;
|
|
if ((addflags & SK_BT_DESC) && !(subkey->sk_flags & SK_BT_DESC))
|
|
subkey->sk_strategy = BTCommuteStrategyNumber(subkey->sk_strategy);
|
|
subkey->sk_flags |= addflags;
|
|
if (subkey->sk_flags & SK_ROW_END)
|
|
break;
|
|
subkey++;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Mark a scankey as "required to continue the scan".
|
|
*
|
|
* Depending on the operator type, the key may be required for both scan
|
|
* directions or just one. Also, if the key is a row comparison header,
|
|
* we have to mark its first subsidiary ScanKey as required. (Subsequent
|
|
* subsidiary ScanKeys are normally for lower-order columns, and thus
|
|
* cannot be required, since they're after the first non-equality scankey.)
|
|
*
|
|
* Note: when we set required-key flag bits in a subsidiary scankey, we are
|
|
* scribbling on a data structure belonging to the index AM's caller, not on
|
|
* our private copy. This should be OK because the marking will not change
|
|
* from scan to scan within a query, and so we'd just re-mark the same way
|
|
* anyway on a rescan. Something to keep an eye on though.
|
|
*/
|
|
static void
|
|
_bt_mark_scankey_required(ScanKey skey)
|
|
{
|
|
int addflags;
|
|
|
|
switch (skey->sk_strategy)
|
|
{
|
|
case BTLessStrategyNumber:
|
|
case BTLessEqualStrategyNumber:
|
|
addflags = SK_BT_REQFWD;
|
|
break;
|
|
case BTEqualStrategyNumber:
|
|
addflags = SK_BT_REQFWD | SK_BT_REQBKWD;
|
|
break;
|
|
case BTGreaterEqualStrategyNumber:
|
|
case BTGreaterStrategyNumber:
|
|
addflags = SK_BT_REQBKWD;
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized StrategyNumber: %d",
|
|
(int) skey->sk_strategy);
|
|
addflags = 0; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
|
|
skey->sk_flags |= addflags;
|
|
|
|
if (skey->sk_flags & SK_ROW_HEADER)
|
|
{
|
|
ScanKey subkey = (ScanKey) DatumGetPointer(skey->sk_argument);
|
|
|
|
/* First subkey should be same column/operator as the header */
|
|
Assert(subkey->sk_flags & SK_ROW_MEMBER);
|
|
Assert(subkey->sk_attno == skey->sk_attno);
|
|
Assert(subkey->sk_strategy == skey->sk_strategy);
|
|
subkey->sk_flags |= addflags;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Test whether an indextuple satisfies all the scankey conditions.
|
|
*
|
|
* Return true if so, false if not. If the tuple fails to pass the qual,
|
|
* we also determine whether there's any need to continue the scan beyond
|
|
* this tuple, and set *continuescan accordingly. See comments for
|
|
* _bt_preprocess_keys(), above, about how this is done.
|
|
*
|
|
* Forward scan callers can pass a high key tuple in the hopes of having
|
|
* us set *continuescan to false, and avoiding an unnecessary visit to
|
|
* the page to the right.
|
|
*
|
|
* scan: index scan descriptor (containing a search-type scankey)
|
|
* tuple: index tuple to test
|
|
* tupnatts: number of attributes in tupnatts (high key may be truncated)
|
|
* dir: direction we are scanning in
|
|
* continuescan: output parameter (will be set correctly in all cases)
|
|
*/
|
|
bool
|
|
_bt_checkkeys(IndexScanDesc scan, IndexTuple tuple, int tupnatts,
|
|
ScanDirection dir, bool *continuescan)
|
|
{
|
|
TupleDesc tupdesc;
|
|
BTScanOpaque so;
|
|
int keysz;
|
|
int ikey;
|
|
ScanKey key;
|
|
|
|
Assert(BTreeTupleGetNAtts(tuple, scan->indexRelation) == tupnatts);
|
|
|
|
*continuescan = true; /* default assumption */
|
|
|
|
tupdesc = RelationGetDescr(scan->indexRelation);
|
|
so = (BTScanOpaque) scan->opaque;
|
|
keysz = so->numberOfKeys;
|
|
|
|
for (key = so->keyData, ikey = 0; ikey < keysz; key++, ikey++)
|
|
{
|
|
Datum datum;
|
|
bool isNull;
|
|
Datum test;
|
|
|
|
if (key->sk_attno > tupnatts)
|
|
{
|
|
/*
|
|
* This attribute is truncated (must be high key). The value for
|
|
* this attribute in the first non-pivot tuple on the page to the
|
|
* right could be any possible value. Assume that truncated
|
|
* attribute passes the qual.
|
|
*/
|
|
Assert(ScanDirectionIsForward(dir));
|
|
continue;
|
|
}
|
|
|
|
/* row-comparison keys need special processing */
|
|
if (key->sk_flags & SK_ROW_HEADER)
|
|
{
|
|
if (_bt_check_rowcompare(key, tuple, tupnatts, tupdesc, dir,
|
|
continuescan))
|
|
continue;
|
|
return false;
|
|
}
|
|
|
|
datum = index_getattr(tuple,
|
|
key->sk_attno,
|
|
tupdesc,
|
|
&isNull);
|
|
|
|
if (key->sk_flags & SK_ISNULL)
|
|
{
|
|
/* Handle IS NULL/NOT NULL tests */
|
|
if (key->sk_flags & SK_SEARCHNULL)
|
|
{
|
|
if (isNull)
|
|
continue; /* tuple satisfies this qual */
|
|
}
|
|
else
|
|
{
|
|
Assert(key->sk_flags & SK_SEARCHNOTNULL);
|
|
if (!isNull)
|
|
continue; /* tuple satisfies this qual */
|
|
}
|
|
|
|
/*
|
|
* Tuple fails this qual. If it's a required qual for the current
|
|
* scan direction, then we can conclude no further tuples will
|
|
* pass, either.
|
|
*/
|
|
if ((key->sk_flags & SK_BT_REQFWD) &&
|
|
ScanDirectionIsForward(dir))
|
|
*continuescan = false;
|
|
else if ((key->sk_flags & SK_BT_REQBKWD) &&
|
|
ScanDirectionIsBackward(dir))
|
|
*continuescan = false;
|
|
|
|
/*
|
|
* In any case, this indextuple doesn't match the qual.
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
if (isNull)
|
|
{
|
|
if (key->sk_flags & SK_BT_NULLS_FIRST)
|
|
{
|
|
/*
|
|
* Since NULLs are sorted before non-NULLs, we know we have
|
|
* reached the lower limit of the range of values for this
|
|
* index attr. On a backward scan, we can stop if this qual
|
|
* is one of the "must match" subset. We can stop regardless
|
|
* of whether the qual is > or <, so long as it's required,
|
|
* because it's not possible for any future tuples to pass. On
|
|
* a forward scan, however, we must keep going, because we may
|
|
* have initially positioned to the start of the index.
|
|
*/
|
|
if ((key->sk_flags & (SK_BT_REQFWD | SK_BT_REQBKWD)) &&
|
|
ScanDirectionIsBackward(dir))
|
|
*continuescan = false;
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* Since NULLs are sorted after non-NULLs, we know we have
|
|
* reached the upper limit of the range of values for this
|
|
* index attr. On a forward scan, we can stop if this qual is
|
|
* one of the "must match" subset. We can stop regardless of
|
|
* whether the qual is > or <, so long as it's required,
|
|
* because it's not possible for any future tuples to pass. On
|
|
* a backward scan, however, we must keep going, because we
|
|
* may have initially positioned to the end of the index.
|
|
*/
|
|
if ((key->sk_flags & (SK_BT_REQFWD | SK_BT_REQBKWD)) &&
|
|
ScanDirectionIsForward(dir))
|
|
*continuescan = false;
|
|
}
|
|
|
|
/*
|
|
* In any case, this indextuple doesn't match the qual.
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
test = FunctionCall2Coll(&key->sk_func, key->sk_collation,
|
|
datum, key->sk_argument);
|
|
|
|
if (!DatumGetBool(test))
|
|
{
|
|
/*
|
|
* Tuple fails this qual. If it's a required qual for the current
|
|
* scan direction, then we can conclude no further tuples will
|
|
* pass, either.
|
|
*
|
|
* Note: because we stop the scan as soon as any required equality
|
|
* qual fails, it is critical that equality quals be used for the
|
|
* initial positioning in _bt_first() when they are available. See
|
|
* comments in _bt_first().
|
|
*/
|
|
if ((key->sk_flags & SK_BT_REQFWD) &&
|
|
ScanDirectionIsForward(dir))
|
|
*continuescan = false;
|
|
else if ((key->sk_flags & SK_BT_REQBKWD) &&
|
|
ScanDirectionIsBackward(dir))
|
|
*continuescan = false;
|
|
|
|
/*
|
|
* In any case, this indextuple doesn't match the qual.
|
|
*/
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/* If we get here, the tuple passes all index quals. */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Test whether an indextuple satisfies a row-comparison scan condition.
|
|
*
|
|
* Return true if so, false if not. If not, also clear *continuescan if
|
|
* it's not possible for any future tuples in the current scan direction
|
|
* to pass the qual.
|
|
*
|
|
* This is a subroutine for _bt_checkkeys, which see for more info.
|
|
*/
|
|
static bool
|
|
_bt_check_rowcompare(ScanKey skey, IndexTuple tuple, int tupnatts,
|
|
TupleDesc tupdesc, ScanDirection dir, bool *continuescan)
|
|
{
|
|
ScanKey subkey = (ScanKey) DatumGetPointer(skey->sk_argument);
|
|
int32 cmpresult = 0;
|
|
bool result;
|
|
|
|
/* First subkey should be same as the header says */
|
|
Assert(subkey->sk_attno == skey->sk_attno);
|
|
|
|
/* Loop over columns of the row condition */
|
|
for (;;)
|
|
{
|
|
Datum datum;
|
|
bool isNull;
|
|
|
|
Assert(subkey->sk_flags & SK_ROW_MEMBER);
|
|
|
|
if (subkey->sk_attno > tupnatts)
|
|
{
|
|
/*
|
|
* This attribute is truncated (must be high key). The value for
|
|
* this attribute in the first non-pivot tuple on the page to the
|
|
* right could be any possible value. Assume that truncated
|
|
* attribute passes the qual.
|
|
*/
|
|
Assert(ScanDirectionIsForward(dir));
|
|
cmpresult = 0;
|
|
if (subkey->sk_flags & SK_ROW_END)
|
|
break;
|
|
subkey++;
|
|
continue;
|
|
}
|
|
|
|
datum = index_getattr(tuple,
|
|
subkey->sk_attno,
|
|
tupdesc,
|
|
&isNull);
|
|
|
|
if (isNull)
|
|
{
|
|
if (subkey->sk_flags & SK_BT_NULLS_FIRST)
|
|
{
|
|
/*
|
|
* Since NULLs are sorted before non-NULLs, we know we have
|
|
* reached the lower limit of the range of values for this
|
|
* index attr. On a backward scan, we can stop if this qual
|
|
* is one of the "must match" subset. We can stop regardless
|
|
* of whether the qual is > or <, so long as it's required,
|
|
* because it's not possible for any future tuples to pass. On
|
|
* a forward scan, however, we must keep going, because we may
|
|
* have initially positioned to the start of the index.
|
|
*/
|
|
if ((subkey->sk_flags & (SK_BT_REQFWD | SK_BT_REQBKWD)) &&
|
|
ScanDirectionIsBackward(dir))
|
|
*continuescan = false;
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* Since NULLs are sorted after non-NULLs, we know we have
|
|
* reached the upper limit of the range of values for this
|
|
* index attr. On a forward scan, we can stop if this qual is
|
|
* one of the "must match" subset. We can stop regardless of
|
|
* whether the qual is > or <, so long as it's required,
|
|
* because it's not possible for any future tuples to pass. On
|
|
* a backward scan, however, we must keep going, because we
|
|
* may have initially positioned to the end of the index.
|
|
*/
|
|
if ((subkey->sk_flags & (SK_BT_REQFWD | SK_BT_REQBKWD)) &&
|
|
ScanDirectionIsForward(dir))
|
|
*continuescan = false;
|
|
}
|
|
|
|
/*
|
|
* In any case, this indextuple doesn't match the qual.
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
if (subkey->sk_flags & SK_ISNULL)
|
|
{
|
|
/*
|
|
* Unlike the simple-scankey case, this isn't a disallowed case.
|
|
* But it can never match. If all the earlier row comparison
|
|
* columns are required for the scan direction, we can stop the
|
|
* scan, because there can't be another tuple that will succeed.
|
|
*/
|
|
if (subkey != (ScanKey) DatumGetPointer(skey->sk_argument))
|
|
subkey--;
|
|
if ((subkey->sk_flags & SK_BT_REQFWD) &&
|
|
ScanDirectionIsForward(dir))
|
|
*continuescan = false;
|
|
else if ((subkey->sk_flags & SK_BT_REQBKWD) &&
|
|
ScanDirectionIsBackward(dir))
|
|
*continuescan = false;
|
|
return false;
|
|
}
|
|
|
|
/* Perform the test --- three-way comparison not bool operator */
|
|
cmpresult = DatumGetInt32(FunctionCall2Coll(&subkey->sk_func,
|
|
subkey->sk_collation,
|
|
datum,
|
|
subkey->sk_argument));
|
|
|
|
if (subkey->sk_flags & SK_BT_DESC)
|
|
INVERT_COMPARE_RESULT(cmpresult);
|
|
|
|
/* Done comparing if unequal, else advance to next column */
|
|
if (cmpresult != 0)
|
|
break;
|
|
|
|
if (subkey->sk_flags & SK_ROW_END)
|
|
break;
|
|
subkey++;
|
|
}
|
|
|
|
/*
|
|
* At this point cmpresult indicates the overall result of the row
|
|
* comparison, and subkey points to the deciding column (or the last
|
|
* column if the result is "=").
|
|
*/
|
|
switch (subkey->sk_strategy)
|
|
{
|
|
/* EQ and NE cases aren't allowed here */
|
|
case BTLessStrategyNumber:
|
|
result = (cmpresult < 0);
|
|
break;
|
|
case BTLessEqualStrategyNumber:
|
|
result = (cmpresult <= 0);
|
|
break;
|
|
case BTGreaterEqualStrategyNumber:
|
|
result = (cmpresult >= 0);
|
|
break;
|
|
case BTGreaterStrategyNumber:
|
|
result = (cmpresult > 0);
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized RowCompareType: %d",
|
|
(int) subkey->sk_strategy);
|
|
result = 0; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
|
|
if (!result)
|
|
{
|
|
/*
|
|
* Tuple fails this qual. If it's a required qual for the current
|
|
* scan direction, then we can conclude no further tuples will pass,
|
|
* either. Note we have to look at the deciding column, not
|
|
* necessarily the first or last column of the row condition.
|
|
*/
|
|
if ((subkey->sk_flags & SK_BT_REQFWD) &&
|
|
ScanDirectionIsForward(dir))
|
|
*continuescan = false;
|
|
else if ((subkey->sk_flags & SK_BT_REQBKWD) &&
|
|
ScanDirectionIsBackward(dir))
|
|
*continuescan = false;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* _bt_killitems - set LP_DEAD state for items an indexscan caller has
|
|
* told us were killed
|
|
*
|
|
* scan->opaque, referenced locally through so, contains information about the
|
|
* current page and killed tuples thereon (generally, this should only be
|
|
* called if so->numKilled > 0).
|
|
*
|
|
* The caller does not have a lock on the page and may or may not have the
|
|
* page pinned in a buffer. Note that read-lock is sufficient for setting
|
|
* LP_DEAD status (which is only a hint).
|
|
*
|
|
* We match items by heap TID before assuming they are the right ones to
|
|
* delete. We cope with cases where items have moved right due to insertions.
|
|
* If an item has moved off the current page due to a split, we'll fail to
|
|
* find it and do nothing (this is not an error case --- we assume the item
|
|
* will eventually get marked in a future indexscan).
|
|
*
|
|
* Note that if we hold a pin on the target page continuously from initially
|
|
* reading the items until applying this function, VACUUM cannot have deleted
|
|
* any items from the page, and so there is no need to search left from the
|
|
* recorded offset. (This observation also guarantees that the item is still
|
|
* the right one to delete, which might otherwise be questionable since heap
|
|
* TIDs can get recycled.) This holds true even if the page has been modified
|
|
* by inserts and page splits, so there is no need to consult the LSN.
|
|
*
|
|
* If the pin was released after reading the page, then we re-read it. If it
|
|
* has been modified since we read it (as determined by the LSN), we dare not
|
|
* flag any entries because it is possible that the old entry was vacuumed
|
|
* away and the TID was re-used by a completely different heap tuple.
|
|
*/
|
|
void
|
|
_bt_killitems(IndexScanDesc scan)
|
|
{
|
|
BTScanOpaque so = (BTScanOpaque) scan->opaque;
|
|
Page page;
|
|
BTPageOpaque opaque;
|
|
OffsetNumber minoff;
|
|
OffsetNumber maxoff;
|
|
int i;
|
|
int numKilled = so->numKilled;
|
|
bool killedsomething = false;
|
|
|
|
Assert(BTScanPosIsValid(so->currPos));
|
|
|
|
/*
|
|
* Always reset the scan state, so we don't look for same items on other
|
|
* pages.
|
|
*/
|
|
so->numKilled = 0;
|
|
|
|
if (BTScanPosIsPinned(so->currPos))
|
|
{
|
|
/*
|
|
* We have held the pin on this page since we read the index tuples,
|
|
* so all we need to do is lock it. The pin will have prevented
|
|
* re-use of any TID on the page, so there is no need to check the
|
|
* LSN.
|
|
*/
|
|
LockBuffer(so->currPos.buf, BT_READ);
|
|
|
|
page = BufferGetPage(so->currPos.buf);
|
|
}
|
|
else
|
|
{
|
|
Buffer buf;
|
|
|
|
/* Attempt to re-read the buffer, getting pin and lock. */
|
|
buf = _bt_getbuf(scan->indexRelation, so->currPos.currPage, BT_READ);
|
|
|
|
/* It might not exist anymore; in which case we can't hint it. */
|
|
if (!BufferIsValid(buf))
|
|
return;
|
|
|
|
page = BufferGetPage(buf);
|
|
if (BufferGetLSNAtomic(buf) == so->currPos.lsn)
|
|
so->currPos.buf = buf;
|
|
else
|
|
{
|
|
/* Modified while not pinned means hinting is not safe. */
|
|
_bt_relbuf(scan->indexRelation, buf);
|
|
return;
|
|
}
|
|
}
|
|
|
|
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
|
|
minoff = P_FIRSTDATAKEY(opaque);
|
|
maxoff = PageGetMaxOffsetNumber(page);
|
|
|
|
for (i = 0; i < numKilled; i++)
|
|
{
|
|
int itemIndex = so->killedItems[i];
|
|
BTScanPosItem *kitem = &so->currPos.items[itemIndex];
|
|
OffsetNumber offnum = kitem->indexOffset;
|
|
|
|
Assert(itemIndex >= so->currPos.firstItem &&
|
|
itemIndex <= so->currPos.lastItem);
|
|
if (offnum < minoff)
|
|
continue; /* pure paranoia */
|
|
while (offnum <= maxoff)
|
|
{
|
|
ItemId iid = PageGetItemId(page, offnum);
|
|
IndexTuple ituple = (IndexTuple) PageGetItem(page, iid);
|
|
|
|
if (ItemPointerEquals(&ituple->t_tid, &kitem->heapTid))
|
|
{
|
|
/* found the item */
|
|
ItemIdMarkDead(iid);
|
|
killedsomething = true;
|
|
break; /* out of inner search loop */
|
|
}
|
|
offnum = OffsetNumberNext(offnum);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Since this can be redone later if needed, mark as dirty hint.
|
|
*
|
|
* Whenever we mark anything LP_DEAD, we also set the page's
|
|
* BTP_HAS_GARBAGE flag, which is likewise just a hint.
|
|
*/
|
|
if (killedsomething)
|
|
{
|
|
opaque->btpo_flags |= BTP_HAS_GARBAGE;
|
|
MarkBufferDirtyHint(so->currPos.buf, true);
|
|
}
|
|
|
|
LockBuffer(so->currPos.buf, BUFFER_LOCK_UNLOCK);
|
|
}
|
|
|
|
|
|
/*
|
|
* The following routines manage a shared-memory area in which we track
|
|
* assignment of "vacuum cycle IDs" to currently-active btree vacuuming
|
|
* operations. There is a single counter which increments each time we
|
|
* start a vacuum to assign it a cycle ID. Since multiple vacuums could
|
|
* be active concurrently, we have to track the cycle ID for each active
|
|
* vacuum; this requires at most MaxBackends entries (usually far fewer).
|
|
* We assume at most one vacuum can be active for a given index.
|
|
*
|
|
* Access to the shared memory area is controlled by BtreeVacuumLock.
|
|
* In principle we could use a separate lmgr locktag for each index,
|
|
* but a single LWLock is much cheaper, and given the short time that
|
|
* the lock is ever held, the concurrency hit should be minimal.
|
|
*/
|
|
|
|
typedef struct BTOneVacInfo
|
|
{
|
|
LockRelId relid; /* global identifier of an index */
|
|
BTCycleId cycleid; /* cycle ID for its active VACUUM */
|
|
} BTOneVacInfo;
|
|
|
|
typedef struct BTVacInfo
|
|
{
|
|
BTCycleId cycle_ctr; /* cycle ID most recently assigned */
|
|
int num_vacuums; /* number of currently active VACUUMs */
|
|
int max_vacuums; /* allocated length of vacuums[] array */
|
|
BTOneVacInfo vacuums[FLEXIBLE_ARRAY_MEMBER];
|
|
} BTVacInfo;
|
|
|
|
static BTVacInfo *btvacinfo;
|
|
|
|
|
|
/*
|
|
* _bt_vacuum_cycleid --- get the active vacuum cycle ID for an index,
|
|
* or zero if there is no active VACUUM
|
|
*
|
|
* Note: for correct interlocking, the caller must already hold pin and
|
|
* exclusive lock on each buffer it will store the cycle ID into. This
|
|
* ensures that even if a VACUUM starts immediately afterwards, it cannot
|
|
* process those pages until the page split is complete.
|
|
*/
|
|
BTCycleId
|
|
_bt_vacuum_cycleid(Relation rel)
|
|
{
|
|
BTCycleId result = 0;
|
|
int i;
|
|
|
|
/* Share lock is enough since this is a read-only operation */
|
|
LWLockAcquire(BtreeVacuumLock, LW_SHARED);
|
|
|
|
for (i = 0; i < btvacinfo->num_vacuums; i++)
|
|
{
|
|
BTOneVacInfo *vac = &btvacinfo->vacuums[i];
|
|
|
|
if (vac->relid.relId == rel->rd_lockInfo.lockRelId.relId &&
|
|
vac->relid.dbId == rel->rd_lockInfo.lockRelId.dbId)
|
|
{
|
|
result = vac->cycleid;
|
|
break;
|
|
}
|
|
}
|
|
|
|
LWLockRelease(BtreeVacuumLock);
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* _bt_start_vacuum --- assign a cycle ID to a just-starting VACUUM operation
|
|
*
|
|
* Note: the caller must guarantee that it will eventually call
|
|
* _bt_end_vacuum, else we'll permanently leak an array slot. To ensure
|
|
* that this happens even in elog(FATAL) scenarios, the appropriate coding
|
|
* is not just a PG_TRY, but
|
|
* PG_ENSURE_ERROR_CLEANUP(_bt_end_vacuum_callback, PointerGetDatum(rel))
|
|
*/
|
|
BTCycleId
|
|
_bt_start_vacuum(Relation rel)
|
|
{
|
|
BTCycleId result;
|
|
int i;
|
|
BTOneVacInfo *vac;
|
|
|
|
LWLockAcquire(BtreeVacuumLock, LW_EXCLUSIVE);
|
|
|
|
/*
|
|
* Assign the next cycle ID, being careful to avoid zero as well as the
|
|
* reserved high values.
|
|
*/
|
|
result = ++(btvacinfo->cycle_ctr);
|
|
if (result == 0 || result > MAX_BT_CYCLE_ID)
|
|
result = btvacinfo->cycle_ctr = 1;
|
|
|
|
/* Let's just make sure there's no entry already for this index */
|
|
for (i = 0; i < btvacinfo->num_vacuums; i++)
|
|
{
|
|
vac = &btvacinfo->vacuums[i];
|
|
if (vac->relid.relId == rel->rd_lockInfo.lockRelId.relId &&
|
|
vac->relid.dbId == rel->rd_lockInfo.lockRelId.dbId)
|
|
{
|
|
/*
|
|
* Unlike most places in the backend, we have to explicitly
|
|
* release our LWLock before throwing an error. This is because
|
|
* we expect _bt_end_vacuum() to be called before transaction
|
|
* abort cleanup can run to release LWLocks.
|
|
*/
|
|
LWLockRelease(BtreeVacuumLock);
|
|
elog(ERROR, "multiple active vacuums for index \"%s\"",
|
|
RelationGetRelationName(rel));
|
|
}
|
|
}
|
|
|
|
/* OK, add an entry */
|
|
if (btvacinfo->num_vacuums >= btvacinfo->max_vacuums)
|
|
{
|
|
LWLockRelease(BtreeVacuumLock);
|
|
elog(ERROR, "out of btvacinfo slots");
|
|
}
|
|
vac = &btvacinfo->vacuums[btvacinfo->num_vacuums];
|
|
vac->relid = rel->rd_lockInfo.lockRelId;
|
|
vac->cycleid = result;
|
|
btvacinfo->num_vacuums++;
|
|
|
|
LWLockRelease(BtreeVacuumLock);
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* _bt_end_vacuum --- mark a btree VACUUM operation as done
|
|
*
|
|
* Note: this is deliberately coded not to complain if no entry is found;
|
|
* this allows the caller to put PG_TRY around the start_vacuum operation.
|
|
*/
|
|
void
|
|
_bt_end_vacuum(Relation rel)
|
|
{
|
|
int i;
|
|
|
|
LWLockAcquire(BtreeVacuumLock, LW_EXCLUSIVE);
|
|
|
|
/* Find the array entry */
|
|
for (i = 0; i < btvacinfo->num_vacuums; i++)
|
|
{
|
|
BTOneVacInfo *vac = &btvacinfo->vacuums[i];
|
|
|
|
if (vac->relid.relId == rel->rd_lockInfo.lockRelId.relId &&
|
|
vac->relid.dbId == rel->rd_lockInfo.lockRelId.dbId)
|
|
{
|
|
/* Remove it by shifting down the last entry */
|
|
*vac = btvacinfo->vacuums[btvacinfo->num_vacuums - 1];
|
|
btvacinfo->num_vacuums--;
|
|
break;
|
|
}
|
|
}
|
|
|
|
LWLockRelease(BtreeVacuumLock);
|
|
}
|
|
|
|
/*
|
|
* _bt_end_vacuum wrapped as an on_shmem_exit callback function
|
|
*/
|
|
void
|
|
_bt_end_vacuum_callback(int code, Datum arg)
|
|
{
|
|
_bt_end_vacuum((Relation) DatumGetPointer(arg));
|
|
}
|
|
|
|
/*
|
|
* BTreeShmemSize --- report amount of shared memory space needed
|
|
*/
|
|
Size
|
|
BTreeShmemSize(void)
|
|
{
|
|
Size size;
|
|
|
|
size = offsetof(BTVacInfo, vacuums);
|
|
size = add_size(size, mul_size(MaxBackends, sizeof(BTOneVacInfo)));
|
|
return size;
|
|
}
|
|
|
|
/*
|
|
* BTreeShmemInit --- initialize this module's shared memory
|
|
*/
|
|
void
|
|
BTreeShmemInit(void)
|
|
{
|
|
bool found;
|
|
|
|
btvacinfo = (BTVacInfo *) ShmemInitStruct("BTree Vacuum State",
|
|
BTreeShmemSize(),
|
|
&found);
|
|
|
|
if (!IsUnderPostmaster)
|
|
{
|
|
/* Initialize shared memory area */
|
|
Assert(!found);
|
|
|
|
/*
|
|
* It doesn't really matter what the cycle counter starts at, but
|
|
* having it always start the same doesn't seem good. Seed with
|
|
* low-order bits of time() instead.
|
|
*/
|
|
btvacinfo->cycle_ctr = (BTCycleId) time(NULL);
|
|
|
|
btvacinfo->num_vacuums = 0;
|
|
btvacinfo->max_vacuums = MaxBackends;
|
|
}
|
|
else
|
|
Assert(found);
|
|
}
|
|
|
|
bytea *
|
|
btoptions(Datum reloptions, bool validate)
|
|
{
|
|
static const relopt_parse_elt tab[] = {
|
|
{"fillfactor", RELOPT_TYPE_INT, offsetof(BTOptions, fillfactor)},
|
|
{"vacuum_cleanup_index_scale_factor", RELOPT_TYPE_REAL,
|
|
offsetof(BTOptions, vacuum_cleanup_index_scale_factor)}
|
|
|
|
};
|
|
|
|
return (bytea *) build_reloptions(reloptions, validate,
|
|
RELOPT_KIND_BTREE,
|
|
sizeof(BTOptions),
|
|
tab, lengthof(tab));
|
|
|
|
}
|
|
|
|
/*
|
|
* btproperty() -- Check boolean properties of indexes.
|
|
*
|
|
* This is optional, but handling AMPROP_RETURNABLE here saves opening the rel
|
|
* to call btcanreturn.
|
|
*/
|
|
bool
|
|
btproperty(Oid index_oid, int attno,
|
|
IndexAMProperty prop, const char *propname,
|
|
bool *res, bool *isnull)
|
|
{
|
|
switch (prop)
|
|
{
|
|
case AMPROP_RETURNABLE:
|
|
/* answer only for columns, not AM or whole index */
|
|
if (attno == 0)
|
|
return false;
|
|
/* otherwise, btree can always return data */
|
|
*res = true;
|
|
return true;
|
|
|
|
default:
|
|
return false; /* punt to generic code */
|
|
}
|
|
}
|
|
|
|
/*
|
|
* btbuildphasename() -- Return name of index build phase.
|
|
*/
|
|
char *
|
|
btbuildphasename(int64 phasenum)
|
|
{
|
|
switch (phasenum)
|
|
{
|
|
case PROGRESS_CREATEIDX_SUBPHASE_INITIALIZE:
|
|
return "initializing";
|
|
case PROGRESS_BTREE_PHASE_INDEXBUILD_TABLESCAN:
|
|
return "scanning table";
|
|
case PROGRESS_BTREE_PHASE_PERFORMSORT_1:
|
|
return "sorting live tuples";
|
|
case PROGRESS_BTREE_PHASE_PERFORMSORT_2:
|
|
return "sorting dead tuples";
|
|
case PROGRESS_BTREE_PHASE_LEAF_LOAD:
|
|
return "loading tuples in tree";
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* _bt_truncate() -- create tuple without unneeded suffix attributes.
|
|
*
|
|
* Returns truncated pivot index tuple allocated in caller's memory context,
|
|
* with key attributes copied from caller's firstright argument. If rel is
|
|
* an INCLUDE index, non-key attributes will definitely be truncated away,
|
|
* since they're not part of the key space. More aggressive suffix
|
|
* truncation can take place when it's clear that the returned tuple does not
|
|
* need one or more suffix key attributes. We only need to keep firstright
|
|
* attributes up to and including the first non-lastleft-equal attribute.
|
|
* Caller's insertion scankey is used to compare the tuples; the scankey's
|
|
* argument values are not considered here.
|
|
*
|
|
* Note that returned tuple's t_tid offset will hold the number of attributes
|
|
* present, so the original item pointer offset is not represented. Caller
|
|
* should only change truncated tuple's downlink. Note also that truncated
|
|
* key attributes are treated as containing "minus infinity" values by
|
|
* _bt_compare().
|
|
*
|
|
* In the worst case (when a heap TID must be appended to distinguish lastleft
|
|
* from firstright), the size of the returned tuple is the size of firstright
|
|
* plus the size of an additional MAXALIGN()'d item pointer. This guarantee
|
|
* is important, since callers need to stay under the 1/3 of a page
|
|
* restriction on tuple size. If this routine is ever taught to truncate
|
|
* within an attribute/datum, it will need to avoid returning an enlarged
|
|
* tuple to caller when truncation + TOAST compression ends up enlarging the
|
|
* final datum.
|
|
*/
|
|
IndexTuple
|
|
_bt_truncate(Relation rel, IndexTuple lastleft, IndexTuple firstright,
|
|
BTScanInsert itup_key)
|
|
{
|
|
TupleDesc itupdesc = RelationGetDescr(rel);
|
|
int16 natts = IndexRelationGetNumberOfAttributes(rel);
|
|
int16 nkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
|
|
int keepnatts;
|
|
IndexTuple pivot;
|
|
ItemPointer pivotheaptid;
|
|
Size newsize;
|
|
|
|
/*
|
|
* We should only ever truncate leaf index tuples. It's never okay to
|
|
* truncate a second time.
|
|
*/
|
|
Assert(BTreeTupleGetNAtts(lastleft, rel) == natts);
|
|
Assert(BTreeTupleGetNAtts(firstright, rel) == natts);
|
|
|
|
/* Determine how many attributes must be kept in truncated tuple */
|
|
keepnatts = _bt_keep_natts(rel, lastleft, firstright, itup_key);
|
|
|
|
#ifdef DEBUG_NO_TRUNCATE
|
|
/* Force truncation to be ineffective for testing purposes */
|
|
keepnatts = nkeyatts + 1;
|
|
#endif
|
|
|
|
if (keepnatts <= natts)
|
|
{
|
|
IndexTuple tidpivot;
|
|
|
|
pivot = index_truncate_tuple(itupdesc, firstright, keepnatts);
|
|
|
|
/*
|
|
* If there is a distinguishing key attribute within new pivot tuple,
|
|
* there is no need to add an explicit heap TID attribute
|
|
*/
|
|
if (keepnatts <= nkeyatts)
|
|
{
|
|
BTreeTupleSetNAtts(pivot, keepnatts);
|
|
return pivot;
|
|
}
|
|
|
|
/*
|
|
* Only truncation of non-key attributes was possible, since key
|
|
* attributes are all equal. It's necessary to add a heap TID
|
|
* attribute to the new pivot tuple.
|
|
*/
|
|
Assert(natts != nkeyatts);
|
|
newsize = IndexTupleSize(pivot) + MAXALIGN(sizeof(ItemPointerData));
|
|
tidpivot = palloc0(newsize);
|
|
memcpy(tidpivot, pivot, IndexTupleSize(pivot));
|
|
/* cannot leak memory here */
|
|
pfree(pivot);
|
|
pivot = tidpivot;
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* No truncation was possible, since key attributes are all equal.
|
|
* It's necessary to add a heap TID attribute to the new pivot tuple.
|
|
*/
|
|
Assert(natts == nkeyatts);
|
|
newsize = IndexTupleSize(firstright) + MAXALIGN(sizeof(ItemPointerData));
|
|
pivot = palloc0(newsize);
|
|
memcpy(pivot, firstright, IndexTupleSize(firstright));
|
|
}
|
|
|
|
/*
|
|
* We have to use heap TID as a unique-ifier in the new pivot tuple, since
|
|
* no non-TID key attribute in the right item readily distinguishes the
|
|
* right side of the split from the left side. Use enlarged space that
|
|
* holds a copy of first right tuple; place a heap TID value within the
|
|
* extra space that remains at the end.
|
|
*
|
|
* nbtree conceptualizes this case as an inability to truncate away any
|
|
* key attribute. We must use an alternative representation of heap TID
|
|
* within pivots because heap TID is only treated as an attribute within
|
|
* nbtree (e.g., there is no pg_attribute entry).
|
|
*/
|
|
Assert(itup_key->heapkeyspace);
|
|
pivot->t_info &= ~INDEX_SIZE_MASK;
|
|
pivot->t_info |= newsize;
|
|
|
|
/*
|
|
* Lehman & Yao use lastleft as the leaf high key in all cases, but don't
|
|
* consider suffix truncation. It seems like a good idea to follow that
|
|
* example in cases where no truncation takes place -- use lastleft's heap
|
|
* TID. (This is also the closest value to negative infinity that's
|
|
* legally usable.)
|
|
*/
|
|
pivotheaptid = (ItemPointer) ((char *) pivot + newsize -
|
|
sizeof(ItemPointerData));
|
|
ItemPointerCopy(&lastleft->t_tid, pivotheaptid);
|
|
|
|
/*
|
|
* Lehman and Yao require that the downlink to the right page, which is to
|
|
* be inserted into the parent page in the second phase of a page split be
|
|
* a strict lower bound on items on the right page, and a non-strict upper
|
|
* bound for items on the left page. Assert that heap TIDs follow these
|
|
* invariants, since a heap TID value is apparently needed as a
|
|
* tiebreaker.
|
|
*/
|
|
#ifndef DEBUG_NO_TRUNCATE
|
|
Assert(ItemPointerCompare(&lastleft->t_tid, &firstright->t_tid) < 0);
|
|
Assert(ItemPointerCompare(pivotheaptid, &lastleft->t_tid) >= 0);
|
|
Assert(ItemPointerCompare(pivotheaptid, &firstright->t_tid) < 0);
|
|
#else
|
|
|
|
/*
|
|
* Those invariants aren't guaranteed to hold for lastleft + firstright
|
|
* heap TID attribute values when they're considered here only because
|
|
* DEBUG_NO_TRUNCATE is defined (a heap TID is probably not actually
|
|
* needed as a tiebreaker). DEBUG_NO_TRUNCATE must therefore use a heap
|
|
* TID value that always works as a strict lower bound for items to the
|
|
* right. In particular, it must avoid using firstright's leading key
|
|
* attribute values along with lastleft's heap TID value when lastleft's
|
|
* TID happens to be greater than firstright's TID.
|
|
*/
|
|
ItemPointerCopy(&firstright->t_tid, pivotheaptid);
|
|
|
|
/*
|
|
* Pivot heap TID should never be fully equal to firstright. Note that
|
|
* the pivot heap TID will still end up equal to lastleft's heap TID when
|
|
* that's the only usable value.
|
|
*/
|
|
ItemPointerSetOffsetNumber(pivotheaptid,
|
|
OffsetNumberPrev(ItemPointerGetOffsetNumber(pivotheaptid)));
|
|
Assert(ItemPointerCompare(pivotheaptid, &firstright->t_tid) < 0);
|
|
#endif
|
|
|
|
BTreeTupleSetNAtts(pivot, nkeyatts);
|
|
BTreeTupleSetAltHeapTID(pivot);
|
|
|
|
return pivot;
|
|
}
|
|
|
|
/*
|
|
* _bt_keep_natts - how many key attributes to keep when truncating.
|
|
*
|
|
* Caller provides two tuples that enclose a split point. Caller's insertion
|
|
* scankey is used to compare the tuples; the scankey's argument values are
|
|
* not considered here.
|
|
*
|
|
* This can return a number of attributes that is one greater than the
|
|
* number of key attributes for the index relation. This indicates that the
|
|
* caller must use a heap TID as a unique-ifier in new pivot tuple.
|
|
*/
|
|
static int
|
|
_bt_keep_natts(Relation rel, IndexTuple lastleft, IndexTuple firstright,
|
|
BTScanInsert itup_key)
|
|
{
|
|
int nkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
|
|
TupleDesc itupdesc = RelationGetDescr(rel);
|
|
int keepnatts;
|
|
ScanKey scankey;
|
|
|
|
/*
|
|
* Be consistent about the representation of BTREE_VERSION 2/3 tuples
|
|
* across Postgres versions; don't allow new pivot tuples to have
|
|
* truncated key attributes there. _bt_compare() treats truncated key
|
|
* attributes as having the value minus infinity, which would break
|
|
* searches within !heapkeyspace indexes.
|
|
*/
|
|
if (!itup_key->heapkeyspace)
|
|
{
|
|
Assert(nkeyatts != IndexRelationGetNumberOfAttributes(rel));
|
|
return nkeyatts;
|
|
}
|
|
|
|
scankey = itup_key->scankeys;
|
|
keepnatts = 1;
|
|
for (int attnum = 1; attnum <= nkeyatts; attnum++, scankey++)
|
|
{
|
|
Datum datum1,
|
|
datum2;
|
|
bool isNull1,
|
|
isNull2;
|
|
|
|
datum1 = index_getattr(lastleft, attnum, itupdesc, &isNull1);
|
|
datum2 = index_getattr(firstright, attnum, itupdesc, &isNull2);
|
|
|
|
if (isNull1 != isNull2)
|
|
break;
|
|
|
|
if (!isNull1 &&
|
|
DatumGetInt32(FunctionCall2Coll(&scankey->sk_func,
|
|
scankey->sk_collation,
|
|
datum1,
|
|
datum2)) != 0)
|
|
break;
|
|
|
|
keepnatts++;
|
|
}
|
|
|
|
return keepnatts;
|
|
}
|
|
|
|
/*
|
|
* _bt_keep_natts_fast - fast bitwise variant of _bt_keep_natts.
|
|
*
|
|
* This is exported so that a candidate split point can have its effect on
|
|
* suffix truncation inexpensively evaluated ahead of time when finding a
|
|
* split location. A naive bitwise approach to datum comparisons is used to
|
|
* save cycles.
|
|
*
|
|
* The approach taken here usually provides the same answer as _bt_keep_natts
|
|
* will (for the same pair of tuples from a heapkeyspace index), since the
|
|
* majority of btree opclasses can never indicate that two datums are equal
|
|
* unless they're bitwise equal after detoasting.
|
|
*
|
|
* These issues must be acceptable to callers, typically because they're only
|
|
* concerned about making suffix truncation as effective as possible without
|
|
* leaving excessive amounts of free space on either side of page split.
|
|
* Callers can rely on the fact that attributes considered equal here are
|
|
* definitely also equal according to _bt_keep_natts.
|
|
*/
|
|
int
|
|
_bt_keep_natts_fast(Relation rel, IndexTuple lastleft, IndexTuple firstright)
|
|
{
|
|
TupleDesc itupdesc = RelationGetDescr(rel);
|
|
int keysz = IndexRelationGetNumberOfKeyAttributes(rel);
|
|
int keepnatts;
|
|
|
|
keepnatts = 1;
|
|
for (int attnum = 1; attnum <= keysz; attnum++)
|
|
{
|
|
Datum datum1,
|
|
datum2;
|
|
bool isNull1,
|
|
isNull2;
|
|
Form_pg_attribute att;
|
|
|
|
datum1 = index_getattr(lastleft, attnum, itupdesc, &isNull1);
|
|
datum2 = index_getattr(firstright, attnum, itupdesc, &isNull2);
|
|
att = TupleDescAttr(itupdesc, attnum - 1);
|
|
|
|
if (isNull1 != isNull2)
|
|
break;
|
|
|
|
if (!isNull1 &&
|
|
!datum_image_eq(datum1, datum2, att->attbyval, att->attlen))
|
|
break;
|
|
|
|
keepnatts++;
|
|
}
|
|
|
|
return keepnatts;
|
|
}
|
|
|
|
/*
|
|
* _bt_check_natts() -- Verify tuple has expected number of attributes.
|
|
*
|
|
* Returns value indicating if the expected number of attributes were found
|
|
* for a particular offset on page. This can be used as a general purpose
|
|
* sanity check.
|
|
*
|
|
* Testing a tuple directly with BTreeTupleGetNAtts() should generally be
|
|
* preferred to calling here. That's usually more convenient, and is always
|
|
* more explicit. Call here instead when offnum's tuple may be a negative
|
|
* infinity tuple that uses the pre-v11 on-disk representation, or when a low
|
|
* context check is appropriate. This routine is as strict as possible about
|
|
* what is expected on each version of btree.
|
|
*/
|
|
bool
|
|
_bt_check_natts(Relation rel, bool heapkeyspace, Page page, OffsetNumber offnum)
|
|
{
|
|
int16 natts = IndexRelationGetNumberOfAttributes(rel);
|
|
int16 nkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
|
|
BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
|
|
IndexTuple itup;
|
|
int tupnatts;
|
|
|
|
/*
|
|
* We cannot reliably test a deleted or half-dead page, since they have
|
|
* dummy high keys
|
|
*/
|
|
if (P_IGNORE(opaque))
|
|
return true;
|
|
|
|
Assert(offnum >= FirstOffsetNumber &&
|
|
offnum <= PageGetMaxOffsetNumber(page));
|
|
|
|
/*
|
|
* Mask allocated for number of keys in index tuple must be able to fit
|
|
* maximum possible number of index attributes
|
|
*/
|
|
StaticAssertStmt(BT_N_KEYS_OFFSET_MASK >= INDEX_MAX_KEYS,
|
|
"BT_N_KEYS_OFFSET_MASK can't fit INDEX_MAX_KEYS");
|
|
|
|
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, offnum));
|
|
tupnatts = BTreeTupleGetNAtts(itup, rel);
|
|
|
|
if (P_ISLEAF(opaque))
|
|
{
|
|
if (offnum >= P_FIRSTDATAKEY(opaque))
|
|
{
|
|
/*
|
|
* Non-pivot tuples currently never use alternative heap TID
|
|
* representation -- even those within heapkeyspace indexes
|
|
*/
|
|
if ((itup->t_info & INDEX_ALT_TID_MASK) != 0)
|
|
return false;
|
|
|
|
/*
|
|
* Leaf tuples that are not the page high key (non-pivot tuples)
|
|
* should never be truncated. (Note that tupnatts must have been
|
|
* inferred, rather than coming from an explicit on-disk
|
|
* representation.)
|
|
*/
|
|
return tupnatts == natts;
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* Rightmost page doesn't contain a page high key, so tuple was
|
|
* checked above as ordinary leaf tuple
|
|
*/
|
|
Assert(!P_RIGHTMOST(opaque));
|
|
|
|
/*
|
|
* !heapkeyspace high key tuple contains only key attributes. Note
|
|
* that tupnatts will only have been explicitly represented in
|
|
* !heapkeyspace indexes that happen to have non-key attributes.
|
|
*/
|
|
if (!heapkeyspace)
|
|
return tupnatts == nkeyatts;
|
|
|
|
/* Use generic heapkeyspace pivot tuple handling */
|
|
}
|
|
}
|
|
else /* !P_ISLEAF(opaque) */
|
|
{
|
|
if (offnum == P_FIRSTDATAKEY(opaque))
|
|
{
|
|
/*
|
|
* The first tuple on any internal page (possibly the first after
|
|
* its high key) is its negative infinity tuple. Negative
|
|
* infinity tuples are always truncated to zero attributes. They
|
|
* are a particular kind of pivot tuple.
|
|
*/
|
|
if (heapkeyspace)
|
|
return tupnatts == 0;
|
|
|
|
/*
|
|
* The number of attributes won't be explicitly represented if the
|
|
* negative infinity tuple was generated during a page split that
|
|
* occurred with a version of Postgres before v11. There must be
|
|
* a problem when there is an explicit representation that is
|
|
* non-zero, or when there is no explicit representation and the
|
|
* tuple is evidently not a pre-pg_upgrade tuple.
|
|
*
|
|
* Prior to v11, downlinks always had P_HIKEY as their offset. Use
|
|
* that to decide if the tuple is a pre-v11 tuple.
|
|
*/
|
|
return tupnatts == 0 ||
|
|
((itup->t_info & INDEX_ALT_TID_MASK) == 0 &&
|
|
ItemPointerGetOffsetNumber(&(itup->t_tid)) == P_HIKEY);
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* !heapkeyspace downlink tuple with separator key contains only
|
|
* key attributes. Note that tupnatts will only have been
|
|
* explicitly represented in !heapkeyspace indexes that happen to
|
|
* have non-key attributes.
|
|
*/
|
|
if (!heapkeyspace)
|
|
return tupnatts == nkeyatts;
|
|
|
|
/* Use generic heapkeyspace pivot tuple handling */
|
|
}
|
|
|
|
}
|
|
|
|
/* Handle heapkeyspace pivot tuples (excluding minus infinity items) */
|
|
Assert(heapkeyspace);
|
|
|
|
/*
|
|
* Explicit representation of the number of attributes is mandatory with
|
|
* heapkeyspace index pivot tuples, regardless of whether or not there are
|
|
* non-key attributes.
|
|
*/
|
|
if ((itup->t_info & INDEX_ALT_TID_MASK) == 0)
|
|
return false;
|
|
|
|
/*
|
|
* Heap TID is a tiebreaker key attribute, so it cannot be untruncated
|
|
* when any other key attribute is truncated
|
|
*/
|
|
if (BTreeTupleGetHeapTID(itup) != NULL && tupnatts != nkeyatts)
|
|
return false;
|
|
|
|
/*
|
|
* Pivot tuple must have at least one untruncated key attribute (minus
|
|
* infinity pivot tuples are the only exception). Pivot tuples can never
|
|
* represent that there is a value present for a key attribute that
|
|
* exceeds pg_index.indnkeyatts for the index.
|
|
*/
|
|
return tupnatts > 0 && tupnatts <= nkeyatts;
|
|
}
|
|
|
|
/*
|
|
*
|
|
* _bt_check_third_page() -- check whether tuple fits on a btree page at all.
|
|
*
|
|
* We actually need to be able to fit three items on every page, so restrict
|
|
* any one item to 1/3 the per-page available space. Note that itemsz should
|
|
* not include the ItemId overhead.
|
|
*
|
|
* It might be useful to apply TOAST methods rather than throw an error here.
|
|
* Using out of line storage would break assumptions made by suffix truncation
|
|
* and by contrib/amcheck, though.
|
|
*/
|
|
void
|
|
_bt_check_third_page(Relation rel, Relation heap, bool needheaptidspace,
|
|
Page page, IndexTuple newtup)
|
|
{
|
|
Size itemsz;
|
|
BTPageOpaque opaque;
|
|
|
|
itemsz = MAXALIGN(IndexTupleSize(newtup));
|
|
|
|
/* Double check item size against limit */
|
|
if (itemsz <= BTMaxItemSize(page))
|
|
return;
|
|
|
|
/*
|
|
* Tuple is probably too large to fit on page, but it's possible that the
|
|
* index uses version 2 or version 3, or that page is an internal page, in
|
|
* which case a slightly higher limit applies.
|
|
*/
|
|
if (!needheaptidspace && itemsz <= BTMaxItemSizeNoHeapTid(page))
|
|
return;
|
|
|
|
/*
|
|
* Internal page insertions cannot fail here, because that would mean that
|
|
* an earlier leaf level insertion that should have failed didn't
|
|
*/
|
|
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
|
|
if (!P_ISLEAF(opaque))
|
|
elog(ERROR, "cannot insert oversized tuple of size %zu on internal page of index \"%s\"",
|
|
itemsz, RelationGetRelationName(rel));
|
|
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
|
|
errmsg("index row size %zu exceeds btree version %u maximum %zu for index \"%s\"",
|
|
itemsz,
|
|
needheaptidspace ? BTREE_VERSION : BTREE_NOVAC_VERSION,
|
|
needheaptidspace ? BTMaxItemSize(page) :
|
|
BTMaxItemSizeNoHeapTid(page),
|
|
RelationGetRelationName(rel)),
|
|
errdetail("Index row references tuple (%u,%u) in relation \"%s\".",
|
|
ItemPointerGetBlockNumber(&newtup->t_tid),
|
|
ItemPointerGetOffsetNumber(&newtup->t_tid),
|
|
RelationGetRelationName(heap)),
|
|
errhint("Values larger than 1/3 of a buffer page cannot be indexed.\n"
|
|
"Consider a function index of an MD5 hash of the value, "
|
|
"or use full text indexing."),
|
|
errtableconstraint(heap, RelationGetRelationName(rel))));
|
|
}
|