* nbtutils.c
* Utility code for Postgres btree implementation.
*
- * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
{
ScanKey skey;
TupleDesc itupdesc;
- int natts;
+ int indnatts PG_USED_FOR_ASSERTS_ONLY;
+ int indnkeyatts;
int16 *indoption;
int i;
itupdesc = RelationGetDescr(rel);
- natts = RelationGetNumberOfAttributes(rel);
+ indnatts = IndexRelationGetNumberOfAttributes(rel);
+ indnkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
indoption = rel->rd_indoption;
- skey = (ScanKey) palloc(natts * sizeof(ScanKeyData));
+ Assert(indnkeyatts > 0);
+ Assert(indnkeyatts <= indnatts);
+ Assert(BTreeTupleGetNAtts(itup, rel) == indnatts ||
+ BTreeTupleGetNAtts(itup, rel) == indnkeyatts);
- for (i = 0; i < natts; i++)
+ /*
+ * We'll execute search using scan key constructed on key columns. Non-key
+ * (INCLUDE index) columns are always omitted from scan keys.
+ */
+ skey = (ScanKey) palloc(indnkeyatts * sizeof(ScanKeyData));
+
+ for (i = 0; i < indnkeyatts; i++)
{
FmgrInfo *procinfo;
Datum arg;
_bt_mkscankey_nodata(Relation rel)
{
ScanKey skey;
- int natts;
+ int indnkeyatts;
int16 *indoption;
int i;
- natts = RelationGetNumberOfAttributes(rel);
+ indnkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
indoption = rel->rd_indoption;
- skey = (ScanKey) palloc(natts * sizeof(ScanKeyData));
+ skey = (ScanKey) palloc(indnkeyatts * sizeof(ScanKeyData));
- for (i = 0; i < natts; i++)
+ for (i = 0; i < indnkeyatts; i++)
{
FmgrInfo *procinfo;
int flags;
*/
if (so->arrayContext == NULL)
so->arrayContext = AllocSetContextCreate(CurrentMemoryContext,
- "BTree Array Context",
- ALLOCSET_SMALL_MINSIZE,
- ALLOCSET_SMALL_INITSIZE,
- ALLOCSET_SMALL_MAXSIZE);
+ "BTree array context",
+ ALLOCSET_SMALL_SIZES);
else
MemoryContextReset(so->arrayContext);
* successive primitive indexscans produce data in index order.
*/
num_elems = _bt_sort_array_elements(scan, cur,
- (indoption[cur->sk_attno - 1] & INDOPTION_DESC) != 0,
+ (indoption[cur->sk_attno - 1] & INDOPTION_DESC) != 0,
elem_values, num_nonnulls);
/*
/*
* _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.
+ * 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)
break;
}
+ /* advance parallel scan */
+ if (scan->parallel_scan != NULL)
+ _bt_parallel_advance_array_keys(scan);
+
return found;
}
* 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,
+ * 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
*
* 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
+ * 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.
*result = DatumGetBool(OidFunctionCall2Coll(cmp_proc,
op->sk_collation,
leftarg->sk_argument,
- rightarg->sk_argument));
+ rightarg->sk_argument));
return true;
}
}
*
* 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.
+ * 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
*
* 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 the appropriate subsidiary ScanKeys as required. In
- * such cases, the first subsidiary key is required, but subsequent ones
- * are required only as long as they correspond to successive index columns
- * and match the leading column as to sort direction.
- * Otherwise the row comparison ordering is different from the index ordering
- * and so we can't stop the scan on the basis of those lower-order columns.
+ * 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
if (skey->sk_flags & SK_ROW_HEADER)
{
ScanKey subkey = (ScanKey) DatumGetPointer(skey->sk_argument);
- AttrNumber attno = skey->sk_attno;
-
- /* First subkey should be same as the header says */
- Assert(subkey->sk_attno == attno);
- for (;;)
- {
- Assert(subkey->sk_flags & SK_ROW_MEMBER);
- if (subkey->sk_attno != attno)
- break; /* non-adjacent key, so not required */
- if (subkey->sk_strategy != skey->sk_strategy)
- break; /* wrong direction, so not required */
- subkey->sk_flags |= addflags;
- if (subkey->sk_flags & SK_ROW_END)
- break;
- subkey++;
- attno++;
- }
+ /* 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;
}
}
bool isNull;
Datum test;
- /*
- * If the scan key has already matched we can skip this key, as long
- * as the index tuple does not contain NULL values.
- */
- if (key->sk_flags & SK_BT_MATCHED && !IndexTupleHasNulls(tuple))
- continue;
-
+ Assert(key->sk_attno <= BTreeTupleGetNAtts(tuple, scan->indexRelation));
/* row-comparison keys need special processing */
if (key->sk_flags & SK_ROW_HEADER)
{
return;
page = BufferGetPage(buf);
- if (PageGetLSN(page) == so->currPos.lsn)
+ if (BufferGetLSNAtomic(buf) == so->currPos.lsn)
so->currPos.buf = buf;
else
{
{
return default_reloptions(reloptions, validate, RELOPT_KIND_BTREE);
}
+
+/*
+ * 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 */
+ }
+}
+
+/*
+ * _bt_nonkey_truncate() -- create tuple without non-key suffix attributes.
+ *
+ * Returns truncated index tuple allocated in caller's memory context, with key
+ * attributes copied from caller's itup argument. Currently, suffix truncation
+ * is only performed to create pivot tuples in INCLUDE indexes, but some day it
+ * could be generalized to remove suffix attributes after the first
+ * distinguishing key attribute.
+ *
+ * Truncated tuple is guaranteed to be no larger than the original, which is
+ * important for staying under the 1/3 of a page restriction on tuple size.
+ *
+ * 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.
+ */
+IndexTuple
+_bt_nonkey_truncate(Relation rel, IndexTuple itup)
+{
+ int nkeyattrs = IndexRelationGetNumberOfKeyAttributes(rel);
+ IndexTuple truncated;
+
+ /*
+ * We should only ever truncate leaf index tuples, which must have both key
+ * and non-key attributes. It's never okay to truncate a second time.
+ */
+ Assert(BTreeTupleGetNAtts(itup, rel) ==
+ IndexRelationGetNumberOfAttributes(rel));
+
+ truncated = index_truncate_tuple(RelationGetDescr(rel), itup, nkeyattrs);
+ BTreeTupleSetNAtts(truncated, nkeyattrs);
+
+ return truncated;
+}
+
+/*
+ * _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.
+ */
+bool
+_bt_check_natts(Relation rel, Page page, OffsetNumber offnum)
+{
+ int16 natts = IndexRelationGetNumberOfAttributes(rel);
+ int16 nkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
+ BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
+ IndexTuple itup;
+
+ /*
+ * We cannot reliably test a deleted or half-deleted 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));
+
+ if (P_ISLEAF(opaque))
+ {
+ if (offnum >= P_FIRSTDATAKEY(opaque))
+ {
+ /*
+ * Leaf tuples that are not the page high key (non-pivot tuples)
+ * should never be truncated
+ */
+ return BTreeTupleGetNAtts(itup, rel) == natts;
+ }
+ else
+ {
+ /*
+ * Rightmost page doesn't contain a page high key, so tuple was
+ * checked above as ordinary leaf tuple
+ */
+ Assert(!P_RIGHTMOST(opaque));
+
+ /* Page high key tuple contains only key attributes */
+ return BTreeTupleGetNAtts(itup, rel) == nkeyatts;
+ }
+ }
+ 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.
+ *
+ * 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 BTreeTupleGetNAtts(itup, rel) == 0 ||
+ ((itup->t_info & INDEX_ALT_TID_MASK) == 0 &&
+ ItemPointerGetOffsetNumber(&(itup->t_tid)) == P_HIKEY);
+ }
+ else
+ {
+ /*
+ * Tuple contains only key attributes despite on is it page high
+ * key or not
+ */
+ return BTreeTupleGetNAtts(itup, rel) == nkeyatts;
+ }
+
+ }
+}
projects / postgresql / blobdiff