*
* nbtutils.cpp
* Utility code for openGauss btree implementation.
*
* Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd.
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/gausskernel/storage/access/nbtree/nbtutils.cpp
*
* -------------------------------------------------------------------------
*/
#include <time.h>
#include "postgres.h"
#include "knl/knl_variable.h"
#include "access/nbtree.h"
#include "access/reloptions.h"
#include "access/relscan.h"
#include "miscadmin.h"
#include "utils/array.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/rel_gs.h"
#include "utils/fmgroids.h"
typedef struct BTSortArrayContext {
FmgrInfo flinfo;
Oid collation;
bool reverse;
} BTSortArrayContextInfo;
static Datum _bt_find_extreme_element(IndexScanDesc scan, ScanKey skey, StrategyNumber strat, const Datum *elems,
int nelems);
static int _bt_compare_array_elements(const void *a, const void *b, void *arg);
static bool _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op, ScanKey leftarg, ScanKey rightarg, bool *result);
static bool _bt_fix_scankey_strategy(ScanKey skey, const int16 *indoption);
static void _bt_mark_scankey_required(ScanKey skey);
static int btree_num_keep_atts(Relation rel, IndexTuple lastleft, IndexTuple firstright, BTScanInsert itup_key);
* _bt_mkscankey
* Build an insertion scan key that contains comparison data from itup
* as well as comparator routines appropriate to the key datatypes.
*
* The result is intended for use with _bt_compare().
*/
BTScanInsert _bt_mkscankey(Relation rel, IndexTuple itup)
{
BTScanInsert key;
TupleDesc itupdesc;
int indnatts PG_USED_FOR_ASSERTS_ONLY;
int indnkeyatts;
int num_tuple_attrs = itup ? BTREE_TUPLE_GET_NUM_OF_ATTS(itup, rel) : 0;
int16* indoption = NULL;
itupdesc = RelationGetDescr(rel);
indnatts = IndexRelationGetNumberOfAttributes(rel);
indnkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
indoption = rel->rd_indoption;
Assert(indnkeyatts != 0);
Assert(indnkeyatts <= indnatts);
Assert(num_tuple_attrs <= indnatts);
* We'll execute search using ScanKey constructed on key columns. Non key
* (included) columns must be omitted.
*/
key = (BTScanInsert)palloc(offsetof(BTScanInsertData, scankeys) + indnkeyatts * sizeof(ScanKeyData));
if (IsSystemRelation(rel) || t_thrd.proc->workingVersionNum < NBTREE_INSERT_OPTIMIZATION_VERSION_NUM) {
key->heapkeyspace = false;
key->allequalimage = false;
} else if (itup) {
btree_meta_version(rel, &key->heapkeyspace, &key->allequalimage);
} else {
key->heapkeyspace = true;
key->allequalimage = false;
}
key->anynullkeys = false;
key->nextkey = false;
key->pivotsearch = false;
key->keysz = Min(indnkeyatts, num_tuple_attrs);
key->scantid = key->heapkeyspace && itup ? btree_tuple_get_heap_tid(itup) : NULL;
for (int i = 0; i < indnkeyatts; i++) {
FmgrInfo* procinfo = NULL;
Datum arg;
bool null = false;
uint32 flags;
* We can use the cached (default) support procs since no cross-type
* comparison can be needed.
*/
procinfo = index_getprocinfo(rel, i + 1, (uint16)BTORDER_PROC);
if (i < num_tuple_attrs)
arg = index_getattr(itup, i + 1, itupdesc, &null);
else
{
arg = (Datum) 0;
null = true;
}
flags = (null ? SK_ISNULL : 0) | (((uint16)indoption[i]) << SK_BT_INDOPTION_SHIFT);
ScanKeyEntryInitializeWithInfo(&key->scankeys[i], flags, (AttrNumber)(i + 1), InvalidStrategy, InvalidOid,
rel->rd_indcollation[i], procinfo, arg);
}
return key;
}
* _bt_mkscankey_nodata
* Build an insertion scan key that contains 3-way comparator routines
* appropriate to the key datatypes, but no comparison data. The
* comparison data ultimately used must match the key datatypes.
*
* The result cannot be used with _bt_compare(), unless comparison
* data is first stored into the key entries. Currently this
* routine is only called by nbtsort.c and tuplesort.c, which have
* their own comparison routines.
*/
ScanKey _bt_mkscankey_nodata(Relation rel)
{
ScanKey skey;
int indnkeyatts;
int16* indoption = NULL;
int i;
indnkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
indoption = rel->rd_indoption;
skey = (ScanKey) palloc(indnkeyatts * sizeof(ScanKeyData));
for (i = 0; i < indnkeyatts; i++) {
FmgrInfo* procinfo = NULL;
uint32 flags;
* We can use the cached (default) support procs since no cross-type
* comparison can be needed.
*/
procinfo = index_getprocinfo(rel, i + 1, (uint16)BTORDER_PROC);
flags = SK_ISNULL | (((uint16)indoption[i]) << SK_BT_INDOPTION_SHIFT);
ScanKeyEntryInitializeWithInfo(&skey[i], flags, (AttrNumber)(i + 1), InvalidStrategy, InvalidOid,
rel->rd_indcollation[i], procinfo, (Datum)0);
}
return skey;
}
* free a scan key made by either _bt_mkscankey or _bt_mkscankey_nodata.
*/
void _bt_freeskey(ScanKey skey)
{
pfree(skey);
skey = NULL;
}
* free a retracement stack made by _bt_search.
*/
void _bt_freestack(BTStack stack)
{
BTStack ostack;
while (stack != NULL) {
ostack = stack;
stack = stack->bts_parent;
pfree(ostack);
ostack = NULL;
}
}
* _bt_preprocess_array_keys() -- Preprocess SK_SEARCHARRAY scan keys
*
* If there are any SK_SEARCHARRAY scan keys, deconstruct the array(s) and
* set up BTArrayKeyInfo info for each one that is an equality-type key.
* Prepare modified scan keys in so->arrayKeyData, which will hold the current
* array elements during each primitive indexscan operation. For inequality
* array keys, it's sufficient to find the extreme element value and replace
* the whole array with that scalar value.
*
* Note: the reason we need so->arrayKeyData, rather than just scribbling
* on scan->keyData, is that callers are permitted to call btrescan without
* supplying a new set of scankey data.
*/
void _bt_preprocess_array_keys(IndexScanDesc scan)
{
BTScanOpaque so = (BTScanOpaque)scan->opaque;
int numberOfKeys = scan->numberOfKeys;
int16 *indoption = scan->indexRelation->rd_indoption;
int numArrayKeys;
ScanKey cur;
int i;
MemoryContext oldContext;
errno_t rc;
numArrayKeys = 0;
for (i = 0; i < numberOfKeys; i++) {
cur = &scan->keyData[i];
if (cur->sk_flags & SK_SEARCHARRAY) {
numArrayKeys++;
Assert(!(cur->sk_flags & (SK_ROW_HEADER | SK_SEARCHNULL | SK_SEARCHNOTNULL)));
if (cur->sk_flags & SK_ISNULL) {
so->numArrayKeys = -1;
so->arrayKeyData = NULL;
return;
}
}
}
if (numArrayKeys == 0) {
so->numArrayKeys = 0;
so->arrayKeyData = NULL;
return;
}
* Make a scan-lifespan context to hold array-associated data, or reset it
* if we already have one from a previous rescan cycle.
*/
if (so->arrayContext == NULL) {
so->arrayContext = AllocSetContextCreate(CurrentMemoryContext, "BTree Array Context", ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE, ALLOCSET_SMALL_MAXSIZE);
} else {
MemoryContextReset(so->arrayContext);
}
oldContext = MemoryContextSwitchTo(so->arrayContext);
so->arrayKeyData = (ScanKey)palloc(scan->numberOfKeys * sizeof(ScanKeyData));
rc = memcpy_s(so->arrayKeyData, scan->numberOfKeys * sizeof(ScanKeyData), scan->keyData,
scan->numberOfKeys * sizeof(ScanKeyData));
securec_check(rc, "", "");
so->arrayKeys = (BTArrayKeyInfo *)palloc0(numArrayKeys * sizeof(BTArrayKeyInfo));
numArrayKeys = 0;
for (i = 0; i < numberOfKeys; i++) {
ArrayType *arrayval = NULL;
int16 elmlen;
bool elmbyval = false;
char elmalign;
int num_elems;
Datum *elem_values = NULL;
bool *elem_nulls = NULL;
int num_nonnulls;
int j;
cur = &so->arrayKeyData[i];
if (!(cur->sk_flags & SK_SEARCHARRAY)) {
continue;
}
* First, deconstruct the array into elements. Anything allocated
* here (including a possibly detoasted array value) is in the
* workspace context.
*/
arrayval = DatumGetArrayTypeP(cur->sk_argument);
get_typlenbyvalalign(ARR_ELEMTYPE(arrayval), &elmlen, &elmbyval, &elmalign);
deconstruct_array(arrayval, ARR_ELEMTYPE(arrayval), elmlen, elmbyval, elmalign, &elem_values, &elem_nulls,
&num_elems);
* Compress out any null elements. We can ignore them since we assume
* all btree operators are strict.
*/
num_nonnulls = 0;
for (j = 0; j < num_elems; j++) {
if (!elem_nulls[j]) {
elem_values[num_nonnulls++] = elem_values[j];
}
}
* If there's no non-nulls, the scan qual is unsatisfiable
*/
if (num_nonnulls == 0) {
numArrayKeys = -1;
break;
}
* If the comparison operator is not equality, then the array qual
* degenerates to a simple comparison against the smallest or largest
* non-null array element, as appropriate.
*/
switch (cur->sk_strategy) {
case BTLessStrategyNumber:
case BTLessEqualStrategyNumber:
cur->sk_argument = _bt_find_extreme_element(scan, cur, BTGreaterStrategyNumber, elem_values,
num_nonnulls);
continue;
case BTEqualStrategyNumber:
break;
case BTGreaterEqualStrategyNumber:
case BTGreaterStrategyNumber:
cur->sk_argument = _bt_find_extreme_element(scan, cur, BTLessStrategyNumber, elem_values, num_nonnulls);
continue;
default:
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unrecognized StrategyNumber: %d", (int)cur->sk_strategy)));
break;
}
* Sort the non-null elements and eliminate any duplicates. We must
* sort in the same ordering used by the index column, so that the
* successive primitive indexscans produce data in index order.
*/
num_elems = _bt_sort_array_elements(scan, cur, (indoption[cur->sk_attno - 1] & INDOPTION_DESC) != 0,
elem_values, num_nonnulls);
* And set up the BTArrayKeyInfo data.
*/
so->arrayKeys[numArrayKeys].scan_key = i;
so->arrayKeys[numArrayKeys].num_elems = num_elems;
so->arrayKeys[numArrayKeys].elem_values = elem_values;
numArrayKeys++;
}
so->numArrayKeys = numArrayKeys;
MemoryContextSwitchTo(oldContext);
}
* _bt_find_extreme_element() -- get least or greatest array element
*
* scan and skey identify the index column, whose opfamily determines the
* comparison semantics. strat should be BTLessStrategyNumber to get the
* least element, or BTGreaterStrategyNumber to get the greatest.
*/
static Datum _bt_find_extreme_element(IndexScanDesc scan, const ScanKey skey, StrategyNumber strat, const Datum *elems,
int nelems)
{
Relation rel = scan->indexRelation;
Oid elemtype, cmp_op;
RegProcedure cmp_proc;
FmgrInfo flinfo;
Datum result;
int i;
* Determine the nominal datatype of the array elements. We have to
* support the convention that sk_subtype == InvalidOid means the opclass
* input type; this is a hack to simplify life for ScanKeyInit().
*/
elemtype = skey->sk_subtype;
if (elemtype == InvalidOid) {
elemtype = rel->rd_opcintype[skey->sk_attno - 1];
}
* Look up the appropriate comparison operator in the opfamily.
*
* Note: it's possible that this would fail, if the opfamily is
* incomplete, but it seems quite unlikely that an opfamily would omit
* non-cross-type comparison operators for any datatype that it supports
* at all.
*/
cmp_op = get_opfamily_member(rel->rd_opfamily[skey->sk_attno - 1], elemtype, elemtype, strat);
if (!OidIsValid(cmp_op)) {
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR), errmsg("missing operator %d(%u,%u) in opfamily %u", strat, elemtype,
elemtype, rel->rd_opfamily[skey->sk_attno - 1])));
}
cmp_proc = get_opcode(cmp_op);
if (!RegProcedureIsValid(cmp_proc)) {
ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("missing oprcode for operator %u", cmp_op)));
}
fmgr_info(cmp_proc, &flinfo);
Assert(nelems > 0);
result = elems[0];
for (i = 1; i < nelems; i++) {
if (DatumGetBool(FunctionCall2Coll(&flinfo, skey->sk_collation, elems[i], result))) {
result = elems[i];
}
}
return result;
}
* _bt_sort_array_elements() -- sort and de-dup array elements
*
* The array elements are sorted in-place, and the new number of elements
* after duplicate removal is returned.
*
* scan and skey identify the index column, whose opfamily determines the
* comparison semantics. If reverse is true, we sort in descending order.
*/
int _bt_sort_array_elements(IndexScanDesc scan, const ScanKey skey, bool reverse, Datum *elems, int nelems)
{
Relation rel = scan->indexRelation;
Oid elemtype;
RegProcedure cmp_proc;
BTSortArrayContext cxt = {0};
int last_non_dup;
int i;
if (nelems <= 1) {
return nelems;
}
* Determine the nominal datatype of the array elements. We have to
* support the convention that sk_subtype == InvalidOid means the opclass
* input type; this is a hack to simplify life for ScanKeyInit().
*/
elemtype = skey->sk_subtype;
if (elemtype == InvalidOid) {
elemtype = rel->rd_opcintype[skey->sk_attno - 1];
}
* Look up the appropriate comparison function in the opfamily.
*
* Note: it's possible that this would fail, if the opfamily is
* incomplete, but it seems quite unlikely that an opfamily would omit
* non-cross-type support functions for any datatype that it supports at
* all.
*/
Oid opclass = GetDefaultOpClass(elemtype, BTREE_AM_OID);
if (InvalidOid == opclass) {
ereport(ERROR,
(errcode(ERRCODE_CASE_NOT_FOUND), errmsg("Invalid opclass for type %d.", elemtype)));
}
Oid opfamily = get_opclass_family(opclass);
cmp_proc = get_opfamily_proc(opfamily, elemtype, elemtype, BTORDER_PROC);
if (!RegProcedureIsValid(cmp_proc)) {
ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR),
errmsg("missing support function %d(%u,%u) in opfamily %u", BTORDER_PROC, elemtype, elemtype,
opfamily)));
}
fmgr_info(cmp_proc, &cxt.flinfo);
cxt.collation = skey->sk_collation;
cxt.reverse = reverse;
qsort_arg((void *)elems, (size_t)nelems, sizeof(Datum), _bt_compare_array_elements, (void *)&cxt);
last_non_dup = 0;
for (i = 1; i < nelems; i++) {
int32 compare;
compare = DatumGetInt32(FunctionCall2Coll(&cxt.flinfo, cxt.collation, elems[last_non_dup], elems[i]));
if (compare != 0) {
elems[++last_non_dup] = elems[i];
}
}
return last_non_dup + 1;
}
* qsort_arg comparator for sorting array elements
*/
static int _bt_compare_array_elements(const void *a, const void *b, void *arg)
{
Datum da = *((const Datum *)a);
Datum db = *((const Datum *)b);
BTSortArrayContext *cxt = (BTSortArrayContext *)arg;
int32 compare;
compare = DatumGetInt32(FunctionCall2Coll(&cxt->flinfo, cxt->collation, da, db));
if (cxt->reverse) {
compare = -compare;
}
return compare;
}
* _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;
for (int 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;
} else {
found = true;
}
} else {
if (++cur_elem >= num_elems) {
cur_elem = 0;
found = false;
} else {
found = true;
}
}
curArrayKey->cur_elem = cur_elem;
skey->sk_argument = curArrayKey->elem_values[cur_elem];
if (found) {
break;
}
}
if (scan->parallelScan != 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;
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);
Assert(so->qual_ok);
}
}
#define RESET_STRATEGY_KEYS(xform) do { \
xform[0] = NULL; \
xform[1] = NULL; \
xform[2] = NULL; \
xform[3] = NULL; \
xform[4] = NULL; \
} while (0)
* _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_flag 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;
bool test_result = false;
int i, j;
AttrNumber attno;
so->qual_ok = true;
so->numberOfKeys = 0;
if (numberOfKeys < 1) {
return;
}
inkeys = (so->arrayKeyData != NULL) ? so->arrayKeyData : scan->keyData;
outkeys = so->keyData;
cur = &inkeys[0];
if (SECUREC_UNLIKELY(cur->sk_attno < 1)){
ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("btree index keys must be ordered by attribute")));
}
if (numberOfKeys == 1) {
if (!_bt_fix_scankey_strategy(cur, indoption)) {
so->qual_ok = false;
}
*outkeys = *cur;
so->numberOfKeys = 1;
if (cur->sk_attno == 1) {
_bt_mark_scankey_required(outkeys);
}
return;
}
ScanKey xform[BTMaxStrategyNumber];
RESET_STRATEGY_KEYS(xform);
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;
* 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) {
if (!_bt_fix_scankey_strategy(cur, indoption)) {
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;
if (SECUREC_UNLIKELY(i < numberOfKeys && cur->sk_attno < attno)) {
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR), errmsg("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) {
so->qual_ok = false;
return;
}
if (_bt_compare_scankey_args(scan, chk, eq, chk, &test_result)) {
if (!test_result) {
so->qual_ok = false;
return;
}
xform[j] = NULL;
}
}
numberOfEqualCols++;
}
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;
}
}
}
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++];
*outkey = *xform[j];
if (priorNumberOfEqualCols == attno - 1) {
_bt_mark_scankey_required(outkey);
}
}
}
if (i == numberOfKeys) {
break;
}
attno = cur->sk_attno;
RESET_STRATEGY_KEYS(xform);
}
j = cur->sk_strategy - 1;
if (cur->sk_flags & SK_ROW_HEADER) {
ScanKey outkey = &outkeys[new_numberOfKeys++];
*outkey = *cur;
if (numberOfEqualCols == attno - 1) {
_bt_mark_scankey_required(outkey);
}
* mess up the numberOfEqualCols tracking. */
Assert(j != (BTEqualStrategyNumber - 1));
continue;
}
if (xform[j] == NULL) {
xform[j] = cur;
} else {
if (_bt_compare_scankey_args(scan, cur, cur, xform[j], &test_result)) {
if (test_result) {
xform[j] = cur;
} else if (j == (BTEqualStrategyNumber - 1)) {
so->qual_ok = false;
return;
}
} 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++];
*outkey = *cur;
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, const ScanKey leftarg, const 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) {
int leftnull;
int rightnull;
if (leftarg->sk_flags & SK_ISNULL) {
Assert(leftarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
leftnull = 1;
} else {
leftnull = 0;
}
if (rightarg->sk_flags & SK_ISNULL) {
Assert(rightarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
rightnull = 1;
} else {
rightnull = 0;
}
* 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 = (uint16)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: {
ereport(ERROR,
(errcode(ERRCODE_INDEX_CORRUPTED), errmsg("unrecognized StrategyNumber: %d", (int)strat)));
*result = false;
break;
}
}
return true;
}
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 = (uint16)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;
}
}
*result = false;
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, const int16 *indoption)
{
int addflags;
addflags = (uint16)(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) {
Assert(!(skey->sk_flags & SK_ROW_HEADER));
skey->sk_flags |= addflags;
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) {
skey->sk_strategy = (skey->sk_flags & SK_BT_NULLS_FIRST) ? BTGreaterStrategyNumber : BTLessStrategyNumber;
skey->sk_subtype = InvalidOid;
skey->sk_collation = InvalidOid;
} else {
return false;
}
return true;
}
if ((addflags & SK_BT_DESC) && !(skey->sk_flags & SK_BT_DESC)) {
skey->sk_strategy = (uint16)BTCommuteStrategyNumber(skey->sk_strategy);
}
skey->sk_flags |= addflags;
if (skey->sk_flags & SK_ROW_HEADER) {
ScanKey subkey = (ScanKey)DatumGetPointer(skey->sk_argument);
for (;;) {
Assert(subkey->sk_flags & SK_ROW_MEMBER);
addflags = (uint16)(indoption[subkey->sk_attno - 1]) << SK_BT_INDOPTION_SHIFT;
if ((addflags & SK_BT_DESC) && !(subkey->sk_flags & SK_BT_DESC)) {
subkey->sk_strategy = (uint16)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:
ereport(ERROR, (errcode(ERRCODE_INDEX_CORRUPTED),
errmsg("unrecognized StrategyNumber: %d", (int)skey->sk_strategy)));
addflags = 0;
break;
}
skey->sk_flags |= addflags;
if (skey->sk_flags & SK_ROW_HEADER) {
ScanKey subkey = (ScanKey)DatumGetPointer(skey->sk_argument);
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.
*
* If so, return the address of the index tuple on the index page.
* If not, return NULL.
*
* 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.
*
* scan: index scan descriptor (containing a search-type scankey)
* page: buffer page containing index tuple
* offnum: offset number of index tuple (must be a valid item!)
* dir: direction we are scanning in
* continuescan: output parameter (will be set correctly in all cases)
*
* Caller must hold pin and lock on the index page.
*/
IndexTuple _bt_checkkeys(IndexScanDesc scan, Page page, OffsetNumber offnum, ScanDirection dir, bool *continuescan)
{
ItemId iid = PageGetItemId(page, offnum);
bool tuple_alive = false;
IndexTuple tuple;
TupleDesc tupdesc;
BTScanOpaque so;
int keysz;
int ikey;
ScanKey key;
*continuescan = true;
* If the scan specifies not to return killed tuples, then we treat a
* killed tuple as not passing the qual. Most of the time, it's a win to
* not bother examining the tuple's index keys, but just return
* immediately with continuescan = true to proceed to the next tuple.
* However, if this is the last tuple on the page, we should check the
* index keys to prevent uselessly advancing to the next page.
*/
if (scan->ignore_killed_tuples && ItemIdIsDead(iid)) {
if (ScanDirectionIsForward(dir)) {
if (offnum < PageGetMaxOffsetNumber(page)) {
return NULL;
}
} else {
BTPageOpaqueInternal opaque = (BTPageOpaqueInternal)PageGetSpecialPointer(page);
if (offnum > P_FIRSTDATAKEY(opaque)) {
return NULL;
}
}
* OK, we want to check the keys so we can set continuescan correctly,
* but we'll return NULL even if the tuple passes the key tests.
*/
tuple_alive = false;
} else {
tuple_alive = true;
}
tuple = (IndexTuple)PageGetItem(page, iid);
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 = false;
bool test;
if (key->sk_flags & SK_ROW_HEADER) {
if (_bt_check_rowcompare(key, tuple, tupdesc, dir, continuescan)) {
continue;
}
return NULL;
}
datum = index_getattr(tuple, key->sk_attno, tupdesc, &isNull);
if (key->sk_flags & SK_ISNULL) {
if (key->sk_flags & SK_SEARCHNULL) {
if (isNull) {
continue;
}
} else {
Assert(key->sk_flags & SK_SEARCHNOTNULL);
if (!isNull) {
continue;
}
}
* 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 NULL;
}
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 NULL;
}
switch (key->sk_func.fn_oid) {
case F_INT8EQ:
test = (int64)datum == (int64)key->sk_argument;
break;
case F_INT48EQ:
test = (int64)(int32)datum == (int64)key->sk_argument;
break;
case F_INT84EQ:
test = (int64)datum == (int64)(int32)key->sk_argument;
break;
case F_INT84LE:
test = (int64)datum <= (int64)(int32)key->sk_argument;
break;
case F_INT84GE:
test = (int64)datum >= (int64)(int32)key->sk_argument;
break;
case F_INT4EQ:
test = (int32)datum == (int32)key->sk_argument;
break;
case F_INT4GT:
test = (int32)datum > (int32)key->sk_argument;
break;
case F_INT4LT:
test = (int32)datum < (int32)key->sk_argument;
break;
case F_INT4LE:
test = (int32)datum <= (int32)key->sk_argument;
break;
case F_INT4GE:
test = (int32)datum >= (int32)key->sk_argument;
break;
case F_DATE_LE:
test = (int32)datum <= (int32)key->sk_argument;
break;
case F_DATE_GE:
test = (int32)datum >= (int32)key->sk_argument;
break;
case F_DATE_EQ:
test = (int32)datum == (int32)key->sk_argument;
break;
default:
test = DatumGetBool(FunctionCall2Coll(&key->sk_func, key->sk_collation, datum, key->sk_argument));
}
if (!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 NULL;
}
}
if (!tuple_alive) {
return NULL;
}
return tuple;
}
* 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.
*/
bool _bt_check_rowcompare(ScanKey skey, IndexTuple tuple, TupleDesc tupdesc, ScanDirection dir,
bool *continuescan)
{
ScanKey subkey = (ScanKey)DatumGetPointer(skey->sk_argument);
int32 cmpresult = 0;
bool result = false;
Assert(subkey->sk_attno == skey->sk_attno);
for (;;) {
Datum datum;
bool isNull = false;
Assert(subkey->sk_flags & SK_ROW_MEMBER);
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;
}
cmpresult =
DatumGetInt32(FunctionCall2Coll(&subkey->sk_func, subkey->sk_collation, datum, subkey->sk_argument));
if (subkey->sk_flags & SK_BT_DESC) {
cmpresult = -cmpresult;
}
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) {
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:
ereport(ERROR, (errcode(ERRCODE_INDEX_CORRUPTED),
errmsg("unrecognized RowCompareType: %d", (int)subkey->sk_strategy)));
result = false;
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->so contains information about the current page and killed tuples
* thereon (generally, this should only be called if so->numKilled > 0).
*
* The caller must have pin on so->currPos.buf, but may or may not have
* read-lock, as indicated by haveLock. Note that we assume 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 because we
* hold 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.)
*/
void _bt_killitems(IndexScanDesc scan, bool haveLock)
{
BTScanOpaque so = (BTScanOpaque)scan->opaque;
Page page;
BTPageOpaqueInternal opaque;
OffsetNumber minoff;
OffsetNumber maxoff;
int i;
bool killedsomething = false;
Oid heapOid = IndexScanGetPartHeapOid(scan);
Assert(BufferIsValid(so->currPos.buf));
if (!haveLock) {
LockBuffer(so->currPos.buf, BT_READ);
}
page = BufferGetPage(so->currPos.buf);
opaque = (BTPageOpaqueInternal)PageGetSpecialPointer(page);
minoff = P_FIRSTDATAKEY(opaque);
maxoff = PageGetMaxOffsetNumber(page);
for (i = 0; i < so->numKilled; i++) {
int itemIndex = so->killedItems[i];
BTScanPosItem *kitem = &so->currPos.items[itemIndex];
OffsetNumber offnum = kitem->indexOffset;
Oid partOid = kitem->partitionOid;
int2 bucketid = kitem->bucketid;
Assert(itemIndex >= so->currPos.firstItem && itemIndex <= so->currPos.lastItem);
if (offnum < minoff) {
continue;
}
while (offnum <= maxoff) {
ItemId iid = PageGetItemId(page, offnum);
IndexTuple ituple = (IndexTuple)PageGetItem(page, iid);
bool killtuple = false;
if (btree_tuple_is_posting(ituple)) {
int posting_idx = i + 1;
int nposting = btree_tuple_get_nposting(ituple);
int j;
for (j = 0; j < nposting; j++) {
ItemPointer item = btree_tuple_get_posting_n(ituple, j);
if (!ItemPointerEquals(item, &kitem->heapTid))
break;
if (posting_idx < so->numKilled)
kitem = &so->currPos.items[so->killedItems[posting_idx++]];
}
if (j == nposting)
killtuple = true;
} else if (ItemPointerEquals(&ituple->t_tid, &kitem->heapTid)) {
Oid currPartOid = scan->xs_want_ext_oid ? index_getattr_tableoid(scan->indexRelation, ituple) : heapOid;
int2 currbktid =
scan->xs_want_bucketid ? index_getattr_bucketid(scan->indexRelation, ituple) : bucketid;
if (currPartOid == partOid && currbktid == bucketid) {
killtuple = true;
}
}
if (killtuple && !ItemIdIsDead(iid)) {
ItemIdMarkDead(iid);
killedsomething = true;
break;
}
offnum = OffsetNumberNext(offnum);
}
}
* Since this can be redone later if needed, it's treated the same as a
* commit-hint-bit status update for heap tuples: we mark the buffer dirty
* but don't make a WAL log entry.
*
* 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);
}
if (!haveLock) {
LockBuffer(so->currPos.buf, BUFFER_LOCK_UNLOCK);
}
* Always reset the scan state, so we don't look for same items on other
* pages.
*/
so->numKilled = 0;
}
* 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 g_instance.shmem_cxt.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;
BTCycleId cycleid;
} BTOneVacInfoNode;
typedef struct BTVacInfo {
BTCycleId cycle_ctr;
int num_vacuums;
int max_vacuums;
BTOneVacInfo vacuums[1];
} BTVacInfoNode;
* _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(const Relation rel)
{
BTCycleId result = 0;
int i;
LWLockAcquire(BtreeVacuumLock, LW_SHARED);
for (i = 0; i < t_thrd.index_cxt.btvacinfo->num_vacuums; i++) {
BTOneVacInfo *vac = &t_thrd.index_cxt.btvacinfo->vacuums[i];
if (vac->relid.relId == rel->rd_lockInfo.lockRelId.relId &&
vac->relid.dbId == rel->rd_lockInfo.lockRelId.dbId &&
vac->relid.bktId == rel->rd_lockInfo.lockRelId.bktId) {
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 = NULL;
LWLockAcquire(BtreeVacuumLock, LW_EXCLUSIVE);
* Assign the next cycle ID, being careful to avoid zero as well as the
* reserved high values.
*/
result = ++(t_thrd.index_cxt.btvacinfo->cycle_ctr);
if (result == 0 || result > MAX_BT_CYCLE_ID) {
result = t_thrd.index_cxt.btvacinfo->cycle_ctr = 1;
}
for (i = 0; i < t_thrd.index_cxt.btvacinfo->num_vacuums; i++) {
vac = &t_thrd.index_cxt.btvacinfo->vacuums[i];
if (vac->relid.relId == rel->rd_lockInfo.lockRelId.relId &&
vac->relid.dbId == rel->rd_lockInfo.lockRelId.dbId &&
vac->relid.bktId == rel->rd_lockInfo.lockRelId.bktId) {
* 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);
ereport(ERROR, (errcode(ERRCODE_INDEX_CORRUPTED),
errmsg("multiple active vacuums for index \"%s\"", RelationGetRelationName(rel))));
}
}
if (t_thrd.index_cxt.btvacinfo->num_vacuums >= t_thrd.index_cxt.btvacinfo->max_vacuums) {
LWLockRelease(BtreeVacuumLock);
ereport(ERROR, (errcode(ERRCODE_INDEX_CORRUPTED), errmsg("out of btvacinfo slots")));
}
vac = &t_thrd.index_cxt.btvacinfo->vacuums[t_thrd.index_cxt.btvacinfo->num_vacuums];
vac->relid = rel->rd_lockInfo.lockRelId;
vac->cycleid = result;
t_thrd.index_cxt.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(const Relation rel)
{
int i;
LWLockAcquire(BtreeVacuumLock, LW_EXCLUSIVE);
for (i = 0; i < t_thrd.index_cxt.btvacinfo->num_vacuums; i++) {
BTOneVacInfo *vac = &t_thrd.index_cxt.btvacinfo->vacuums[i];
if (vac->relid.relId == rel->rd_lockInfo.lockRelId.relId &&
vac->relid.dbId == rel->rd_lockInfo.lockRelId.dbId &&
vac->relid.bktId == rel->rd_lockInfo.lockRelId.bktId) {
*vac = t_thrd.index_cxt.btvacinfo->vacuums[t_thrd.index_cxt.btvacinfo->num_vacuums - 1];
t_thrd.index_cxt.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 = offsetof(BTVacInfo, vacuums[0]);
size = add_size(size, mul_size((Size)g_instance.shmem_cxt.MaxBackends, sizeof(BTOneVacInfo)));
return size;
}
* BTreeShmemInit --- initialize this module's shared memory
*/
void BTreeShmemInit(void)
{
bool found = false;
t_thrd.index_cxt.btvacinfo = (BTVacInfo *)ShmemInitStruct("BTree Vacuum State", BTreeShmemSize(), &found);
if (!IsUnderPostmaster) {
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.
*/
t_thrd.index_cxt.btvacinfo->cycle_ctr = (BTCycleId)time(NULL);
t_thrd.index_cxt.btvacinfo->num_vacuums = 0;
t_thrd.index_cxt.btvacinfo->max_vacuums = g_instance.shmem_cxt.MaxBackends;
} else {
Assert(found);
}
}
Datum btoptions(PG_FUNCTION_ARGS)
{
Datum reloptions = PG_GETARG_DATUM(0);
bool validate = PG_GETARG_BOOL(1);
bytea *result = NULL;
result = default_reloptions(reloptions, validate, RELOPT_KIND_BTREE);
if (result != NULL) {
PG_RETURN_BYTEA_P(result);
}
PG_RETURN_NULL();
}
* _bt_nonkey_truncate() -- remove non-key (INCLUDE) attributes from index
* tuple.
*
* Transforms an ordinal B-tree leaf index tuple into pivot tuple to be used
* as hikey or non-leaf page tuple with downlink. Note that t_tid offset
* will be overritten in order to represent number of present tuple attributes.
*/
IndexTuple btree_truncate(Relation rel, IndexTuple lastleft, IndexTuple firstright, BTScanInsert itup_key)
{
Assert(!btree_tuple_is_pivot(lastleft));
Assert(!btree_tuple_is_pivot(firstright));
TupleDesc itupdesc = RelationGetDescr(rel);
int nkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
int keepnatts = btree_num_keep_atts(rel, lastleft, firstright, itup_key);
#ifdef DEBUG_NO_TRUNCATE
keepnatts = nkeyatts + 1;
#endif
IndexTuple pivot = index_truncate_tuple(itupdesc, firstright, Min(keepnatts, nkeyatts));
if (btree_tuple_is_posting(pivot)) {
Assert(keepnatts == nkeyatts || keepnatts == nkeyatts + 1);
Assert(IndexRelationGetNumberOfAttributes(rel) == nkeyatts);
pivot->t_info &= ~INDEX_SIZE_MASK;
pivot->t_info |= MAXALIGN(btree_tuple_get_posting_off(firstright));
}
if (keepnatts <= nkeyatts) {
btree_tuple_set_num_of_atts(pivot, (uint16)keepnatts, false);
return pivot;
}
Size newsize = MAXALIGN(IndexTupleSize(pivot)) + MAXALIGN(sizeof(ItemPointerData));
IndexTuple tid_pivot = (IndexTuple)palloc0(newsize);
errno_t rc = memcpy_s(tid_pivot, newsize, pivot, MAXALIGN(IndexTupleSize(pivot)));
securec_check(rc, "", "");
pfree(pivot);
tid_pivot->t_info &= ~INDEX_SIZE_MASK;
tid_pivot->t_info |= newsize;
btree_tuple_set_num_of_atts(tid_pivot, (uint16)nkeyatts, true);
ItemPointer pivot_heaptid = btree_tuple_get_heap_tid(tid_pivot);
Assert(pivot_heaptid);
ItemPointerCopy(btree_tuple_get_max_heap_tid(lastleft), pivot_heaptid);
#ifndef DEBUG_NO_TRUNCATE
Assert(ItemPointerCompare(btree_tuple_get_max_heap_tid(lastleft), btree_tuple_get_heap_tid(firstright)) <= 0);
Assert(ItemPointerCompare(pivot_heaptid, btree_tuple_get_heap_tid(lastleft)) >= 0);
Assert(ItemPointerCompare(pivot_heaptid, btree_tuple_get_heap_tid(firstright)) <= 0);
#else
ItemPointerCopy(btree_tuple_get_heap_tid(firstright), pivot_heaptid);
ItemPointerSetOffsetNumber(pivot_heaptid, OffsetNumberPrev(ItemPointerGetOffsetNumber(pivot_heaptid)));
Assert(ItemPointerCompare(pivot_heaptid, btree_tuple_get_heap_tid(firstright)) < 0);
#endif
return tid_pivot;
}
static int btree_num_keep_atts(Relation rel, IndexTuple lastleft, IndexTuple firstright, BTScanInsert itup_key)
{
int num_key_atts = IndexRelationGetNumberOfKeyAttributes(rel);
if (!itup_key->heapkeyspace) {
return num_key_atts;
}
TupleDesc itupdesc = RelationGetDescr(rel);
int num_keep_atts = 1;
ScanKey scankey = itup_key->scankeys;
for (int attnum = 1; attnum <= num_key_atts; attnum++, scankey++) {
bool is_null_1, is_null_2;
Datum datum1 = index_getattr(lastleft, attnum, itupdesc, &is_null_1);
Datum datum2 = index_getattr(firstright, attnum, itupdesc, &is_null_2);
if (is_null_1 != is_null_2)
break;
if (!is_null_1 && DatumGetInt32(FunctionCall2Coll(&scankey->sk_func, scankey->sk_collation, datum1, datum2)) != 0)
break;
num_keep_atts++;
}
Assert(!itup_key->allequalimage || num_keep_atts == btree_num_keep_atts_fast(rel, lastleft, firstright));
return num_keep_atts;
}
int btree_num_keep_atts_fast(Relation rel, IndexTuple lastleft, IndexTuple firstright)
{
int num_key_atts = IndexRelationGetNumberOfKeyAttributes(rel);
TupleDesc itup_desc = RelationGetDescr(rel);
int num_keep_atts = 1;
for (int attnum = 1; attnum <= num_key_atts; attnum++) {
bool is_null_1, is_null_2;
Form_pg_attribute att;
Datum datum1 = index_getattr(lastleft, attnum, itup_desc, &is_null_1);
Datum datum2 = index_getattr(firstright, attnum, itup_desc, &is_null_2);
att = TupleDescAttr(itup_desc, attnum - 1);
if (is_null_1 != is_null_2)
break;
if (!is_null_1 && !DatumImageEq(datum1, datum2, att->attbyval, att->attlen))
break;
num_keep_atts++;
}
return num_keep_atts;
}
void btree_check_third_page(Relation rel, Relation heap, bool need_heaptid_space, Page page, IndexTuple tuple)
{
Size itemsz = MAXALIGN(IndexTupleSize(tuple));
if (itemsz <= BTREE_MAX_ITEM_SIZE(page))
return;
if (!need_heaptid_space && itemsz <= BTREE_MAX_ITEM_SIZE_NO_HEAP_TID(page)) {
return;
}
if (!P_ISLEAF((BTPageOpaqueInternal)PageGetSpecialPointer(page))) {
ereport(ERROR, (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("cannot insert oversized tuple of size %lu on internal page of index \"%s\"",
(unsigned long)itemsz, RelationGetRelationName(rel))));
}
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("index row size %lu exceeds maximum %lu for index \"%s\"",
(unsigned long)itemsz,
(unsigned long)BTREE_MAX_ITEM_SIZE(page),
RelationGetRelationName(rel)),
errdetail("Index row references tuple (%u,%hu) in relation \"%s\".",
ItemPointerGetBlockNumber(&tuple->t_tid),
ItemPointerGetOffsetNumber(&tuple->t_tid),
heap ? RelationGetRelationName(heap) : "unknown"),
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.")));
}
bool btree_allequalimage(Relation rel, bool debugmessage)
{
if (t_thrd.proc->workingVersionNum < NBTREE_DEDUPLICATION_VERSION_NUM ||
IndexRelationGetNumberOfAttributes(rel) != IndexRelationGetNumberOfKeyAttributes(rel) || IsSystemRelation(rel))
return false;
bool allequalimage = true;
for (int i = 0; i < IndexRelationGetNumberOfKeyAttributes(rel); i++) {
Oid opfamily = rel->rd_opfamily[i];
Oid opcintype = rel->rd_opcintype[i];
Oid collation = rel->rd_indcollation[i];
Oid equalimage_proc = get_opfamily_proc(opfamily, opcintype, opcintype, BTEQUALIMAGE_PROC);
if (!OidIsValid(equalimage_proc) ||
!DatumGetBool(OidFunctionCall1Coll(equalimage_proc, collation, ObjectIdGetDatum(opcintype)))) {
allequalimage = false;
break;
}
}
if (debugmessage) {
if (allequalimage)
elog(DEBUG1, "index \"%s\" can safely use deduplication", RelationGetRelationName(rel));
else
elog(DEBUG1, "index \"%s\" cannot use deduplication", RelationGetRelationName(rel));
}
return allequalimage;
}
