/*
* Setup a ScanKey for a search in the relation 'rel' for a tuple 'key' that
* is setup to match 'rel' (*NOT* idxrel!).
*
* Returns whether any column contains NULLs.
*
* This is not generic routine, it expects the idxrel to be replication
* identity of a rel and meet all limitations associated with that.
*/
static bool
build_replindex_scan_key(ScanKey skey, Relation rel, Relation idxrel,
TupleTableSlot *searchslot)
{
int attoff;
bool isnull;
Datum indclassDatum;
oidvector *opclass;
int2vector *indkey = &idxrel->rd_index->indkey;
bool hasnulls = false;
Assert(RelationGetReplicaIndex(rel) == RelationGetRelid(idxrel));
indclassDatum = SysCacheGetAttr(INDEXRELID, idxrel->rd_indextuple,
Anum_pg_index_indclass, &isnull);
Assert(!isnull);
opclass = (oidvector *) DatumGetPointer(indclassDatum);
/* Build scankey for every attribute in the index. */
for (attoff = 0; attoff < IndexRelationGetNumberOfKeyAttributes(idxrel); attoff++)
{
Oid operator;
Oid opfamily;
RegProcedure regop;
int pkattno = attoff + 1;
int mainattno = indkey->values[attoff];
Oid optype = get_opclass_input_type(opclass->values[attoff]);
/*
* Load the operator info. We need this to get the equality operator
* function for the scan key.
*/
opfamily = get_opclass_family(opclass->values[attoff]);
operator = get_opfamily_member(opfamily, optype,
optype,
BTEqualStrategyNumber);
if (!OidIsValid(operator))
elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
BTEqualStrategyNumber, optype, optype, opfamily);
regop = get_opcode(operator);
/* Initialize the scankey. */
ScanKeyInit(&skey[attoff],
pkattno,
BTEqualStrategyNumber,
regop,
searchslot->tts_values[mainattno - 1]);
/* Check for null value. */
if (searchslot->tts_isnull[mainattno - 1])
{
hasnulls = true;
skey[attoff].sk_flags |= SK_ISNULL;
}
}
return hasnulls;
}
/*
* get_relation_info -
* Retrieves catalog information for a given relation.
*
* Given the Oid of the relation, return the following info into fields
* of the RelOptInfo struct:
*
* min_attr lowest valid AttrNumber
* max_attr highest valid AttrNumber
* indexlist list of IndexOptInfos for relation's indexes
* pages number of pages
* tuples number of tuples
*
* Also, initialize the attr_needed[] and attr_widths[] arrays. In most
* cases these are left as zeroes, but sometimes we need to compute attr
* widths here, and we may as well cache the results for costsize.c.
*
* If inhparent is true, all we need to do is set up the attr arrays:
* the RelOptInfo actually represents the appendrel formed by an inheritance
* tree, and so the parent rel's physical size and index information isn't
* important for it.
*/
void
get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
RelOptInfo *rel)
{
Index varno = rel->relid;
Relation relation;
bool hasindex;
List *indexinfos = NIL;
/*
* We need not lock the relation since it was already locked, either by
* the rewriter or when expand_inherited_rtentry() added it to the query's
* rangetable.
*/
relation = heap_open(relationObjectId, NoLock);
/* Temporary and unlogged relations are inaccessible during recovery. */
if (!RelationNeedsWAL(relation) && RecoveryInProgress())
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot access temporary or unlogged relations during recovery")));
rel->min_attr = FirstLowInvalidHeapAttributeNumber + 1;
rel->max_attr = RelationGetNumberOfAttributes(relation);
rel->reltablespace = RelationGetForm(relation)->reltablespace;
Assert(rel->max_attr >= rel->min_attr);
rel->attr_needed = (Relids *)
palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(Relids));
rel->attr_widths = (int32 *)
palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(int32));
/*
* Estimate relation size --- unless it's an inheritance parent, in which
* case the size will be computed later in set_append_rel_pathlist, and we
* must leave it zero for now to avoid bollixing the total_table_pages
* calculation.
*/
if (!inhparent)
estimate_rel_size(relation, rel->attr_widths - rel->min_attr,
&rel->pages, &rel->tuples, &rel->allvisfrac);
/*
* Make list of indexes. Ignore indexes on system catalogs if told to.
* Don't bother with indexes for an inheritance parent, either.
*/
if (inhparent ||
(IgnoreSystemIndexes && IsSystemClass(relation->rd_rel)))
hasindex = false;
else
hasindex = relation->rd_rel->relhasindex;
if (hasindex)
{
List *indexoidlist;
ListCell *l;
LOCKMODE lmode;
indexoidlist = RelationGetIndexList(relation);
/*
* For each index, we get the same type of lock that the executor will
* need, and do not release it. This saves a couple of trips to the
* shared lock manager while not creating any real loss of
* concurrency, because no schema changes could be happening on the
* index while we hold lock on the parent rel, and neither lock type
* blocks any other kind of index operation.
*/
if (rel->relid == root->parse->resultRelation)
lmode = RowExclusiveLock;
else
lmode = AccessShareLock;
foreach(l, indexoidlist)
{
Oid indexoid = lfirst_oid(l);
Relation indexRelation;
Form_pg_index index;
IndexOptInfo *info;
int ncolumns;
int i;
/*
* Extract info from the relation descriptor for the index.
*/
indexRelation = index_open(indexoid, lmode);
index = indexRelation->rd_index;
/*
* Ignore invalid indexes, since they can't safely be used for
* queries. Note that this is OK because the data structure we
* are constructing is only used by the planner --- the executor
* still needs to insert into "invalid" indexes!
*/
if (!index->indisvalid)
{
index_close(indexRelation, NoLock);
continue;
}
/*
* If the index is valid, but cannot yet be used, ignore it; but
* mark the plan we are generating as transient. See
* src/backend/access/heap/README.HOT for discussion.
*/
if (index->indcheckxmin &&
!TransactionIdPrecedes(HeapTupleHeaderGetXmin(indexRelation->rd_indextuple->t_data),
TransactionXmin))
{
root->glob->transientPlan = true;
index_close(indexRelation, NoLock);
continue;
}
info = makeNode(IndexOptInfo);
info->indexoid = index->indexrelid;
info->reltablespace =
RelationGetForm(indexRelation)->reltablespace;
info->rel = rel;
info->ncolumns = ncolumns = index->indnatts;
info->indexkeys = (int *) palloc(sizeof(int) * ncolumns);
info->indexcollations = (Oid *) palloc(sizeof(Oid) * ncolumns);
info->opfamily = (Oid *) palloc(sizeof(Oid) * ncolumns);
info->opcintype = (Oid *) palloc(sizeof(Oid) * ncolumns);
for (i = 0; i < ncolumns; i++)
{
info->indexkeys[i] = index->indkey.values[i];
info->indexcollations[i] = indexRelation->rd_indcollation[i];
info->opfamily[i] = indexRelation->rd_opfamily[i];
info->opcintype[i] = indexRelation->rd_opcintype[i];
}
info->relam = indexRelation->rd_rel->relam;
info->amcostestimate = indexRelation->rd_am->amcostestimate;
info->canreturn = index_can_return(indexRelation);
info->amcanorderbyop = indexRelation->rd_am->amcanorderbyop;
info->amoptionalkey = indexRelation->rd_am->amoptionalkey;
info->amsearcharray = indexRelation->rd_am->amsearcharray;
info->amsearchnulls = indexRelation->rd_am->amsearchnulls;
info->amhasgettuple = OidIsValid(indexRelation->rd_am->amgettuple);
info->amhasgetbitmap = OidIsValid(indexRelation->rd_am->amgetbitmap);
/*
* Fetch the ordering information for the index, if any.
*/
if (info->relam == BTREE_AM_OID)
{
/*
* If it's a btree index, we can use its opfamily OIDs
* directly as the sort ordering opfamily OIDs.
*/
Assert(indexRelation->rd_am->amcanorder);
info->sortopfamily = info->opfamily;
info->reverse_sort = (bool *) palloc(sizeof(bool) * ncolumns);
info->nulls_first = (bool *) palloc(sizeof(bool) * ncolumns);
for (i = 0; i < ncolumns; i++)
{
int16 opt = indexRelation->rd_indoption[i];
info->reverse_sort[i] = (opt & INDOPTION_DESC) != 0;
info->nulls_first[i] = (opt & INDOPTION_NULLS_FIRST) != 0;
}
}
else if (indexRelation->rd_am->amcanorder)
{
/*
* Otherwise, identify the corresponding btree opfamilies by
* trying to map this index's "<" operators into btree. Since
* "<" uniquely defines the behavior of a sort order, this is
* a sufficient test.
*
* XXX This method is rather slow and also requires the
* undesirable assumption that the other index AM numbers its
* strategies the same as btree. It'd be better to have a way
* to explicitly declare the corresponding btree opfamily for
* each opfamily of the other index type. But given the lack
* of current or foreseeable amcanorder index types, it's not
* worth expending more effort on now.
*/
info->sortopfamily = (Oid *) palloc(sizeof(Oid) * ncolumns);
info->reverse_sort = (bool *) palloc(sizeof(bool) * ncolumns);
info->nulls_first = (bool *) palloc(sizeof(bool) * ncolumns);
for (i = 0; i < ncolumns; i++)
{
int16 opt = indexRelation->rd_indoption[i];
Oid ltopr;
Oid btopfamily;
Oid btopcintype;
int16 btstrategy;
info->reverse_sort[i] = (opt & INDOPTION_DESC) != 0;
info->nulls_first[i] = (opt & INDOPTION_NULLS_FIRST) != 0;
ltopr = get_opfamily_member(info->opfamily[i],
info->opcintype[i],
info->opcintype[i],
BTLessStrategyNumber);
if (OidIsValid(ltopr) &&
get_ordering_op_properties(ltopr,
&btopfamily,
&btopcintype,
&btstrategy) &&
btopcintype == info->opcintype[i] &&
btstrategy == BTLessStrategyNumber)
{
/* Successful mapping */
info->sortopfamily[i] = btopfamily;
}
else
{
/* Fail ... quietly treat index as unordered */
info->sortopfamily = NULL;
info->reverse_sort = NULL;
info->nulls_first = NULL;
break;
}
}
}
else
{
info->sortopfamily = NULL;
info->reverse_sort = NULL;
info->nulls_first = NULL;
}
/*
* Fetch the index expressions and predicate, if any. We must
* modify the copies we obtain from the relcache to have the
* correct varno for the parent relation, so that they match up
* correctly against qual clauses.
*/
info->indexprs = RelationGetIndexExpressions(indexRelation);
info->indpred = RelationGetIndexPredicate(indexRelation);
if (info->indexprs && varno != 1)
ChangeVarNodes((Node *) info->indexprs, 1, varno, 0);
if (info->indpred && varno != 1)
ChangeVarNodes((Node *) info->indpred, 1, varno, 0);
/* Build targetlist using the completed indexprs data */
info->indextlist = build_index_tlist(root, info, relation);
info->predOK = false; /* set later in indxpath.c */
info->unique = index->indisunique;
info->immediate = index->indimmediate;
info->hypothetical = false;
/*
* Estimate the index size. If it's not a partial index, we lock
* the number-of-tuples estimate to equal the parent table; if it
* is partial then we have to use the same methods as we would for
* a table, except we can be sure that the index is not larger
* than the table.
*/
if (info->indpred == NIL)
{
info->pages = RelationGetNumberOfBlocks(indexRelation);
info->tuples = rel->tuples;
}
else
{
double allvisfrac; /* dummy */
estimate_rel_size(indexRelation, NULL,
&info->pages, &info->tuples, &allvisfrac);
if (info->tuples > rel->tuples)
info->tuples = rel->tuples;
}
index_close(indexRelation, NoLock);
indexinfos = lcons(info, indexinfos);
}
list_free(indexoidlist);
}
/*
* Compare two scankey values using a specified operator. Both values
* must be already known non-NULL.
*
* 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. We don't worry about
* NULLS FIRST/LAST either, since the given values are never nulls.
*/
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;
/*
* 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(FunctionCall2(&op->sk_func,
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_mark_scankey_with_indoption, 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(OidFunctionCall2(cmp_proc,
leftarg->sk_argument,
rightarg->sk_argument));
return true;
}
}
/* Can't make the comparison */
*result = false; /* suppress compiler warnings */
return false;
}
/**
* @fn Datum reorg_get_index_keys(PG_FUNCTION_ARGS)
* @brief Get key definition of the index.
*
* reorg_get_index_keys(index, table)
*
* @param index Oid of target index.
* @param table Oid of table of the index.
* @retval Create index DDL for temp table.
*
* FIXME: this function is named get_index_keys, but actually returns
* an expression for ORDER BY clause. get_order_by() might be a better name.
*/
Datum
reorg_get_index_keys(PG_FUNCTION_ARGS)
{
Oid index = PG_GETARG_OID(0);
Oid table = PG_GETARG_OID(1);
IndexDef stmt;
char *token;
char *next;
StringInfoData str;
Relation indexRel = NULL;
int nattr;
parse_indexdef(&stmt, index, table);
elog(DEBUG2, "indexdef.create = %s", stmt.create);
elog(DEBUG2, "indexdef.index = %s", stmt.index);
elog(DEBUG2, "indexdef.table = %s", stmt.table);
elog(DEBUG2, "indexdef.type = %s", stmt.type);
elog(DEBUG2, "indexdef.columns = %s", stmt.columns);
elog(DEBUG2, "indexdef.options = %s", stmt.options);
/*
* FIXME: this is very unreliable implementation but I don't want to
* re-implement customized versions of pg_get_indexdef_string...
*
* TODO: Support ASC/DESC and NULL FIRST/LAST.
*/
initStringInfo(&str);
for (nattr = 0, next = stmt.columns; next; nattr++)
{
char *opcname;
token = next;
while (isspace((unsigned char) *token))
token++;
next = skip_until(index, next, ',');
opcname = skip_until(index, token, ' ');
if (opcname)
{
/* lookup default operator name from operator class */
Oid opclass;
Oid oprid;
int16 strategy = BTLessStrategyNumber;
Oid opcintype;
Oid opfamily;
HeapTuple tp;
Form_pg_opclass opclassTup;
opclass = OpclassnameGetOpcid(BTREE_AM_OID, opcname);
/* Retrieve operator information. */
tp = SearchSysCache(CLAOID, ObjectIdGetDatum(opclass), 0, 0, 0);
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for opclass %u", opclass);
opclassTup = (Form_pg_opclass) GETSTRUCT(tp);
opfamily = opclassTup->opcfamily;
opcintype = opclassTup->opcintype;
ReleaseSysCache(tp);
if (!OidIsValid(opcintype))
{
if (indexRel == NULL)
indexRel = index_open(index, NoLock);
opcintype = RelationGetDescr(indexRel)->attrs[nattr]->atttypid;
}
oprid = get_opfamily_member(opfamily, opcintype, opcintype, strategy);
if (!OidIsValid(oprid))
elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
strategy, opcintype, opcintype, opfamily);
opcname[-1] = '\0';
appendStringInfo(&str, "%s USING %s", token, get_opname(oprid));
}
else
appendStringInfoString(&str, token);
if (next)
appendStringInfoString(&str, ", ");
}
if (indexRel != NULL)
index_close(indexRel, NoLock);
PG_RETURN_TEXT_P(cstring_to_text(str.data));
}
/*
* 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 struct 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_cmp_scankey_args(
struct index_scan *scan,
struct scankey *op,
struct scankey *leftarg,
struct scankey *rightarg,
bool* result)
{
struct relation *rel;
oid_t lefttype;
oid_t righttype;
oid_t optype;
oid_t opcintype;
oid_t cmp_op;
oid_t opfamily;
strat_nr_t strat;
rel = scan->indexRelation;
/*
* 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 = BT_COMMUTE_STRAT_NR(strat);
switch (strat) {
case BT_LT_STRAT_NR:
*result = (leftnull < rightnull);
break;
case BT_LE_STRAT_NR:
*result = (leftnull <= rightnull);
break;
case BT_EQ_STRAT_NR:
*result = (leftnull == rightnull);
break;
case BT_GE_STRAT_NR:
*result = (leftnull >= rightnull);
break;
case BT_GT_STRAT_NR:
*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 struct scankey * arguments. We have to
* support the convention that sk_subtype == INVALID_OID means the opclass
* input type; this is a hack to simplify life for scankey_init().
*/
lefttype = leftarg->sk_subtype;
if (lefttype == INVALID_OID)
lefttype = opcintype;
righttype = rightarg->sk_subtype;
if (righttype == INVALID_OID)
righttype = opcintype;
optype = op->sk_subtype;
if (optype == INVALID_OID)
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 = D_TO_BOOL(fc_2coll(
&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 = BT_COMMUTE_STRAT_NR(strat);
opfamily = rel->rd_opfamily[leftarg->sk_attno - 1];
cmp_op = get_opfamily_member(opfamily, lefttype, righttype, strat);
if (OID_VALID(cmp_op)) {
regproc_t cmp_proc = get_opcode(cmp_op);
if (REGPROC_VALID(cmp_proc)) {
*result = D_TO_BOOL(oid_fc_2coll(
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;
}
/*
* 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;
}
