int OGRFeatureQuery::CanUseIndex( OGRLayer *poLayer )
{
swq_expr_node *psExpr = (swq_expr_node *) pSWQExpr;
/* -------------------------------------------------------------------- */
/* Do we have an index on the targetted layer? */
/* -------------------------------------------------------------------- */
if ( poLayer->GetIndex() == FALSE )
return FALSE;
return CanUseIndex( psExpr, poLayer );
}
int OGRFeatureQuery::CanUseIndex( swq_expr_node *psExpr,
OGRLayer *poLayer )
{
OGRAttrIndex *poIndex;
/* -------------------------------------------------------------------- */
/* Does the expression meet our requirements? */
/* -------------------------------------------------------------------- */
if( psExpr == NULL ||
psExpr->eNodeType != SNT_OPERATION )
return FALSE;
if ((psExpr->nOperation == SWQ_OR || psExpr->nOperation == SWQ_AND) &&
psExpr->nSubExprCount == 2)
{
return CanUseIndex( psExpr->papoSubExpr[0], poLayer ) &&
CanUseIndex( psExpr->papoSubExpr[1], poLayer );
}
if( !(psExpr->nOperation == SWQ_EQ || psExpr->nOperation == SWQ_IN)
|| psExpr->nSubExprCount < 2 )
return FALSE;
swq_expr_node *poColumn = psExpr->papoSubExpr[0];
swq_expr_node *poValue = psExpr->papoSubExpr[1];
if( poColumn->eNodeType != SNT_COLUMN
|| poValue->eNodeType != SNT_CONSTANT )
return FALSE;
poIndex = poLayer->GetIndex()->GetFieldIndex( poColumn->field_index );
if( poIndex == NULL )
return FALSE;
/* -------------------------------------------------------------------- */
/* OK, we have an index */
/* -------------------------------------------------------------------- */
return TRUE;
}
TRI_aql_index_t* TRI_DetermineIndexAql (TRI_aql_context_t* const context,
const TRI_vector_pointer_t* const availableIndexes,
const char* const collectionName,
const TRI_vector_pointer_t* candidates) {
TRI_aql_index_t* picked = NULL;
TRI_vector_pointer_t matches;
size_t i, n;
TRI_InitVectorPointer(&matches, TRI_UNKNOWN_MEM_ZONE);
assert(context);
assert(collectionName);
assert(candidates);
n = availableIndexes->_length;
for (i = 0; i < n; ++i) {
TRI_index_t* idx = (TRI_index_t*) availableIndexes->_buffer[i];
size_t numIndexFields;
bool lastTypeWasExact;
size_t j;
if (! CanUseIndex(idx)) {
continue;
}
LogIndexString("checking", idx, collectionName);
TRI_ClearVectorPointer(&matches);
lastTypeWasExact = true;
numIndexFields = idx->_fields._length;
// now loop over all index fields, from left to right
// index field order is important because skiplists can be used with leftmost prefixes as well,
// but not with rightmost prefixes
for (j = 0; j < numIndexFields; ++j) {
char* indexedFieldName;
char* fieldName;
size_t k;
indexedFieldName = idx->_fields._buffer[j];
if (indexedFieldName == NULL) {
continue;
}
// now loop over all candidates
for (k = 0; k < candidates->_length; ++k) {
TRI_aql_field_access_t* candidate = (TRI_aql_field_access_t*) TRI_AtVectorPointer(candidates, k);
if (candidate->_type == TRI_AQL_ACCESS_IMPOSSIBLE ||
candidate->_type == TRI_AQL_ACCESS_ALL) {
// wrong index type, doesn't help us at all
continue;
}
fieldName = candidate->_fullName + candidate->_variableNameLength + 1;
if (idx->_type == TRI_IDX_TYPE_PRIMARY_INDEX) {
// primary index key names must be treated differently. _id and _key are the same
if (! TRI_EqualString("_id", fieldName) && ! TRI_EqualString(TRI_VOC_ATTRIBUTE_KEY, fieldName)) {
continue;
}
}
else if (idx->_type == TRI_IDX_TYPE_EDGE_INDEX) {
// edge index key names must be treated differently. _from and _to can be used independently
if (! TRI_EqualString(TRI_VOC_ATTRIBUTE_FROM, fieldName) &&
! TRI_EqualString(TRI_VOC_ATTRIBUTE_TO, fieldName)) {
continue;
}
}
else if (! TRI_EqualString(indexedFieldName, fieldName)) {
// different attribute, doesn't help
continue;
}
// attribute is used in index
if (idx->_type == TRI_IDX_TYPE_PRIMARY_INDEX || idx->_type == TRI_IDX_TYPE_EDGE_INDEX) {
if (! IsExactCandidate(candidate)) {
// wrong access type for primary index
continue;
}
TRI_PushBackVectorPointer(&matches, candidate);
}
else if (idx->_type == TRI_IDX_TYPE_HASH_INDEX) {
if (! IsExactCandidate(candidate)) {
// wrong access type for hash index
continue;
}
if (candidate->_type == TRI_AQL_ACCESS_LIST && numIndexFields != 1) {
// we found a list, but the index covers multiple attributes. that means we cannot use list access
continue;
}
TRI_PushBackVectorPointer(&matches, candidate);
}
else if (idx->_type == TRI_IDX_TYPE_BITARRAY_INDEX) {
if (! IsExactCandidate(candidate)) {
// wrong access type for hash index
continue;
}
if (candidate->_type == TRI_AQL_ACCESS_LIST) {
// we found a list, but the index covers multiple attributes. that means we cannot use list access
continue;
}
TRI_PushBackVectorPointer(&matches, candidate);
}
else if (idx->_type == TRI_IDX_TYPE_SKIPLIST_INDEX) {
bool candidateIsExact;
if (candidate->_type != TRI_AQL_ACCESS_EXACT &&
candidate->_type != TRI_AQL_ACCESS_LIST &&
candidate->_type != TRI_AQL_ACCESS_RANGE_SINGLE &&
candidate->_type != TRI_AQL_ACCESS_RANGE_DOUBLE &&
candidate->_type != TRI_AQL_ACCESS_REFERENCE) {
// wrong access type for skiplists
continue;
}
if (candidate->_type == TRI_AQL_ACCESS_LIST && numIndexFields != 1) {
// we found a list, but the index covers multiple attributes. that means we cannot use list access
continue;
}
candidateIsExact = IsExactCandidate(candidate);
if ((candidateIsExact && ! lastTypeWasExact) ||
(! candidateIsExact && ! lastTypeWasExact)) {
// if we already had a range query, we cannot check for equality after that
// if we already had a range query, we cannot check another range after that
continue;
}
if (candidate->_type == TRI_AQL_ACCESS_RANGE_SINGLE) {
// range type. check if the compare value is a list or an object
TRI_json_t* value = candidate->_value._singleRange._value;
if (TRI_IsListJson(value) || TRI_IsArrayJson(value)) {
// list or object, we cannot use this for comparison in a skiplist
continue;
}
}
else if (candidate->_type == TRI_AQL_ACCESS_RANGE_DOUBLE) {
// range type. check if the compare value is a list or an object
TRI_json_t* value = candidate->_value._between._lower._value;
if (TRI_IsListJson(value) || TRI_IsArrayJson(value)) {
// list or object, we cannot use this for comparison in a skiplist
continue;
}
value = candidate->_value._between._upper._value;
if (TRI_IsListJson(value) || TRI_IsArrayJson(value)) {
// list or object, we cannot use this for comparison in a skiplist
continue;
}
}
lastTypeWasExact = candidateIsExact;
TRI_PushBackVectorPointer(&matches, candidate);
}
}
// finished iterating over all candidates
if (matches._length != j + 1) {
// we already have picked less candidate fields than we should
break;
}
}
if (matches._length < 1) {
// nothing found
continue;
}
// we now do or don't have an index candidate in the matches vector
if (matches._length < numIndexFields &&
TRI_NeedsFullCoverageIndex(idx->_type)) {
// the matches vector does not fully cover the indexed fields, but the index requires it
continue;
}
// if we can use the primary index, we'll use it
picked = PickIndex(context, picked, idx, &matches);
}
TRI_DestroyVectorPointer(&matches);
if (picked) {
LogIndexString("using", picked->_idx, collectionName);
}
return picked;
}