Examples with HASH com.hazelcast.config.IndexType.HASH used on opensource projects

Example 1 with HASH

use of com.hazelcast.config.IndexType.HASH in project hazelcast by hazelcast.

the class IndexResolver method prepareSingleColumnCandidates.

/**
 * Creates a map from the scan column ordinal to expressions that could be potentially used by indexes created over
 * this column.
 *
 * @param expressions             CNF nodes
 * @param allIndexedFieldOrdinals ordinals of all columns that have some indexes. Helps to filter out candidates that
 *                                definitely cannot be used earlier.
 */
private static Map<Integer, List<IndexComponentCandidate>> prepareSingleColumnCandidates(List<RexNode> expressions, QueryParameterMetadata parameterMetadata, Set<Integer> allIndexedFieldOrdinals) {
    Map<Integer, List<IndexComponentCandidate>> res = new HashMap<>();
    // Iterate over each CNF component of the expression.
    for (RexNode expression : expressions) {
        // Try creating a candidate for the expression. The candidate is created iff the expression could be used
        // by some index implementation (SORTED, HASH)
        IndexComponentCandidate candidate = prepareSingleColumnCandidate(expression, parameterMetadata);
        if (candidate == null) {
            // Expression cannot be used by any index implementation, skip
            continue;
        }
        if (!allIndexedFieldOrdinals.contains(candidate.getColumnIndex())) {
            // Therefore, the expression could not be used, skip
            continue;
        }
        // Group candidates by column. E.g. {a>1 AND a<3} is grouped into a single map entry: a->{>1},{<3}
        res.computeIfAbsent(candidate.getColumnIndex(), (k) -> new ArrayList<>()).add(candidate);
    }
    return res;
}