arina-ielchiieva commented on a change in pull request #1914: DRILL-7458: Base framework for storage plugins URL: https://github.com/apache/drill/pull/1914#discussion_r368561344
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/store/base/filter/FilterSpec.java ########## @@ -0,0 +1,150 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.drill.exec.store.base.filter; + +import java.util.List; + +import org.apache.drill.exec.store.base.PlanStringBuilder; + +import com.fasterxml.jackson.annotation.JsonCreator; +import com.fasterxml.jackson.annotation.JsonIgnore; +import com.fasterxml.jackson.annotation.JsonInclude; +import com.fasterxml.jackson.annotation.JsonProperty; +import com.fasterxml.jackson.annotation.JsonPropertyOrder; +import com.fasterxml.jackson.annotation.JsonInclude.Include; + +@JsonInclude(value=Include.NON_EMPTY, content=Include.NON_NULL) +@JsonPropertyOrder({"andTerms", "orTerms"}) +public class FilterSpec { + + private final List<RelOp> andTerms; + private final DisjunctionFilterSpec orTerms; + + @JsonCreator + public FilterSpec( + @JsonProperty("andTerms") List<RelOp> andFilters, + @JsonProperty("orTerms") DisjunctionFilterSpec orFilters) { + this.andTerms = andFilters == null || andFilters.isEmpty() ? null : andFilters; + this.orTerms = orFilters == null || orFilters.values.length == 0 ? null : orFilters; + } + + public static FilterSpec build(List<RelOp> andFilters, DisjunctionFilterSpec orFilters) { + FilterSpec spec = new FilterSpec(andFilters, orFilters); + return spec.isEmpty() ? null : spec; + } + + @JsonProperty("andTerms") + public List<RelOp> andTerms() { return andTerms; } + + @JsonProperty("orTerms") + public DisjunctionFilterSpec orTerms() { return orTerms; } + + /** + * The number of partitions in the sense of scan "segments" given + * by an OR clause. (May not correspond to HDFS file partitions.) + * + * @return the number of logical partitions, which is the number + * of OR clause terms (or 1 if no OR terms exist) + */ + + public int partitionCount() { + return orTerms == null ? 1 : orTerms.values.length; + } + + public static int parititonCount(FilterSpec filters) { + return filters == null ? 1 : filters.partitionCount(); + } + + public List<RelOp> distribute(int orTerm) { + return DisjunctionFilterSpec.distribute(andTerms, orTerms, orTerm); + } + + /** + * Compute selectivity of a CNF form of equality conditions. Without stats, + * Drill assumes a selectivity of 0.15 for each equality, then multiplies + * the selectivity of multiple columns. Place a lower limit of 0.001 on + * the result, assuming the user wants to return some rows. + * + * @param andTerms list of AND filters (in CNF form), or null if no + * filters apply to a scan + * @return selectivity of the filters + */ + + public double cnfSelectivity() { + if (andTerms == null || andTerms.isEmpty()) { + return 1.0; + } + double selectivity = 1.0; + for (RelOp relOp : andTerms) { + selectivity *= relOp.op.selectivity(); + } + return Math.max(0.001, selectivity); + } + + /** + * Compute the combined selectivity of a set of AND (CNF) and OR + * (DNF) filters. We assume the DNF returns a subset of rows, which + * the CNF terms further reduce. Selectivity will be at least + * 0.001, which assumes the user wants to return some rows. + * + * @param andTerms and filters for the scan, or null if none + * @param orTerms or filters for the scan, or null if none + * @return combined selectivity + */ + + public double selectivity() { + double selectivity = cnfSelectivity(); + if (orTerms != null) { + selectivity = Math.max(0.001, selectivity * orTerms.selectivity()); + } + return selectivity; + } + + /** + * Drill scan stats want a row count, the selectivity is a means to + * that end. Apply the selectivity of a set of filters to the given + * row count to produce a reduced row count. + * + * @param andTerms and filters for the scan, or null if none Review comment: Same here. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
