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ASF GitHub Bot commented on PHOENIX-2722: ----------------------------------------- Github user ankitsinghal commented on a diff in the pull request: https://github.com/apache/phoenix/pull/154#discussion_r58588402 --- Diff: phoenix-core/src/main/java/org/apache/phoenix/iterate/OffsetScanGrouper.java --- @@ -0,0 +1,44 @@ +/* + * 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.phoenix.iterate; + +import java.util.List; + +import org.apache.hadoop.hbase.client.Scan; +import org.apache.phoenix.compile.QueryPlan; + +/** + * Default implementation that creates a scan group if a plan is row key ordered (which requires a merge sort), + * or if a scan crosses a region boundary and the table is salted or a local index. + */ +public class OffsetScanGrouper implements ParallelScanGrouper { --- End diff -- It is needed to avoid scans in parallel even in serialIterators. should I use a anonymous class while creating SerialIterators to do offset on server? > support mysql "limit,offset" clauses > ------------------------------------- > > Key: PHOENIX-2722 > URL: https://issues.apache.org/jira/browse/PHOENIX-2722 > Project: Phoenix > Issue Type: New Feature > Reporter: Ankit Singhal > Assignee: Ankit Singhal > Priority: Minor > Attachments: PHOENIX-2722.patch, PHOENIX-2722_formatted.patch > > > For serial query(query with “serial" hint or “limit" without "order by”), we > can limit each scan(using page filter) to “limit+offset” instead of limit > earlier. > And then, for all queries, we can forward the relevant client iterators to > the offset provided and then return the result. > syntax > {code} > [ LIMIT { count } ] > [ OFFSET start [ ROW | ROWS ] ] > [ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY ] > {code} > Some new keywords(OFFSET,FETCH,ROW, ROWS,ONLY) are getting introduced so > users might need to see that they are not using them as column name or > something. > WDYT, [~jamestaylor] -- This message was sent by Atlassian JIRA (v6.3.4#6332)