[ 
https://issues.apache.org/jira/browse/DRILL-4729?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15412376#comment-15412376
 ] 

ASF GitHub Bot commented on DRILL-4729:
---------------------------------------

Github user sudheeshkatkam commented on a diff in the pull request:

    https://github.com/apache/drill/pull/530#discussion_r73945212
  
    --- Diff: 
exec/java-exec/src/main/java/org/apache/drill/exec/work/prepare/PreparedStatementProvider.java
 ---
    @@ -0,0 +1,427 @@
    +/**
    + * 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
    + * <p/>
    + * http://www.apache.org/licenses/LICENSE-2.0
    + * <p/>
    + * 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.work.prepare;
    +
    +import static 
org.apache.drill.exec.ExecConstants.CREATE_PREPARE_STATEMENT_TIMEOUT_MILLIS;
    +import static org.apache.drill.exec.proto.UserProtos.RequestStatus.FAILED;
    +import static org.apache.drill.exec.proto.UserProtos.RequestStatus.OK;
    +import static org.apache.drill.exec.proto.UserProtos.RequestStatus.TIMEOUT;
    +
    +import org.apache.drill.common.exceptions.ErrorHelper;
    +import org.apache.drill.common.types.TypeProtos.DataMode;
    +import org.apache.drill.common.types.TypeProtos.MajorType;
    +import org.apache.drill.common.types.TypeProtos.MinorType;
    +import org.apache.drill.common.types.Types;
    +import org.apache.drill.exec.physical.impl.materialize.QueryWritableBatch;
    +import org.apache.drill.exec.proto.ExecProtos.ServerPreparedStatementState;
    +import org.apache.drill.exec.proto.GeneralRPCProtos.Ack;
    +import org.apache.drill.exec.proto.UserBitShared.DrillPBError;
    +import org.apache.drill.exec.proto.UserBitShared.DrillPBError.ErrorType;
    +import org.apache.drill.exec.proto.UserBitShared.QueryId;
    +import org.apache.drill.exec.proto.UserBitShared.QueryResult;
    +import org.apache.drill.exec.proto.UserBitShared.QueryResult.QueryState;
    +import org.apache.drill.exec.proto.UserBitShared.QueryType;
    +import org.apache.drill.exec.proto.UserBitShared.SerializedField;
    +import org.apache.drill.exec.proto.UserProtos.ColumnSearchability;
    +import org.apache.drill.exec.proto.UserProtos.ColumnUpdatability;
    +import org.apache.drill.exec.proto.UserProtos.CreatePreparedStatementReq;
    +import org.apache.drill.exec.proto.UserProtos.CreatePreparedStatementResp;
    +import org.apache.drill.exec.proto.UserProtos.PreparedStatement;
    +import org.apache.drill.exec.proto.UserProtos.PreparedStatementHandle;
    +import org.apache.drill.exec.proto.UserProtos.RequestStatus;
    +import org.apache.drill.exec.proto.UserProtos.ResultColumnMetadata;
    +import org.apache.drill.exec.proto.UserProtos.RpcType;
    +import org.apache.drill.exec.proto.UserProtos.RunQuery;
    +import org.apache.drill.exec.rpc.Acks;
    +import org.apache.drill.exec.rpc.Response;
    +import org.apache.drill.exec.rpc.ResponseSender;
    +import org.apache.drill.exec.rpc.RpcOutcomeListener;
    +import org.apache.drill.exec.rpc.user.UserServer.UserClientConnection;
    +import org.apache.drill.exec.rpc.user.UserSession;
    +import org.apache.drill.exec.store.ischema.InfoSchemaConstants;
    +import org.apache.drill.exec.work.user.UserWorker;
    +import org.joda.time.Period;
    +
    +import com.google.common.collect.ImmutableMap;
    +
    +import io.netty.buffer.ByteBuf;
    +import io.netty.channel.ChannelFuture;
    +import java.math.BigDecimal;
    +import java.net.SocketAddress;
    +import java.sql.Date;
    +import java.sql.ResultSetMetaData;
    +import java.sql.Time;
    +import java.sql.Timestamp;
    +import java.util.List;
    +import java.util.Map;
    +import java.util.UUID;
    +import java.util.concurrent.CountDownLatch;
    +import java.util.concurrent.TimeUnit;
    +
    +/**
    + * Contains worker {@link Runnable} for creating a prepared statement and 
helper methods.
    + */
    +public class PreparedStatementProvider {
    +  private static final org.slf4j.Logger logger = 
org.slf4j.LoggerFactory.getLogger(PreparedStatementProvider.class);
    +
    +  /**
    +   * Static list of mappings from {@link MinorType} to JDBC ResultSet 
class name (to be returned through
    +   * {@link ResultSetMetaData#getColumnClassName(int)}.
    +   */
    +  private static final Map<MinorType, String> DRILL_TYPE_TO_JDBC_CLASSNAME 
= ImmutableMap.<MinorType, String>builder()
    +      .put(MinorType.INT, Integer.class.getName())
    +      .put(MinorType.BIGINT, Long.class.getName())
    +      .put(MinorType.FLOAT4, Float.class.getName())
    +      .put(MinorType.FLOAT8, Double.class.getName())
    +      .put(MinorType.VARCHAR, String.class.getName())
    +      .put(MinorType.BIT, Boolean.class.getName())
    +      .put(MinorType.DATE, Date.class.getName())
    +      .put(MinorType.DECIMAL9, BigDecimal.class.getName())
    +      .put(MinorType.DECIMAL18, BigDecimal.class.getName())
    +      .put(MinorType.DECIMAL28SPARSE, BigDecimal.class.getName())
    +      .put(MinorType.DECIMAL38SPARSE, BigDecimal.class.getName())
    +      .put(MinorType.TIME, Time.class.getName())
    +      .put(MinorType.TIMESTAMP, Timestamp.class.getName())
    +      .put(MinorType.VARBINARY, byte[].class.getName())
    +      .put(MinorType.INTERVALYEAR, Period.class.getName())
    +      .put(MinorType.INTERVALDAY, Period.class.getName())
    +      .put(MinorType.MAP, Object.class.getName())
    +      .put(MinorType.LIST, Object.class.getName())
    +      .put(MinorType.UNION, Object.class.getName())
    +      .build();
    +
    +  /**
    +   * Runnable that creates a prepared statement for given {@link 
CreatePreparedStatementReq} and
    +   * sends the response at the end.
    +   */
    +  public static class PreparedStatementWorker implements Runnable {
    +    private final UserClientConnection connection;
    +    private final UserWorker userWorker;
    +    private final ResponseSender responseSender;
    +    private final CreatePreparedStatementReq req;
    +
    +    public PreparedStatementWorker(final UserClientConnection connection, 
final UserWorker userWorker,
    +        final ResponseSender responseSender, final 
CreatePreparedStatementReq req) {
    +      this.connection = connection;
    +      this.userWorker = userWorker;
    +      this.responseSender = responseSender;
    +      this.req = req;
    +    }
    +
    +    @Override
    +    public void run() {
    +      final CreatePreparedStatementResp.Builder respBuilder = 
CreatePreparedStatementResp.newBuilder();
    +      try {
    +        UserClientConnectionWrapper wrapper = new 
UserClientConnectionWrapper(connection);
    +
    +        final RunQuery limit0Query =
    +            RunQuery.newBuilder()
    +                .setType(QueryType.SQL)
    +                .setPlan(String.format("SELECT * FROM (%s) LIMIT 0", 
req.getSqlQuery()))
    +                .build();
    +
    +        final QueryId limit0QueryId = userWorker.submitWork(wrapper, 
limit0Query);
    +
    +        final long timeout_millis =
    --- End diff --
    
    timeoutMillis


> Add support for prepared statement implementation on server side
> ----------------------------------------------------------------
>
>                 Key: DRILL-4729
>                 URL: https://issues.apache.org/jira/browse/DRILL-4729
>             Project: Apache Drill
>          Issue Type: Sub-task
>          Components: Metadata
>            Reporter: Venki Korukanti
>            Assignee: Venki Korukanti
>             Fix For: 1.8.0
>
>
> Currently Drill JDBC/ODBC driver implements its own prepared statement 
> implementation, which basically issues limit 0 query to get the metadata and 
> then executes the actual query. So the query is planned twice (for metadata 
> fetch and actual execution). Proposal is to move that logic to server where 
> we can make optimizations without disrupting/updating the JDBC/ODBC drivers.
> *  {{PreparedStatement createPreparedStatement(String query)}}. 
> {{PreparedStatement}} object contains the following:
> ** {{ResultSetMetadata getResultSetMetadata()}}
> *** {{ResultsSetMetadata}} contains methods to fetch info about output 
> columns of the query. What info these methods provide is given in this 
> [spreadsheet|https://docs.google.com/spreadsheets/d/1A6nqUQo5xJaZDQlDTittpVrK7t4Kylycs3P32Yn_O5k/edit?usp=sharing].
>  It lists the ODBC/JDBC requirements and what Drill will provided through 
> object {{ResultsSetMetadata}}.
> *** Server can put more info here which is opaque to client and use it in 
> server when the client sends execute prepared statement query request. 
> Overload the current submit query API to take the {{PreparedStatement}} 
> returned above. 
> In the initial implementation, server side implementation of 
> {{createPreparedStatement}} API is implemented as follows:
> * Runs the query with {{LIMIT 0}}, gets the schema
> * Convert the query into a binary blob and set it as opaque object in 
> {{PreparedStatement}}.
> When the {{PreparedStatement}} is submitted for execution, reconstruct the 
> query from binary blob in opaque component of {{PreparedStatement}} and 
> execute it from scratch. 
> Opaque component of the {{PreparedStatement}} is where we can save more 
> information which we can use for optimizations/speedups.
> NOTE: We are not going to worry about parameters in prepared query in initial 
> implementation. We can provide the functionality later if there is sufficient 
> demand from Drill community.
> Changes in this patch are going to include protobuf messages, server side 
> messages and Java client APIs. Native client changes are going to be tracked 
> in a separate JIRA.



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