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https://issues.apache.org/jira/browse/DRILL-4729?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15412232#comment-15412232
]
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_r73929114
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/work/prepare/PreparedStatementProvider.java
---
@@ -0,0 +1,419 @@
+/**
+ * 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 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);
+
+ private static final int LIMIT_0_QUERY_TIMEOUT_MINS = 10;
--- End diff --
Or make this a system property?
We have seen cases where `LIMIT 0` queries take longer than 10 minutes.
Although there is [an option (disabled by
default)](https://issues.apache.org/jira/browse/DRILL-3623) to avoid
full-fledged execution for queries on _tables with known schema_, on other
tables, `LIMIT 0` queries may take 10 minutes. They should not, but they may
(due to single fragment execution).
> 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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