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Overview

This document describes the Fetch Timeout message.

 

Version

All the versions of ALTIBASE HDB

Symptom

Altibase Server

In the Altibase server log, the following logs can be checked.

  • Check the Altibase server log ($ALTIBASE_HOME/trc/altibase_boot.log).

  • The output format is different for each version, so refer to the results below.

  • Comprehensively check the log output time, CLIENT_INFO, and Caused by Query to see if it is related to the client-side phenomenon.

  • Altibase HDB 5 or later

    Altibase HDB version 5 or later

  • ALTIBASE HDB 4.3.9

    Client IP information cannot be checked in the ALTIBASE HDB 4.3.9 server log. It should be judged with log output time and Caused by Query.
    Altibase HDB 4.3.9

Altibase Client

The following situations occur on the Altibase client side.

  • The error message can be checked when the client sends a request to the Altibase server.
    Therefore, it may occur after the time left on the Altibase server-side (altibase_boot.log).

  • The connection to the Altibase server is disconnected during SELECT (when Fetch is requested).

  • When an application processes a fetch result and requests a FETCH back to the database, a disconnected error occurs.

  • The session has been closed by the server in the client log. (For ALTIBASE HDB 5.5.1 or later versions)

  • The Server closed the connection in the client log. (For ALTIBASE HDB 5.5.1 or later versions.)

Refer to the following for the types of error messages for each client.

Orange for ALTIBASE

  • The following error message occurs when scrolling down the result window below after executing SELECT.

    Orange for ALTIBASE

iSQL

  • The following error message occurs while executing SELECT in iSQL.

    iSQL

APRE(SESC), SQLCLI, ODBC, CAPI

  • "Communication link failure during fetch in APRE, SQL CLI, ODBC, and CAPI. Server closed the connection." occurs.

  • This applies to ALTIBASE HDB version 5 or later

    APRE
    SQLCLI, ODBC

  • SESC (ALTIBASE HDB 4 ~ 5.1.5)

    SESC

JDBC

  • In ALTIBASE HDB 4.3.9, the following error occurs during FETCH execution and the application may be stopped.

    $ java SimpleSQL
    ...Omitted...
      ENO, DNO, SALARY : 20 40020
    FETCH ERROR CODE    : 0
    FETCH ERROR MESSAGE : Altibase JDBC $Revision: 24725 $ ERROR:read time out
    java.sql.SQLException: Altibase JDBC $Revision: 24725 $ ERROR:read time out
            at Altibase.jdbc.driver.cmProtocol.fireIOError(cmProtocol.java:87)
            at Altibase.jdbc.driver.cmProtocolTCP.execFetch(cmProtocolTCP.java:817)
            at Altibase.jdbc.driver.AltibaseConnection.execFetch(AltibaseConnection.java:298)
            at Altibase.jdbc.driver.AltibaseResultSet.next(AltibaseResultSet.java:1126)
            at SimpleSQL.main(SimpleSQL.java:105)

  • From ALTIBASE HDB 5 to 6.1.1, an error occurs during FETCH, and a disconnection error occurs whenever an application sends a request to the Altibase server afterward.

    JDBC-ALTIBASE HDB 5, 6.1.1 Occurrence type 1

    $ java SimpleSQL
    ...Omitted...
      ENO, DNO, SALARY : 19 40021800000
      ENO, DNO, SALARY : 20 40020
    FETCH ERROR CODE    : 0
    FETCH ERROR MESSAGE : The connection is reset by the peer. (errno:232)
    java.sql.SQLException: The connection is reset by the peer. (errno:232)
            at Altibase.jdbc.driver.ex.exception(ex.java:52)
            at Altibase.jdbc.driver.ex.exception(ex.java:37)
            at Altibase.jdbc.driver.cmnTCP.recv(cmnTCP.java:130)
            at Altibase.jdbc.driver.cmp.flush(cmp.java:247)
            at Altibase.jdbc.driver.cmp.writeFetchRequest(cmp.java:1066)
            at Altibase.jdbc.driver.ABConnection.writeFetchRequest(ABConnection.java:335)
            at Altibase.jdbc.driver.ABResultSet.fetchPosition(ABResultSet.java:1184)
            at Altibase.jdbc.driver.ABResultSet.next(ABResultSet.java:719)
            at SimpleSQL.main(SimpleSQL.java:105)
    sPreStmt.close ERROR CODE    : 0
    sPreStmt.close ERROR MESSAGE : Broken pipe. (errno:32)
    java.sql.SQLException: The pipe is damaged. (errno:32)
            at Altibase.jdbc.driver.ex.exception(ex.java:52)
            at Altibase.jdbc.driver.ex.exception(ex.java:37)
            at Altibase.jdbc.driver.cmnTCP.send(cmnTCP.java:153)
            at Altibase.jdbc.driver.cmp.flush(cmp.java:246)
            at Altibase.jdbc.driver.cmp.free(cmp.java:1085)
            at Altibase.jdbc.driver.ABConnection.free(ABConnection.java:346)
            at Altibase.jdbc.driver.ABStatement.close(ABStatement.java:174)
            at SimpleSQL.main(SimpleSQL.java:133)
    sCon.close ERROR CODE    : 0
    sCon.close ERROR MESSAGE : Broken pipe. (errno:32)
    java.sql.SQLException: The pipe is damaged. (errno:32)
            at Altibase.jdbc.driver.ex.exception(ex.java:52)
            at Altibase.jdbc.driver.ex.exception(ex.java:37)
            at Altibase.jdbc.driver.cmnTCP.send(cmnTCP.java:153)
            at Altibase.jdbc.driver.cmp.flush(cmp.java:246)
            at Altibase.jdbc.driver.cmp.disconnect(cmp.java:775)
            at Altibase.jdbc.driver.ABConnection.close(ABConnection.java:226)       
            at SimpleSQL.main(SimpleSQL.java:142)

    JDBC-ALTIBASE HDB 5, 6.1.1 Occurrence type 2

    $ java SimpleSQL
    ...Omitted...
      ENO, DNO, SALARY : 19 40021800000
      ENO, DNO, SALARY : 20 40020
    FETCH ERROR CODE    : 331817
    FETCH ERROR MESSAGE : Communication link failure
    java.sql.SQLException: Communication link failure
            at Altibase.jdbc.driver.ex.exception(ex.java:57)
            at Altibase.jdbc.driver.ex.exception(ex.java:32)
            at Altibase.jdbc.driver.ex.test(ex.java:83)
            at Altibase.jdbc.driver.cmnTCP.recv(cmnTCP.java:110)
            at Altibase.jdbc.driver.cmp.flush(cmp.java:253)
            at Altibase.jdbc.driver.cmp.writeFetchRequest(cmp.java:1167)
            at Altibase.jdbc.driver.ABConnection.writeFetchRequest(ABConnection.java:628)
            at Altibase.jdbc.driver.ABResultSet.fetchPosition(ABResultSet.java:1184)
            at Altibase.jdbc.driver.ABResultSet.next(ABResultSet.java:719)
            at SimpleSQL.main(SimpleSQL.java:105)
    sPreStmt.close ERROR CODE    : 331817
    sPreStmt.close ERROR MESSAGE : Broken pipe
    java.sql.SQLException: Broken pipe
            at Altibase.jdbc.driver.ex.exception(ex.java:76)
            at Altibase.jdbc.driver.cmnTCP.send(cmnTCP.java:156)
            at Altibase.jdbc.driver.cmp.flush(cmp.java:252)
            at Altibase.jdbc.driver.cmp.free(cmp.java:1186)
            at Altibase.jdbc.driver.ABConnection.free(ABConnection.java:655)
            at Altibase.jdbc.driver.ABStatement.close(ABStatement.java:179)
            at SimpleSQL.main(SimpleSQL.java:134)
    Caused by: java.io.IOException: Broken pipe
            at sun.nio.ch.FileDispatcher.write0(Native Method)
            at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:29)
            at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:69)
            at sun.nio.ch.IOUtil.write(IOUtil.java:26)
            at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:336)
            at Altibase.jdbc.driver.cmnTCP.send(cmnTCP.java:147)
            ... 5 more
    sCon.close ERROR CODE    : 331817
    sCon.close ERROR MESSAGE : Broken pipe
    java.sql.SQLException: Broken pipe
            at Altibase.jdbc.driver.ex.exception(ex.java:76)
            at Altibase.jdbc.driver.cmnTCP.send(cmnTCP.java:156)
            at Altibase.jdbc.driver.cmp.flush(cmp.java:252)
            at Altibase.jdbc.driver.cmp.disconnect(cmp.java:877)
            at Altibase.jdbc.driver.ABConnection.close(ABConnection.java:366)
            at SimpleSQL.main(SimpleSQL.java:143)
    Caused by: java.io.IOException: Broken pipe
            at sun.nio.ch.FileDispatcher.write0(Native Method)
            at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:29)
            at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:69)
            at sun.nio.ch.IOUtil.write(IOUtil.java:26)
            at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:336)
            at Altibase.jdbc.driver.cmnTCP.send(cmnTCP.java:147)
            ... 4 more

  • From ALTIBASE HDB 6.3.1, the session has been closed by the server error message that occurs during FETCH execution, and a connection disconnection error occurs whenever a request is sent to the Altibase server.

    JDBC - ALTIBASE HDB 6.3.1

    FETCH ERROR CODE    : 4163
    FETCH ERROR MESSAGE : The session has been closed by the server
    java.sql.SQLException: The session has been closed by the server
            at Altibase.jdbc.driver.ex.Error.processServerError(Error.java:320)
            at Altibase.jdbc.driver.AltibaseForwardOnlyResultSet.next(AltibaseForwardOnlyResultSet.java:151)
            at SimpleSQL.main(SimpleSQL.java:105)
    sPreStmt.close ERROR CODE    : 334337
    sPreStmt.close ERROR MESSAGE : Communication link failure: There was no response from the server, and the channel has reached end-of-stream.
    java.sql.SQLException: Communication link failure: There was no response from the server, and the channel has reached end-of-stream.
            at Altibase.jdbc.driver.ex.Error.throwSQLExceptionInternal(Error.java:162)
            at Altibase.jdbc.driver.ex.Error.throwSQLException(Error.java:102)
            at Altibase.jdbc.driver.cm.CmChannel.readFromSocket(CmChannel.java:1042)
            at Altibase.jdbc.driver.cm.CmChannel.receivePacket(CmChannel.java:1001)
            at Altibase.jdbc.driver.cm.CmChannel.sendAndReceive(CmChannel.java:821)
            at Altibase.jdbc.driver.cm.CmProtocol.freeStatement(CmProtocol.java:424)
            at Altibase.jdbc.driver.AltibaseStatement.close(AltibaseStatement.java:436)
            at SimpleSQL.main(SimpleSQL.java:133)
    sCon.close ERROR CODE    : 334337
    sCon.close ERROR MESSAGE : Communication link failure: Broken pipe
    java.sql.SQLException: Communication link failure: Broken pipe
            at Altibase.jdbc.driver.ex.Error.throwCommunicationErrorException(Error.java:237)
            at Altibase.jdbc.driver.cm.CmChannel.sendPacket(CmChannel.java:921)
            at Altibase.jdbc.driver.cm.CmChannel.sendAndReceive(CmChannel.java:819)
            at Altibase.jdbc.driver.cm.CmProtocol.disconnect(CmProtocol.java:95)
            at Altibase.jdbc.driver.AltibaseConnection.disconnect(AltibaseConnection.java:616)
            at Altibase.jdbc.driver.AltibaseConnection.close(AltibaseConnection.java:601)
            at SimpleSQL.main(SimpleSQL.java:142)
    Caused by: java.net.SocketException: Broken pipe
            at java.net.SocketOutputStream.socketWrite0(Native Method)
            at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:109)
            at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
            at java.nio.channels.Channels$WritableByteChannelImpl.write(Channels.java:292)
            at Altibase.jdbc.driver.cm.CmChannel.sendPacket(CmChannel.java:916)
            ... 5 more

Cause

This is a notification message left by the SessionManager as it cleans up the sessions stuck on FETCH_TMEOUT.

FETCH_TMEOUT is an Altibase server property. this is a property provided to prevent an abnormal increase of DBMS resources as the time to execute the SELECT statement increases.

When the client requests fetch, the DBMS divides the fetch result by a certain amount (in the communication buffer) and sends it to the client. When the client reads all the result sets in the communication buffer, it requests the next result set to the DB server.

If the time interval for requesting the next result set exceeds the value set for FETCH_TIMEOUT, the session is cleaned up and the transaction in progress is rolled back.

If the old image created by the change transaction is viewed by the inquiry transaction, the old image is not cleaned up even when the change transaction ends.

For this reason, if the SELECT statement is executed for a long time, the following symptoms may occur.
  • For memory tables, memory usage increases
  • For disk tables, undo tablespace usage increases

 

Solution

Checking the application logic

  • FETCH_TIMEOUT can be a problem if the application mainly processes the fetch result to perform other tasks, and this processing takes longer.

  • So, take a look at how the application handles fetch results, determine if there is room for improvement, and then take action. (Take measures after checking if there are any of the following parts)

    JDBC example
    APRE example

Changing FETCH_TIMEOUT setting value

  • The default value for the FETCH_TIMEOUT property is 60 seconds. If it is determined that this value is small in the operating environment, it can be changed and used.
  • This property can be changed with a system property or a session property.

Changing session property

  • Session property is applied to the session that executed ALTER SESSIOn on a per session basis and applied to queries executed after ALTER SESSION was executed.

    iSQL-How to change session properties

  •  It can also be changed in the application.

    JDBC example
    APRE/SESC example

Changing system property

  • System property affects a connected session after executing ALTER SYSTEM.

    iSQL-How to change system properties

  • To keep the changed system property values even after restarting the Altibase server process, you need to modify the altibase.properties file.

    iSQL-How to change system properties

How to check the FETCH_TIMEOUT property value

  • How to check the property value applied to the session

    Since FETCH_TIMEOUT can be changed on a per-session basis, the value set for each session may be different.
    The property value set in the session can be checked in V$SESSION.

  • Check system property value
    It can be changed with ALTER SYSTEM or check the value set in altibase.properties in V$PROPERTY.

    How to check the property value applied to the session

 

 

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