Tag Archives: Connection

Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.

by apollo89 Posted on 2010년 10월 8일

mysql 접속시에 자꾸 아래와 같은 에러가 나서..

Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.

1	Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.

context.xml의 설정을 아래와 같이 바꿔주니 해결된듯하다.

    <Resource auth="Container"
              driverClassName="com.mysql.jdbc.Driver"
              url="jdbc:mysql://xxx.xxx.xxx.xxx:3306/dbname?characterEncoding=utf-8&amp;interactiveClient=true&amp;autoReconnect=true&amp;autoReconnectForPools=true&amp;useUnicode=true&amp;characterSetResults=UTF-8"
              type="javax.sql.DataSource"
              name="jdbc/xxxxx"
              username="userid"
              password="userpw"
              initialSize="0"
              maxActive="20"
              maxIdle="10"
              minIdle="0"
              maxWait="-1"
              validationQuery="SELECT 1"
              testOnBorrow="true"
              poolPreparedStatements="true"
              removeAbandoned="true"
              removeAbandonedTimeout="60"
              logAbandoned="true"
              loginTimeout="10"
    />

<Resource auth="Container"

driverClassName="com.mysql.jdbc.Driver"

url="jdbc:mysql://xxx.xxx.xxx.xxx:3306/dbname?characterEncoding=utf-8&interactiveClient=true&autoReconnect=true&autoReconnectForPools=true&useUnicode=true&characterSetResults=UTF-8"

type="javax.sql.DataSource"

name="jdbc/xxxxx"

username="userid"

password="userpw"

initialSize="0"

maxActive="20"

maxIdle="10"

minIdle="0"

maxWait="-1"

validationQuery="SELECT 1"

testOnBorrow="true"

poolPreparedStatements="true"

removeAbandoned="true"

removeAbandonedTimeout="60"

logAbandoned="true"

loginTimeout="10"

Posted in Database, Java/JSP | Tagged Connection, context, mysql, 에러, 톰켓 | Leave a comment

DBCP + JDBC(MySQL) 사용시 간혹 뜨는 Could not open JDBC Connection for transaction

by apollo89 Posted on 2010년 1월 13일

DBCP(Database Connection Pool)을 사용하다 보면 가끔씩 만나게 되는 에러가 있다. 내 추측에는 DBCP의 특성상 많은 수의 커넥션을 미리 맺어 놓고, 어플리케이션이 풀에서 커넥션을 빌려다 사용하고 환원하는 식인데, 맺어놓은 커넥션을 MySQL의 커넥터가 끊어버리는듯 하다. 그래서 풀에 정상적으로 요청을 하였지만 그것이 … Continue reading →

Posted in Database, Java/JSP | Tagged Connection, DBCP, JDBC, 에러 | Leave a comment

java.sql.SQLException Io exception: Connection reset

by apollo89 Posted on 2009년 10월 5일

Connection reset은 DB 서버측에서 커넥션이 종료되었으나 WAS는 그것을 알아차리지 못할때 발생합니다. TOMCAT의 경우 , evicator라는 것이 있어 정기적으로 비정상종료된 커넥션을 없애주는 옵션이 있습니다. 아래 스크립트를 참고하세요 – validationQuery=”SELECT 1 FROM DUAL” – testWhileIdle=”true” – timeBetweenEvictionRunsMillis=”3000″

<Resource name="WmsPool" auth="Container"
        type="javax.sql.DataSource" driverClassName="oracle.jdbc.OracleDriver"
        factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"
        url="jdbc:oracle:thin:@<ip>:<port>:<sid>"
        username="<유저>" password="<패스워드>" 
        initialSize="5" validationQuery="SELECT 1 FROM DUAL" 
        testOnReturn="true" testWhileIdle="true"
        timeBetweenEvictionRunsMillis="3000"
        maxActive="5" maxIdle="2" maxWait="10000"
        removeAbandoned="true"
        removeAbandonedTimeout="60"
        logAbandoned="true"
/>

<Resource name="WmsPool" auth="Container"

type="javax.sql.DataSource" driverClassName="oracle.jdbc.OracleDriver"

factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"

url="jdbc:oracle:thin:@<ip>:<port>:<sid>"

username="<유저>" password="<패스워드>"

initialSize="5" validationQuery="SELECT 1 FROM DUAL"

testOnReturn="true" testWhileIdle="true"

timeBetweenEvictionRunsMillis="3000"

maxActive="5" maxIdle="2" maxWait="10000"

removeAbandoned="true"

removeAbandonedTimeout="60"

logAbandoned="true"

결론적으로는 DB Restart … Continue reading →

Posted in Database, Java/JSP, WEB/WAS | Tagged Connection, 데이터베이스, 에러, 자바, 톰켓 | Leave a comment

Cannot get a connection, pool exhausted

by apollo89 Posted on 2007년 12월 3일

################################# Exception #############################
org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted
at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:103)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)

################################# Exception #############################

org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted

at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:103)

at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)

위와 같은 증상에선..테스트 소스는 별 의미가 없습니다. 리소스(Connection)가 어디서 새는지 해당 소스를 찾아내시는 방법밖에 없습니다. 리뷰할 소스가 방대하고 성능관리 툴이 없는 상황이시라면 정말 위로의 말씀을 전해드리고 싶군요..ㅠ.ㅜ 그나마 일단 시도해 볼 수 있는 방법은 이렇습니다. 서비스에 지장이 없는 … Continue reading →

Posted in Database, Java/JSP, WEB/WAS | Tagged Connection, maxWait, pool exhausted | Leave a comment

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Tag Archives: Connection

Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.

DBCP + JDBC(MySQL) 사용시 간혹 뜨는 Could not open JDBC Connection for transaction

java.sql.SQLException Io exception: Connection reset

Cannot get a connection, pool exhausted

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