Connection reset after "Refresh Server List" by enableSysplexWLB

Technical Blog Post

Abstract

Body

To utilize the transaction-level workload balancing with purescale, you can set enableSysplexWLB as true from your java client application(ref 1). This will distribute your workload to the members in purescale.

For this distribution, a new connection could be made to a member of purescale if your java appclication did not have any connection with that member based on the server list with the connection detail(IP address, port, and weight) for the members of the DB2 purescale instance(ref 2).

However, a new thing I found out is that JDBC driver will reset the connection for the next SQL after server list refresh(server list update from purescale server to client application). This means that one of your connections previously made in your java application could be reset due to this server list refresh.

To confirm this situation, I made a small java program(ref 3) and run it with JDBC trace(ref 4). In this test, I saw that connection reset is done for the next SQL whenever the message "Refresh Server List" happens. And I also checked source code and got confirmation from area expert that this is current design of workload balancing.

To prevent connection reset by server list refresh, you might change the refresh interval by "db2.jcc.maxRefreshInterval" configuration property(ref 2). If you set it as longer value, you can decrease the number of connection reset. But the WLB information from servers will be updated slower for WLB algorithm.

To understand WLB algorithm deeply, please see the ref 5.

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ref 1

Configuration of DB2 for Linux, UNIX, and Windows workload balancing support for Java clients

https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.1.0/com.ibm.db2.luw.apdv.java.doc/src/tpc/imjcc_c0056603.html

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ref 2

Operation of workload balancing for connections to DB2 for Linux, UNIX, and Windows

https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.1.0/com.ibm.db2.luw.apdv.java.doc/src/tpc/imjcc_c0056656.html

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ref 3 test java program

: This program executes 10 SQLs to purescale server.

(the only difference is the read cnt to distinguish each SQL)

$ cat tst.java

import java.sql.*;

import java.lang.*;

public class tst {

public static void main(String [] args) {

String urlPrefix = "jdbc:db2:";

String url;

String user;

String password;

String dummy;

Connection con;

Statement stmt;

ResultSet rs;

int cnt = 10;

System. out.println ("**** Enter class tst" );

// Check the that first argument has the correct form for the portion

// of the URL that follows jdbc:db2:,

// as described

// in the Connecting to a data source using the DriverManager

// interface with the IBM Data Server Driver for JDBC and SQLJ topic.

// For example, for IBM Data Server Driver for

// JDBC and SQLJ type 2 connectivity,

// args [0] might be MVS1DB2M. For

// type 4 connectivity, args[0] might

// be //stlmvs1:10110/MVS1DB2M.

if (args.length !=3)

{

System. err.println ("Invalid value. First argument appended to " +

"jdbc:db2: must specify a valid URL." );

System. err.println ("Second argument must be a valid user ID." );

System. err.println ("Third argument must be the password for the user ID.");

System. exit(1);

}

url = urlPrefix + args[0];

user = args[1];

password = args[2];

try {

Class. forName("com.ibm.db2.jcc.DB2Driver");

// Create the connection using the IBM Driver for JDBC and SQLJ

System. out.println(url);

con = DriverManager. getConnection(url, user, password);

con.setAutoCommit( true);

System. out.println("**** Created a JDBC connection to the data source");

// Create the Statement

stmt = con.createStatement();

System. out.println("**** Created JDBC Statement object" );

while (cnt > 0) {

// Execute a query and generate a ResultSet instance

rs = stmt.executeQuery( "SELECT " + cnt +" FROM SYSIBM.SYSDUMMY1");

System. out.println("**** Created JDBC ResultSet object" );

while (rs.next()) {

dummy = rs.getString(1);

System. out.println("number = " + dummy);

}

rs.close();

System. out.println("**** Closed JDBC ResultSet" );

System. out.println("**** Thread sleep now" );

try {

Thread.sleep(5000); // 5 seconds

} catch(InterruptedException ex) {

Thread.currentThread().interrupt();

}

cnt--;

}

// Close the Statement

stmt.close();

System. out.println("**** Closed JDBC Statement" );

// Connection must be on a unit-of-work boundary to allow close

con.commit();

System. out.println ( "**** Transaction committed" );

// Close the connection

con.close();

System. out.println("**** Disconnected from data source" );

System. out.println("**** JDBC Exit from class tst - no errors" );

}

catch(ClassNotFoundException e) {

System. err.println("Could not load JDBC driver" );

System. out.println("Exception: " + e);

e.printStackTrace();

}

catch(SQLException ex) {

System. err.println("SQLException information" );

while(ex!=null ) {

System. err.println ("Error msg: " + ex.getMessage());

System. err.println ("SQLSTATE: " + ex.getSQLState());

System. err.println ("Error code: " + ex.getErrorCode());

ex.printStackTrace();

ex = ex.getNextException(); // For drivers that support chained exceptions

}

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ref 4 JDBC trace from the test java program

The following the snippet of egrep result of JDBC trace. I extracted some meaningful information to confirm connection reset.

########################

>>>>> each keyword was used to see the following information

Refresh: To see "Refresh Sever List" message

bestMember: To see assigned member for the SQL

executeQuery: To check query execution

resetConnectionAtFirstSql_: To see if connection reset happens for the next SQL

got Transport: To check the next query is using same Transport object.

Success: To see the connection reset message.

########################

...

[jcc]findBestSysplexMember [time:2017-09-06-16:57:19.436][Thread:main][tracepoint:250] Refresh Server List {SWLBG@462399a1: lpar214ps3/192.168.159.225 1565 SAMPLE 4 0 0 0 main

[jcc][t4] [time:2017-09-06-16:57:19.478][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 0 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:19.479][Thread:main][tracepoint:640]newTransport.dbConnected_ = false resetConnectionAtFirstSql_ = true

[jcc][Connection@1eb56685] Successfully connected to server jdbc:db2://lpar214ps3:1565/SAMPLE

>>>>> first connection

[jcc][Time:2017-09-06-16:57:20.979][Thread:main][Statement@d7d5010a]executeQuery (SELECT 10 FROM SYSIBM.SYSDUMMY1) called

>>>>> first SQL

[jcc]findBestSysplexMember [time:2017-09-06-16:57:20.988][Thread:main][tracepoint:202] transaction count is zero. tryingMember:0 lastBestMember: 0 bestMember: 0 workloadRatio: 0.79879093 tryingMemberRatio: 0.48979592 bestMemberPriority: 96 bestMemberRatio: 0.48979592 bestMemberTransportsInUse_: 0 tryingMemberPriority: 96 tryingMemberRatio: 0.48979592 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:57:20.989][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 96 0.48979592 false 0 4 1 1 0 true

[jcc][t4] [time:2017-09-06-16:57:20.991][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:20.992][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = false

>>>>> connection reset does not occur

[jcc][Time:2017-09-06-16:57:21.052][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@150e2be6

[jcc][Time:2017-09-06-16:57:26.064][Thread:main][Statement@d7d5010a]executeQuery (SELECT 9 FROM SYSIBM.SYSDUMMY1) called

>>>>> second SQL

[jcc]findBestSysplexMember [time:2017-09-06-16:57:26.065][Thread:main][tracepoint:202] transaction count is zero. tryingMember:1 lastBestMember: 0 bestMember: 0 workloadRatio: 0.7124681 tryingMemberRatio: 0.5102041 bestMemberPriority: 96 bestMemberRatio: 0.48979592 bestMemberTransportsInUse_: 0 tryingMemberPriority: 100 tryingMemberRatio: 0.5102041 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:57:26.066][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 96 0.48979592 false 10 4 1 2 0 true

[jcc][t4] [time:2017-09-06-16:57:26.068][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:26.068][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = false

>>>>> connection reset does not occur

[jcc][Time:2017-09-06-16:57:26.077][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@8db1c653

[jcc][Time:2017-09-06-16:57:31.088][Thread:main][Statement@d7d5010a]executeQuery (SELECT 8 FROM SYSIBM.SYSDUMMY1) called

>>>>> third SQL

[jcc]findBestSysplexMember [time:2017-09-06-16:57:31.089][Thread:main][tracepoint:250] Refresh Server List {SWLBG@462399a1: lpar214ps3/192.168.159.225 1565 SAMPLE 4 2 0 196 main

>>>>> Server list is refreshed

[jcc]findBestSysplexMember [time:2017-09-06-16:57:31.089][Thread:main][tracepoint:202] transaction count is zero. tryingMember:0 lastBestMember: 0 bestMember: 0 workloadRatio: 0.58786815 tryingMemberRatio: 0.48979592 bestMemberPriority: 96 bestMemberRatio: 0.48979592 bestMemberTransportsInUse_: 0 tryingMemberPriority: 96 tryingMemberRatio: 0.48979592 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:57:31.090][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 96 0.48979592 false 10 4 1 3 0 true

[jcc][t4] [time:2017-09-06-16:57:31.092][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:31.092][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = true

[jcc][Connection@1eb56685]Successfully reset connection to server jdbc:db2://lpar214ps3:1565/SAMPLE

>>>>> connection reset DOES occur

>>>>> you might see that this connection reset is done even if 2nd and 3rd SQLs are using same member(member 0)

[jcc][Time:2017-09-06-16:57:32.329][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@5b27b542

[jcc][Time:2017-09-06-16:57:37.337][Thread:main][Statement@d7d5010a]executeQuery (SELECT 7 FROM SYSIBM.SYSDUMMY1) called

[jcc]findBestSysplexMember [time:2017-09-06-16:57:37.338][Thread:main][tracepoint:202] transaction count is zero. tryingMember:0 lastBestMember: 0 bestMember: 0 workloadRatio: 0.9449462 tryingMemberRatio: 0.5025126 bestMemberPriority: 100 bestMemberRatio: 0.5025126 bestMemberTransportsInUse_: 0 tryingMemberPriority: 100 tryingMemberRatio: 0.5025126 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:57:37.339][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 100 0.5025126 false 10 4 1 4 0 true

[jcc][t4] [time:2017-09-06-16:57:37.340][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:37.340][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = false

[jcc][Time:2017-09-06-16:57:37.350][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@e79ea41c

[jcc][Time:2017-09-06-16:57:42.357][Thread:main][Statement@d7d5010a]executeQuery (SELECT 6 FROM SYSIBM.SYSDUMMY1) called

[jcc]findBestSysplexMember [time:2017-09-06-16:57:42.358][Thread:main][tracepoint:250] Refresh Server List {SWLBG@462399a1: lpar214ps3/192.168.159.225 1565 SAMPLE 4 2 0 199 main

[jcc]findBestSysplexMember [time:2017-09-06-16:57:42.359][Thread:main][tracepoint:202] transaction count is zero. tryingMember:0 lastBestMember: 0 bestMember: 0 workloadRatio: 0.8682259 tryingMemberRatio: 0.5025126 bestMemberPriority: 100 bestMemberRatio: 0.5025126 bestMemberTransportsInUse_: 0 tryingMemberPriority: 100 tryingMemberRatio: 0.5025126 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:57:42.359][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 100 0.5025126 false 10 4 1 5 0 true

[jcc][t4] [time:2017-09-06-16:57:42.362][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:42.362][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = true

[jcc][Connection@1eb56685]Successfully reset connection to server jdbc:db2://lpar214ps3:1565/SAMPLE

[jcc][Time:2017-09-06-16:57:43.660][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@7124feb8

[jcc][Time:2017-09-06-16:57:48.674][Thread:main][Statement@d7d5010a]executeQuery (SELECT 5 FROM SYSIBM.SYSDUMMY1) called

[jcc]findBestSysplexMember [time:2017-09-06-16:57:48.675][Thread:main][tracepoint:202] transaction count is zero. tryingMember:0 lastBestMember: 0 bestMember: 0 workloadRatio: 0.52446806 tryingMemberRatio: 0.49748743 bestMemberPriority: 99 bestMemberRatio: 0.49748743 bestMemberTransportsInUse_: 0 tryingMemberPriority: 99 tryingMemberRatio: 0.49748743 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:57:48.676][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 99 0.49748743 false 10 4 1 6 0 true

[jcc][t4] [time:2017-09-06-16:57:48.678][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:48.678][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = false

[jcc][Time:2017-09-06-16:57:48.687][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@2dd414e2

[jcc][Time:2017-09-06-16:57:53.704][Thread:main][Statement@d7d5010a]executeQuery (SELECT 4 FROM SYSIBM.SYSDUMMY1) called

[jcc]findBestSysplexMember [time:2017-09-06-16:57:53.705][Thread:main][tracepoint:250] Refresh Server List {SWLBG@462399a1: lpar214ps3/192.168.159.225 1565 SAMPLE 4 2 0 199 main

[jcc]findBestSysplexMember [time:2017-09-06-16:57:53.705][Thread:main][tracepoint:202] transaction count is zero. tryingMember:0 lastBestMember: 0 bestMember: 0 workloadRatio: 0.5708327 tryingMemberRatio: 0.49748743 bestMemberPriority: 99 bestMemberRatio: 0.49748743 bestMemberTransportsInUse_: 0 tryingMemberPriority: 99 tryingMemberRatio: 0.49748743 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:57:53.706][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 99 0.49748743 false 10 4 1 7 0 true

[jcc][t4] [time:2017-09-06-16:57:53.708][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:57:53.708][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = true

[jcc][Connection@1eb56685]Successfully reset connection to server jdbc:db2://lpar214ps3:1565/SAMPLE

[jcc][Time:2017-09-06-16:57:54.991][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@1081c6b1

[jcc][Time:2017-09-06-16:57:59.999][Thread:main][Statement@d7d5010a]executeQuery (SELECT 3 FROM SYSIBM.SYSDUMMY1) called

[jcc]findBestSysplexMember [time:2017-09-06-16:58:00.000][Thread:main][tracepoint:201] transaction count is zero. tryingMember:1 lastBestMember: 0 bestMember: 1 workloadRatio: 0.19599104 tryingMemberRatio: 0.5102041 bestMemberPriority: 100 bestMemberRatio: 0.5102041 bestMemberTransportsInUse_: 0 tryingMemberPriority: 100 tryingMemberRatio: 0.5102041 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:58:00.001][Thread:main][tracepoint:345] bestMember: 1 {SWLBN@827c9a82: lpar215ps4/192.168.159.226 1565 100 0.5102041 false 0 4 0 0 0 true

>>>>> this query goes to member 1

[jcc][t4] [time:2017-09-06-16:58:00.003][Thread:main][tracepoint:635]got Transport: {T4GTPK@5c9f22ae: 192.168.159.226 1565 db2inst1 3 SAMPLE 4 -2140671891 109 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@295d537d

[jcc][t4] [time:2017-09-06-16:58:00.004][Thread:main][tracepoint:640]newTransport.dbConnected_ = false resetConnectionAtFirstSql_ = false

[jcc][t4] [time:2017-09-06-16:58:00.004][Thread:main][tracepoint:645]newTransport.dbConnected_ = false resetConnectionAtFirstSql_ = false

[jcc][Connection@1eb56685] Successfully connected to server jdbc:db2://lpar214ps3:1565/SAMPLE

>>>>> new connection made with member 1

[jcc][Time:2017-09-06-16:58:01.216][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@62f9c20e

[jcc][Time:2017-09-06-16:58:06.224][Thread:main][Statement@d7d5010a]executeQuery (SELECT 2 FROM SYSIBM.SYSDUMMY1) called

[jcc]findBestSysplexMember [time:2017-09-06-16:58:06.225][Thread:main][tracepoint:201] transaction count is zero. tryingMember:1 lastBestMember: 1 bestMember: 1 workloadRatio: 0.42732596 tryingMemberRatio: 0.5235602 bestMemberPriority: 100 bestMemberRatio: 0.5235602 bestMemberTransportsInUse_: 0 tryingMemberPriority: 100 tryingMemberRatio: 0.5235602 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:58:06.226][Thread:main][tracepoint:345] bestMember: 1 {SWLBN@827c9a82: lpar215ps4/192.168.159.226 1565 100 0.5235602 false 10 4 1 1 0 true

[jcc][t4] [time:2017-09-06-16:58:06.227][Thread:main][tracepoint:635]got Transport: {T4GTPK@5c9f22ae: 192.168.159.226 1565 db2inst1 3 SAMPLE 4 -2140671891 109 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@295d537d

[jcc][t4] [time:2017-09-06-16:58:06.227][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = false

[jcc][Time:2017-09-06-16:58:06.235][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@98778a85

[jcc][Time:2017-09-06-16:58:11.244][Thread:main][Statement@d7d5010a]executeQuery (SELECT 1 FROM SYSIBM.SYSDUMMY1) called

[jcc]findBestSysplexMember [time:2017-09-06-16:58:11.245][Thread:main][tracepoint:250] Refresh Server List {SWLBG@462399a1: lpar214ps3/192.168.159.225 1565 SAMPLE 4 2 0 191 main

[jcc]findBestSysplexMember [time:2017-09-06-16:58:11.245][Thread:main][tracepoint:201] transaction count is zero. tryingMember:0 lastBestMember: 1 bestMember: 0 workloadRatio: 0.29110628 tryingMemberRatio: 0.4764398 bestMemberPriority: 91 bestMemberRatio: 0.4764398 bestMemberTransportsInUse_: 0 tryingMemberPriority: 91 tryingMemberRatio: 0.4764398 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:58:11.246][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 91 0.4764398 false 10 4 1 8 0 true

[jcc][t4] [time:2017-09-06-16:58:11.248][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:58:11.248][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = true

[jcc][Connection@1eb56685]Successfully reset connection to server jdbc:db2://lpar214ps3:1565/SAMPLE

[jcc][Time:2017-09-06-16:58:12.385][Thread:main][Statement@d7d5010a]executeQuery () returned ResultSet@9428ade

[jcc]findBestSysplexMember [time:2017-09-06-16:58:17.396][Thread:main][tracepoint:202] transaction count is zero. tryingMember:0 lastBestMember: 0 bestMember: 0 workloadRatio: 0.58333516 tryingMemberRatio: 0.45945945 bestMemberPriority: 85 bestMemberRatio: 0.45945945 bestMemberTransportsInUse_: 0 tryingMemberPriority: 85 tryingMemberRatio: 0.45945945 tryingMemberTransportsInUse_: 0 total connection: 0

[jcc]findBestSysplexMember [time:2017-09-06-16:58:17.397][Thread:main][tracepoint:345] bestMember: 0 {SWLBN@ee7039a8: lpar214ps3/192.168.159.225 1565 85 0.45945945 false 10 4 1 9 0 true

[jcc][t4] [time:2017-09-06-16:58:17.398][Thread:main][tracepoint:635]got Transport: {T4GTPK@342ebc2f: 192.168.159.225 1565 db2inst1 3 SAMPLE 4 -2140671892 108 false true isOrphan false DB2SimpleDataSource@2cb93053:1,2147483647 a@9172654e true com.ibm.db2.jcc.t4.ac@899a31d9

[jcc][t4] [time:2017-09-06-16:58:17.398][Thread:main][tracepoint:640]newTransport.dbConnected_ = true resetConnectionAtFirstSql_ = false

-------------------------------------

ref 5

Increase scalability and failure resilience of applications with IBM Data Server Driver for JDBC and SQLJ

https://www.ibm.com/developerworks/data/library/techarticle/dm-1407purescalesysplex/dm-1407purescalesysplex-pdf.pdf

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Connection reset after "Refresh Server List" by enableSysplexWLB

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