recovering connections on jdbc connection pool
Hello all, is there any way to recover lost connectios on a pool? Here's the issue, for an application, using postgresql jdbc (same happens with mysql as i tried), having query errors syntax or duplicated keys, actually no big deal, it throws an sqlexception upon que sql error, as this call executes ~150 queries to insert, on each query i lost the connection, so suddenly i have all my connections lost and my app useless. How can i do from the catch clause of the SQLException to ask the pool to reconnect? Because today we are in debug stage but soon to be production and when this happens (we've corrected a lot of queries and situations but for sure some new one will arise) we need to restart the webapp. thanks in advance. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: recovering connections on jdbc connection pool
Am Sonntag, den 08.05.2011, 11:42 -0300 schrieb alexis: Hello all, is there any way to recover lost connectios on a pool? Here's the issue, for an application, using postgresql jdbc (same happens with mysql as i tried), having query errors syntax or duplicated keys, actually no big deal, it throws an sqlexception upon que sql error, as this call executes ~150 queries to insert, on each query i lost the connection, so suddenly i have all my connections lost and my app useless. How can i do from the catch clause of the SQLException to ask the pool to reconnect? Because today we are in debug stage but soon to be production and when this happens (we've corrected a lot of queries and situations but for sure some new one will arise) we need to restart the webapp. SQL Connections should not get lost when used properly. You have to close the connections and every resources you got out of that connection in case of a program error. Look for jdbc try finally. As a helper to find connections, you did not close properly you can configure your jdbc pool to show your abandoned connections. Another safety net are the validation queries. For further information look at http://tomcat.apache.org/tomcat-7.0-doc/jndi-datasource-examples-howto.html Regards Felix thanks in advance. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: recovering connections on jdbc connection pool
Here's a snippet of my code, this method was with the described problem
public void insertVDNInfo(VDNInfo vdns) throws SQLException {
Calendar c = Calendar.getInstance();
IteratorVDNInfo.VDN it = vdns.getVdns().iterator();
Connection c1 = null;
Statement s1 = null;
try {
while (it.hasNext()) {
c1 = getConnection();
s1 = c1.createStatement();
VDNInfo.VDN v = it.next();
String query = INSERT INTO list.vdn VALUES (
+ ' + v.getName() + ', + v.getExt() + , +
v.isVdnovr() + , + v.getCor() + , + v.getTn() + , + v.getVecNum() + ,'
+ v.getMeas() + ',
+ v.isOrigAnnc() + , + v.isEvntNotiAdj() + ,' +
sdfTimestamp.format(c.getTime()) + ');
s1.execute(query);
}
} finally {
if (s1 != null) {
s1.close();
}
s1 = null;
if (c1 != null) {
c1.close();
}
c1 = null;
}
}
Objects are created like
private Connection getConnection() {
DataSource ds = null;
Connection c1 = null;
try {
ds = (DataSource) new
InitialContext().lookup(java:/comp/env/jdbc/pgsql);
c1 = ds.getConnection();
} catch (NamingException ex) {
log.error(, ex);
} catch (SQLException ex) {
log.error(, ex);
}
return c1;
}
what i can see different from the example on
http://tomcat.apache.org/tomcat-7.0-doc/jndi-datasource-examples-howto.html is
that the SQLException is now thrown but catched locally in the method.
and here's my resource pool config
Context antiJARLocking=true path=/xcall3
Resource
auth=Container
driverClassName=org.postgresql.Driver
maxActive=10
maxIdle=3
name=jdbc/pgsql
password=xcall3
type=javax.sql.DataSource
url=jdbc:postgresql://localhost/xcall3
username=xcall3
validationQuery=select version();
maxWait = 5000
/
here's what logs the database
2011-05-07 23:02:25 ARTLOG: execute unnamed: INSERT INTO list.vdn VALUES
('Atencion a Clientes',7022,false,1,1,33,'int',false,false,'2011-05-07
23:02:25')
2011-05-07 23:02:25 ARTLOG: unexpected EOF on client connection
until i lose all my connections.
here's what i got from the webapp log after that
2011-05-06 13:34:38,430 ERROR DAO:47 -
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot get a connection,
general error
at
org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:118)
at
org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
at com.lesi.xcall3.core.DAO.getConnection(DAO.java:43)
at com.lesi.xcall3.core.DAO.getSchedulerTasks(DAO.java:317)
at com.lesi.xcall3.core.Scheduler.run(Scheduler.java:35)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.InterruptedException
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:485)
at
org.apache.tomcat.dbcp.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1104)
at
org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:106)
... 5 more
Exception in thread XCALL3-Scheduler java.lang.NullPointerException
at java.util.ArrayList.toArray(ArrayList.java:303)
at com.lesi.xcall3.core.DAO.getSchedulerTasks(DAO.java:384)
at com.lesi.xcall3.core.Scheduler.run(Scheduler.java:35)
at java.lang.Thread.run(Thread.java:662)
On May 8, 2011, at 12:19 PM, Felix Schumacher wrote:
Am Sonntag, den 08.05.2011, 11:42 -0300 schrieb alexis:
Hello all, is there any way to recover lost connectios on a pool?
Here's the issue, for an application, using postgresql jdbc (same happens
with mysql as i tried), having query errors syntax or duplicated keys,
actually no big deal, it throws an sqlexception upon que sql error, as this
call executes ~150 queries to insert, on each query i lost the connection,
so suddenly i have all my connections lost and my app useless.
How can i do from the catch clause of the SQLException to ask the pool to
reconnect? Because today we are in debug stage but soon to be production and
when this happens (we've corrected a lot of queries and situations but for
sure some new one will arise) we need to restart the webapp.
SQL Connections should not get lost when used properly. You have to
close the connections and every resources you got out of that connection
in case of a program error. Look for jdbc try finally.
As a helper to find connections, you did not close properly you can
configure your jdbc pool to show your abandoned connections. Another
safety net are the validation queries. For further information look at
Re: recovering connections on jdbc connection pool
Am Sonntag, den 08.05.2011, 12:29 -0300 schrieb alexis:
Here's a snippet of my code, this method was with the described problem
public void insertVDNInfo(VDNInfo vdns) throws SQLException {
Why do you want to throw a SQLException?
Calendar c = Calendar.getInstance();
IteratorVDNInfo.VDN it = vdns.getVdns().iterator();
Seems like you can use
for (VDNInfo.VND v: vdns.getVdns()) {
...
}
instead of x=y.iterator() combined with while(x.hasNext())
{ v=x.next(); }
Connection c1 = null;
Statement s1 = null;
try {
while (it.hasNext()) {
c1 = getConnection();
Your getConnection method can return null, so you should guard against
it.
s1 = c1.createStatement();
VDNInfo.VDN v = it.next();
String query = INSERT INTO list.vdn VALUES (
+ ' + v.getName() + ', + v.getExt() + , +
v.isVdnovr() + , + v.getCor() + , + v.getTn() + , + v.getVecNum() +
,' + v.getMeas() + ',
+ v.isOrigAnnc() + , + v.isEvntNotiAdj() + ,' +
sdfTimestamp.format(c.getTime()) + ');
You should read about SQL-injections and Prepared Statements. You can
declare the prepared statement outside of your loop and set the values
inside the loop.
s1.execute(query);
}
} finally {
if (s1 != null) {
s1.close();
}
if s1.close() throws an error you will not close c1, so you have to
catch that exception:
if (s1!=null) { try { s1.close } catch (SQLException e) { // Ignore
or event better log
};
s1 = null;
if (c1 != null) {
c1.close();
catch the possible Exception
if (c1!=null) { try {c1.close();} catch (SQLException e) { // Ignore
or log
};
}
c1 = null;
}
}
Objects are created like
private Connection getConnection() {
DataSource ds = null;
Connection c1 = null;
try {
ds = (DataSource) new
InitialContext().lookup(java:/comp/env/jdbc/pgsql);
c1 = ds.getConnection();
} catch (NamingException ex) {
log.error(, ex);
Error messages should be a bit more meaningful than .
} catch (SQLException ex) {
log.error(, ex);
}
return c1;
You will return null, if you have catched an Exception. Is that what you
want?
}
what i can see different from the example on
http://tomcat.apache.org/tomcat-7.0-doc/jndi-datasource-examples-howto.html
is that the SQLException is now thrown but catched locally in the method.
That difference can be essential, as explained above.
and here's my resource pool config
Context antiJARLocking=true path=/xcall3
Resource
auth=Container
driverClassName=org.postgresql.Driver
maxActive=10
maxIdle=3
name=jdbc/pgsql
password=xcall3
type=javax.sql.DataSource
url=jdbc:postgresql://localhost/xcall3
username=xcall3
validationQuery=select version();
I think you should not place the ; at the end of the statement.
maxWait = 5000
/
here's what logs the database
2011-05-07 23:02:25 ARTLOG: execute unnamed: INSERT INTO list.vdn VALUES
('Atencion a Clientes',7022,false,1,1,33,'int',false,false,'2011-05-07
23:02:25')
2011-05-07 23:02:25 ARTLOG: unexpected EOF on client connection
until i lose all my connections.
here's what i got from the webapp log after that
2011-05-06 13:34:38,430 ERROR DAO:47 -
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot get a connection,
general error
at
org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:118)
at
org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
at com.lesi.xcall3.core.DAO.getConnection(DAO.java:43)
at com.lesi.xcall3.core.DAO.getSchedulerTasks(DAO.java:317)
at com.lesi.xcall3.core.Scheduler.run(Scheduler.java:35)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.InterruptedException
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:485)
at
org.apache.tomcat.dbcp.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1104)
at
org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:106)
... 5 more
Exception in thread XCALL3-Scheduler java.lang.NullPointerException
at java.util.ArrayList.toArray(ArrayList.java:303)
at com.lesi.xcall3.core.DAO.getSchedulerTasks(DAO.java:384)
at com.lesi.xcall3.core.Scheduler.run(Scheduler.java:35)
at java.lang.Thread.run(Thread.java:662)
Do you get any abandoned log entries, if you add the configuration
...
removeAbandoned=true
removeAbandonedTimeout=60
logAbandoned=true
...
to
Re: recovering connections on jdbc connection pool
On May 8, 2011, at 1:22 PM, Felix Schumacher wrote:
Am Sonntag, den 08.05.2011, 12:29 -0300 schrieb alexis:
Here's a snippet of my code, this method was with the described problem
public void insertVDNInfo(VDNInfo vdns) throws SQLException {
Why do you want to throw a SQLException?
Because all methods regarding database access are called from the same class,
im throwing the sqlexception and then catch that exception on the class that
call all those methods.
Calendar c = Calendar.getInstance();
IteratorVDNInfo.VDN it = vdns.getVdns().iterator();
Seems like you can use
for (VDNInfo.VND v: vdns.getVdns()) {
...
}
instead of x=y.iterator() combined with while(x.hasNext())
{ v=x.next(); }
yes, you're right
Connection c1 = null;
Statement s1 = null;
try {
while (it.hasNext()) {
c1 = getConnection();
Your getConnection method can return null, so you should guard against
it.
s1 = c1.createStatement();
VDNInfo.VDN v = it.next();
String query = INSERT INTO list.vdn VALUES (
+ ' + v.getName() + ', + v.getExt() + , +
v.isVdnovr() + , + v.getCor() + , + v.getTn() + , + v.getVecNum() +
,' + v.getMeas() + ',
+ v.isOrigAnnc() + , + v.isEvntNotiAdj() + ,' +
sdfTimestamp.format(c.getTime()) + ');
You should read about SQL-injections and Prepared Statements. You can
declare the prepared statement outside of your loop and set the values
inside the loop.
Yes, im aware about injection, but there's no chance in the way this app works
that injection can be done, all public access has no way to reach database or
methods that uses the database at all. But, im aware that using
preparedstatements is more effective and easy to code.
s1.execute(query);
}
} finally {
if (s1 != null) {
s1.close();
}
if s1.close() throws an error you will not close c1, so you have to
catch that exception:
if (s1!=null) { try { s1.close } catch (SQLException e) { // Ignore
or event better log
};
s1 = null;
if (c1 != null) {
c1.close();
catch the possible Exception
if (c1!=null) { try {c1.close();} catch (SQLException e) { // Ignore
or log
};
yes, you're right. i will
}
c1 = null;
}
}
Objects are created like
private Connection getConnection() {
DataSource ds = null;
Connection c1 = null;
try {
ds = (DataSource) new
InitialContext().lookup(java:/comp/env/jdbc/pgsql);
c1 = ds.getConnection();
} catch (NamingException ex) {
log.error(, ex);
Error messages should be a bit more meaningful than .
} catch (SQLException ex) {
log.error(, ex);
}
return c1;
You will return null, if you have catched an Exception. Is that what you
want?
no problem with that only if i handle the null after that (ill correct the call
to handle the null)
}
what i can see different from the example on
http://tomcat.apache.org/tomcat-7.0-doc/jndi-datasource-examples-howto.html
is that the SQLException is now thrown but catched locally in the method.
That difference can be essential, as explained above.
good to know, thanks again. changing now
and here's my resource pool config
Context antiJARLocking=true path=/xcall3
Resource
auth=Container
driverClassName=org.postgresql.Driver
maxActive=10
maxIdle=3
name=jdbc/pgsql
password=xcall3
type=javax.sql.DataSource
url=jdbc:postgresql://localhost/xcall3
username=xcall3
validationQuery=select version();
I think you should not place the ; at the end of the statement.
maxWait = 5000
/
here's what logs the database
2011-05-07 23:02:25 ARTLOG: execute unnamed: INSERT INTO list.vdn VALUES
('Atencion a Clientes',7022,false,1,1,33,'int',false,false,'2011-05-07
23:02:25')
2011-05-07 23:02:25 ARTLOG: unexpected EOF on client connection
until i lose all my connections.
here's what i got from the webapp log after that
2011-05-06 13:34:38,430 ERROR DAO:47 -
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot get a connection,
general error
at
org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:118)
at
org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
at com.lesi.xcall3.core.DAO.getConnection(DAO.java:43)
at com.lesi.xcall3.core.DAO.getSchedulerTasks(DAO.java:317)
at com.lesi.xcall3.core.Scheduler.run(Scheduler.java:35)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.InterruptedException
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:485)
at
Re: recovering connections on jdbc connection pool
try {
while (it.hasNext()) {
c1 = getConnection();
You should move getConnection() outside of the while() block.
- Bob
-
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
For additional commands, e-mail: users-h...@tomcat.apache.org
Re: recovering connections on jdbc connection pool
yes, that looks bad too , sorry.
actually i changed the whole method.
On May 8, 2011, at 2:38 PM, Bob Hall wrote:
try {
while (it.hasNext()) {
c1 = getConnection();
You should move getConnection() outside of the while() block.
- Bob
-
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
For additional commands, e-mail: users-h...@tomcat.apache.org
-
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