c3p0 | a mature , highly concurrent JDBC Connection | FTP library
kandi X-RAY | c3p0 Summary
kandi X-RAY | c3p0 Summary
c3p0 is a mature, highly concurrent JDBC Connection pooling library, with support for caching and reuse of PreparedStatements. It is licensed under LGPL v.2.1 or EPL v.1.0, at your option. c3p0 is now maintained on github.
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Top functions reviewed by kandi - BETA
- Mark a connection as closed
- Reset txn state
- Check all statements in the database
- Check statement
- Generate extra declarations
- Write the detach body
- Generate helper methods
- Find the XML configuration
- Prints a warning for the common xml configuration file
- String representation of this class
- Check in all managed pools
- Initialize pools
- Main entry point
- Print the statistics
- Load the default ConnectionTester
- Entry point to the database
- Entry point for testing
- Removes expired resources from the pool
- Allocates a new connection tester
- Invoke an operation on the MBean
- Command line
- Gets the HTTP GET request
- Returns an array with all the operations needed for this pool
- Attempt to kill this resource
- Runs a JDBC driver
- Command - line generator
c3p0 Key Features
c3p0 Examples and Code Snippets
Community Discussions
Trending Discussions on c3p0
QUESTION
I have a legacy spring module which has data bean definitions from dataSource to transactionManager( based on C3P0 and Hibernate). I want to re-use all those bean definitions in Spring Boot app. The Spring boot build files are generated by default from initializr. While running, I encountered the following error :
...ANSWER
Answered 2021-May-20 at 02:51The solution was to exclude autconfiguration on datasource:
QUESTION
I've been using Java to make my own discord bot for a while, and all of a sudden I can't run the code anymore.
The code compiles without any problem, but when I try to run it I get this error:
...ANSWER
Answered 2021-May-12 at 06:39The cause of this weird exit code was my code itself, in which I had a call to
QUESTION
I'm trying to figure out class mapping via xml in hibernate, following the tutorial from the official site, and I keep getting the same error - org.hibernate.boot.MappingNotFoundException: Mapping (RESOURCE) not found, as a result i cannot get SessionFactory and Session. I have thoroughly checked all the paths and project structure, tried using both maven and gradle but nothing has helped so far. I'm using postgres DB. Here's my project structure:
Here's pom.xml:
...ANSWER
Answered 2021-May-05 at 16:58I have deleted everything about config, cause project structure was changed.
You should update your pom.xml and add build info for your case
QUESTION
I'm using sql server jdbc driver mssql-jdbc-9.2.1.jre8-sources.jar and create an object of com.microsoft.sqlserver.jdbc.SQLServerDataSource.
After setting it up with host-credential-etc, opening Connection and closing Connection, how do I close SQLServerDataSource object itself, I could not find any method in API.
Note to closer: I'm NOT using C3P0 connection pool, that may have close option.
...ANSWER
Answered 2021-May-03 at 08:16The SQLServerDataSource is a simple data source that does not provide any form of connection pooling, it only serves as a factory of physical, non-pooled JDBC connections. As such, you do not need to close, destroy or otherwise dispose of this class (other than normal garbage collection).
The need to close a data source only exists for data sources that are backed by a connection pool (like c3p0), to release those pooled connections and maybe end house-keeping threads.
QUESTION
my log
...ANSWER
Answered 2021-Apr-16 at 23:18It seems that the package "br.com.api.entities" was not scanned so your entity is not known. You should add:
QUESTION
I observed that Hikari validates the connection before giving it to the requester. At that point, if the connection is found to be dead, a new connection is created.
Is there a way that idle connections are regularly validated (even if no one is asking for a new connection)?
Something similar is present in C3P0 as 'idle_test_period'.
...ANSWER
Answered 2021-Apr-07 at 04:29You can define keepaliveTime to validate idle connections
"keepalive" will only occur on an idle connection. When the time arrives for a "keepalive" against a given connection, that connection will be removed from the pool, "pinged", and then returned to the pool. The 'ping' is one of either: invocation of the JDBC4 isValid() method, or execution of the connectionTestQuery.
QUESTION
We recently upgraded from mysql 5.6 to mysql 8.0 on a few servers, one of the servers was fine, and has had no problems, but it has significantly less load than one of our other servers which has been running out of memory.
Our server launches, then grabs 300 connections, and keeps them open with a C3P0 pool to the mysql server.
We were running these servers on AWS on MySQL 5.6 with the same overridden parameters on 8GB of RAM, when we upgraded to MySQL 8.0.21 we started running out of RAM in about 1 day. We grew the server to 32Gb but didn't change the parameters. It's gone over 15 GB used and still going up.
We're pretty sure it's related to the per connection thread memory, but not sure why. From looking at MySQL tuner it looks like the variables that control per thread memory are:
...ANSWER
Answered 2021-Jan-18 at 19:41You're calculating the per-thread memory usage wrong. Those variables (and tmp_table_size which you didn't include) are not all used at the same time. Don't add them up. And even if you were to add them up, at least two might be allocated multiple times for a single query, so you can't just sum them anyway.
Basically, the memory usage calculated by MySQLTuner is totally misleading, and you shouldn't believe it. I have written about this before: What does "MySQL's maximum memory usage is dangerously high" mean by mysqltuner?
If you want to understand actual memory usage, use the PERFORMANCE_SCHEMA, or the slightly easier to read views on it, in the SYS schema.
The documentation for PS or SYS is pretty dense, so instead I'd look for better examples in blogs like this one:
https://www.percona.com/blog/2020/11/02/understanding-mysql-memory-usage-with-performance-schema/
QUESTION
How to use addCacheableFile
I'm trying to optimize my hibernate initialization and I found out that we can use addCacheableFile.
However, I'm not understanding correctly how to use it. I tried to set to the same cfg.xml I'm using but it then causes Could not deserialize cache file.
ANSWER
Answered 2021-Jan-16 at 14:36The usage Configuration.addCacheableFile assume that you use obsolete xml mapping.
Example.
Let assume you have Employee entity mapped by the Employee.hbm.xml file:
QUESTION
I have a Java webapp running on Jetty (version 9.4.20). It uses a custom library for accessing MySql database, which has always worked well.
At random, sometimes, this exception is thrown:
...ANSWER
Answered 2020-Oct-07 at 18:44Jetty is starting with system temp directory for the Java system property java.io.tmpdir.
This is typically the system /tmp directory.
Jetty unpacks wars and accesses deep resources from your webapp from this temp directory.
What happens on some Linux distributions is that the the system temp directory (/tmp) is periodically cleaned up. This can break a running Jetty instance as the content it needs has now been removed out from underneath it.
The key is to use a temp directory for Jetty that isn't the system temp directory.
You can change the temp directory that Jetty uses in a number of ways.
QUESTION
We have a spec file which specifies the table structure and java programme creates the table on installation, The spec file is as below,
...ANSWER
Answered 2020-Dec-18 at 08:10We have kept the sql_mode as empty and then it worked.
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
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Install c3p0
You can use c3p0 like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the c3p0 component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .
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