HikariCP

<h1><img src="https://github.com/brettwooldridge/HikariCP/wiki/Hikari.png"> HikariCP<sup><sup>&nbsp;It's Faster.</sup></sup><sub><sub><sup>Hi·ka·ri [hi·ka·'lē] &#40;<i>Origin: Japanese</i>): light; ray.</sup></sub></sub></h1><br>

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Fast, simple, reliable.  HikariCP is a "zero-overhead" production ready JDBC connection pool.  At roughly 165Kb, the library is very light.  Read about [how we do it here](https://github.com/brettwooldridge/HikariCP/wiki/Down-the-Rabbit-Hole).

&nbsp;&nbsp;&nbsp;<sup>**"Simplicity is prerequisite for reliability."**<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;- *Dr. Edsger Dijkstra*</sup>

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> [!IMPORTANT]
> In order to avoid a rare condition where the pool goes to zero and does not recover it is necessary to configure *TCP keepalive*. Some JDBC drivers support this via properties, for example ``tcpKeepAlive=true`` on PostgreSQL, but in any case it can also be configured at the OS-level. See [Setting OS TCP Keepalive](https://github.com/brettwooldridge/HikariCP/wiki/Setting-Driver-or-OS-TCP-Keepalive) and/or [TCP keepalive for a better PostgreSQL experience](https://www.cybertec-postgresql.com/en/tcp-keepalive-for-a-better-postgresql-experience/#setting-tcp-keepalive-parameters-on-the-operating-system).

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### Index
* [Artifacts](#artifacts)
* [JMH Benchmarks](#checkered_flag-jmh-benchmarks)
* [Analyses](#microscope-analyses)
  * [Spike Demand Pool Comparison](#spike-demand-pool-comparison)
  * [You're probably doing it wrong](#youre-probably-doing-it-wrong)
  * [WIX Engineering Analysis](#wix-engineering-analysis)
  * [Failure: Pools behaving badly](#failure-pools-behaving-badly)
* [User Testimonials](#family-user-testimonials) <br>
* [Configuration](#gear-configuration-knobs-baby) <br>
  * [Essentials](#essentials)
  * [Frequently used](#frequently-used)
  * [Infrequently used](#infrequently-used)
* [Initialization](#rocket-initialization)

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### Artifacts

_**Java 11+** maven artifact:_
```xml
<dependency>
   <groupId>com.zaxxer</groupId>
   <artifactId>HikariCP</artifactId>
   <version>7.1.0</version>
</dependency>
```
_Java 8 maven artifact (*deprecated*):_
```xml
<dependency>
   <groupId>com.zaxxer</groupId>
   <artifactId>HikariCP</artifactId>
   <version>4.0.3</version>
</dependency>
```
_Java 7 maven artifact (*deprecated*):_
```xml
<dependency>
   <groupId>com.zaxxer</groupId>
   <artifactId>HikariCP-java7</artifactId>
   <version>2.4.13</version>
</dependency>
```
_Java 6 maven artifact (*depreca