hikari-cp

A Clojure wrapper to HikariCP - "zero-overhead" production ready JDBC connection pool.

Installation

Add the following dependency to your project.clj file:

[hikari-cp "3.0.1"]

hikari-cp version 3.x targets Clojure 1.11. Version 2.14.3 was the last release for Clojure 1.9. Version 1.8.3 was the last release for Clojure 1.8.

Note that hikari-cp requires Java 11 or newer. Version 2.14.3 was the last release for Java 8.

You'll also need to add the JDBC driver needed for your database.

Configuration options

Option	Required	Default value	Description
:auto-commit	No	true	This property controls the default auto-commit behavior of connections returned from the pool. It is a boolean value.
:read-only	No	false	This property controls whether Connections obtained from the pool are in read-only mode by default.
:connection-timeout	No	30000	This property controls the maximum number of milliseconds that a client will wait for a connection from the pool. If this time is exceeded without a connection becoming available, a SQLException will be thrown. 1000ms is the minimum value.
:validation-timeout	No	5000	This property controls the maximum amount of time that a connection will be tested for aliveness. This value must be less than the :connection-timeout. The lowest accepted validation timeout is 1000ms (1 second).
:idle-timeout	No	600000	This property controls the maximum amount of time (in milliseconds) that a connection is allowed to sit idle in the pool.
:max-lifetime	No	1800000	This property controls the maximum lifetime of a connection in the pool. A value of 0 indicates no maximum lifetime (infinite lifetime).
:minimum-idle	No	10	This property controls the minimum number of idle connections that HikariCP tries to maintain in the pool.
:maximum-pool-size	No	10	This property controls the maximum size that the pool is allowed to reach, including both idle and in-use connections. Basically this value will determine the maximum number of actual connections to the database backend.
:pool-name	No	Auto-generated	This property represents a user-defined name for the connection pool and appears mainly in logging and JMX management consoles to identify pools and pool configurations.
:jdbc-url	Yes¹	None	This property sets the JDBC connection URL. Please note the h2 adapter expects :url instead of :jdbc-url.
:driver-class-name	No	None	This property sets the JDBC driver class.
:adapter	Yes¹	None	This property sets the database adapter. Please check Adapters and corresponding datasource class names for the full list of supported adapters and their datasource class names. The value should be provided as a string.
:username	No	None	This property sets the default authentication username used when obtaining Connections from the underlying driver.
:password	No	None	This property sets the default authentication password used when obtaining Connections from the underlying driver.
:database-name	No	None	This property sets the database name.
:server-name	No	Depends on the adapter	This property sets the hostname client connects to.
:port-number	No	Depends on the adapter	This property sets the port clients connects on.
:connection-test-query	No	None	If your driver supports JDBC4 we strongly recommend not setting this property. This is for "legacy" databases that do not support the JDBC4 Connection.isValid() API. This is the query that will be executed just before a connection is given to you from the pool to validate that the connection to the database is still alive.
:leak-detection-threshold	No	0	This property controls the amount of time that a connection can be out of the pool before a message is logged indicating a possible connection leak. A value of 0 means leak detection is disabled, minimum accepted value is 2000 (ms). ( ps: it's rarely needed option, use only for debugging )
:register-mbeans	No	false	This property register mbeans which can be used in jmx to monitor hikari-cp.
:connection-init-sql	No	None	This property sets a SQL statement that will be executed after every new connection creation before adding it to the pool.
:datasource	No	None	This property allows you to directly set the instance of the DataSource to be wrapped by the pool.
:datasource-class-name	No	None	This is the name of the DataSource class provided by the JDBC driver.
:metric-registry	No	None	This is an instance of a Dropwizard metrics MetricsRegistry.
:health-check-registry	No	None	This is an instance of a Dropwizard metrics HealthCheckRegistry.
:metrics-tracker-factory	No	None	This is an implementation of a MetricsTrackerFactory (CodahaleMetricsTrackerFactory, MicrometerMetricsTrackerFactory, PrometheusMetricsTrackerFactory).
:transaction-isolation	No	None	Constant name from the Connection interface such as TRANSACTION_READ_COMMITTED, TRANSACTION_REPEATABLE_READ, etc.

¹ :adapter and :jdbc-url are mutually exclusive.

You can also add other datasource-specific configuration options. By default, keywords will be converted to the camelCase format add added as a datasource property, unless a special translation is defined:

;; {:tcp-keep-alive true} will be:
(.addDataSourceProperty config "tcpKeepAlive" true)

;; {:use-ssl false} has a custom translation, so it will be:
(.addDataSourceProperty config "useSSL" false)

;; {:tinyInt1isBit false} also has a custom translation to support
;; the incorrect property casing in the original java class.

Custom translations of properties can be added by extending the translate-property multimethod.

Please note: All time values are specified in milliseconds.

Adapters and corresponding datasource class names

Adapter	Datasource class name	Tested with hikari-cp
derby	org.apache.derby.jdbc.ClientDataSource	No
firebird	org.firebirdsql.pool.FBSimpleDataSource	No
db2	com.ibm.db2.jcc.DB2SimpleDataSource	No
h2	org.h2.jdbcx.JdbcDataSource	Yes
hsqldb	org.hsqldb.jdbc.JDBCDataSource	No
mariadb	org.mariadb.jdbc.MySQLDataSource	No
mysql	com.mysql.jdbc.jdbc2.optional.MysqlDataSource	Yes
mysql8	com.mysql.cj.jdbc.MysqlDataSource	No
neo4j	org.neo4j.jdbc.DataSource	No
sqlserver-jtds	net.sourceforge.jtds.jdbcx.JtdsDataSource	Yes
sqlserver	com.microsoft.sqlserver.jdbc.SQLServerDataSource	Yes
oracle	oracle.jdbc.pool.OracleDataSource	Yes
pgjdbc-ng	com.impossibl.postgres.jdbc.PGDataSource	No
postgresql	org.postgresql.ds.PGSimpleDataSource	Yes
fdbsql	com.foundationdb.sql.jdbc.ds.FDBSimpleDataSource	No
sybase	com.sybase.jdbc4.jdbc.SybDataSource	Yes
sqlite	org.sqlite.SQLiteDataSource	No

Usage

PostgreSQL example

(ns hikari-cp.example
  (:require [hikari-cp.core :refer :all]
            [next.jdbc :as jdbc]))

(def datasource-options {:auto-commit        true
                         :read-only          false
                         :connection-timeout 30000
                         :validation-timeout 5000
                         :idle-timeout       600000
                         :max-lifetime       1800000
                         :minimum-idle       10
                         :maximum-pool-size  10
                         :pool-name          "db-pool"
                         :adapter            "postgresql"
                         :username           "username"
                         :password           "password"
                         :database-name      "database"
                         :server-name        "localhost"
                         :port-number        5432
                         :register-mbeans    false})

(defonce datasource
  (delay (make-datasource datasource-options)))

(defn -main [& args]
  (with-open [conn (jdbc/get-connection @datasource {})]
    (let [rows (jdbc/query conn "SELECT 0")]
      (println rows)))
  (close-datasource @datasource))

Neo4j

(ns hikari-cp.example
  (:require [hikari-cp.core :refer :all]
            [next.jdbc :as jdbc]))

(def datasource-options {:jdbc-url "jdbc:neo4j:bolt://host:port/?username=neo4j&password=xxxx&debug=true"})

(defonce datasource
  (delay (make-datasource datasource-options)))

(defn -main [& args]
  (with-open [conn (jdbc/get-connection @datasource {})]
    (let [rows (jdbc/query conn ["MATCH (n:Foo) WHERE n.name = ? RETURN n" "john"])]
      (println rows)))
  (close-datasource @datasource))

H2 minimal config example

(def datasource-options {:adapter "h2"
                         :url     "jdbc:h2:~/test"})

Oracle example

(ns hikari-cp.example
  (:require [hikari-cp.core :refer :all]
            [next.jdbc :as jdbc]))

(def datasource-options {:username      "username"
                         :password      "password"
                         :database-name "database"
                         :server-name   "localhost"
                         :port-number   1521
                         :driverType    "thin"       ; Other options are oci8, oci or kprb. See jdbc.pool.OracleDataSource.makeURL()
                         :adapter       "oracle"})

(defonce datasource
  (delay (make-datasource datasource-options)))

(defn -main [& args]
  (with-open [conn (jdbc/get-connection @datasource {})]
    (let [rows (jdbc/query conn "SELECT 0 FROM dual")]
      (println rows)))
  (close-datasource @datasource))

Sybase example

(ns hikari-cp.example
  (:require [hikari-cp.core :refer :all]
            [next.jdbc :as jdbc]))

(def datasource-options {:username      "username"
                         :password      "password"
                         :database-name "database"
                         :server-name   "localhost"
                         :port-number   5900
                         :adapter       "sybase"}) ; assumes jconn4.jar (com.sybase.jdbc4.jdbc.SybDataSource)

; if you're using jconn2.jar or jconn3.jar replace :adapter "sybase" with the following
; :datasource-class-name "com.sybase.jdbc3.jdbc.SybDataSource"
; or
; :datasource-class-name "com.sybase.jdbc2.jdbc.SybDataSource"

(defonce datasource
  (delay (make-datasource datasource-options)))

(defn -main [& args]
  (with-open [conn (jdbc/get-connection @datasource {})]
    (let [rows (jdbc/query conn "SELECT 0")]
      (println rows)))
  (close-datasource @datasource))

SQLite example

(def datasource-options {:jdbc-url "jdbc:sqlite:db/database.db"})

ClickHouse example

hikari-cp can be used with official ClickHouse driver in following two ways:

1. Using :datasource property:

• Official ClickHouse JDBC driver's ClickHouseDataSource does not have a zero arity constructor.
• This mandates creating ClickHouseDataSource separately and setting :datasource property in datasource-options

(ns hikari-cp.example
  (:require
    [hikari-cp.core :refer :all]
    [next.jdbc :as jdbc])
  (:import
    [java.util Properties]
    [com.clickhouse.jdbc ClickHouseDataSource]))

(defonce clickhouse-datasource
  (let [jdbc-url "jdbc:ch://localhost:8123/test_db"
        properties (doto
                     (Properties.)
                     (.setProperty "user" "username")
                     (.setProperty "password" "password")
                     (.setProperty "client_name" "test_client")
                     (.setProperty "custom_http_params" "max_query_size=1000000"))]
    (ClickHouseDataSource. jdbc-url properties)))

(def datasource-options
  {:datasource clickhouse-datasource
   :connection-timeout 5000
   :maximum-pool-size 20
   :max-lifetime 300000
   :pool-name "clickhouse-conn-pool"})

(defonce datasource
  (delay (make-datasource datasource-options)))

(defn -main
  [& args]
  (with-open [conn (jdbc/get-connection @datasource {})]
    (let [rows (jdbc/execute! conn ["SELECT 0"])]
      (println rows)))
  (close-datasource @datasource))

2. Using :jdbc-url and :driver-class-name properties:

(ns hikari-cp.example
  (:require
    [hikari-cp.core :refer :all]
    [next.jdbc :as jdbc]))

(def datasource-options-2
  {:jdbc-url "jdbc:ch://localhost:8123/test_db"
   :username "username"
   :password "password"
   :driver-class-name "com.clickhouse.jdbc.ClickHouseDriver"
   :connection-timeout 5000
   :maximum-pool-size 20
   :max-lifetime 300000
   :pool-name "clickhouse-conn-pool"})

(defonce datasource
  (delay (make-datasource datasource-options)))

(defn -main
  [& args]
  (with-open [conn (jdbc/get-connection @datasource {})]
    (let [rows (jdbc/execute! conn ["SELECT 0"])]
      (println rows)))
  (close-datasource @datasource))

Notice

make-datasource will throw IllegalArgumentException when invalid arguments are provided:

(make-datasource (dissoc config :username :database-name))
;; IllegalArgumentException: Invalid configuration options: (:username :database-name)

License

Copyright © 2014 - 2022 Tomek Wałkuski and Jan Stępień

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.