PostgreSQL JDBC Driver

PostgreSQL JDBC Driver (PgJDBC for short) allows Java programs to connect to a PostgreSQL database using standard, database independent Java code. Is an open source JDBC driver written in Pure Java (Type 4), and communicates in the PostgreSQL native network protocol.

Status

Supported PostgreSQL and Java versions

The current version of the driver should be compatible with PostgreSQL 8.4 and higher using the version 3.0 of the protocol and Java 8 (JDBC 4.2) or above. Unless you have unusual requirements (running old applications or JVMs), this is the driver you should be using.

PgJDBC regression tests are run against all PostgreSQL versions since 9.1, including “build PostgreSQL from git master” version. There are other derived forks of PostgreSQL but they have not been certified to run with PgJDBC. If you find a bug or regression on supported versions, please file an Issue.

Get the Driver

Most people do not need to compile PgJDBC. You can download the precompiled driver (jar) from the PostgreSQL JDBC site or using your chosen dependency management tool:

Maven Central

You can search on The Central Repository with GroupId and ArtifactId com.aliyun.polardb2:postgresql.

<!-- Add the following dependency to your pom.xml, -->
<!-- replacing LATEST with specific version as required -->

<dependency>
  <groupId>com.aliyun.polardb2</groupId>
  <artifactId>postgresql</artifactId>
  <version>LATEST</version>
</dependency>

Development snapshots

Snapshot builds (builds from master branch) are also deployed to OSS Sonatype Snapshot Repository, so you can test current development version (test some bugfix) by enabling the repository and using the latest SNAPSHOT version.

There are also available (snapshot) binary RPMs in Fedora’s Copr repository.

Documentation

For more information you can read the PgJDBC driver documentation or for general JDBC documentation please refer to The Java™ Tutorials.

Driver and DataSource class

Implements	Class
java.sql.Driver	com.aliyun.polardb2.Driver
javax.sql.DataSource	com.aliyun.polardb2.ds.PGSimpleDataSource
javax.sql.ConnectionPoolDataSource	com.aliyun.polardb2.ds.PGConnectionPoolDataSource
javax.sql.XADataSource	com.aliyun.polardb2.xa.PGXADataSource

Building the Connection URL

The driver recognises JDBC URLs of the form:

jdbc:polardb:database
jdbc:polardb:
jdbc:polardb://host/database
jdbc:polardb://host/
jdbc:polardb://host:port/database
jdbc:polardb://host:port/
jdbc:polardb://?service=myservice

The general format for a JDBC URL for connecting to a PostgreSQL server is as follows, with items in square brackets ([ ]) being optional:

jdbc:polardb:[//host[:port]/][database][?property1=value1[&property2=value2]...]

where:

jdbc:polardb: (Required) is known as the sub-protocol and is constant.
host (Optional) is the server address to connect. This could be a DNS or IP address, or it could be localhost or 127.0.0.1 for the local computer. To specify an IPv6 address your must enclose the host parameter with square brackets (jdbc:polardb://[::1]:5740/accounting). Defaults to localhost.
port (Optional) is the port number listening on the host. Defaults to 5432.
database (Optional) is the database name. Defaults to the same name as the user name used in the connection.
propertyX (Optional) is one or more option connection properties. For more information see Connection properties.

Logging

PgJDBC uses java.util.logging for logging. To configure log levels and control log output destination (e.g. file or console), configure your java.util.logging properties accordingly for the com.aliyun.polardb2 logger. Note that the most detailed log levels, “FINEST“, may include sensitive information such as connection details, query SQL, or command parameters.

Connection Properties

In addition to the standard connection parameters the driver supports a number of additional properties which can be used to specify additional driver behaviour specific to PostgreSQL™. These properties may be specified in either the connection URL or an additional Properties object parameter to DriverManager.getConnection.

Property	Type	Default	Description
user	String	null	The database user on whose behalf the connection is being made.
password	String	null	The database user’s password.
options	String	null	Specify ‘options’ connection initialization parameter.
service	String	null	Specify ‘service’ name described in pg_service.conf file. References: The Connection Service File and The Password File. ‘service’ file can provide all properties including ‘hostname=’, ‘port=’ and ‘dbname=’.
ssl	Boolean	false	Control use of SSL (true value causes SSL to be required)
sslfactory	String	com.aliyun.polardb2.ssl.LibPQFactory	Provide a SSLSocketFactory class when using SSL.
sslfactoryarg (deprecated)	String	null	Argument forwarded to constructor of SSLSocketFactory class.
sslmode	String	prefer	Controls the preference for opening using an SSL encrypted connection.
sslcert	String	null	The location of the client’s SSL certificate
sslkey	String	null	The location of the client’s PKCS#8 SSL key
sslrootcert	String	null	The location of the root certificate for authenticating the server.
sslhostnameverifier	String	null	The name of a class (for use in Class.forName(String)) that implements javax.net.ssl.HostnameVerifier and can verify the server hostname.
sslpasswordcallback	String	null	The name of a class (for use in Class.forName(String)) that implements javax.security.auth.callback.CallbackHandler and can handle PasswordCallback for the ssl password.
sslpassword	String	null	The password for the client’s ssl key (ignored if sslpasswordcallback is set)
sendBufferSize	Integer	-1	Socket write buffer size
receiveBufferSize	Integer	-1	Socket read buffer size
logServerErrorDetail	Boolean	true	Allows server error detail (such as sql statements and values) to be logged and passed on in exceptions. Setting to false will mask these errors so they won’t be exposed to users, or logs.
allowEncodingChanges	Boolean	false	Allow for changes in client_encoding
logUnclosedConnections	Boolean	false	When connections that are not explicitly closed are garbage collected, log the stacktrace from the opening of the connection to trace the leak source
binaryTransfer	Boolean	true	Use binary format for sending and receiving data if possible. Setting this to false disables any binary transfer
binaryTransferEnable	String	“”	Comma separated list of types to enable binary transfer. Either OID numbers or names
binaryTransferDisable	String	“”	Comma separated list of types to disable binary transfer. Either OID numbers or names. Overrides values in the driver default set and values set with binaryTransferEnable.
prepareThreshold	Integer	5	Statement prepare threshold. A value of -1 stands for forceBinary
preparedStatementCacheQueries	Integer	256	Specifies the maximum number of entries in per-connection cache of prepared statements. A value of 0 disables the cache.
preparedStatementCacheSizeMiB	Integer	5	Specifies the maximum size (in megabytes) of a per-connection prepared statement cache. A value of 0 disables the cache.
defaultRowFetchSize	Integer	0	Positive number of rows that should be fetched from the database when more rows are needed for ResultSet by each fetch iteration
loginTimeout	Integer	0	Specify how long in seconds max(2147484) to wait for establishment of a database connection.
connectTimeout	Integer	10	The timeout value in seconds max(2147484) used for socket connect operations.
socketTimeout	Integer	0	The timeout value in seconds max(2147484) used for socket read operations.
sslResponseTimeout	Integer	5000	Socket timeout in milliseconds waiting for a response from a request for SSL upgrade from the server.
tcpKeepAlive	Boolean	false	Enable or disable TCP keep-alive.
tcpNoDelay	Boolean	true	Enable or disable TCP no delay.
ApplicationName	String	PostgreSQL JDBC Driver	The application name (require server version >= 9.0). If assumeMinServerVersion is set to >= 9.0 this will be sent in the startup packets, otherwise after the connection is made
readOnly	Boolean	false	Puts this connection in read-only mode
disableColumnSanitiser	Boolean	false	Enable optimization that disables column name sanitiser
assumeMinServerVersion	String	null	Assume the server is at least that version
currentSchema	String	null	Specify the schema (or several schema separated by commas) to be set in the search-path
targetServerType	String	any	Specifies what kind of server to connect, possible values: any, master, slave (deprecated), secondary, preferSlave (deprecated), preferSecondary, preferPrimary
hostRecheckSeconds	Integer	10	Specifies period (seconds) after which the host status is checked again in case it has changed
loadBalanceHosts	Boolean	false	If disabled hosts are connected in the given order. If enabled hosts are chosen randomly from the set of suitable candidates
socketFactory	String	null	Specify a socket factory for socket creation
socketFactoryArg (deprecated)	String	null	Argument forwarded to constructor of SocketFactory class.
autosave	String	never	Specifies what the driver should do if a query fails, possible values: always, never, conservative
cleanupSavepoints	Boolean	false	In Autosave mode the driver sets a SAVEPOINT for every query. It is possible to exhaust the server shared buffers. Setting this to true will release each SAVEPOINT at the cost of an additional round trip.
preferQueryMode	String	extended	Specifies which mode is used to execute queries to database, possible values: extended, extendedForPrepared, extendedCacheEverything, simple
reWriteBatchedInserts	Boolean	false	Enable optimization to rewrite and collapse compatible INSERT statements that are batched.
escapeSyntaxCallMode	String	select	Specifies how JDBC escape call syntax is transformed into underlying SQL (CALL/SELECT), for invoking procedures or functions (requires server version >= 11), possible values: select, callIfNoReturn, call
maxResultBuffer	String	null	Specifies size of result buffer in bytes, which can’t be exceeded during reading result set. Can be specified as particular size (i.e. “100”, “200M” “2G”) or as percent of max heap memory (i.e. “10p”, “20pct”, “50percent”)
gssLib	String	auto	Permissible values are auto (default, see below), sspi (force SSPI) or gssapi (force GSSAPI-JSSE).
gssResponseTimeout	Integer	5000	Socket timeout in milliseconds waiting for a response from a request for GSS encrypted connection from the server.
gssEncMode	String	allow	Controls the preference for using GSSAPI encryption for the connection, values are disable, allow, prefer, and require
useSpnego	String	false	Use SPNEGO in SSPI authentication requests
adaptiveFetch	Boolean	false	Specifies if number of rows fetched in ResultSet by each fetch iteration should be dynamic. Number of rows will be calculated by dividing maxResultBuffer size into max row size observed so far. Requires declaring maxResultBuffer and defaultRowFetchSize for first iteration.
adaptiveFetchMinimum	Integer	0	Specifies minimum number of rows, which can be calculated by adaptiveFetch. Number of rows used by adaptiveFetch cannot go below this value.
adaptiveFetchMaximum	Integer	-1	Specifies maximum number of rows, which can be calculated by adaptiveFetch. Number of rows used by adaptiveFetch cannot go above this value. Any negative number set as adaptiveFetchMaximum is used by adaptiveFetch as infinity number of rows.
localSocketAddress	String	null	Hostname or IP address given to explicitly configure the interface that the driver will bind the client side of the TCP/IP connection to when connecting.
quoteReturningIdentifiers	Boolean	true	By default we double quote returning identifiers. Some ORM’s already quote them. Switch allows them to turn this off
authenticationPluginClassName	String	null	Fully qualified class name of the class implementing the AuthenticationPlugin interface. If this is null, the password value in the connection properties will be used.
unknownLength	Integer	Integer.MAX_LENGTH	Specifies the length to return for types of unknown length
stringtype	String	null	Specify the type to use when binding `PreparedStatement` parameters set via `setString()`
blobAsBytea	Boolean	false	Treat Blobs as bytea fields instead of as LargeObjects
clobAsText	Boolean	false	Treat Clobs as text fields instead of as LargeObjects
channelBinding	String	prefer	This option controls the client’s use of channel binding. `require` means that the connection must employ channel binding, `prefer` means that the client will choose channel binding if available, and `disable` prevents the use of channel binding.

Contributing

For information on how to contribute to the project see the Contributing Guidelines