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Lens –

Jdbc driver configuration


The configuration parameters and their default values
No. Property Name Default Value Description
1 driver.max.concurrent.launched.queries 15 Maximum queries which can be launched simultaneously on this driver. This should be equal to lens.driver.jdbc.pool.max.size. This configuration value is only useful when MaxConcurrentDriverQueriesConstraint is enabled by using org.apache.lens.server.api.query.constraint.MaxConcurrentDriverQueriesConstraintFactory as one of the factories in lens.driver.jdbc.query.constraint.factories property.
2 lens.cube.query.driver.supported.storages List of comma separated storage names that supported by a driver. If no value is specified, all storages are valid
3 lens.cube.query.partition.where.clause.format yyyy-MM-dd HH:mm:ss The simple date format of how the queried partition should be put in where clause. If nothing is specified, it will use the format from org.apache.lens.cube.metadata.UpdatePeriod for each type of partition
4 lens.cube.query.replace.timedim false Tells whether timedim attribute queried in the time range should be replaced with its corresponding partition column name.
5 lens.cube.query.time.range.writer.class org.apache.lens.cube.parse.BetweenTimeRangeWriter The timerange writer class which specifies how the resolved partitions in timeranges should be written in final query. Available writers are org.apache.lens.cube.parse.ORTimeRangeWriter and org.apache.lens.cube.parse.BetweenTimeRangeWriter
6 lens.driver.jdbc.connection.properties Connection properties for jdbc connection.
7 lens.driver.jdbc.connection.provider A contract for obtaining JDBC connections
8 lens.driver.jdbc.db.password The database user's password
9 lens.driver.jdbc.db.uri JDBC connection URL in the format jdbc:dbms://host:port/dbname
10 lens.driver.jdbc.db.user The database user on whose behalf the connection is being made
11 lens.driver.jdbc.driver.class com.mysql.jdbc.Driver Type of JDBC driver used to connect backend database
12 lens.driver.jdbc.enable.resultset.streaming.retrieval false Flag to enable row by row retrieval of result set from the database server. This is used to enable streaming result sets for MySQL. This is set to false by default.
13 lens.driver.jdbc.estimate.connection.properties Connection properties for jdbc estimate connection.
14 lens.driver.jdbc.estimate.db.password The database user's password, for estimate queries. If this property is unspecified, value for lens.driver.jdbc.db.password would be used. Override this property to tune estimate connection pool
15 lens.driver.jdbc.estimate.db.uri JDBC connection URL in the format jdbc:dbms://host:port/dbname for estimate queries. If this property is unspecified, value for lens.driver.jdbc.db.uri will be used.
16 lens.driver.jdbc.estimate.db.user The database user on whose behalf the connection is being made, for estimate queries. If this property is unspecified, value for lens.driver.jdbc.db.user would be used. Override this property to tune estimate connection pool
17 lens.driver.jdbc.estimate.driver.class Type of JDBC driver used to connect backend database for estimate queries. If This property is not specified, value for lens.driver.jdbc.driver.class will be used. Override this property to tune estimate connection pool
18 lens.driver.jdbc.estimate.get.connection.timeout Response timeout in milliseconds of any JDBC call invoking data transmission over a connection socket , for estimate queries. If this property is not specified, value for lens.driver.jdbc.get.connection.timeout would be used. Override this property to tune estimate connection pool.
19 lens.driver.jdbc.estimate.pool.idle.time Maximum idle time in sec before a connection is closed, for estimate queries. If this property is not specified, value for lens.driver.jdbc.pool.idle.time would be used. Override this property to tune estimate connection pool.
20 lens.driver.jdbc.estimate.pool.max.size Maximum number of concurrent connections allowed in pool, for estimate queries. If this property is unspecified, value for lens.driver.jdbc.pool.max.size would be used. Override this property to tune estimate connection pool
21 lens.driver.jdbc.estimate.pool.max.statements Maximum number of prepared statements to cache per connection, for estimate queries. If this property is not specified, value for lens.driver.jdbc.pool.max.statements would be used.
22 lens.driver.jdbc.explain.keyword Explain Explain keyword used to get the query plan of underlying database
23 lens.driver.jdbc.fetch.size 1000 Fetch size for JDBC result set
24 lens.driver.jdbc.get.connection.timeout 10000 The number of milliseconds a client calling getConnection() will wait for a Connection to be checked-in or acquired when the pool is exhausted. Zero means wait indefinitely. Setting any positive value will cause the getConnection () call to time-out and break with an SQLException after the specified number of milliseconds. The default value of this property is 10 secs.
25 lens.driver.jdbc.pool.idle.time 600 Maximum idle time in sec before a connection is closed
26 lens.driver.jdbc.pool.max.size 15 Maximum number of concurrent connections allowed in pool
27 lens.driver.jdbc.pool.max.statements 20 Maximum number of prepared statements to cache per connection
28 org.apache.lens.driver.jdbc.MaxJDBCConnectionCheckConstraintFactory lens.driver.jdbc.query.launching.constraint.factories Factories used to instantiate constraints enforced on queries by driver. A query will be launched only if all constraints pass. Every Factory should be an implementation of org.apache.lens.server.api.common.ConfigBasedObjectCreationFactory and create an implementation of org.apache.lens.server.api.query.constraint.QueryLaunchingConstraint. org.apache.lens.server.api.query.constraint.MaxConcurrentDriverQueriesConstraintFactory,
29 lens.driver.jdbc.query.rewriter org.apache.lens.driver.jdbc.ColumnarSQLRewriter Rewriting the HQL to optimized sql queries
30 lens.driver.jdbc.regex.replacement.values to_date=date, format_number=format, date_sub ((.*?) , s*([0-9]+ s*) )=date_sub($1 , interval $2 day), date_add ((.*?) , s*([0-9]+ s*) )=date_add($1 , interval $2 day) Rewriting the HQL to optimized sql queries
31 lens.driver.jdbc.statement.cancel.supported true Flag to indicate Whether cancel on JDBC statement is supported. If not supported, framework wont call cancel on JDBC statement.
32 lens.driver.jdbc.validate.through.prepare true Flag to enable query syntactic and semantic validation using prepared statement.
33 lens.driver.jdbc.waiting.queries.selection.policy.factories org.apache.lens.server.api.query.collect.DriverSpecificWaitingQueriesSelectionPolicyFactory Factories used to instantiate driver specific waiting queries selection policies. Every factory should be an implementation of org.apache.lens.server.api.common.ConfigBasedObjectCreationFactory and create an implementation of org.apache.lens.server.api.query.collect.WaitingQueriesSelectionPolicy.
34 lens.query.timeout.millis 3600000 The runtime(millis) of the query after which query will be timedout and cancelled. Default is 1 hour for jdbc queries.