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Lens –

OLAP query configuration


The configuration parameters and their default values
No. Property Name Default Value Description
1 lens.cube.query.bridge.table.field.aggregator collect_set The field aggregator function to be used for aggregating fields from bridge tables. Would be used only when flattening is enabled. The value can be passed for each query. During typical deployments it would be passed for each driver, as the function could be different for each driver.
2 lens.cube.query.disable.aggregate.resolver true Tells whether to disable automatic resolution of aggregations for measures in a cube. To enable automatic resolution, this value should be false.
3 lens.cube.query.disable.auto.join true Tells whether to disable automatic resolution of join conditions between tables involved. To enable automatic resolution, this value should be false.
4 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
5 lens.cube.query.enable.attrfields.add.distinct true When the query has only attribute fields projected from cube and the flag is set to true, distinct clause will be added for the projection so that no duplicate values will be projected. If flag is set to false, projection wont be changed, result might include duplicate values.
6 lens.cube.query.enable.flattening.bridge.tables false Flag specifies if fields selected have to be flattened or not, if they are coming from tables with many to many relationship in join. If false, field selection will be simple join and selecting the field. If true, the fields from bridge tables will be aggregated grouped by join key.
7 lens.cube.query.fail.if.data.partial false Whether to fail the query of data is partial
8 lens.cube.query.join.type INNER Tells what the join type is, in-case of automatic resolution of joins is enabled
9 lens.cube.query.lookahead.ptparts.forinterval.$interval 1 The value of number of lookahead process time partitions for interval specified. Interval can be any Update period.
10 lens.cube.query.max.interval Maximum value of the update period that the query timed dimensions can take values of. For example, if query involves month ranges, user can say query maximum interval is daily, then no monthly partitions will be picked.
11 lens.cube.query.nonexisting.partitions The list of comma separated non existing partitions, if query can run with partial data. The value will be set by the cube query rewriter
12 lens.cube.query.partition.where.clause.format 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
13 lens.cube.query.pick.lightest.fact.first false If set to true, lightest fact will be resolved first than resolving storages. Otherwise, storages will be resolved to check all partitions exist and then pick lightest fact among candidates
14 lens.cube.query.process.time.partition.column The column name which is a process time column. If process time column is specified, query rewriter will look ahead the partitions of other timed dimensions inside this column.
15 lens.cube.query.promote.groupby.toselect false Tells whether to promote group by clauses to be promoted to select expressions if they are already not projected. To enable automatic promotion, this value should be true.
16 lens.cube.query.promote.select.togroupby false Tells whether to promote select expressions which is not inside any aggregate, to be promoted to groupby clauses, if they are already not part of groupby clauses. To enable automatic promotion, this value should be true.
17 lens.cube.query.replace.timedim true Tells whether timedim attribute queried in the time range should be replaced with its corresponding partition column name.
18 lens.cube.query.time.range.writer.class org.apache.lens.cube.parse.ORTimeRangeWriter 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
19 lens.cube.query.valid.$cubename.facttables List of comma separated fact tables that are valid for cube. If no value is specified, all fact tables are valid
20 lens.cube.query.valid.dim.storgaetables List of comma separated dimension storage tables that are valid. If no value is specified, all tables are valid
21 lens.cube.query.valid.fact.$facttable.storage.$storagename.updateperiods List of comma separated update periods that are valid for a fact on a storage. If no value is specified, all update periods are valid
22 lens.cube.query.valid.fact.$facttable.storagetables List of comma separated storage tables that are valid for a fact. If no value is specified, all storage tables are valid