BI Connector provides the following environment variables:
Default Value (Atlas-hosted)
Default Value (On Premises)
Specifies whether a query error is returned for queries with
clauses that aren't fully translated to the MongoDB query language.
SQL query predicates are used to filter data returned by the query.
Specifies the logging level for BI Connector:
-1: Do not log.
0: Log only messages for database users, such as basic
mongosqld events and state changes.
1: Log messages for database users and mongosqld administrators.
2: For internal use only.
2 (Atlas-hosted) and 0 (self-managed)
Specifies the maximum number of unique nested field paths that
mongosqld maps to a relational table for a collection.
The maximum number of unique fields that mongosqld maps to
relational columns for a collection.
Specifies the maximum string length returned for columns using
the VARCHAR data type. A value of 0 specifies
Determines how BI Connector evaluates document fields that are
specified with multiple data types. For example, count
could be a number in one document and a string in another.
The data type that BI Connector selects depends on the value
of the schema_mapping_mode system variable. A value of
majority causes BI Connector to select the type
that appears in the majority of document fields, while a value
of lattice would cause BI Connector to select string as the
data type for count. See Cached Sampling
for more information.
Set polymorphic_type_conversion_mode to one of the following
Queries may fail if you do not explicitly cast
document fields that are specified with multiple data types.
BI Connector converts only document fields that
appeared as multiple data types during sampling.
BI Connector converts all document fields to the data type
discovered during sampling, even if the fields do not appear
as multiple data types.
Specifies how frequently, in seconds, that the BI Connector schema
is updated. A value of 0 specifies that the schema is not
refreshed after BI Connector starts.
majority: BI Connector assigns the most common data type for
a field occuring in a sample.
Specifies the semantics that BI Connector uses for type conversions,
such as the CAST function.
Setting System Variables
You must have the atlasAdmin database role to set environment
variables on an Atlas-hosted BI Connector. To set them for a self-managed
BI Connector, you must have the inprog privilege on the
MongoDB database to which you've connected the BI Connector.
Use any SQL client that is connected to BI Connector to set these
variables. The following example sets mongodb_max_varchar_length
SET GLOBAL mongodb_max_varchar_length = 100
You must start a new connection to the BI Connector after setting a system
variable. The connection you used to set the system variable is not affected.