CONNECT System Variables

This page documents system variables related to the CONNECT storage engine. See Server System Variables for instructions on setting them.

See also the Full list of MariaDB options, system and status variables.

connect_class_path

• Description: Java class path

• Command line: --connect-class-path=value

• Scope: Global

• Dynamic:

connect_cond_push

• Description: Enable condition pushdown

• Command line: --connect-cond-push={0|1}

• Scope: Global, Session

• Dynamic: Yes

connect_conv_size

• Description: The size of the created when converting from a type. See .

• Command line: --connect-conv-size=#

• Scope: Global, Session

• Dynamic: Yes

connect_default_depth

• Description: Default depth used by Json, XML and Mongo discovery.

• Command line: --connect-default-depth=#

• Scope: Global, Session

• Dynamic: Yes

connect_default_prec

• Description: Default precision used for doubles.

• Command line: --connect-default-prec=#

• Scope: Global, Session

• Dynamic: Yes

connect_enable_mongo

• Description: Enable the .

• Command line: --connect-enable-mongo={0|1}

• Scope: Global, Session

• Dynamic:

connect_exact_info

• Description: Whether the CONNECT engine should return an exact record number value to information queries. It is OFF by default because this information can take a very long time for large variable record length tables or for remote tables, especially if the remote server is not available. It can be set to ON when exact values are desired, for instance when querying the repartition of rows in a partition table.

• Command line: --connect-exact-info={0|1}

• Scope: Global, Session

connect_force_bson

• Description: Force using BSON for JSON tables. Starting with these releases, the internal way JSON was parsed and handled was changed. The main advantage of the new way is to reduce the memory required to parse JSON (from 6 to 10 times the size of the JSON source to now only 2 to 4 times). However, this is in Beta mode and JSON tables are still handled using the old mode. To use the new mode, tables should be created with TABLE_TYPE=BSON, or by setting this session variable to 1 or ON. Then, all JSON tables are handled as BSON. This is temporary until the new way replaces the old way by default.

• Command line: --connect-force-bson={0|1}

• Scope: Global, Session

connect_indx_map

• Description: Enable file mapping for index files. To accelerate the indexing process, CONNECT makes an index structure in memory from the index file. This can be done by reading the index file or using it as if it was in memory by “file mapping”. Set to 0 (file read, the default) or 1 (file mapping).

• Command line: --connect-indx-map=#

• Scope: Global

• Dynamic: Yes

connect_java_wrapper

• Description: Java wrapper.

• Command line: --connect-java-wrapper=val

• Scope: Global, Session

• Dynamic: Yes

connect_json_all_path

• Description: Discovery to generate json path for all columns if ON (the default) or do not when the path is the column name.

• Command line: --connect-json-all-path={0|1}

• Scope: Global, Session

• Dynamic: Yes

connect_json_grp_size

• Description: Max number of rows for JSON aggregate functions.

• Command line: --connect-json-grp-size=#

• Scope: Global, Session

• Dynamic: Yes

connect_json_null

• Description: Representation of JSON null values.

• Command line: --connect-json-null=value

• Scope: Global, Session

• Dynamic: Yes

connect_jvm_path

• Description: Path to JVM library.

• Command line: --connect-jvm_path=value

• Scope: Global

• Dynamic:

connect_type_conv

• Description: Determines the handling of columns.

  • NO: The default until Connect 1.06.005, no conversion takes place, and a TYPE_ERROR is returned, resulting in a “not supported” message.

  • YES: The default from Connect 1.06.006. The column is internally converted to a column declared as VARCHAR(n), n being the value of .

connect_use_tempfile

• Description:

  • NO: The first algorithm is always used. Because it can cause errors when updating variable record length tables, this value should be set only for testing.

  • AUTO: This is the default value. It leaves CONNECT to choose the algorithm to use. Currently it is equivalent to NO, except when updating variable record length tables (, or ) with file mapping forced to OFF.

connect_work_size

• Description: Size of the CONNECT work area used for memory allocation. Permits allocating a larger memory sub-allocation space when dealing with very large if sub-allocation fails. If the specified value is too big and memory allocation fails, the size of the work area remains but the variable value is not modified and should be reset.

• Command line: --connect-work-size=#

• Scope: Global, Session (Session-only from CONNECT 1.03.005)

connect_xtrace

• Description: Console trace value. Set to 0 (no trace), or to other values if a console tracing is desired. Note that to test this handler, MariaDB should be executed with the parameter because CONNECT prints some error and trace messages on the console. In some Linux versions, this is re-routed into the error log file. Console tracing can be set on the command line or later by names or values. Valid values (from Connect 1.06.006) include:

  • 0: No trace

  • YES

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