System Variables in 1.4

MariaDB Enterprise Server configuration is handled through a series of special variables called system variables. You can define system variables using a configuration file (such as my.cnf) or through command-line options passed to the Server when it starts. Additionally, some system variables are dynamic and can be defined using the SET command.

System variables for MariaDB ColumnStore have the columnstore_ prefix.

Variable

Description

columnstore_compression_type

Controls compression algorithm for create tables. Possible values are: NO_COMPRESSION segment files aren't compressed; SNAPPY segment files are Snappy compressed (default);

columnstore_decimal_scale

The default decimal precision for calculated column sub-operations

columnstore_derived_handler

Enable/Disable the MCS derived_handler

columnstore_diskjoin_bucketsize

The maximum size in MB of each 'small side' table in memory.

columnstore_diskjoin_largesidelimit

The maximum amount of disk space in MB to use per join for storing 'large side' table data for a disk-based join. (0 = unlimited)

columnstore_diskjoin_smallsidelimit

The maximum amount of disk space in MB to use per query for storing 'small side' tables for a disk-based join. (0 = unlimited)

columnstore_double_for_decimal_math

Enable/disable for ColumnStore to replace DECIMAL with DOUBLE in arithmetic operation.

columnstore_group_by_handler

Enable/Disable the MCS group_by_handler

columnstore_import_for_batchinsert_delimiter

ASCII value of the delimiter used by LDI and INSERT..SELECT

columnstore_import_for_batchinsert_enclosed_by

ASCII value of the quote symbol used by batch data ingestion

columnstore_local_query

Enable/disable the ColumnStore local PM query only feature.

columnstore_orderby_threads

Number of parallel threads used by ORDER BY. (default to 16)

columnstore_ordered_only

Always use the first table in the from clause as the large side table for joins

columnstore_replication_slave

Allow this MariaDB server to apply replication changes to ColumnStore

columnstore_select_handler

Enable/Disable the MCS select_handler

columnstore_string_scan_threshold

Max number of blocks in a dictionary file to be scanned for filtering

columnstore_stringtable_threshold

The minimum width of a string column to be stored in a string table

columnstore_um_mem_limit

Per user Memory limit(MB). Switch to disk-based JOIN when limit is reached

columnstore_use_decimal_scale

Enable/disable the MCS decimal scale to be used internally

columnstore_use_import_for_batchinsert

LOAD DATA INFILE and INSERT..SELECT will use cpimport internally

columnstore_varbin_always_hex

Always display/process varbinary columns as if they have been hexified.