Session VariablesΒΆ

Each client connection to TajoMaster creates a unique session, and the client and TajoMaster uses the session until disconnect. A session provides session variables which are used for various configs per session.

tsql provides the meta command \set to manipulate session variables. Just \set command shows all session variables.

default> \set
'name1'='val1'
'name2'='val2'
'name3'='val3'
     ...

\set key val will set the session variable named key with the value val.

default> \set
'CURRENT_DATABASE'='default'

default> \set key1 val1

default> \set
'CURRENT_DATABASE'='default'
'key1'='val1'

Also, \unset key will unset the session variable named key.

Now, tajo provides the following session variables.

  • DIST_QUERY_BROADCAST_JOIN_THRESHOLD
  • DIST_QUERY_JOIN_TASK_VOLUME
  • DIST_QUERY_SORT_TASK_VOLUME
  • DIST_QUERY_GROUPBY_TASK_VOLUME
  • DIST_QUERY_JOIN_PARTITION_VOLUME
  • DIST_QUERY_GROUPBY_PARTITION_VOLUME
  • DIST_QUERY_TABLE_PARTITION_VOLUME
  • EXECUTOR_EXTERNAL_SORT_BUFFER_SIZE
  • EXECUTOR_HASH_JOIN_SIZE_THRESHOLD
  • EXECUTOR_INNER_HASH_JOIN_SIZE_THRESHOLD
  • EXECUTOR_OUTER_HASH_JOIN_SIZE_THRESHOLD
  • EXECUTOR_GROUPBY_INMEMORY_HASH_THRESHOLD
  • MAX_OUTPUT_FILE_SIZE
  • CODEGEN
  • CLIENT_SESSION_EXPIRY_TIME
  • CLI_MAX_COLUMN
  • CLI_NULL_CHAR
  • CLI_PRINT_PAUSE_NUM_RECORDS
  • CLI_PRINT_PAUSE
  • CLI_PRINT_ERROR_TRACE
  • CLI_OUTPUT_FORMATTER_CLASS
  • CLI_ERROR_STOP
  • TIMEZONE
  • DATE_ORDER
  • TEXT_NULL
  • DEBUG_ENABLED
  • BEHAVIOR_ARITHMETIC_ABORT
  • RESULT_SET_FETCH_ROWNUM