Available Session Variables:

\set SESSION_EXPIRY_TIME [int value] - session expiry time (secs)
\set CLI_COLUMNS [int value] - Sets the width for the wrapped format
\set CLI_FORMATTER_CLASS [text value] - Sets the output format class to display results
\set CLI_NULL_CHAR [text value] - Sets the string to be printed in place of a null value.
\set CLI_PAGE_ROWS [int value] - Sets the number of rows for paging
\set CLI_PAGING_ENABLED [true or false] - Enable paging of result display
\set CLI_DISPLAY_ERROR_TRACE [true or false] - Enable display of error trace
\set ON_ERROR_STOP [true or false] - tsql will exist if an error occurs.
\set TIMEZONE [text value] - Sets timezone
\set DATE_ORDER [text value] - date order (default is YMD)
\set LANG [text value] - Language
\set LC_ALL [text value] - String sort order
\set LC_COLLATE [text value] - String sort order
\set LC_CTYPE [text value] - Character classification (What is a letter? Its upper-case equivalent?)
\set LC_MESSAGES [text value] - Language of messages
\set LC_MONETARY [text value] - Formatting of currency amounts
\set LC_NUMERIC [text value] - Formatting of numbers
\set LC_TIME [text value] - Formatting of dates and times
\set BROADCAST_NON_CROSS_JOIN_THRESHOLD [long value] - restriction for the total size of broadcasted table for non-cross join (kb)
\set BROADCAST_CROSS_JOIN_THRESHOLD [long value] - restriction for the total size of broadcasted table for cross join (kb)
\set JOIN_TASK_INPUT_SIZE [int value] - join task input size (mb) 
\set SORT_TASK_INPUT_SIZE [int value] - sort task input size (mb)
\set GROUPBY_TASK_INPUT_SIZE [int value] - group by task input size (mb)
\set JOIN_PER_SHUFFLE_SIZE [int value] - shuffle output size for join (mb)
\set GROUPBY_PER_SHUFFLE_SIZE [int value] - shuffle output size for sort (mb)
\set TABLE_PARTITION_PER_SHUFFLE_SIZE [int value] - shuffle output size for partition table write (mb)
\set GROUPBY_MULTI_LEVEL_ENABLED [true or false] - Multiple level groupby enabled
\set QUERY_EXECUTE_PARALLEL [int value] - Maximum parallel running of execution blocks for a query
\set EXTSORT_BUFFER_SIZE [long value] - sort buffer size for external sort (mb)
\set HASH_JOIN_SIZE_LIMIT [long value] - limited size for hash join (mb)
\set INNER_HASH_JOIN_SIZE_LIMIT [long value] - limited size for hash inner join (mb)
\set OUTER_HASH_JOIN_SIZE_LIMIT [long value] - limited size for hash outer join (mb)
\set HASH_GROUPBY_SIZE_LIMIT [long value] - limited size for hash groupby (mb)
\set MAX_OUTPUT_FILE_SIZE [int value] - Maximum per-output file size (mb). 0 means infinite.
\set NULL_CHAR [text value] - null char of text file output
\set CODEGEN [true or false] - Runtime code generation enabled (experiment)
\set AGG_HASH_TABLE_SIZE [int value] - Aggregation hash table size
\set SORT_HASH_TABLE_SIZE [int value] - Sort hash table size
\set JOIN_HASH_TABLE_SIZE [int value] - Join hash table size
\set INDEX_ENABLED [true or false] - index scan enabled
\set INDEX_SELECTIVITY_THRESHOLD [real value] - the selectivity threshold for index scan
\set PARTITION_NO_RESULT_OVERWRITE_ENABLED [true or false] - If True, a partitioned table is overwritten even if a sub query leads to no result. Otherwise, the table data will be kept if there is no result
\set ARITHABORT [true or false] - If true, a running query will be terminated when an overflow or divide-by-zero occurs.
\set FETCH_ROWNUM [int value] - Sets the number of rows at a time from Master
\set BLOCK_ON_RESULT [true or false] - Whether to block result set on query execution
\set COMPRESSED_RESULT_TRANSFER [true or false] - Use compression to optimize result transmission.
\set DEBUG_ENABLED [true or false] - (debug only) debug mode enabled