How to find the SQL statements that caused tempdb growth?

There are three DMVs you can use to track tempdb usage:

• sys.dm_db_task_space_usage
• sys.dm_db_session_space_usage
• sys.dm_db_file_space_usage

The first two will allow you to track allocations at a query & session level. The third tracks allocations across version store, user and internal objects.

The following example query will give you allocations per session:

SELECT
  sys.dm_exec_sessions.session_id AS [SESSION ID]
  ,DB_NAME(database_id) AS [DATABASE Name]
  ,HOST_NAME AS [System Name]
  ,program_name AS [Program Name]
  ,login_name AS [USER Name]
  ,status
  ,cpu_time AS [CPU TIME (in milisec)]
  ,total_scheduled_time AS [Total Scheduled TIME (in milisec)]
  ,total_elapsed_time AS    [Elapsed TIME (in milisec)]
  ,(memory_usage * 8)      AS [Memory USAGE (in KB)]
  ,(user_objects_alloc_page_count * 8) AS [SPACE Allocated FOR USER Objects (in KB)]
  ,(user_objects_dealloc_page_count * 8) AS [SPACE Deallocated FOR USER Objects (in KB)]
  ,(internal_objects_alloc_page_count * 8) AS [SPACE Allocated FOR Internal Objects (in KB)]
  ,(internal_objects_dealloc_page_count * 8) AS [SPACE Deallocated FOR Internal Objects (in KB)]
  ,CASE is_user_process
             WHEN 1      THEN 'user session'
             WHEN 0      THEN 'system session'
  END         AS [SESSION Type], row_count AS [ROW COUNT]
FROM 
  sys.dm_db_session_space_usage
INNER join
  sys.dm_exec_sessions
ON  sys.dm_db_session_space_usage.session_id = sys.dm_exec_sessions.session_id

If you want to track usage over a period of time, consider collecting data with sp_whoisactive, as demonstrated by Kendra Little.

There can be various sources of a problem:

• usage of table variables or temporary tables
• sql server created intermediate resultsets as worktables in tempdb - usually for sorting purposes (usually is a sign of absent indexes/out-of-date statistics)
• sql server decided to pre-evaluate the resultset of table valued function and in this case it stores the data in tempdb
• recreating indexes with option SORT_IN_TEMPDB = ON