The NoSpool mode exports the contents of a table as fast as possible without reading the table into a spool file or distributing the file to all AMPs before extracting it. Three options for spooling are:
- (Default) SPOOL the data.
- Use the NOSPOOLONLY mode, but return an error if NOSPOOL is not supported.
- Use the NOSPOOL mode when possible; otherwise spool the data in the database.
Limitations and Functionality
- NOSPOOL mode applies only to simple SELECT statements. The following are not supported:
- Access to nondata tables, such as SELECT DATE or SELECT USER
- USING modifier; instead, define restraint parameters by using a FastExport IMPORT command with supporting FIELD and FILLER commands
- Contains a SORT (ORDER BY), HAVING, or WITH clauses
- Aggregations (Explain shows SUM step)
- TABLE functions
- Ordered-analytic (OLAP) functions
- Multiple SELECT statements or multistatement requests
- Statements with zero or more than one, retrieve or sampling step
- NOSPOOL mode only retrieves data from a single table, but the SELECT statement can be selective about which columns are exported and can constrain the job to a subset of rows.
- Scalar expressions/functions are allowed.
- The Sample and partition eliminating constraints are supported.
- The Activity Count returned for a regular spooled job indicates the number of affected blocks; however, for non-spooled jobs, the number of blocks is unknown, so the response message contains ActivityType (instead of Activity Count) to indicate the NOSPOOL process.
Disadvantages of the NOSPOOL Mode
- Locks are maintained during the entire export process.
- Data conversion errors previously detected during the spooling phase will not be detected until the block is read, which could occur during any time during the export.
- Row order (because of the absence of the ORDER BY clause) may or may not be consistent between runs; therefore, NOSPOOL mode offers no guarantee of consistency.
For more information on Spool/NoSpool mode, see Teradata® FastExport Reference, B035-2410.