CREATE VIEW statements issued with SELECTs; multiple instances of SELECT sent to db
We are using the Microsoft SSIS Teradata Connector v2.0 (for SSIS 2012) and v1.2 (for SSIS 2008/2008R2).
When we use the Teradata Source to extract data from Teradata (i.e., source statement is a SELECT statement) our Teradata DBA is seeing:
1) CREATE VIEW statements being issued to Teradata, presumably issued behind the scenes by the Attunity Teradata Connector, where the CREATE VIEW statement is in the form:
CREATE VIEW SSIS_YYYYMMDDHHMMSS_NNN AS (<SELECT sourcequery>)
We have read-only access to the Teradata database, so these CREATE VIEW statements fail, but the extraction still works/succeeds. Can you help us to explain why the Attunity Connector is issuing the CREATE VIEW statements before the TPT Export, their potential benefits it those CREATE VIEW statements succeed, and the implications when the statements fail (due to lack of db privileges to create views)?
I have attached a screenshot provided by the Teradata DBA that shows the SQL that Teradata sees.
2) Secondly, a single SELECT defined with a Teradata source in SSIS apparently results in multiple (six) instances of the SELECT statement being issued to the Teradata database.
Please see the same attached screenshot. The pertinent statement is the SELECT ... FROM ha_hap_com_laborder_p. From our SSIS developer perspective, the query should be issued once, but according to the Teradata logs provided by the Teradata DBA the query is issued six times. Could you help us to explain why multiple SELECTs are sent to the database?
Any explanations you can provide to better understand the statements sent to the database with a SELECT/extraction using the Teradata Attunity Connector would be most appreciated. The need arises in troubleshooting performance issues, when we work with the DBA to correlate what our SSIS package is doing logically with the statements that the DBA sees that are being issued to the Teradata database.
Thank you very much.