I created some jobs in TOS in order to implement Insert-Update between tables from different schemas on Redshift.
For both cases, I used ELT components, using "Mapping Redshift". No problem for "Insert" task.
Actually, I am not able to implement UPDATE. Use case: One table on a schema that has to update another table on a different schema. This is what I've done:
Set correctly keys on both tables;
"Action on data" : Update (tELTJDBCOutput);
Correct mapping on ELTMap. No joins required (one input table that has to update output table). I tried also to inner join input table with a copy (in input) of the output table on key fields.
WHERE Clauses : ""
The error that the job returns is "single-row subquery returns more than one row".
I tried to use also tRedshiftOutput component and tRedshiftRow for the update, and in this case everything is ok. I have to use ELT component because is much faster with lots of data to move.
first of all you could try to check in the Code tab - what SQL query generated and try to run it manually on Redshift
but in case of simple UPDATE you could always use tRedshiftRow and write your update manually, it will work same as tELT - run all code on the server without transfer data
Could you please check the keys that you have set for updation have unique values in both tables. Normally this error is thrown when the keys which are used to join are not unique.
