Laurent Raufaste wrote:
> The problem was that the optimiser didn't know how to run the queries
> well and used millions of tuples for simple queries. For each tuple
> used it was updating some bit in the table file, resulting in a huge
> writing activity to that file.
Good that you solved your problem.
PostgreSQL doesn't write into the table files when it SELECTs data.
Without an EXPLAIN plan it is impossible to say what PostgreSQL
was doing, but most likely it was building a large hash structure
or something similar and had to dump data into temporary files.
Yours,
Laurenz Albe