On 4 May 2016, at 9:32pm, Nikolaos Tsikoudis <tsikudis at brandeis.edu> wrote:
> I execute a query and I see that SQLite creates temporary data that are > never written to the disk and I am trying to understand what happens. Use the EXPLAIN QUERY PLAN command: <https://www.sqlite.org/eqp.html> It will show you how SQLite decides to best execute your query. > select > sum() > from > table1 t1 > table2 t2 > where ( > t1.a = t2.a and ... > ) or ( > t1.a = t2.a and ... > ) or ( > t1.a = t2.a and ... > ); Do you have indexes on table1.a and table2.a ? If not, then SQLite might decide it has to make up a temporary index in order to process your query quickly. That would be a 'transient indices' as you describe in your question. Simon.
