None of the queries named requires more than 1 parameter to xFilter. Why should they?
xBestIndex will be called once with no usable constraints and once with (value1, "="). The difference is that xFilter will be called once for each constraint value, i.e. once for query 1 and twice for queries 2..4. I guess you are setting argvIndex to 1 for a constraint that is not marked usable. The exact calling sequence should be: xBestIndex (1 constraint, not usable) => rows should be set to number of rows in vt xBestIndex ( value1, "=" ) => rows should be set to 1 (if field value1 is a unique key for the table) xFilter ( 7 ) => locate the row xColumn ( ... ) => return the contents of the field xNext => set eof flag xEof => return TRUE xFilter ( 8 ) => locate the row xColumn ( ... ) => return the contents of the field xNext => set eof flag xEof => return TRUE -----Urspr?ngliche Nachricht----- Von: Emmanouil Karvounis [mailto:manosk at di.uoa.gr] Gesendet: Donnerstag, 21. Mai 2015 17:21 An: sqlite-users at mailinglists.sqlite.org Cc: Stamatios Christoforidis Betreff: [sqlite] BestIndex problem Greetings, We are having an issue with BestIndex in our Virtual Table implementation. Allow us to illustrate the problem with a simple example. We create a virtual table named 'vt' that conceptually has 3 columns "value1, value2, value3" and then we want to execute the following queries: 1) select value1 from vt where value1 = 7; In this case, BestIndex passes the equal constraint on the first column and by setting the output as pdxInfo->aConstraintUsage[0].argvIndex = 1, we indicate that we accept this specific constraint. So, at Filter we get the value 7 as argument0. Everything behaves normally so far. However, in case we run any of the following equivalent queries (that should pass to Filter more than one value), we get an error message "xBestIndex returned an invalid plan": 2) select value1 from vt where value1 = 7 or value1 = 8; 3) select value1 from vt where value1 in (select * from tableA); // suppose tableA contains an integer 'id' column and records (7, 8) 4) select value1 from vt, tableA where value1 = tableA.id; Again, in each case we set pdxInfo->aConstraintUsage[0].argvIndex = 1 but we get the above error message. This behavior seems rather weird, so we'd like some expert help on what we might be doing wrong. Thank you for your time, Manos Karvounis Stamatis Christoforidis _______________________________________________ sqlite-users mailing list sqlite-users at mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick Software Engineer Scientific Games International GmbH FN 157284 a, HG Wien Klitschgasse 2-4, A-1130 Vienna, Austria Tel: +43 1 80100 0 E-Mail: hick at scigames.at This communication (including any attachments) is intended for the use of the intended recipient(s) only and may contain information that is confidential, privileged or legally protected. Any unauthorized use or dissemination of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail message and delete all copies of the original communication. Thank you for your cooperation.
