On the topic of increasing the stack size, it's curious that we are able to recurse on the same parse tree without stack overflow in java...
On 9/5/13 5:51 PM, "Enns, Steven" <[email protected]> wrote: >Thanks John and Dominique! > >Unfortunately our column has a keyword index, so we are unable to use "in" >queries. We will try to balance our parentheses. > >Have either of you had success increasing the stack size? I tried using >ulimit and setrlimit, but neither seemed to work. > >John - Have you considered changing the methods that operate on the parse >tree to be iterative rather than recursive? I started looking at >ibis::qExpr::simplify and I noticed two challenges: > >1. ibis::qExpr::simplify requires post-order traversal, which is somewhat >unnatural to implement iteratively >2. There are possibly many other methods which would need to be modified > > >On 9/5/13 5:17 PM, "K. John Wu" <[email protected]> wrote: > >>Hi, Dominique and Steve, >> >>If your long list of ORs are most related to a single column (or a >>small number of columns), then it is possible to convert them into an >>expression of the form >> >>column_name IN (list_of_strings_or_numbers ) >> >>The list in the parentheses has to be either a list of numbers of a >>list of strings (a mixture will be treated as a list of strings). >> >>Hope this helps. >> >>John >> >>PS: more information about expressions of a where clause is available at >> >>http://lbl.gov/~kwu/fastbit/doc/html/classibis_1_1whereClause.html >> >> >>On 9/5/13 3:39 PM, Prunier, Dominique wrote: >>> Steve, >>> >>> >>> >>> We faced the same issue and we worked around that by carefully >>> balancing the big OR with parenthesis so that you don¹t go deeper that >>> log2(OR count). >>> >>> >>> >>> Hope this helps ! >>> >>> >>> >>> Thanks, >>> >>> >>> >>> *From:*[email protected] >>> [mailto:[email protected]] *On Behalf Of *Enns, >>>Steven >>> *Sent:* Thursday, September 05, 2013 6:16 PM >>> *To:* FastBit Users >>> *Subject:* [FastBit-users] stack overflow on large queries >>> >>> >>> >>> Hi John, >>> >>> >>> >>> I am running a query of 2140 OR clauses and observing segmentation >>> fault in ibis::qExpr::simplify(ibis::qExpr*&) at recursive depth of >>> 1087. Could you help us debug this? >>> >>> >>> >>> Thanks! >>> >>> Steve >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> _______________________________________________ >>> FastBit-users mailing list >>> [email protected] >>> https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users >>> >>_______________________________________________ >>FastBit-users mailing list >>[email protected] >>https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users > >_______________________________________________ >FastBit-users mailing list >[email protected] >https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
