Hi, we're working on an application that does a lot of select count(*) ... and thus suffers performance on SAP DB compared to o*ther dbms.
Searching for information about b*-trees in the internet I found a suggestion by Simon Tatham for count maintenance: http://www.chiark.greenend.org.uk/~sgtatham/algorithms/cbtree.html I also found a thread in the suse-adabas list regarding "[suse-adabas] ADABAS Performance", where Joerg Bruehe pointed out that maintaining these counts up to the root node has negative impact on parallel transaction handling. So there are (at least) two positions: - prefer maintaining count for optimzing query execution and handling bags - prefer table scan to keep update collisions low What is your opinion? Henry ________________________________________________________________ Keine verlorenen Lotto-Quittungen, keine vergessenen Gewinne mehr! Beim WEB.DE Lottoservice: http://tippen2.web.de/?x=13
