On Mon, 4 Dec 2006, Simon Riggs wrote: > On Tue, 2006-12-05 at 00:18 +1100, Gavin Sherry wrote: > > > o Determine if we need to provide anything for rm_startup, rm_cleanup, > > rm_safe_restartpoint RmgrData function pointers. > > safe_restartpoint gives true/false based upon whether there are > multi-record WAL states that have only been partially received. For > example, a btree index split needs multiple WAL records as it recurses > up the index tree. If you've got one record but not the others yet you > have an incomplete state and so cannot safely write a restartpoint. > > I'll document that if you/anyone might suggest where the best place is?
transam/README ? > > > o Look into adding an AM option such that the user can determine word size > > at index creation time. For higher-cardinality data (above 1000 distinct > > values), 16 bit word sizes can really help with performance. Although > > the word size is not just assumed to be a certain size across the code, > > macros are used extensively to interact with the word size. Making it > > different for each index might be a little messy. > > ...and is is it a typical case to have a bitmap with less than 1000 > distinct values?? Surely we want that as the sole assumption? > > Nearly unique bitmaps can suffer a little I think, if it makes the most > common case faster. But I'd like to see the perf results first, I guess. I'll put together some performance data on different word sizes. Thanks, Gavin ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings