Mathieu Othacehe <othac...@gnu.org> writes: > Hello Chris, > >> I believe SQLite checkpoints the WAL file after transactions commit, if >> the WAL is over 1000 pages in size. At least for the Guix Build >> Coordinator though, that didn't seem to be working/happening as the WAL >> file seemed to just grow and grow. > > I have noticed that the WAL file size had a strong impact on Cuirass > performances on berlin[1]. > > My conclusion was that, WAL file is nice when doing a lot of writing, > but it makes reading really slow over time. I did set the checkpoint > value to 16 pages of 32KiB as recommended here[2]. > >> Switching focus to Cuirass, I think it's got similar issues. I've pushed >> a few commits to this branch [1], the important one being [2] which >> rewrites a few procedures to call sqlite-reset when the statement is >> finished with, rather than calling it before starting to read from the >> statement. > > The first two commits look nice. Regarding the third one, it makes sense > to finalize or reset a statement once done with it, but I cannot find > anything in SQLite documentation insisting on that point. > > Have you found some resources elaborating on that?
No, that's fustrated me as well. Given sqlite-prepare resets cached statements, I did try removing most of the sqlite-reset calls from the Guix Build Coordinator, but that went very badly so I reverted it shortly after. I was also struggling to find documentation on what to do/not do. I'll neaten up these commits later and push them, hopefully it'll help with the WAL size and/or query performance. Chris
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