> Von: Tom Lane > Gesendet: Montag, 29. Mai 2017 18:17 > > OK, so open_datasync and fdatasync are nonfunctional on Windows, which is > unsurprising. The other cases are evidently doing *something*, but the amount > of overhead is variable from one sync method to another, which is likewise > unsurprising. The whole reason why we have these options at all is that some > systems handle some of them better than others. In this case, I think the > relevant conclusion is that correct configuration for Debian is to use > open_datasync or fdatasync, while correct configuration for Windows is to use > fsync or fsync_writethrough, and when you compare those two configurations, > yes Windows is slower. Excellent answer, thanks. Correct me if I'm wrong: I understand that synchronous_commit = off in combination with fdatasync (Debian) or fsync_writethrough (Windows) is „safe“ (for regular interactive desktop applications). These options gave the following results: Windows Debian 40 clients READ/WRITE 5400 7400 1 client READ/WRITE 400 390 Single client READ/WRITE tests are on now the same level. In the multi client test, Debian is performing significantly better than Windows. > > If you're a paranoid sort you would want to do plug-pull testing to ensure that > your selected setting actually does prevent data corruption during a system > crash. That’s certainly an option before we take this into production. Regards Klaus |
