(If that seems surprising, the reason is mentioned in the sibling c++ library announcement: "performance in these cases is effectively governed by the number of cache misses, not the number of key-compare operations" -- https://opensource.googleblog.com/2013/01/c-containers-that-save-memory-and-time.html ... so the game turns into how few pointers you can chase. Turns out in memory b-trees are great for this. On Friday, March 14, 2025 at 6:09:56 AM UTC Jason E. Aten wrote:
> I do keep seeing references to Java concurrent stuff people are porting to > Go. I have to check it out. > > I need an ordered k/v store (find the next key greater-than)... and I was > trying to see how > concurrency could be added to things like https://github.com/google/btree, > which, in > turns out, at least in single goroutine form, wipes the floor soundly > against red-black > trees and radix trees. It's even way faster than the built in Go map, > while giving ordered key lookup, > not just hash table operations. The only trade-off is that it is suuuuper > slow for deletes. > > On Friday, March 14, 2025 at 5:32:08 AM UTC Robert Engels wrote: > >> I know some people are put off by stuff like this, but reading the Java >> JDK concurrent package provides a wealth of information- it is well >> documented and almost all are referenced implementations of academic >> papers. In this case, the Java concurrent hash map would be an applicable >> design. >> >> You can see some of this - not nearly as good or complete - in my >> github.com/robaho/go-concurrency-test >> >> On Mar 14, 2025, at 12:17 AM, Jason E. Aten <j.e....@gmail.com> wrote: >> >> oh nice. I like the hashing idea to pick a shard lock out of >> array...that way >> >> I don't have to stick locks on, and bloat, every node in the btree. I can >> just take the hash value modulo a the size of a fixed set of locks... >> Thanks Robert. >> >> p.s. awl, thanks, yes... saw that. thank you. >> >> On Friday, March 14, 2025 at 4:29:46 AM UTC Robert Engels wrote: >> >>> I think it is easier to just hash and shard the data set the lock is >>> protecting - ie a lock per shard. >>> >>> On Mar 13, 2025, at 10:52 PM, atomly <ato...@gmail.com> wrote: >>> >>> >>> >>> On Thu, Mar 13, 2025 at 20:29 Jason E. Aten <j.e....@gmail.com> wrote: >>> >>>> Is there a common way to do sharded read-write locks now? >>>> I mean faster than sync.RWMutex. >>>> >>>> I tried https://github.com/jonhoo/drwmutex which is from quite a >>>> while back... >>>> >>> >>> Have you read the original thread that spawned this, you might find it >>> pretty informative if not: >>> >>> >>> https://groups.google.com/g/golang-nuts/c/zt_CQssHw4M/m/TteNG44geaEJ?pli=1 >>> >>> >>> -awl >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "golang-nuts" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to golang-nuts...@googlegroups.com. >>> To view this discussion visit >>> https://groups.google.com/d/msgid/golang-nuts/CAA_Y42wUOYwnaO0ZDyC2USCMsZqVQXGck9q%2Bfb8inWoxG01brA%40mail.gmail.com >>> >>> <https://groups.google.com/d/msgid/golang-nuts/CAA_Y42wUOYwnaO0ZDyC2USCMsZqVQXGck9q%2Bfb8inWoxG01brA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts...@googlegroups.com. >> >> To view this discussion visit >> https://groups.google.com/d/msgid/golang-nuts/08738a3e-2c94-4f52-8f49-16b287303c6bn%40googlegroups.com >> >> <https://groups.google.com/d/msgid/golang-nuts/08738a3e-2c94-4f52-8f49-16b287303c6bn%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >> -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/golang-nuts/d3081e16-37f2-4509-95d6-9cbd32bb38ebn%40googlegroups.com.
