If you absolutely must make sure you ever create 2 instances of any value in the map then I guess you have to lock. Otherwise you can maybe use map.LoadOrStore?
fre 1 sep. 2017 kl 00:18 skrev bep <bjorn.erik.peder...@gmail.com>: > sync.Map in Go 1.9 is a little low on examples/doc in the wild, so I > thought I should ask here. > > The new type is promoted as a replacement for RWMutex in mostly read use > cases with stable keys. I assume that a typical in memory cache would fit > that description. > > With RWMutex, if the cost of creating the cache item is high, I would > maybe do something ala: > > mu.RLock() > // Check cache > mu.RUnclock() > > // Return if found > > // If Not found: > mu.Lock() > defer mu.Unlock() > // Double check cache, return if found > // Create item and put in cache > > > > > I don't see how the above can be written with a sync.Map without adding a > mutex. > > bep > > -- > 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. > For more options, visit https://groups.google.com/d/optout. > -- 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. For more options, visit https://groups.google.com/d/optout.
