HostInfo: reduce mutex.Locks #165
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host_source.go
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| @@ -410,16 +410,43 @@ func (h *HostInfo) IsUp() bool { | |||
| } | |||
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| func (h *HostInfo) HostnameAndPort() string { | |||
| // Fast path: in 99.9% hostname is not empty | |||
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How did you deduce this number?
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99.9% is certainly a big number.
We actively use the public methods Hostname() and HostnameAndPort() in metrics.QueryObserver. Accordingly, for each request in scylladb we call Hostname()/HostnameAndPort(), but if the cluster is stable and no reccconections occur, then hostname in most cases is not empty.
I'll attach go profile of mutex (before -> after) later
host_source.go
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| addr, _ := h.connectAddressLocked() | ||
| h.hostname = addr.String() | ||
| } | ||
| return net.JoinHostPort(h.hostname, strconv.Itoa(h.port)) | ||
| } | ||
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| func (h *HostInfo) Hostname() string { | ||
| // Fast path: in 99.9% hostname is not empty |
moguchev
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Please add a descriptive commit message to your commit. |
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I would recommend to use Since |
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@moguchev - can you refresh the PR, addressing above comments? |
Yes, I’ll do it |
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@moguchev , I have given a try to |
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Thanks @moguchev for your contribution! |
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1.14.2 was released with your contribution @moguchev - thanks again! |
I know that there is comment by @Zariel to reduce locking.
I didn't thoroughly refactor the code, but I found fast and cheap optimization in functions
(*HostInfo).HostNameand(*HostInfo).HostNameAndPort.In our case of #164
(*HostInfo).HostNameleads to spending a lot of time in Lock...Also in
QueryObserverandBatchObserverwe calls public methods ofHostInfo(HostName,HostNameAndPort) for metrics and we have a lot of mutex locks.