Previously, NewChild elements of querytracer could be referenced by concurrent
storageNode goroutines. After earlier return ( if search.skipSlowReplicas is set), it is
possible, that tracer objects could be still in-use by concurrent workers.
It may cause panics and data races. Most probable case is when parent tracer is finished, but children
still could write data to itself via Donef() method. It triggers read-write data race at trace
formatting.
This commit adds a new methods to the querytracer package, that allows to
create children not referenced by parent and add it to the parent later.
Orphaned child must be registered at the parent, when goroutine returns. It's done synchronously by the single caller via finishQueryTracer call.
If child didn't finished work and reference for it is used by concurrent goroutine, new child must be created instead with
context message.
It prevents panics and possible data races.
Related issue:
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8114
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Signed-off-by: f41gh7 <nik@victoriametrics.com>
Co-authored-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
'any' type is supported starting from Go1.18. Let's consistently use it
instead of 'interface{}' type across the code base, since `any` is easier to read than 'interface{}'.
* lib/querytracer: makes package concurrent safe to use
it must fix various issues with concurrent code usage.
Especially, when it's not reasonable to wait for all goroutines to be finished
* wip
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Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This should simplify further debugging, since the first thing to start the debugging by query trace
is to know the version of VictoriaMetrics, which produced this trace.
