Details
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Improvement
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Resolution: Fixed
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Major
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7.1.1
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0
Description
Background
As seen in recent issues, not all SDK clients enable HELO::Tracing on their mcbp connections - either because they don't enable it by default (e.g. Query prior to MB-64530 / 7.5.0), or because the application has explicitly disabled it.
If Tracing is not enabled then KV-Engine does not generate trace spans for the low-level operation phases if they are not already timed - and as such it can be confusing to try to debug why these "Slow operations" were slow.
As part of MB-54645, KV-Engine is changing the default behaviour to always collect trace information (and report as part of Slow operation logging), to avoid the problems with some clients not enabling it.
While there is a memcached.json to do this already (always_collect_trace_info), it is not exposed via ns_server.
Improvement
We should add support for configuring memcachd.json always_collect_trace_info. This is a boolean, and the new default value should be "true", but users should be able to change this dynamically at runtime - KV-Engine already supports this.