tree a4fe94568f7a75f5fa87baab43b0a76d7afc520b
parent 75b6838ee2dbb050337ad4c19a03ae5ba5d7b63f
author Will Holley <willholley@gmail.com> 1578404432 +0000
committer Will Holley <willholley@gmail.com> 1578511685 +0000

Fix missing mango execution stats (part 2)

The previous implementation of Mango execution stats relied on
passing the docs_examined count from each shard to the coordinator
in the view_row record. This failed to collect the count of
documents read which weren't followed by a match (in a given shard).
For example, if an index was scanned but no documents were matched,
the docs_examined would be 0, when it should be equal to the number
of documents in the index.

This commit changes the implementation so that docs examined is passed
only when each shard has completed its index scan.

The work is split into 2 commits to support mixed-version cluster
upgrades - the previous commit adds the message handlers only
so can be safely rolled out without breaking in-flight requests.