PR #107719 - ui: add latency info to explain plan tab

[cockroach-teamcity]

Exalate commented:

Related PR: cockroachdb/cockroach#107719
Commit: cockroachdb/cockroach@11acdea
Fixes: CRDB-29003

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Release note (ui change): Add columns for p50, p90, p99 percentiles
and latency min and max on Explain Plan tab on Statement Details
page.

Jira Issue: DOC-8446

[exalate-issue-sync]

Kevin Ngo (kevin-v-ngo) commented:
Add sampling strategy as well for each columns and how the P90s are computed.

[exalate-issue-sync]

Florence Morris (florence-crl) commented:
{quote}Add sampling strategy as well for each columns and how the P90s are computed.{quote}

Marylia Gutierrezwould you be able to provide more detail about sampling strategy or how the percentiles are computed?

[exalate-issue-sync]

Marylia Gutierrez (maryliag) commented:
We didn’t go into much level of details into the sampling because it’s a little obscure for the user, is from an internal system also used by Insights, so it would be a little hard to explain to the user, so this is why we decided even on the tooltip to just say sampled.
If you want more details, we decide the sample on events that were detected by Insights, so only events part of Insights are sampled.

Now on to how percentiles are computed, there is nothing different here, is just how any other percentile is calculated. We get the values for all the ones we sampled and then calculate the percentiles based on that.