patch: debuginfod sqlite3 metrics

[Mark Wielaard]

Hi Frank,

On Mon, 2020-11-23 at 20:07 -0500, Frank Ch. Eigler via Elfutils-devel
wrote:
> From 0b61f4c758a507fcc2243357363e44140bd13d82 Mon Sep 17 00:00:00
> 2001 ?!??!!
> From: "Frank Ch. Eigler" <fche@redhat.com>
> Date: Mon, 23 Nov 2020 19:58:10 -0500
> Subject: [PATCH] debuginfod: sqlite3 metrics
> 
> Add metrics for tracking sqlite3 error counts and query performance.
> 
> The former looks like a new sibling of the "error_count" family, and
> is tested by dd-corrupting a live database file then triggering some
> debuginfod activity.
> 
>     error_count{sqlite3="file is not a database"} 1
> 
> The latter looks like _count/_sum pairs for each type of sqlite
> prepared-statement used in the code, and is grep smoke-tested.  They
> should assist a sysadmin in tuning db storage.  This example shows a
> 6.4 ms/operation cost:
> 
>     sqlite3_milliseconds_count{step-done="rpm-file-intern"} 318
>     sqlite3_milliseconds_sum{reset="rpm-file-intern"} 2033

Looks good. Just one question about the RAII timing metrics.
It is using gettimeofday which I believe might jump around since it
tracks "human time". Might it be better to use clock_gettime
(CLOCK_MONOTONIC) instead? Note that uses nanoseconds instead of
microseconds, so needs adjusting a factor 1000.

Cheers,

Mark