disable read cache while populating stakes cache on load

[jeffwashington]

Problem

stakes cache reads tons of accounts. These fill up the read cache. We then spend time evicting all these accounts, which hurts performance of startup and tx processing.

Summary of Changes

skip populating the read cache while loading stake accounts.

Fixes #

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.8%. Comparing base (e261e27) to head (f566b04).
Report is 7 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##           master     #482     +/-   ##
=========================================
- Coverage    81.8%    81.8%   -0.1%     
=========================================
  Files         842      842             
  Lines      228436   228442      +6     
=========================================
- Hits       187063   187026     -37     
- Misses      41373    41416     +43     

[alessandrod]

Adding the disable_read_cache_updates field seems fine for this use case, but how about adding it as an explicit parameter to some load_account*() variant? Tx execution will likely want something like this too to implement #180, and there I don't think we can set a db-global bool

[brooksprumo]

[..] how about adding it as an explicit parameter to some load_account*() variant?

This also sounds good to me.

[HaoranYi]

lgtm.
It is a tradeoff. I like the simplicity of this change, which will be easy to backport.

[brooksprumo]

[..] which will be easy to backport.

Probably not a candidate to backport. v1.18 is rolling out to mnb very soon. So we should only be backporting critical bug fixes. More details in Discord: https://discord.com/channels/428295358100013066/439194979856809985/1222663250206789673.

[brooksprumo]