[TieredStorage] Deprecate the use of account-hash in HotStorage

[yhchiang-sol]

Problem

TieredStorage stores account hash as an optional field inside its HotStorage.
However, the field isn't used and we have already decided to deprecate
the account hash.

Summary of Changes

Remove account-hash from the tiered-storage.

Test Plan

Existing tiered-storage tests.
Running validators w/ tiered-storage in mainnet-beta w/o storing account-hash.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.8%. Comparing base (3f9a7a5) to head (3229e60).
Report is 15 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##           master      #93     +/-   ##
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- Coverage    81.8%    81.8%   -0.1%     
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  Files         837      838      +1     
  Lines      225922   225871     -51     
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- Hits       184955   184868     -87     
- Misses      40967    41003     +36     

[brooksprumo]

Removing the lifetime is a nice bonus!

[brooksprumo]

[jeffwashington]

For compressed state, we need to store the hash per account. We also likely need to store a heterogenous mixture of full accounts or hash.
It seems it is costing us 1 bit per account to be able to store an account's hash.
My inclination is that this pr should be reverted. Thoughts?

[yhchiang-sol]

For compressed state, we need to store the hash per account. We also likely need to store a heterogenous mixture of full accounts or hash.
It seems it is costing us 1 bit per account to be able to store an account's hash.
My inclination is that this pr should be reverted. Thoughts?

If we want to use the minimum storage size to handle state-compressed accounts, then having a dedicated block for all the state-compressed accounts would probably lead to the best result. The resulting tiered-storage file would look something like this:

• accounts blocks
• index block
• owners block
• state compressed block
• filter block (e.g. a bloomfilter to determine whether an account might exist in this file)
• footer

A state-compressed block can be simply:

<pubkey-1><hash-1>
<pubkey-2><hash-2>
...