Database schema changes 2024

[michaelsproul]

Description

This is a meta-issue for scheduling database schema changes in Lighthouse.

The Lighthouse v5.2.0 schema was v19.

v20 was:

• Electra: Remaining Consensus Data Structures #5712

v21 was (released in Lighthouse v5.3.0):

• Store pubkey cache decompressed on disk #5897

v22 will be:

• Hierarchical state diffs #5978

v23 will be:

• Store linear blocks in freezer db #5905

v24 will be:

• HotStateSummary cleanup + CompactBeaconState. TODO: do it without ValidatorTrait.
• Delete PRUNING_CHECKPOINT_KEY

[michaelsproul]

Something else to consider is that we already used some of the versions in this range for preliminary tree-states releases. The latest being v24 which will not be compatible with the final v24 envisioned here. Maybe we could skip a few numbers to avoid confusion