On-chain compression for inactive accounts to recover locked rent

[ZygmuntJakub]

Hey folks! I was curious how much rent could be unlocked on Drift using on-chain compression, so I scanned all 207,987 User accounts on mainnet (filtered by discriminator + dataSize: 4376). "Inactive" = no transaction in the last 30 days.

Scan script here

Status	Count	%
Inactive (no tx > 30 d)	193,866	93.2%
Active	11,727	5.6%
Errors skipped	2,394	1.1%

That's a lot of 4,376 B accounts sitting idle.

I then ran an on-chain benchmark using densol, a no_std LZ4 library that compresses inside the SBF VM. It fetched 100 random inactive accounts from mainnet and ran compression on localnet:

Benchmark script here

SOL price: $88.98 (Binance)

Sampled 100 accounts from 193,866 inactive

  #  Pubkey              CompSz   Ratio     CompCU   DecompCU   RentSaved
────────────────────────────────────────────────────────────────────────────
  1  2b4TRt…aMUkqF        166 B   26.4x     20,896     69,913  0.0293 SOL
  2  G6eZG7…cA4naE        263 B   16.6x     26,352     69,373  0.0286 SOL
  ...
 99  2a3xye…1guAKx        244 B   17.9x     25,647     68,101  0.0288 SOL
100  3yCuU2…cpSHH9        150 B   29.2x     20,126     69,935  0.0294 SOL

────────────────────────────────────────────────────────────────────────────
Compressed size:   226 B avg  (min 109 B, max 906 B)
Compression ratio: 21.86x avg
Compress CU:       24,299  (one-time keeper cost)
Decompress CU:     69,401  (per read, on demand)
Rent saved:        0.028887 SOL/account
────────────────────────────────────────────────────────────────────────────
Extrapolation — all Drift User accounts on mainnet:
  (source: benchmark/drift/scan.ts, full scan March 2026)
  total accounts:    207,987
  inactive (>30 d):  193,866  (93.2%)
  recoverable rent:  ~5600 SOL  (~$498306 at $88.98/SOL)

Estimated total recoverable across all inactive accounts is ~5,600 SOL. Compression could be reversed automatically when an account sees traffic again. Decompress on first access, recompress if it goes quiet.

Has this ever been considered? Would love to hear your thoughts on this.