Missing slots with getBlock

Question

The Dune team was going through all the slots in the Solana blockchain and from slot 1634073 to 1690556 (56k) we are receiving, on "getBlock" method, error -32009 with message "Slot XXX was skipped, or missing in long-term storage".

The Solana explorer fails to fetch these slots.

The next slot after these errors (1690557) has parent 1690556, so they seem to exist (https://explorer.solana.com/block/1690557).

The previous slot before these errors (1634072) has no child slot, this is odd (https://explorer.solana.com/block/1634072).

Questions:

1. Were these slots lost, so nothing can be done to recover them?
2. Will these slots be retrievable in the future?
3. Are they recoverable in some other way?

Answer 1

So long as a copy of a ledger that contains those shreds exists they can be recovered.

It seems that these should have those blocks: https://storage.googleapis.com/mainnet-beta-ledger-us-ny5/1595200/rocksdb.tar.bz2 https://storage.googleapis.com/mainnet-beta-ledger-europe-fr2/1595228/rocksdb.tar.bz2

I haven't checked myself yet, but I'll try to patch them up later this week.

Answer 2

Joe had it mostly covered but to be explicit:

1. Were these slots lost, so nothing can be done to recover them?

No, they were not lost. They just weren't loaded into our bigtable instance.

2. Will these slots be retrievable in the future?
3. Are they recoverable in some other way?

Same as above, yes we have the blocks so they are retrievable / are not lost.

This item was brought to my attention in https://github.com/solana-labs/solana/issues/32714, and as of today (2023.08.27), I have uploaded these missing slots so we can consider this issue resolved