Ingestion congestion from inserting backfill_items

[kespinola]

Issue

At Triton, we observed slow processing of transactions and excessive accesshare and exclusive locks on the backfill_items caused by the select scanning for already existing backfill_items.

https://github.com/metaplex-foundation/digital-asset-rpc-infrastructure/blob/main/nft_ingester/src/program_transformers/bubblegum/db.rs#L138

Rate of transaction processing goes from 10/s to 125/s after removing the code related to backfill_item insertion. This is running 1 ingester processes with 4 TXN workers. Locks on the postgres database before and after removing backfill_item insertion.

Fix

We have removed the code for inserting the backfill_items because the new tree backfiller we developed does not rely on backfill_items. It works with the new cl_audits_v2.

rpcpool#128