feat: shared LRU block cache across all three DBs#202
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EddieHouston wants to merge 1 commit intoBlockstream:new-indexfrom
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feat: shared LRU block cache across all three DBs#202EddieHouston wants to merge 1 commit intoBlockstream:new-indexfrom
EddieHouston wants to merge 1 commit intoBlockstream:new-indexfrom
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Single shared cache for txstore, history, and cache DBs instead of per-DB caches. --db-block-cache-mb now controls the total cache size. Eliminates wasted allocation on the tiny cache_db and lets txstore and history claim cache proportional to actual usage via LRU eviction.
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Randy808
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Mar 31, 2026
| let mut block_opts = rocksdb::BlockBasedOptions::default(); | ||
| let cache_size_bytes = config.db_block_cache_mb * 1024 * 1024; | ||
| block_opts.set_block_cache(&rocksdb::Cache::new_lru_cache(cache_size_bytes)); | ||
| let owned_cache; |
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Consider adding a type annotation for readability:
let owned_cache: rocksdb::Cache;
Randy808
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Mar 31, 2026
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Summary
rocksdb::Cachepassed to all three DBs (txstore, history, cache) instead of each DB creating its own--db-block-cache-mbnow controls the total cache size, not per-DBBackground
electrs maintains three RocksDB instances: txstore (~900 GB), history (~555 GB), and cache (~3 MB). Previously each got its own block cache of
--db-block-cache-mbsize, so the total was 3x the configured value. The cache_db's allocation satalmost entirely unused.
With a shared cache, the same total memory is used more efficiently. txstore (which holds the bulk of the data and handles the most lookups) naturally claims the lion's share through LRU eviction, while cache_db uses only what it needs.
Migration note:
--db-block-cache-mbnow means total, not per-DB. To match previous behavior, triple the old value (e.g. old--db-block-cache-mb=6144= 18 GB total → new--db-block-cache-mb=18432).Note: future step is to convert the LRU --> HyperClockCache
Test plan
cargo check/cargo buildwith default featurescargo build --features liquidblock-cache-capacitymetric is identical across all three DBsblock-cache-usagereflects shared pool (not 3 independent pools)