Geth has two independent snapshot tiers, each with its own disable
mechanism:
1. In-memory snapshot cache: controlled by SnapshotLimit (derived from
ethconfig.SnapshotCache). Setting SnapshotCache=0 disables it.
2. On-disk snapshot generator: a background goroutine in pathdb that
iterates the entire state trie to build flat key-value snapshots.
Controlled by pathdb.Config.SnapshotNoBuild.
The partial state configuration (cmd/utils/flags.go) already set
SnapshotCache=0 to disable the in-memory cache. However, SnapshotNoBuild
was never set, so pathdb.Enable() — called after snap sync completes —
still launched the background generator goroutine.
This generator immediately hits missing storage tries for untracked
contracts (whose storage was intentionally skipped during partial sync),
logs "Trie missing, snapshotting paused", and blocks forever on its
abort channel — a permanent goroutine leak with no recovery path.
Additionally, BlockChainConfig.SnapshotNoBuild was never propagated to
pathdb.Config.SnapshotNoBuild in the triedbConfig() conversion. The
field only reached the hash-scheme snapshot module (core/blockchain.go
setupSnapshot), which is already skipped for path-scheme databases. This
plumbing gap meant pathdb.Config.SnapshotNoBuild was never set in
production code — only in tests.
Fix both issues:
- Set SnapshotNoBuild=true when partial state is enabled
- Propagate BlockChainConfig.SnapshotNoBuild into pathdb.Config
4cd7b3ba6c