Propagate WAL write failures instead of silently discarding them#105
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Propagate WAL write failures instead of silently discarding them#105
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insert_internal() used `let _ = self.wal.append(...)` which caused the key to be written to the memtable even when the WAL failed, making recovery after a crash impossible for those writes. Change insert_internal, insert_ts, insert, insert_ns_ts, and insert_ns to return std::io::Result<()> and return an Err immediately on WAL failure so the data is never inserted into the memtable. Update callers: - exec_insert, exec_update, exec_delete (query.rs): propagate as QueryError::Other so the client receives an explicit error. - register_table, save_schema (query.rs): log at ERROR level since these helpers currently have no return type. - lwt_commit (cluster.rs): log at ERROR level since it is fire-and-forget. https://claude.ai/code/session_011eyXTLxHcSEAeV6PRG3izJ
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The previous fix logged the error but still cleared the slot, so a chosen LWT value was permanently dropped on this replica whenever the WAL append failed (e.g. I/O error in sync mode). The coordinator could still report success because it achieved quorum, leaving this replica silently diverged with no retry path. Fix by only removing the composite key from the Paxos slot map when the WAL write succeeds. On failure the slot is kept in memory so that the next prepare round from any coordinator can re-commit the chosen value through the normal Paxos flow. https://claude.ai/code/session_011eyXTLxHcSEAeV6PRG3izJ
Both helpers previously swallowed write errors: after the fail-fast insert_internal change, a WAL failure would leave _tables/_schemas unpopulated while CREATE TABLE still returned success, producing a false-positive DDL acknowledgement and broken metadata state. Change register_table and save_schema to return std::io::Result<()> and propagate WAL failures to their callers. The CreateTable branch in exec_statement now maps those errors to QueryError::Other so the client receives an explicit failure instead of a silent lie. https://claude.ai/code/session_011eyXTLxHcSEAeV6PRG3izJ
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insert_internal() used
let _ = self.wal.append(...)which caused the key to be written to the memtable even when the WAL failed, making recovery after a crash impossible for those writes.Change insert_internal, insert_ts, insert, insert_ns_ts, and insert_ns to return std::io::Result<()> and return an Err immediately on WAL failure so the data is never inserted into the memtable.
Update callers:
https://claude.ai/code/session_011eyXTLxHcSEAeV6PRG3izJ