fix: prevent data loss on restart after unclean shutdown#7
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nicoloboschi merged 1 commit intomainfrom Mar 26, 2026
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After an unclean shutdown (SIGKILL, OOM, power loss), a stale postmaster.pid is left behind. On restart, the postgresql_embedded library's Drop impl would delete the entire data directory because `temporary` defaults to `true`. Two fixes: - Set `temporary: false` so the library never deletes the data dir - Proactively remove stale postmaster.pid before restarting Adds a regression test that SIGKILLs postgres and verifies data survives the restart. Closes #6
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Summary
Fixes #6 —
pg0 startwas deleting the entire data directory after an unclean shutdown (SIGKILL, OOM kill, power loss, VM reboot), causing silent data loss.Root cause: The
postgresql_embeddedlibrary defaultsSettings.temporarytotrue. When thePostgreSQLstruct is dropped (on any error path during start), itsDropimpl callsremove_dir_allon the data directory. On the happy path,std::mem::forget()prevents this, but ifpg_ctl startfails (e.g., due to a stalepostmaster.pid), the Drop fires and destroys all data.Fixes:
temporary: falseexplicitly so the library never deletes the data directory — pg0 manages data lifecycle via itsdropcommandpostmaster.pidwhen a dead instance is detected, so PostgreSQL can restart cleanly with existing dataTest plan
test_data_survives_crash: starts postgres, inserts data, SIGKILLs the process (leaving stale postmaster.pid), restarts, and verifies data is intactcargo checkpasses