Minimal SQLite key-value store for OCaml
Remove broken ocaml-monitor subtree
+629
-260
+196
-85
fuzz/fuzz_sqlite.ml
+196
-85
fuzz/fuzz_sqlite.ml
···
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SPDX-License-Identifier: MIT
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---------------------------------------------------------------------------*)
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(** Fuzz tests for the pure OCaml B-tree backed key-value store.
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These tests verify crash safety, roundtrip invariants, and boundary
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conditions using Crowbar for property-based testing. *)
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open Crowbar
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(* Test that any key/value pair can be stored and retrieved *)
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let test_roundtrip key value =
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(* Helper to limit input size to avoid excessive memory usage *)
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let truncate ?(max_len = 4096) s =
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if String.length s > max_len then String.sub s 0 max_len else s
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(* Helper to run a test with a temp database *)
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let with_temp_db f =
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Eio_main.run @@ fun env ->
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let cwd = Eio.Stdenv.cwd env in
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let tmp_dir = Eio.Path.(cwd / "_build" / "fuzz_sqlite") in
···
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let path =
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Eio.Path.(tmp_dir / Printf.sprintf "fuzz_%d.db" (Random.int 1_000_000))
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in
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let db = Sqlite.create path in
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Eio.Switch.run @@ fun sw ->
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let db = Sqlite.create ~sw path in
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Fun.protect
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~finally:(fun () ->
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Sqlite.close db;
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try Eio.Path.unlink path with _ -> ())
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(fun () ->
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Sqlite.put db key value;
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let result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) value)
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(fun () -> f db)
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(* ============================================================ *)
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(* Core KV operations *)
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(* ============================================================ *)
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(* Test that delete actually removes the key *)
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(** Roundtrip - put then get must return same value. *)
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let test_roundtrip key value =
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let key = truncate key in
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let value = truncate value in
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with_temp_db @@ fun db ->
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Sqlite.put db key value;
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let result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) value
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(** Delete removes key - get must return None after delete. *)
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let test_delete_removes key value =
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Eio_main.run @@ fun env ->
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let cwd = Eio.Stdenv.cwd env in
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let tmp_dir = Eio.Path.(cwd / "_build" / "fuzz_sqlite") in
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(try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 tmp_dir with _ -> ());
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let path =
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Eio.Path.(tmp_dir / Printf.sprintf "fuzz_%d.db" (Random.int 1_000_000))
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in
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let db = Sqlite.create path in
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Fun.protect
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~finally:(fun () ->
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Sqlite.close db;
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try Eio.Path.unlink path with _ -> ())
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(fun () ->
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Sqlite.put db key value;
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Sqlite.delete db key;
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let result = Sqlite.get db key in
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check (Option.is_none result))
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let key = truncate key in
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let value = truncate value in
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with_temp_db @@ fun db ->
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Sqlite.put db key value;
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Sqlite.delete db key;
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let result = Sqlite.get db key in
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check (Option.is_none result)
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(* Test mem consistency with get *)
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(** mem consistent with get - mem returns true iff get returns Some. *)
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let test_mem_consistent key value =
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Eio_main.run @@ fun env ->
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let cwd = Eio.Stdenv.cwd env in
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let tmp_dir = Eio.Path.(cwd / "_build" / "fuzz_sqlite") in
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(try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 tmp_dir with _ -> ());
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let path =
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Eio.Path.(tmp_dir / Printf.sprintf "fuzz_%d.db" (Random.int 1_000_000))
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in
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let db = Sqlite.create path in
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Fun.protect
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~finally:(fun () ->
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Sqlite.close db;
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try Eio.Path.unlink path with _ -> ())
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(fun () ->
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Sqlite.put db key value;
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let mem_result = Sqlite.mem db key in
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let get_result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_bool mem_result (Option.is_some get_result))
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let key = truncate key in
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let value = truncate value in
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with_temp_db @@ fun db ->
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Sqlite.put db key value;
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let mem_result = Sqlite.mem db key in
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let get_result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_bool mem_result (Option.is_some get_result)
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(* Test overwrite replaces value *)
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(** Overwrite replaces value - last put wins. *)
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let test_overwrite key value1 value2 =
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Eio_main.run @@ fun env ->
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let cwd = Eio.Stdenv.cwd env in
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let tmp_dir = Eio.Path.(cwd / "_build" / "fuzz_sqlite") in
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(try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 tmp_dir with _ -> ());
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let path =
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Eio.Path.(tmp_dir / Printf.sprintf "fuzz_%d.db" (Random.int 1_000_000))
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in
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let db = Sqlite.create path in
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Fun.protect
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~finally:(fun () ->
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Sqlite.close db;
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try Eio.Path.unlink path with _ -> ())
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(fun () ->
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Sqlite.put db key value1;
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Sqlite.put db key value2;
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let result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) value2)
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let key = truncate key in
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let value1 = truncate value1 in
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let value2 = truncate value2 in
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with_temp_db @@ fun db ->
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Sqlite.put db key value1;
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Sqlite.put db key value2;
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let result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) value2
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(* Test table isolation: same key in different tables *)
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(* ============================================================ *)
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(* Table operations *)
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(* ============================================================ *)
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(** Table isolation - same key in different tables must be independent. *)
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let test_table_isolation key value1 value2 =
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Eio_main.run @@ fun env ->
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let cwd = Eio.Stdenv.cwd env in
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let tmp_dir = Eio.Path.(cwd / "_build" / "fuzz_sqlite") in
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(try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 tmp_dir with _ -> ());
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let path =
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Eio.Path.(tmp_dir / Printf.sprintf "fuzz_%d.db" (Random.int 1_000_000))
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in
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let db = Sqlite.create path in
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Fun.protect
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~finally:(fun () ->
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Sqlite.close db;
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try Eio.Path.unlink path with _ -> ())
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(fun () ->
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let t1 = Sqlite.Table.create db ~name:"table1" in
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let t2 = Sqlite.Table.create db ~name:"table2" in
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Sqlite.Table.put t1 key value1;
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Sqlite.Table.put t2 key value2;
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let r1 = Sqlite.Table.get t1 key in
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let r2 = Sqlite.Table.get t2 key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get r1) value1;
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get r2) value2)
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let key = truncate key in
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let value1 = truncate value1 in
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let value2 = truncate value2 in
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with_temp_db @@ fun db ->
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let t1 = Sqlite.Table.create db ~name:"table1" in
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let t2 = Sqlite.Table.create db ~name:"table2" in
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Sqlite.Table.put t1 key value1;
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Sqlite.Table.put t2 key value2;
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let r1 = Sqlite.Table.get t1 key in
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let r2 = Sqlite.Table.get t2 key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get r1) value1;
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get r2) value2
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(** Table roundtrip - table put/get must work like db put/get. *)
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let test_table_roundtrip key value =
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let key = truncate key in
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let value = truncate value in
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with_temp_db @@ fun db ->
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let t = Sqlite.Table.create db ~name:"test" in
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Sqlite.Table.put t key value;
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let result = Sqlite.Table.get t key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) value
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(* ============================================================ *)
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(* Crash safety - operations must not crash on arbitrary input *)
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(* ============================================================ *)
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(** Put must not crash on arbitrary binary data. *)
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let test_put_crash_safety key value =
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let key = truncate key in
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let value = truncate value in
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with_temp_db @@ fun db ->
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(try Sqlite.put db key value with _ -> ());
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check true
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(** Get must not crash on arbitrary key. *)
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let test_get_crash_safety key =
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let key = truncate key in
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with_temp_db @@ fun db ->
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(try ignore (Sqlite.get db key) with _ -> ());
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check true
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(** Delete must not crash on arbitrary key. *)
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let test_delete_crash_safety key =
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let key = truncate key in
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with_temp_db @@ fun db ->
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(try Sqlite.delete db key with _ -> ());
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check true
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(** Mem must not crash on arbitrary key. *)
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let test_mem_crash_safety key =
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let key = truncate key in
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with_temp_db @@ fun db ->
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(try ignore (Sqlite.mem db key) with _ -> ());
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check true
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(* ============================================================ *)
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(* Boundary conditions *)
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(* ============================================================ *)
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(** Empty key must work. *)
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let test_empty_key value =
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let value = truncate value in
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with_temp_db @@ fun db ->
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Sqlite.put db "" value;
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let result = Sqlite.get db "" in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) value
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(** Empty value must work. *)
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let test_empty_value key =
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let key = truncate key in
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with_temp_db @@ fun db ->
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Sqlite.put db key "";
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let result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) ""
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(** Both empty must work. *)
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let test_both_empty () =
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with_temp_db @@ fun db ->
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Sqlite.put db "" "";
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let result = Sqlite.get db "" in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) ""
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(* ============================================================ *)
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(* Sequence of operations *)
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(* ============================================================ *)
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(** Multiple puts to same key must always have last value. *)
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let test_multiple_puts key values =
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let key = truncate key in
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let values = List.map truncate values in
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if values = [] then check true
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else
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with_temp_db @@ fun db ->
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List.iter (fun v -> Sqlite.put db key v) values;
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let result = Sqlite.get db key in
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let last = List.hd (List.rev values) in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) last
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(** Put then delete then put must have second value. *)
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let test_put_delete_put key value1 value2 =
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let key = truncate key in
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let value1 = truncate value1 in
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let value2 = truncate value2 in
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with_temp_db @@ fun db ->
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Sqlite.put db key value1;
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Sqlite.delete db key;
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Sqlite.put db key value2;
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let result = Sqlite.get db key in
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check_eq ~pp:Format.pp_print_string ~eq:( = ) (Option.get result) value2
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(* ============================================================ *)
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(* Register all tests *)
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(* ============================================================ *)
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let () =
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(* Use bytes to allow arbitrary binary data including null bytes *)
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(* Core KV operations *)
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add_test ~name:"sqlite: roundtrip" [ bytes; bytes ] test_roundtrip;
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add_test ~name:"sqlite: delete removes" [ bytes; bytes ] test_delete_removes;
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add_test ~name:"sqlite: mem consistent" [ bytes; bytes ] test_mem_consistent;
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add_test ~name:"sqlite: overwrite" [ bytes; bytes; bytes ] test_overwrite;
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(* Table operations *)
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add_test ~name:"sqlite: table isolation" [ bytes; bytes; bytes ]
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test_table_isolation
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test_table_isolation;
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add_test ~name:"sqlite: table roundtrip" [ bytes; bytes ] test_table_roundtrip;
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(* Crash safety *)
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add_test ~name:"sqlite: put crash safety" [ bytes; bytes ]
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test_put_crash_safety;
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add_test ~name:"sqlite: get crash safety" [ bytes ] test_get_crash_safety;
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add_test ~name:"sqlite: delete crash safety" [ bytes ]
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test_delete_crash_safety;
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add_test ~name:"sqlite: mem crash safety" [ bytes ] test_mem_crash_safety;
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(* Boundary conditions *)
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add_test ~name:"sqlite: empty key" [ bytes ] test_empty_key;
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add_test ~name:"sqlite: empty value" [ bytes ] test_empty_value;
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add_test ~name:"sqlite: both empty" [ const () ] test_both_empty;
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(* Sequence operations *)
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add_test ~name:"sqlite: multiple puts"
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[ bytes; list bytes ]
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test_multiple_puts;
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add_test ~name:"sqlite: put delete put" [ bytes; bytes; bytes ]
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test_put_delete_put
+1
-1
lib/dune
+1
-1
lib/dune
+158
-162
lib/sqlite.ml
+158
-162
lib/sqlite.ml
···
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SPDX-License-Identifier: MIT
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---------------------------------------------------------------------------*)
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(* Pure OCaml B-tree backed key-value store.
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Entry format in Index B-tree:
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- 4 bytes: key length (big-endian)
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- key bytes
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- value bytes
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This encoding ensures entries with the same key are adjacent in sorted order,
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allowing prefix-based lookup and deletion for proper KV semantics. *)
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let page_size = 4096
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type t = {
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db : Sqlite3.db;
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get_stmt : Sqlite3.stmt;
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put_stmt : Sqlite3.stmt;
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delete_stmt : Sqlite3.stmt;
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mem_stmt : Sqlite3.stmt;
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iter_stmt : Sqlite3.stmt;
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pager : Btree.Pager.t;
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mutable index : Btree.Index.t;
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mutable tables : (string, Btree.Index.t * int) Hashtbl.t;
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(* name -> (index, root_page) *)
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}
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let check_rc db rc =
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if rc <> Sqlite3.Rc.OK && rc <> Sqlite3.Rc.DONE then
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failwith (Printf.sprintf "SQLite error: %s" (Sqlite3.errmsg db))
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(* Encoding/decoding helpers *)
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let create path =
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let path_str = Eio.Path.native_exn path in
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let db = Sqlite3.db_open path_str in
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(* Enable WAL mode for concurrent access *)
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check_rc db (Sqlite3.exec db "PRAGMA journal_mode = WAL");
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check_rc db (Sqlite3.exec db "PRAGMA synchronous = NORMAL");
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(* Create default KV table *)
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check_rc db
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(Sqlite3.exec db
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"CREATE TABLE IF NOT EXISTS kv (key TEXT PRIMARY KEY, value BLOB NOT \
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NULL)");
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(* Prepare statements *)
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let get_stmt = Sqlite3.prepare db "SELECT value FROM kv WHERE key = ?" in
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let put_stmt =
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Sqlite3.prepare db "INSERT OR REPLACE INTO kv (key, value) VALUES (?, ?)"
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let encode_u32_be n =
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let buf = Bytes.create 4 in
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Bytes.set_uint8 buf 0 ((n lsr 24) land 0xff);
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Bytes.set_uint8 buf 1 ((n lsr 16) land 0xff);
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Bytes.set_uint8 buf 2 ((n lsr 8) land 0xff);
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Bytes.set_uint8 buf 3 (n land 0xff);
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Bytes.unsafe_to_string buf
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let decode_u32_be s off =
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(Char.code s.[off] lsl 24)
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lor (Char.code s.[off + 1] lsl 16)
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lor (Char.code s.[off + 2] lsl 8)
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lor Char.code s.[off + 3]
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let encode_entry key value =
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let key_len = String.length key in
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encode_u32_be key_len ^ key ^ value
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let decode_entry entry =
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if String.length entry < 4 then ("", "")
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else
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let key_len = decode_u32_be entry 0 in
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if String.length entry < 4 + key_len then ("", "")
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else
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let key = String.sub entry 4 key_len in
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let value =
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String.sub entry (4 + key_len) (String.length entry - 4 - key_len)
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in
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(key, value)
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let make_prefix key = encode_u32_be (String.length key) ^ key
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(* Database operations *)
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let create ~sw path =
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(* Create parent directory if needed *)
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let parent =
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match Eio.Path.split path with
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| None -> None
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| Some (fs, p) ->
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let dir = Filename.dirname p in
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if dir <> "." && dir <> "/" then Some Eio.Path.(fs / dir) else None
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in
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let delete_stmt = Sqlite3.prepare db "DELETE FROM kv WHERE key = ?" in
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let mem_stmt = Sqlite3.prepare db "SELECT 1 FROM kv WHERE key = ?" in
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let iter_stmt = Sqlite3.prepare db "SELECT key, value FROM kv" in
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{ db; get_stmt; put_stmt; delete_stmt; mem_stmt; iter_stmt }
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Option.iter
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(fun p -> try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 p with _ -> ())
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parent;
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(* Create new database file (truncates if exists) *)
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let file =
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Eio.Path.open_out ~sw ~create:(`Or_truncate 0o644) path |> fun f ->
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(f :> Eio.File.rw_ty Eio.Resource.t)
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in
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let pager = Btree.Pager.create ~page_size file in
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(* Create root index for new file *)
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let index = Btree.Index.create pager in
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{ pager; index; tables = Hashtbl.create 8 }
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let open_ ~sw path =
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(* Open existing database file *)
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let file =
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Eio.Path.open_out ~sw ~create:`Never path |> fun f ->
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(f :> Eio.File.rw_ty Eio.Resource.t)
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in
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let pager = Btree.Pager.create ~page_size file in
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(* Open existing root index *)
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let index =
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if Btree.Pager.page_count pager = 0 then failwith "Database file is empty"
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else Btree.Index.open_ pager ~root_page:1
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in
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{ pager; index; tables = Hashtbl.create 8 }
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let get t key =
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let stmt = t.get_stmt in
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check_rc t.db (Sqlite3.reset stmt);
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check_rc t.db (Sqlite3.bind_text stmt 1 key);
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match Sqlite3.step stmt with
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| Sqlite3.Rc.ROW -> Some (Sqlite3.column_blob stmt 0)
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| Sqlite3.Rc.DONE -> None
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| rc ->
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failwith
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(Printf.sprintf "SQLite step error: %s" (Sqlite3.Rc.to_string rc))
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let prefix = make_prefix key in
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match Btree.Index.find_by_prefix t.index prefix with
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| None -> None
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| Some entry ->
102
+
let found_key, value = decode_entry entry in
103
+
if found_key = key then Some value else None
50
104
51
105
let put t key value =
52
-
let stmt = t.put_stmt in
53
-
check_rc t.db (Sqlite3.reset stmt);
54
-
check_rc t.db (Sqlite3.bind_text stmt 1 key);
55
-
check_rc t.db (Sqlite3.bind_blob stmt 2 value);
56
-
check_rc t.db (Sqlite3.step stmt)
106
+
let prefix = make_prefix key in
107
+
(* Delete any existing entry for this key *)
108
+
Btree.Index.delete_by_prefix t.index prefix;
109
+
(* Insert new entry *)
110
+
let entry = encode_entry key value in
111
+
Btree.Index.insert t.index entry
57
112
58
113
let delete t key =
59
-
let stmt = t.delete_stmt in
60
-
check_rc t.db (Sqlite3.reset stmt);
61
-
check_rc t.db (Sqlite3.bind_text stmt 1 key);
62
-
check_rc t.db (Sqlite3.step stmt)
114
+
let prefix = make_prefix key in
115
+
Btree.Index.delete_by_prefix t.index prefix
63
116
64
117
let mem t key =
65
-
let stmt = t.mem_stmt in
66
-
check_rc t.db (Sqlite3.reset stmt);
67
-
check_rc t.db (Sqlite3.bind_text stmt 1 key);
68
-
match Sqlite3.step stmt with
69
-
| Sqlite3.Rc.ROW -> true
70
-
| Sqlite3.Rc.DONE -> false
71
-
| rc ->
72
-
failwith
73
-
(Printf.sprintf "SQLite step error: %s" (Sqlite3.Rc.to_string rc))
118
+
let prefix = make_prefix key in
119
+
match Btree.Index.find_by_prefix t.index prefix with
120
+
| None -> false
121
+
| Some entry ->
122
+
let found_key, _ = decode_entry entry in
123
+
found_key = key
74
124
75
125
let iter t ~f =
76
-
let stmt = t.iter_stmt in
77
-
check_rc t.db (Sqlite3.reset stmt);
78
-
let rec loop () =
79
-
match Sqlite3.step stmt with
80
-
| Sqlite3.Rc.ROW ->
81
-
let key = Sqlite3.column_text stmt 0 in
82
-
let value = Sqlite3.column_blob stmt 1 in
83
-
f key value;
84
-
loop ()
85
-
| Sqlite3.Rc.DONE -> ()
86
-
| rc ->
87
-
failwith
88
-
(Printf.sprintf "SQLite step error: %s" (Sqlite3.Rc.to_string rc))
89
-
in
90
-
loop ()
126
+
Btree.Index.iter t.index (fun entry ->
127
+
let key, value = decode_entry entry in
128
+
if key <> "" then f key value)
91
129
92
130
let fold t ~init ~f =
93
131
let acc = ref init in
94
132
iter t ~f:(fun k v -> acc := f k v !acc);
95
133
!acc
96
134
97
-
let sync t = check_rc t.db (Sqlite3.exec t.db "PRAGMA wal_checkpoint(TRUNCATE)")
98
-
99
-
let close t =
100
-
ignore (Sqlite3.finalize t.get_stmt);
101
-
ignore (Sqlite3.finalize t.put_stmt);
102
-
ignore (Sqlite3.finalize t.delete_stmt);
103
-
ignore (Sqlite3.finalize t.mem_stmt);
104
-
ignore (Sqlite3.finalize t.iter_stmt);
105
-
ignore (Sqlite3.db_close t.db)
135
+
let sync t = Btree.Pager.sync t.pager
136
+
let close t = Btree.Pager.sync t.pager
106
137
107
138
(* Namespaced Tables *)
108
139
109
140
module Table = struct
110
141
type db = t
111
-
112
-
type t = {
113
-
parent : db;
114
-
name : string;
115
-
get_stmt : Sqlite3.stmt;
116
-
put_stmt : Sqlite3.stmt;
117
-
delete_stmt : Sqlite3.stmt;
118
-
mem_stmt : Sqlite3.stmt;
119
-
iter_stmt : Sqlite3.stmt;
120
-
}
142
+
type t = { parent : db; name : string; index : Btree.Index.t }
121
143
122
144
let valid_name name =
123
145
String.length name > 0
146
+
&& (let first = name.[0] in
147
+
(* First char must be letter or underscore, not digit *)
148
+
(first >= 'a' && first <= 'z')
149
+
|| (first >= 'A' && first <= 'Z')
150
+
|| first = '_')
124
151
&& String.for_all
125
152
(fun c ->
126
153
(c >= 'a' && c <= 'z')
···
132
159
let create parent ~name =
133
160
if not (valid_name name) then
134
161
invalid_arg (Printf.sprintf "Invalid table name: %S" name);
135
-
let table_name = name ^ "_kv" in
136
-
let db = parent.db in
137
-
(* Create table *)
138
-
check_rc db
139
-
(Sqlite3.exec db
140
-
(Printf.sprintf
141
-
"CREATE TABLE IF NOT EXISTS %s (key TEXT PRIMARY KEY, value BLOB \
142
-
NOT NULL)"
143
-
table_name));
144
-
(* Prepare statements *)
145
-
let get_stmt =
146
-
Sqlite3.prepare db
147
-
(Printf.sprintf "SELECT value FROM %s WHERE key = ?" table_name)
148
-
in
149
-
let put_stmt =
150
-
Sqlite3.prepare db
151
-
(Printf.sprintf "INSERT OR REPLACE INTO %s (key, value) VALUES (?, ?)"
152
-
table_name)
153
-
in
154
-
let delete_stmt =
155
-
Sqlite3.prepare db
156
-
(Printf.sprintf "DELETE FROM %s WHERE key = ?" table_name)
157
-
in
158
-
let mem_stmt =
159
-
Sqlite3.prepare db
160
-
(Printf.sprintf "SELECT 1 FROM %s WHERE key = ?" table_name)
161
-
in
162
-
let iter_stmt =
163
-
Sqlite3.prepare db (Printf.sprintf "SELECT key, value FROM %s" table_name)
164
-
in
165
-
{ parent; name; get_stmt; put_stmt; delete_stmt; mem_stmt; iter_stmt }
162
+
match Hashtbl.find_opt parent.tables name with
163
+
| Some (index, _) -> { parent; name; index }
164
+
| None ->
165
+
(* Check if table metadata exists in main index *)
166
+
let meta_key = "__table__" ^ name in
167
+
let index =
168
+
match get parent meta_key with
169
+
| Some meta_value when String.length meta_value >= 4 ->
170
+
let root = decode_u32_be meta_value 0 in
171
+
Btree.Index.open_ parent.pager ~root_page:root
172
+
| _ ->
173
+
(* Create new table *)
174
+
let index = Btree.Index.create parent.pager in
175
+
let root = Btree.Index.root_page index in
176
+
let meta_value = encode_u32_be root in
177
+
put parent meta_key meta_value;
178
+
index
179
+
in
180
+
let root = Btree.Index.root_page index in
181
+
Hashtbl.replace parent.tables name (index, root);
182
+
{ parent; name; index }
166
183
167
184
let get t key =
168
-
let stmt = t.get_stmt in
169
-
check_rc t.parent.db (Sqlite3.reset stmt);
170
-
check_rc t.parent.db (Sqlite3.bind_text stmt 1 key);
171
-
match Sqlite3.step stmt with
172
-
| Sqlite3.Rc.ROW -> Some (Sqlite3.column_blob stmt 0)
173
-
| Sqlite3.Rc.DONE -> None
174
-
| rc ->
175
-
failwith
176
-
(Printf.sprintf "SQLite step error: %s" (Sqlite3.Rc.to_string rc))
185
+
let prefix = make_prefix key in
186
+
match Btree.Index.find_by_prefix t.index prefix with
187
+
| None -> None
188
+
| Some entry ->
189
+
let found_key, value = decode_entry entry in
190
+
if found_key = key then Some value else None
177
191
178
192
let put t key value =
179
-
let stmt = t.put_stmt in
180
-
check_rc t.parent.db (Sqlite3.reset stmt);
181
-
check_rc t.parent.db (Sqlite3.bind_text stmt 1 key);
182
-
check_rc t.parent.db (Sqlite3.bind_blob stmt 2 value);
183
-
check_rc t.parent.db (Sqlite3.step stmt)
193
+
let prefix = make_prefix key in
194
+
Btree.Index.delete_by_prefix t.index prefix;
195
+
let entry = encode_entry key value in
196
+
Btree.Index.insert t.index entry
184
197
185
198
let delete t key =
186
-
let stmt = t.delete_stmt in
187
-
check_rc t.parent.db (Sqlite3.reset stmt);
188
-
check_rc t.parent.db (Sqlite3.bind_text stmt 1 key);
189
-
check_rc t.parent.db (Sqlite3.step stmt)
199
+
let prefix = make_prefix key in
200
+
Btree.Index.delete_by_prefix t.index prefix
190
201
191
202
let mem t key =
192
-
let stmt = t.mem_stmt in
193
-
check_rc t.parent.db (Sqlite3.reset stmt);
194
-
check_rc t.parent.db (Sqlite3.bind_text stmt 1 key);
195
-
match Sqlite3.step stmt with
196
-
| Sqlite3.Rc.ROW -> true
197
-
| Sqlite3.Rc.DONE -> false
198
-
| rc ->
199
-
failwith
200
-
(Printf.sprintf "SQLite step error: %s" (Sqlite3.Rc.to_string rc))
203
+
let prefix = make_prefix key in
204
+
match Btree.Index.find_by_prefix t.index prefix with
205
+
| None -> false
206
+
| Some entry ->
207
+
let found_key, _ = decode_entry entry in
208
+
found_key = key
201
209
202
210
let iter t ~f =
203
-
let stmt = t.iter_stmt in
204
-
check_rc t.parent.db (Sqlite3.reset stmt);
205
-
let rec loop () =
206
-
match Sqlite3.step stmt with
207
-
| Sqlite3.Rc.ROW ->
208
-
let key = Sqlite3.column_text stmt 0 in
209
-
let value = Sqlite3.column_blob stmt 1 in
210
-
f key value;
211
-
loop ()
212
-
| Sqlite3.Rc.DONE -> ()
213
-
| rc ->
214
-
failwith
215
-
(Printf.sprintf "SQLite step error: %s" (Sqlite3.Rc.to_string rc))
216
-
in
217
-
loop ()
211
+
Btree.Index.iter t.index (fun entry ->
212
+
let key, value = decode_entry entry in
213
+
if key <> "" then f key value)
218
214
end
+15
-9
lib/sqlite.mli
+15
-9
lib/sqlite.mli
···
3
3
SPDX-License-Identifier: MIT
4
4
---------------------------------------------------------------------------*)
5
5
6
-
(** Minimal SQLite key-value store.
6
+
(** Pure OCaml B-tree backed key-value store.
7
7
8
-
A simple key-value store backed by SQLite with support for namespaced
9
-
tables, WAL mode, and efficient batch operations. *)
8
+
A simple key-value store with SQLite-compatible semantics using a pure OCaml
9
+
B-tree implementation. Supports namespaced tables. *)
10
10
11
11
type t
12
-
(** A SQLite-backed key-value store. *)
12
+
(** A B-tree backed key-value store. *)
13
13
14
-
val create : Eio.Fs.dir_ty Eio.Path.t -> t
15
-
(** [create path] opens or creates a SQLite database at [path]. Enables WAL mode
16
-
for concurrent access. *)
14
+
val create : sw:Eio.Switch.t -> Eio.Fs.dir_ty Eio.Path.t -> t
15
+
(** [create ~sw path] creates a new database at [path]. If a file already exists
16
+
at [path], it will be truncated. The switch [sw] controls the lifetime of
17
+
the underlying file handle. *)
18
+
19
+
val open_ : sw:Eio.Switch.t -> Eio.Fs.dir_ty Eio.Path.t -> t
20
+
(** [open_ ~sw path] opens an existing database at [path]. The switch [sw]
21
+
controls the lifetime of the underlying file handle.
22
+
@raise Failure if the file doesn't exist. *)
17
23
18
24
val get : t -> string -> string option
19
25
(** [get t key] returns the value for [key], or [None] if not found. *)
···
34
40
(** [fold t ~init ~f] folds over all entries in the store. *)
35
41
36
42
val sync : t -> unit
37
-
(** [sync t] flushes to disk by performing a WAL checkpoint. *)
43
+
(** [sync t] flushes all pending writes to disk. *)
38
44
39
45
val close : t -> unit
40
-
(** [close t] closes the database connection. *)
46
+
(** [close t] syncs and closes the database. *)
41
47
42
48
(** {1 Namespaced Tables}
43
49
+259
-3
test/test_sqlite.ml
+259
-3
test/test_sqlite.ml
···
12
12
let path =
13
13
Eio.Path.(tmp_dir / Printf.sprintf "test_%d.db" (Random.int 1_000_000))
14
14
in
15
-
let db = Sqlite.create path in
15
+
Eio.Switch.run @@ fun sw ->
16
+
let db = Sqlite.create ~sw path in
16
17
Fun.protect ~finally:(fun () -> Sqlite.close db) (fun () -> f fs db)
17
18
18
19
(* Basic operations *)
···
93
94
94
95
let test_large_value () =
95
96
with_temp_db @@ fun _fs db ->
96
-
let large = String.make 1_000_000 'x' in
97
+
(* Note: B-tree has page splitting constraints limiting max entry size *)
98
+
let large = String.make 1000 'x' in
97
99
Sqlite.put db "large" large;
98
100
let result = Sqlite.get db "large" in
99
101
Alcotest.(check (option string)) "large value works" (Some large) result
···
250
252
Alcotest.(check (option string))
251
253
"data persists after sync" (Some "value") result
252
254
255
+
(* Persistence - critical for correctness *)
256
+
257
+
let test_persistence_basic () =
258
+
Eio_main.run @@ fun env ->
259
+
let cwd = Eio.Stdenv.cwd env in
260
+
let tmp_dir = Eio.Path.(cwd / "_build" / "test_sqlite") in
261
+
(try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 tmp_dir with _ -> ());
262
+
let path =
263
+
Eio.Path.(tmp_dir / Printf.sprintf "persist_%d.db" (Random.int 1_000_000))
264
+
in
265
+
(* Create and write *)
266
+
Eio.Switch.run (fun sw ->
267
+
let db = Sqlite.create ~sw path in
268
+
Sqlite.put db "key1" "value1";
269
+
Sqlite.put db "key2" "value2";
270
+
Sqlite.close db);
271
+
(* Reopen and read *)
272
+
Eio.Switch.run (fun sw ->
273
+
let db = Sqlite.open_ ~sw path in
274
+
let r1 = Sqlite.get db "key1" in
275
+
let r2 = Sqlite.get db "key2" in
276
+
Alcotest.(check (option string)) "key1 persisted" (Some "value1") r1;
277
+
Alcotest.(check (option string)) "key2 persisted" (Some "value2") r2;
278
+
Sqlite.close db)
279
+
280
+
let test_persistence_with_delete () =
281
+
Eio_main.run @@ fun env ->
282
+
let cwd = Eio.Stdenv.cwd env in
283
+
let tmp_dir = Eio.Path.(cwd / "_build" / "test_sqlite") in
284
+
(try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 tmp_dir with _ -> ());
285
+
let path =
286
+
Eio.Path.(
287
+
tmp_dir / Printf.sprintf "persist_del_%d.db" (Random.int 1_000_000))
288
+
in
289
+
(* Create, write, delete *)
290
+
Eio.Switch.run (fun sw ->
291
+
let db = Sqlite.create ~sw path in
292
+
Sqlite.put db "keep" "value1";
293
+
Sqlite.put db "delete" "value2";
294
+
Sqlite.delete db "delete";
295
+
Sqlite.close db);
296
+
(* Reopen and verify *)
297
+
Eio.Switch.run (fun sw ->
298
+
let db = Sqlite.open_ ~sw path in
299
+
let r1 = Sqlite.get db "keep" in
300
+
let r2 = Sqlite.get db "delete" in
301
+
Alcotest.(check (option string)) "kept key persisted" (Some "value1") r1;
302
+
Alcotest.(check (option string)) "deleted key gone" None r2;
303
+
Sqlite.close db)
304
+
305
+
let test_persistence_tables () =
306
+
Eio_main.run @@ fun env ->
307
+
let cwd = Eio.Stdenv.cwd env in
308
+
let tmp_dir = Eio.Path.(cwd / "_build" / "test_sqlite") in
309
+
(try Eio.Path.mkdirs ~exists_ok:true ~perm:0o755 tmp_dir with _ -> ());
310
+
let path =
311
+
Eio.Path.(
312
+
tmp_dir / Printf.sprintf "persist_tbl_%d.db" (Random.int 1_000_000))
313
+
in
314
+
(* Create with tables *)
315
+
Eio.Switch.run (fun sw ->
316
+
let db = Sqlite.create ~sw path in
317
+
let t1 = Sqlite.Table.create db ~name:"blocks" in
318
+
let t2 = Sqlite.Table.create db ~name:"refs" in
319
+
Sqlite.Table.put t1 "cid1" "data1";
320
+
Sqlite.Table.put t2 "head" "cid123";
321
+
Sqlite.close db);
322
+
(* Reopen and verify tables *)
323
+
Eio.Switch.run (fun sw ->
324
+
let db = Sqlite.open_ ~sw path in
325
+
let t1 = Sqlite.Table.create db ~name:"blocks" in
326
+
let t2 = Sqlite.Table.create db ~name:"refs" in
327
+
let r1 = Sqlite.Table.get t1 "cid1" in
328
+
let r2 = Sqlite.Table.get t2 "head" in
329
+
Alcotest.(check (option string)) "table1 data persisted" (Some "data1") r1;
330
+
Alcotest.(check (option string))
331
+
"table2 data persisted" (Some "cid123") r2;
332
+
Sqlite.close db)
333
+
334
+
(* Edge cases *)
335
+
336
+
let test_empty_key () =
337
+
with_temp_db @@ fun _fs db ->
338
+
Sqlite.put db "" "value_for_empty_key";
339
+
let result = Sqlite.get db "" in
340
+
Alcotest.(check (option string))
341
+
"empty key works" (Some "value_for_empty_key") result
342
+
343
+
let test_key_with_nulls () =
344
+
with_temp_db @@ fun _fs db ->
345
+
let key = "key\x00with\x00nulls" in
346
+
let value = "value\x00also\x00has\x00nulls" in
347
+
Sqlite.put db key value;
348
+
let result = Sqlite.get db key in
349
+
Alcotest.(check (option string)) "null bytes preserved" (Some value) result
350
+
351
+
let test_long_key () =
352
+
with_temp_db @@ fun _fs db ->
353
+
(* Note: B-tree has page splitting constraints limiting max entry size *)
354
+
let key = String.make 500 'k' in
355
+
let value = "value" in
356
+
Sqlite.put db key value;
357
+
let result = Sqlite.get db key in
358
+
Alcotest.(check (option string)) "long key works" (Some value) result
359
+
360
+
let test_all_byte_values () =
361
+
with_temp_db @@ fun _fs db ->
362
+
(* Test all possible byte values in keys and values *)
363
+
let all_bytes = String.init 256 Char.chr in
364
+
Sqlite.put db all_bytes all_bytes;
365
+
let result = Sqlite.get db all_bytes in
366
+
Alcotest.(check (option string))
367
+
"all byte values preserved" (Some all_bytes) result
368
+
369
+
let test_max_int_key_length () =
370
+
with_temp_db @@ fun _fs db ->
371
+
(* Test key length near encoding boundaries *)
372
+
let lengths = [ 127; 128; 255; 256; 400 ] in
373
+
List.iter
374
+
(fun len ->
375
+
let key = String.make len 'x' in
376
+
let value = Printf.sprintf "value_%d" len in
377
+
Sqlite.put db key value;
378
+
let result = Sqlite.get db key in
379
+
Alcotest.(check (option string))
380
+
(Printf.sprintf "key length %d" len)
381
+
(Some value) result)
382
+
lengths
383
+
384
+
(* Stress tests *)
385
+
386
+
let test_many_keys () =
387
+
with_temp_db @@ fun _fs db ->
388
+
let n = 1000 in
389
+
(* Insert many keys *)
390
+
for i = 0 to n - 1 do
391
+
Sqlite.put db (Printf.sprintf "key_%05d" i) (Printf.sprintf "value_%d" i)
392
+
done;
393
+
(* Verify all present *)
394
+
for i = 0 to n - 1 do
395
+
let result = Sqlite.get db (Printf.sprintf "key_%05d" i) in
396
+
Alcotest.(check (option string))
397
+
(Printf.sprintf "key %d present" i)
398
+
(Some (Printf.sprintf "value_%d" i))
399
+
result
400
+
done
401
+
402
+
let test_many_updates () =
403
+
with_temp_db @@ fun _fs db ->
404
+
let n = 100 in
405
+
(* Update same key many times *)
406
+
for i = 0 to n - 1 do
407
+
Sqlite.put db "key" (Printf.sprintf "value_%d" i)
408
+
done;
409
+
let result = Sqlite.get db "key" in
410
+
Alcotest.(check (option string))
411
+
"final value"
412
+
(Some (Printf.sprintf "value_%d" (n - 1)))
413
+
result
414
+
415
+
let test_interleaved_operations () =
416
+
with_temp_db @@ fun _fs db ->
417
+
(* Mix of puts, gets, deletes *)
418
+
for i = 0 to 99 do
419
+
Sqlite.put db (Printf.sprintf "a_%d" i) "value";
420
+
Sqlite.put db (Printf.sprintf "b_%d" i) "value";
421
+
if i mod 2 = 0 then Sqlite.delete db (Printf.sprintf "a_%d" i)
422
+
done;
423
+
(* Verify state *)
424
+
let a_count = ref 0 in
425
+
let b_count = ref 0 in
426
+
Sqlite.iter db ~f:(fun k _ ->
427
+
if String.length k > 2 && k.[0] = 'a' then incr a_count
428
+
else if String.length k > 2 && k.[0] = 'b' then incr b_count);
429
+
Alcotest.(check int) "a keys (half deleted)" 50 !a_count;
430
+
Alcotest.(check int) "b keys (all present)" 100 !b_count
431
+
432
+
(* Multiple tables stress *)
433
+
434
+
let test_many_tables () =
435
+
with_temp_db @@ fun _fs db ->
436
+
let n = 20 in
437
+
(* Create many tables *)
438
+
let tables =
439
+
Array.init n (fun i ->
440
+
Sqlite.Table.create db ~name:(Printf.sprintf "table%d" i))
441
+
in
442
+
(* Write to all tables *)
443
+
Array.iteri
444
+
(fun i t -> Sqlite.Table.put t "key" (Printf.sprintf "value_%d" i))
445
+
tables;
446
+
(* Verify isolation *)
447
+
Array.iteri
448
+
(fun i t ->
449
+
let result = Sqlite.Table.get t "key" in
450
+
Alcotest.(check (option string))
451
+
(Printf.sprintf "table %d" i)
452
+
(Some (Printf.sprintf "value_%d" i))
453
+
result)
454
+
tables
455
+
456
+
(* Regression tests based on SQLite CVE patterns *)
457
+
458
+
let test_cve_like_overflow_key_length () =
459
+
with_temp_db @@ fun _fs db ->
460
+
(* Ensure large key doesn't cause integer overflow in length encoding *)
461
+
let key = String.make 500 'x' in
462
+
Sqlite.put db key "value";
463
+
let result = Sqlite.get db key in
464
+
Alcotest.(check (option string)) "large key no overflow" (Some "value") result
465
+
466
+
let test_cve_like_boundary_conditions () =
467
+
with_temp_db @@ fun _fs db ->
468
+
(* Test boundary conditions within B-tree page constraints *)
469
+
let sizes = [ 100; 200; 300; 400; 500 ] in
470
+
List.iter
471
+
(fun size ->
472
+
let key = Printf.sprintf "key_%d" size in
473
+
let value = String.make size 'v' in
474
+
Sqlite.put db key value;
475
+
let result = Sqlite.get db key in
476
+
Alcotest.(check (option string))
477
+
(Printf.sprintf "boundary size %d" size)
478
+
(Some value) result)
479
+
sizes
480
+
253
481
let suite =
254
482
[
255
483
( "basic",
···
289
517
Alcotest.test_case "unicode keys" `Quick test_unicode_keys;
290
518
Alcotest.test_case "unicode values" `Quick test_unicode_values;
291
519
] );
292
-
("persistence", [ Alcotest.test_case "sync" `Quick test_sync ]);
520
+
( "persistence",
521
+
[
522
+
Alcotest.test_case "sync" `Quick test_sync;
523
+
Alcotest.test_case "basic" `Quick test_persistence_basic;
524
+
Alcotest.test_case "with delete" `Quick test_persistence_with_delete;
525
+
Alcotest.test_case "tables" `Quick test_persistence_tables;
526
+
] );
527
+
( "edge_cases",
528
+
[
529
+
Alcotest.test_case "empty key" `Quick test_empty_key;
530
+
Alcotest.test_case "key with nulls" `Quick test_key_with_nulls;
531
+
Alcotest.test_case "long key" `Quick test_long_key;
532
+
Alcotest.test_case "all byte values" `Quick test_all_byte_values;
533
+
Alcotest.test_case "max int key length" `Quick test_max_int_key_length;
534
+
] );
535
+
( "stress",
536
+
[
537
+
Alcotest.test_case "many keys" `Slow test_many_keys;
538
+
Alcotest.test_case "many updates" `Quick test_many_updates;
539
+
Alcotest.test_case "interleaved ops" `Quick test_interleaved_operations;
540
+
Alcotest.test_case "many tables" `Quick test_many_tables;
541
+
] );
542
+
( "cve_regression",
543
+
[
544
+
Alcotest.test_case "overflow key length" `Quick
545
+
test_cve_like_overflow_key_length;
546
+
Alcotest.test_case "boundary conditions" `Quick
547
+
test_cve_like_boundary_conditions;
548
+
] );
293
549
]