#39

src/tidesdb.lua

@@ -93,6 +93,7 @@ ffi.cdef[[
         size_t max_open_sstables;
         int log_to_file;
         size_t log_truncation_at;
+        size_t max_memory_usage;
     } tidesdb_config_t;
 
     typedef struct {
@@ -361,6 +362,7 @@ function tidesdb.default_config()
         max_open_sstables = 256,
         log_to_file = false,
         log_truncation_at = 24 * 1024 * 1024,
+        max_memory_usage = 0,
     }
 end
 
@@ -848,6 +850,7 @@ function TidesDB.new(config)
     c_config.max_open_sstables = config.max_open_sstables or 256
     c_config.log_to_file = config.log_to_file and 1 or 0
     c_config.log_truncation_at = config.log_truncation_at or 24 * 1024 * 1024
+    c_config.max_memory_usage = config.max_memory_usage or 0
 
     local db_ptr = ffi.new("void*[1]")
     local result = lib.tidesdb_open(c_config, db_ptr)
@@ -868,6 +871,7 @@ function TidesDB.open(path, options)
         max_open_sstables = options.max_open_sstables or 256,
         log_to_file = options.log_to_file or false,
         log_truncation_at = options.log_truncation_at or 24 * 1024 * 1024,
+        max_memory_usage = options.max_memory_usage or 0,
     }
     return TidesDB.new(config)
 end

tests/test_tidesdb.lua

@@ -762,6 +762,43 @@ function tests.test_commit_hook()
     print("PASS: test_commit_hook")
 end
 
+function tests.test_max_memory_usage()
+    local path = "./test_db_max_mem"
+    cleanup_db(path)
+
+    -- Test default config includes max_memory_usage
+    local default_cfg = tidesdb.default_config()
+    assert_true(default_cfg.max_memory_usage ~= nil, "max_memory_usage should exist in default config")
+
+    -- Test opening database with default max_memory_usage (0 = unlimited)
+    local db1 = tidesdb.TidesDB.open(path)
+    assert_true(db1 ~= nil, "database should open with default max_memory_usage")
+    db1:close()
+    cleanup_db(path)
+
+    -- Test opening database with custom max_memory_usage
+    local db2 = tidesdb.TidesDB.open(path, {
+        max_memory_usage = 512 * 1024 * 1024  -- 512 MB
+    })
+    assert_true(db2 ~= nil, "database should open with custom max_memory_usage")
+    db2:close()
+    cleanup_db(path)
+
+    -- Test with TidesDB.new() constructor
+    local config = {
+        db_path = path,
+        num_flush_threads = 2,
+        num_compaction_threads = 2,
+        max_memory_usage = 256 * 1024 * 1024  -- 256 MB
+    }
+    local db3 = tidesdb.TidesDB.new(config)
+    assert_true(db3 ~= nil, "database should be created with TidesDB.new() and max_memory_usage")
+    db3:close()
+
+    cleanup_db(path)
+    print("PASS: test_max_memory_usage")
+end
+
 -- Run all tests
 local function run_tests()
     print("Running TidesDB Lua tests...")