检查点按 LSN 部分截断

chusql-core/storage/tests/runtime_test.rs

@@ -1394,6 +1394,43 @@ fn already_applied_create_table_is_skipped_on_restart() -> Result<(), Box<dyn st
     Ok(())
 }
 
+/// 检查点跟着每组提交走，LSN 跨重启不回头
+#[test]
+fn checkpoint_advances_and_lsn_survives_restart() -> Result<(), Box<dyn std::error::Error>> {
+    let checkpoint = |data: &tempfile::TempDir| -> Result<u64, Box<dyn std::error::Error>> {
+        let bytes = std::fs::read(data.path().join("databases/main/wal.checkpoint"))?;
+        Ok(u64::from_le_bytes(bytes[..8].try_into()?))
+    };
+
+    let (server, data) = start_server();
+    let mut c = connect()?;
+    request_ok(&mut c, serde_json::json!({"method":"create_table","table":"m6_seq","columns":[{"name":"id","ty":"int"}]}))?;
+    request_ok(&mut c, serde_json::json!({"method":"insert","table":"m6_seq","row":{"id":1}}))?;
+    drop(c);
+    let first = checkpoint(&data)?;
+    assert!(first > 0, "提交后检查点要前进: {first}");
+    drop(server);
+
+    // 重启后接着写，新的 LSN 必须落在检查点之后
+    let _server = start_server_in(data.path());
+    let mut c = connect()?;
+    request_ok(&mut c, serde_json::json!({"method":"insert","table":"m6_seq","row":{"id":2}}))?;
+    drop(c);
+    let second = checkpoint(&data)?;
+    assert!(second > first, "重启后 LSN 要接着检查点走: {second} vs {first}");
+
+    // 数据都在，日志本身是空的：每组提交后就按边界截掉了
+    let mut c = connect()?;
+    let rows: serde_json::Value =
+        serde_json::from_str(&send(&mut c, r#"{"method":"scan","table":"m6_seq"}"#))?;
+    assert_eq!(rows["rows"].as_array().map(Vec::len), Some(2), "{rows}");
+    assert_eq!(
+        std::fs::metadata(data.path().join("databases/main/wal.log"))?.len(),
+        0
+    );
+    Ok(())
+}
+
 /// 给第二列建索引后能按那一列查
 #[test]
 fn create_index_on_secondary_column() {

chusql-core/storage/tests/wal_test.rs

@@ -1,5 +1,5 @@
 use chusql_core_storage::protocol::Row;
-use chusql_core_storage::wal::{committed_ops, Wal, WalOp};
+use chusql_core_storage::wal::{committed_ops, records_after, Wal, WalOp};
 use serde_json::json;
 
 // WAL 测试：追加、读取、清空、截断尾巴、LSN 与提交标记。
@@ -218,3 +218,81 @@ fn checkpoint_round_trips() {
     assert_eq!(wal.read_checkpoint().unwrap(), Some(7));
 }
 
+/// 按 LSN 截断只丢边界以内的帧
+#[test]
+fn truncate_before_keeps_newer_records() {
+    let dir = tempfile::tempdir().unwrap();
+    let path = dir.path().join("wal.log");
+    let wal = Wal::new(&path);
+
+    let second_op = WalOp::Insert {
+        table: "t".into(),
+        row: row(&[("id", json!(2))]),
+    };
+    let first = wal
+        .append_group(&[WalOp::Insert {
+            table: "t".into(),
+            row: row(&[("id", json!(1))]),
+        }])
+        .unwrap();
+    let second = wal.append_group(std::slice::from_ref(&second_op)).unwrap();
+    assert!(second > first);
+
+    // 提交号是第一组的最后一条；边界以内的操作与提交标记都该丢掉
+    wal.truncate_before(first).unwrap();
+    let kept = wal.read_all().unwrap();
+    assert!(kept.records.iter().all(|(lsn, _)| *lsn > first));
+    let ops: Vec<&WalOp> = kept
+        .records
+        .iter()
+        .map(|(_, op)| op)
+        .filter(|op| **op != WalOp::Commit)
+        .collect();
+    assert_eq!(ops, vec![&second_op], "只剩第二组的操作");
+
+    // 边界划到最后一条之后，日志就空了
+    wal.truncate_before(second).unwrap();
+    assert_eq!(std::fs::metadata(&path).unwrap().len(), 0);
+    assert!(wal.read_all().unwrap().records.is_empty());
+}
+
+/// 日志被截断后 LSN 也不回头
+#[test]
+fn lsn_continues_from_the_checkpoint() {
+    let dir = tempfile::tempdir().unwrap();
+    let path = dir.path().join("wal.log");
+    let op = WalOp::Insert {
+        table: "t".into(),
+        row: row(&[("id", json!(1))]),
+    };
+
+    let first = {
+        let wal = Wal::new(&path);
+        let lsn = wal.append_group(std::slice::from_ref(&op)).unwrap();
+        wal.write_checkpoint(lsn).unwrap();
+        wal.truncate_before(lsn).unwrap();
+        lsn
+    };
+
+    // 重新打开：号从检查点续
+    let wal = Wal::new(&path);
+    let next = wal.append_group(std::slice::from_ref(&op)).unwrap();
+    assert!(next > first, "重启后 LSN 要接着检查点走: {next} vs {first}");
+}
+
+/// 过滤只留下检查点之后的记录
+#[test]
+fn records_after_keeps_only_the_tail() {
+    let records = vec![
+        (1u64, WalOp::Insert { table: "t".into(), row: row(&[("id", json!(1))]) }),
+        (2, WalOp::Commit),
+        (3, WalOp::Insert { table: "t".into(), row: row(&[("id", json!(2))]) }),
+        (4, WalOp::Commit),
+    ];
+    let kept = records_after(&records, 2);
+    let lsn: Vec<u64> = kept.iter().map(|(lsn, _)| *lsn).collect();
+    assert_eq!(lsn, vec![3, 4]);
+    assert_eq!(records_after(&records, 4).len(), 0);
+    assert_eq!(records_after(&records, 0).len(), 4);
+}
+