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Posted to notifications@shardingsphere.apache.org by "makssent (via GitHub)" <gi...@apache.org> on 2026/10/19 17:49:38 UTC
[I] Firebird Proxy ignores NO WAIT and LOCK TIMEOUT of a transaction, and an update of a locked row hangs [shardingsphere]
makssent opened a new issue, #40286:
URL: https://github.com/apache/shardingsphere/issues/40286
### Before reporting a bug
- [x] I have searched open and closed [GitHub issues](https://github.com/apache/shardingsphere/issues).
- [x] I have read the [ShardingSphere documentation](https://shardingsphere.apache.org/document/current/en/overview).
### ShardingSphere version
master, commit [`01446d4fad4`](https://github.com/apache/shardingsphere/commit/01446d4fad48450e7fc3eb3b3631b25d6bf411df)
### ShardingSphere project
ShardingSphere-Proxy
### Expected behavior
The proxy should apply the transaction parameters [`isc_tpb_nowait`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/jrd/tra.cpp#L3111-L3135) and [`isc_tpb_lock_timeout`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/jrd/tra.cpp#L3320-L3383) of [`op_transaction`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/remote/server/server.cpp#L5147-L5148) as the Firebird server does, so that an update of a locked row fails at once or after the lock timeout.
### Actual behavior
The proxy does not apply these parameters, and an update of a locked row waits until the lock is released.
The same steps were executed directly on the Firebird server and through the proxy, and the rows were read directly from the server:
| Steps | Firebird server | Proxy |
| --- | --- | --- |
| Another transaction, directly on the Firebird server, updates the row with ID = 8953 and does not commit. A transaction with [`isc_tpb_nowait`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/jrd/tra.cpp#L3111-L3135) updates the same row | Error [`isc_lock_conflict`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/lock/lock.cpp#L552-L553) "lock conflict on no wait transaction; update conflicts with concurrent update" | No answer within 5 seconds. After the other transaction rolls back, success |
| The same with [`isc_tpb_wait`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/jrd/tra.cpp#L3018-L3033) and [`isc_tpb_lock_timeout`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/jrd/tra.cpp#L3320-L3383) 1 instead of [`isc_tpb_nowait`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/jrd/tra.cpp#L3111-L3135) | Error [`isc_lock_timeout`](https://github.com/FirebirdSQL/firebird/blob/v5.0.4/src/lock/lock.cpp#L552-L553) "lock time-out on wait transaction; update conflicts with concurrent update" | No answer within 5 seconds. After the other transaction rolls back, success |
So through the proxy the updates of a locked row hang until the lock is released, while the Firebird server answers them with an error.
### Reason analysis
- [`FirebirdStartTransactionPacket`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/database/protocol/dialect/firebird/src/main/java/org/apache/shardingsphere/database/protocol/firebird/packet/command/query/transaction/FirebirdStartTransactionPacket.java#L31) reads from the TPB only [`isAutoCommit`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/database/protocol/dialect/firebird/src/main/java/org/apache/shardingsphere/database/protocol/firebird/packet/command/query/transaction/FirebirdStartTransactionPacket.java#L48-L50), [`isReadOnly`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/database/protocol/dialect/firebird/src/main/java/org/apache/shardingsphere/database/protocol/firebird/packet/command/query/transaction/FirebirdStartTransactionPacket.java#L57-L59) and [`getIsolationLevel`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d
6bf411df/database/protocol/dialect/firebird/src/main/java/org/apache/shardingsphere/database/protocol/firebird/packet/command/query/transaction/FirebirdStartTransactionPacket.java#L66-L77). The items [`WAIT`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/database/protocol/dialect/firebird/src/main/java/org/apache/shardingsphere/database/protocol/firebird/constant/buffer/type/FirebirdTransactionParameterBufferType.java#L42), [`NOWAIT`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/database/protocol/dialect/firebird/src/main/java/org/apache/shardingsphere/database/protocol/firebird/constant/buffer/type/FirebirdTransactionParameterBufferType.java#L43) and [`LOCK_TIMEOUT`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/database/protocol/dialect/firebird/src/main/java/org/apache/shardingsphere/database/protocol/firebird/constant/buffer/type/FirebirdTransactionParamete
rBufferType.java#L57) are parsed, but nothing reads them.
- [`FirebirdStartTransactionCommandExecutor#execute`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/proxy/frontend/dialect/firebird/src/main/java/org/apache/shardingsphere/proxy/frontend/firebird/command/query/transaction/FirebirdStartTransactionCommandExecutor.java#L44-L51) puts only [auto-commit, read-only and the isolation level](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/proxy/frontend/dialect/firebird/src/main/java/org/apache/shardingsphere/proxy/frontend/firebird/command/query/transaction/FirebirdStartTransactionCommandExecutor.java#L46-L48) into [`ConnectionSession`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/session/ConnectionSession.java#L44), so the wait mode and the lock timeout never reach the transaction on the Firebird server.
- [`ConnectionSession`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/session/ConnectionSession.java#L57-L61) has no fields for the wait mode and the lock timeout, and [`ProxyDatabaseConnectionManager#replayTransactionOptions`](https://github.com/apache/shardingsphere/blob/01446d4fad48450e7fc3eb3b3631b25d6bf411df/proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/connector/ProxyDatabaseConnectionManager.java#L227-L235) replays only read-only and the isolation level. JDBC has no API for these parameters, so the backend connection would need the Jaybird method [`FirebirdConnection#setTransactionParameters`](https://github.com/FirebirdSQL/jaybird/blob/v5.0.13/src/main/org/firebirdsql/jdbc/FirebirdConnection.java#L147).
### Steps to reproduce
#### Environment
- Firebird server 5.0.
- Client: Jaybird 6.0.7.
#### Steps
1. Create the table on the Firebird server:
```sql
CREATE TABLE T_PLAIN (ID INTEGER NOT NULL PRIMARY KEY, NAME VARCHAR(20));
```
2. Start ShardingSphere-Proxy with this configuration:
```yaml
# global.yaml
authority:
users:
- user: root@%
password: root
privilege:
type: ALL_PERMITTED
props:
proxy-frontend-database-protocol-type: Firebird
```
```yaml
# database-firebird.yaml
databaseName: firebird_db
dataSources:
ds_0:
url: jdbc:firebirdsql://<host>/<database file>?encoding=UTF8
username: <user>
password: <password>
rules:
- !SINGLE
tables:
- "*.*"
```
3. Execute the steps from the table under "Actual behavior" through the proxy and directly on the Firebird server, and compare the results. "Example code" runs all of them.
### Example code
All cases on Jaybird 6.0.7, one method per case. The comment above each method shows what it prints against the Firebird server and through the proxy.
```java
import org.firebirdsql.gds.TransactionParameterBuffer;
import org.firebirdsql.jaybird.fb.constants.TpbItems;
import org.firebirdsql.jdbc.FirebirdConnection;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
public class TransactionWaitMode {
// The proxy; put the URL, user and password of the Firebird server here to compare
static final String URL = "jdbc:firebirdsql://<proxy host>:<proxy port>/firebird_db?encoding=UTF8&wireCrypt=DISABLED";
static final String USER = "root";
static final String PASSWORD = "root";
// The Firebird server, to lock the row
static final String SERVER_URL = "jdbc:firebirdsql://<host>/<database file>";
static final String SERVER_USER = "<user>";
static final String SERVER_PASSWORD = "<password>";
public static void main(final String[] args) throws Exception {
executeOnServer("DELETE FROM T_PLAIN WHERE ID BETWEEN 8951 AND 8953");
executeOnServer("INSERT INTO T_PLAIN (ID, NAME) VALUES (8953, 'locked')");
noWait();
lockTimeout();
executeOnServer("DELETE FROM T_PLAIN WHERE ID BETWEEN 8951 AND 8953");
}
// Firebird server: "NO WAIT, update: lock conflict on no wait transaction; update conflicts with concurrent update;
// concurrent transaction number is N [SQLState:40001, ISC error code:335544345]", where N is the number of the other transaction;
// proxy: "NO WAIT, update: no answer within 5 seconds", "NO WAIT, update after the other transaction rolled back: success"
static void noWait() throws Exception {
try (Connection connection = DriverManager.getConnection(URL, USER, PASSWORD)) {
TransactionParameterBuffer tpb = tpb(connection);
tpb.addArgument(TpbItems.isc_tpb_nowait);
updateLockedRow("NO WAIT", connection, tpb);
}
}
// Firebird server: "LOCK TIMEOUT 1, update: lock time-out on wait transaction; update conflicts with concurrent update;
// concurrent transaction number is N [SQLState:40001, ISC error code:335544510]";
// proxy: "LOCK TIMEOUT 1, update: no answer within 5 seconds", "LOCK TIMEOUT 1, update after the other transaction rolled back: success"
static void lockTimeout() throws Exception {
try (Connection connection = DriverManager.getConnection(URL, USER, PASSWORD)) {
TransactionParameterBuffer tpb = tpb(connection);
tpb.addArgument(TpbItems.isc_tpb_wait);
tpb.addArgument(TpbItems.isc_tpb_lock_timeout, 1);
updateLockedRow("LOCK TIMEOUT 1", connection, tpb);
}
}
// A transaction with read committed, record version and read-write; the case adds its wait mode
static TransactionParameterBuffer tpb(final Connection connection) throws SQLException {
TransactionParameterBuffer result = connection.unwrap(FirebirdConnection.class).createTransactionParameterBuffer();
result.addArgument(TpbItems.isc_tpb_read_committed);
result.addArgument(TpbItems.isc_tpb_rec_version);
result.addArgument(TpbItems.isc_tpb_write);
return result;
}
// Another transaction, directly on the Firebird server, updates the row with ID = 8953 and does not commit.
// Then the connection under test updates the same row in a transaction with the given TPB.
static void updateLockedRow(final String name, final Connection connection, final TransactionParameterBuffer tpb) throws Exception {
ExecutorService executor = Executors.newSingleThreadExecutor();
try (Connection holder = DriverManager.getConnection(SERVER_URL, SERVER_USER, SERVER_PASSWORD)) {
holder.setAutoCommit(false);
execute(holder, "UPDATE T_PLAIN SET NAME = 'holder' WHERE ID = 8953");
connection.setAutoCommit(false);
connection.unwrap(FirebirdConnection.class).setTransactionParameters(tpb);
Future<String> update = executor.submit(() -> execute(connection, "UPDATE T_PLAIN SET NAME = 'second' WHERE ID = 8953"));
try {
System.out.println(name + ", update: " + update.get(5, TimeUnit.SECONDS));
holder.rollback();
} catch (final TimeoutException ex) {
System.out.println(name + ", update: no answer within 5 seconds");
// Releases the lock, so that the waiting update can go on
holder.rollback();
System.out.println(name + ", update after the other transaction rolled back: " + update.get(10, TimeUnit.SECONDS));
}
connection.rollback();
} finally {
executor.shutdownNow();
}
}
static String execute(final Connection connection, final String sql) {
try (Statement statement = connection.createStatement()) {
statement.executeUpdate(sql);
return "success";
} catch (final SQLException ex) {
return ex.getMessage();
}
}
static void executeOnServer(final String sql) throws SQLException {
try (Connection connection = DriverManager.getConnection(SERVER_URL, SERVER_USER, SERVER_PASSWORD)) {
connection.createStatement().execute(sql);
}
}
}
```
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