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Retry on Deadlock to Transaction 

Recommended behavior for MySQL deadlock is to retry the transaction.

Added code that performs 3 attempts with recursion if deadlocks occur.

Affects issues:
- Fixed #1212
This commit is contained in:
Rsl1122 2019-11-02 12:36:59 +02:00
parent 8749d12128
commit 2970b6590e
1 changed files with 39 additions and 10 deletions
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49
Plan/common/src/main/java/com/djrapitops/plan/storage/database/transactions/Transaction.java
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@ -36,6 +36,8 @@ public abstract class Transaction {
// SQLite version on 1.8.8 does not support savepoints, see createSavePoint() method
private static final AtomicBoolean SUPPORTS_SAVE_POINTS = new AtomicBoolean(true);
// Limit for Deadlock attempts.
private static final int ATTEMPT_LIMIT = 3;
private SQLDB db;
protected DBType dbType;
@ -44,9 +46,11 @@ public abstract class Transaction {
private Savepoint savepoint;
protected boolean success;
protected int attempts;
protected Transaction() {
success = false;
attempts = 0;
}
public void executeTransaction(SQLDB db) {
@ -61,31 +65,56 @@ public abstract class Transaction {
return;
}
attempts++; // Keeps track how many attempts have been made to avoid infinite recursion.
try {
initializeTransaction(db);
performOperations();
if (connection != null) connection.commit();
success = true;
} catch (Exception statementFail) {
} catch (SQLException statementFail) {
manageFailure(statementFail); // Throws a DBOpException.
} finally {
db.returnToPool(connection);
}
}
private void manageFailure(Exception statementFail) {
private void manageFailure(SQLException statementFail) {
String failMsg = getClass().getSimpleName() + " failed: " + statementFail.getMessage();
if (!SUPPORTS_SAVE_POINTS.get()) {
throw new DBOpException(failMsg + ", additionally rollbacks are not supported on this server version.", statementFail);
String rollbackStatusMsg = rollbackTransaction();
// Retry if deadlock occurs.
int errorCode = statementFail.getErrorCode();
boolean mySQLDeadlock = dbType == DBType.MYSQL && errorCode == 1213;
boolean h2Deadlock = dbType == DBType.H2 && errorCode == 40001;
boolean deadlocked = mySQLDeadlock || h2Deadlock;
if (deadlocked && attempts < ATTEMPT_LIMIT) {
executeTransaction(db); // Recurse to attempt again.
return;
}
try {
if (Verify.notNull(connection, savepoint)) {
connection.rollback(savepoint);
if (attempts >= ATTEMPT_LIMIT) {
failMsg += " (Attempted " + attempts + " times)";
}
throw new DBOpException(failMsg + rollbackStatusMsg, statementFail);
}
private String rollbackTransaction() {
String rollbackStatusMsg = ", Transaction was rolled back.";
boolean hasNoSavepoints = !SUPPORTS_SAVE_POINTS.get();
if (hasNoSavepoints) {
rollbackStatusMsg = ", additionally rollbacks are not supported on this server version.";
} else {
// Rollbacks are supported.
try {
if (Verify.notNull(connection, savepoint)) {
connection.rollback(savepoint);
}
} catch (SQLException rollbackFail) {
rollbackStatusMsg = ", additionally Transaction rollback failed: " + rollbackFail.getMessage();
}
} catch (SQLException rollbackFail) {
throw new DBOpException(failMsg + ", additionally Transaction rollback failed: " + rollbackFail.getMessage(), statementFail);
}
throw new DBOpException(failMsg + ", Transaction was rolled back.", statementFail);
return rollbackStatusMsg;
}
/**