/**
* Each shard have a database connection, the worker thread may concurrently use a shard
* connection executing SQL (such as executing ddl statement), If the JDBC driver is
* spec-compliant, then technically yes, the object is thread-safe, MySQL Connector/J, all methods
* to execute statements lock the connection with a synchronized block.
*
* @param options
* @return
*/
protected Connection getConnectionWithStrategy(Options options) {
String shardName = options.shardName;
Connection conn;
switch (holderStrategy) {
case STRICTLY:
if (connectionMap.isEmpty()) {
conn = getRawConnection(options);
connectionMap.put(shardName, conn);
} else {
conn = connectionMap.get(shardName);
if (conn == null) {
String lastTransactionNode = connectionMap.keySet().iterator().next();
throw DbException.get(
ErrorCode.GENERAL_ERROR_1,
"STRICTLY transaction mode not supported operation on multi-node, opend on "
+ lastTransactionNode
+ " and try on "
+ shardName);
}
}
break;
case ALLOW_CROSS_SHARD_READ:
if (options.readOnly) {
conn = connectionMap.get(shardName);
if (conn == null) {
conn = getRawConnectionForReadOnly(options);
}
} else {
if (connectionMap.isEmpty()) {
conn = getRawConnection(options);
connectionMap.put(shardName, conn);
} else {
conn = connectionMap.get(shardName);
if (conn == null) {
String lastTransactionNode = connectionMap.keySet().iterator().next();
throw DbException.get(
ErrorCode.GENERAL_ERROR_1,
"ALLOW_READ_CROSS_DB transaction mode not supported writing operation on multi-node, opend on "
+ lastTransactionNode
+ " and try on "
+ shardName);
}
}
}
break;
case BESTEFFORTS_1PC:
conn = connectionMap.get(shardName);
if (conn == null) {
conn = getRawConnection(options);
connectionMap.put(shardName, conn);
}
break;
default:
throw DbException.getInvalidValueException("transactionMode", holderStrategy);
}
return conn;
}
private HolderStrategy transactionMode(String mode) {
try {
HolderStrategy holderStrategy =
StringUtils.isNullOrEmpty(mode)
? HolderStrategy.BESTEFFORTS_1PC
: HolderStrategy.valueOf(mode);
return holderStrategy;
} catch (Exception e) {
throw DbException.getInvalidValueException("transactionMode", mode);
}
}