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Unified Java client for ClickHouse
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package com.clickhouse.client;
import java.io.Serializable;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import com.clickhouse.data.ClickHouseFormat;
import com.clickhouse.data.ClickHouseRecord;
import com.clickhouse.data.ClickHouseUtils;
import com.clickhouse.data.value.UnsignedLong;
import com.clickhouse.logging.Logger;
import com.clickhouse.logging.LoggerFactory;
/**
* This class represents a transaction in ClickHouse. Besides transaction ID
* {@code Tuple(snapshotVersion UInt64, localTxCounter UInt64, hostId UUID)}, it
* also contains session ID and references to the connected server and client
* for issuing queries.
*/
public final class ClickHouseTransaction implements Serializable {
/**
* This class encapsulates transaction ID, which is defined as
* {@code Tuple(snapshotVersion UInt64, localTxCounter UInt64, hostId UUID)}.
*/
public static class XID implements Serializable {
private static final long serialVersionUID = 4907177669971332404L;
public static final XID EMPTY = new XID(0L, 0L, new UUID(0L, 0L).toString());
/**
* Creates transaction ID from the given tuple.
*
* @param list non-null tuple with 3 elements
* @return non-null transaction ID
*/
public static XID of(List list) {
if (list == null || list.size() != 3) {
throw new IllegalArgumentException(
"Non-null tuple with 3 elements(long, long, String) is required");
}
long snapshotVersion = ((UnsignedLong) list.get(0)).longValue();
long localTxCounter = ((UnsignedLong) list.get(1)).longValue();
String hostId = String.valueOf(list.get(2));
if (EMPTY.snapshotVersion == snapshotVersion && EMPTY.localTxCounter == localTxCounter
&& EMPTY.hostId.equals(hostId)) {
return EMPTY;
}
return new XID(snapshotVersion, localTxCounter, hostId);
}
private final long snapshotVersion;
private final long localTxCounter;
private final String hostId;
protected XID(long snapshotVersion, long localTxCounter, String hostId) {
this.snapshotVersion = snapshotVersion;
this.localTxCounter = localTxCounter;
this.hostId = hostId;
}
public long getSnapshotVersion() {
return snapshotVersion;
}
public long getLocalTransactionCounter() {
return localTxCounter;
}
public String getHostId() {
return hostId;
}
public String asTupleString() {
return new StringBuilder().append('(').append(snapshotVersion).append(',').append(localTxCounter)
.append(",'").append(hostId).append("')").toString();
}
@Override
public int hashCode() {
final int prime = 31;
int result = prime + (int) (snapshotVersion ^ (snapshotVersion >>> 32));
result = prime * result + (int) (localTxCounter ^ (localTxCounter >>> 32));
result = prime * result + hostId.hashCode();
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
} else if (obj == null || getClass() != obj.getClass()) {
return false;
}
XID other = (XID) obj;
return snapshotVersion == other.snapshotVersion && localTxCounter == other.localTxCounter
&& hostId.equals(other.hostId);
}
@Override
public String toString() {
return new StringBuilder().append("TransactionId [snapshotVersion=").append(snapshotVersion)
.append(", localTxCounter=").append(localTxCounter).append(", hostId=").append(hostId).append("]@")
.append(hashCode()).toString();
}
}
private static final Logger log = LoggerFactory.getLogger(ClickHouseTransaction.class);
private static final long serialVersionUID = -4618710299106666829L;
private static final String[] NAMES = new String[] {
"New", "Active", "Failed", "Commited", "RolledBack"
};
static final String QUERY_SELECT_TX_ID = "SELECT transactionID()";
public static final String COMMAND_BEGIN = "BEGIN";
public static final String COMMAND_COMMIT = "COMMIT";
public static final String COMMAND_ROLLBACK = "ROLLBACK";
// transaction state
public static final int NEW = 0;
public static final int ACTIVE = 1;
public static final int FAILED = 2;
public static final int COMMITTED = 3;
public static final int ROLLED_BACK = 4;
// reserved CSN - see
// https://github.com/ClickHouse/ClickHouse/blob/master/src/Common/TransactionID.h
public static final long CSN_UNKNOWN = 0L; // For transactions that are probably not committed (yet)
public static final long CSN_PREHISTORIC = 1L; // For changes were made without creating a transaction
// Special reserved values
public static final long CSN_COMMITTING = 2L;
public static final long CSN_EVERYTHING_VISIBLE = 3L;
public static final long CSN_MAX_RESERVED = 32L;
public static final String SETTING_IMPLICIT_TRANSACTION = "implicit_transaction";
public static final String SETTING_THROW_ON_UNSUPPORTED_QUERY_INSIDE_TRANSACTION = "throw_on_unsupported_query_inside_transaction";
public static final String SETTING_WAIT_CHANGES_BECOME_VISIBLE_AFTER_COMMIT_MODE = "wait_changes_become_visible_after_commit_mode";
/**
* Updates the given request by enabling or disabling implicit transaction.
*
* @param request non-null request to update
* @param enable whether enable implicit transaction or not
* @throws ClickHouseException when failed to enable or disable implicit
* transaction
*/
static void setImplicitTransaction(ClickHouseRequest request, boolean enable) throws ClickHouseException {
if (enable) {
request.set(SETTING_IMPLICIT_TRANSACTION, 1).transaction(null);
} else {
request.removeSetting(SETTING_IMPLICIT_TRANSACTION);
}
}
private final ClickHouseNode server;
private final String sessionId;
private final int timeout;
private final boolean implicit;
private final AtomicReference id;
private final AtomicInteger state;
/**
* Constructs a unique transaction in {@link #ACTIVE} state.
* {@link ClickHouseRequestManager#createSessionId()} will be used to ensure
* uniquness of the transaction.
*
* @param server non-null server of the transaction
* @param timeout transaction timeout
* @param implicit whether it's an implicit transaction or not
* @throws ClickHouseException when failed to start transaction
*/
protected ClickHouseTransaction(ClickHouseNode server, int timeout, boolean implicit) throws ClickHouseException {
this.server = server;
this.sessionId = ClickHouseRequestManager.getInstance().createSessionId();
this.timeout = timeout < 1 ? 0 : timeout;
this.implicit = implicit;
this.id = new AtomicReference<>(XID.EMPTY);
this.state = new AtomicInteger(NEW);
try {
id.updateAndGet(x -> {
boolean success = false;
try {
issue("BEGIN TRANSACTION", false, Collections.emptyMap());
XID txId = XID.of(issue(QUERY_SELECT_TX_ID).getValue(0).asTuple());
if (XID.EMPTY.equals(txId)) {
throw new ClickHouseTransactionException(
ClickHouseTransactionException.ERROR_UNKNOWN_STATUS_OF_TRANSACTION,
ClickHouseUtils.format("Failed to start transaction(implicit=%s)", implicit), this);
}
success = state.compareAndSet(NEW, ACTIVE);
return txId;
} catch (ClickHouseException e) {
throw new IllegalStateException(e);
} finally {
if (!success) {
state.compareAndSet(NEW, FAILED);
}
}
});
log.debug("Began transaction(implicit=%s): %s", this.implicit, this);
} catch (IllegalStateException e) {
if (e.getCause() instanceof ClickHouseException) {
throw (ClickHouseException) e.getCause();
} else {
throw e;
}
}
}
/**
* Constructs a transaction in {@link #NEW} state, hence {@link #begin()} or
* {@link #begin(Map)} must be called before commit/rollback and
* {@link #isImplicit()} is always {@code false}.
*
* @param server non-null server of the transaction
* @param sessionId non-empty session ID for the transaction
* @param timeout transaction timeout
* @param id optional transaction ID
*/
protected ClickHouseTransaction(ClickHouseNode server, String sessionId, int timeout, XID id) {
this.server = server;
this.sessionId = sessionId;
this.timeout = timeout < 1 ? 0 : timeout;
this.implicit = false;
if (id == null || XID.EMPTY.equals(id)) {
this.id = new AtomicReference<>(XID.EMPTY);
this.state = new AtomicInteger(NEW);
} else {
this.id = new AtomicReference<>(id);
this.state = new AtomicInteger(ACTIVE);
}
}
/**
* Ensures client and server are using the exact same transaction ID.
*
* @throws ClickHouseException when transaction ID is inconsistent between
* client and server
*/
protected void ensureTransactionId() throws ClickHouseException {
if (!implicit) {
XID serverTxId = XID.of(issue(QUERY_SELECT_TX_ID).getValue(0).asTuple());
if (!serverTxId.equals(id.get())) {
throw new ClickHouseTransactionException(
ClickHouseUtils.format(
"Inconsistent transaction ID - client expected %s but found %s on server.",
id.get(), serverTxId),
this);
}
}
}
/**
* Issues transaction related query. Same as
* {@code issue(command, true, Collections.emptyMap())}.
*
* @param command non-empty transaction related query
* @return non-null record
* @throws ClickHouseException when failed to issue the query
*/
protected final ClickHouseRecord issue(String command) throws ClickHouseException {
return issue(command, true, Collections.emptyMap());
}
/**
* Issues transaction related query.
*
* @param command non-empty transaction related query
* @param sessionCheck whether to enable session check
* @param settings optional server settings
* @return non-null record
* @throws ClickHouseException when failed to issue the query
*/
protected ClickHouseRecord issue(String command, boolean sessionCheck, Map settings)
throws ClickHouseException {
ClickHouseRecord result = ClickHouseRecord.EMPTY;
try (ClickHouseResponse response = ClickHouseClient.newInstance(server.getProtocol()).read(server)
.format(ClickHouseFormat.RowBinaryWithNamesAndTypes)
.settings(settings).session(sessionId, sessionCheck, timeout > 0 ? timeout : null)
.query(command).executeAndWait()) {
Iterator records = response.records().iterator();
if (records.hasNext()) {
result = records.next();
}
} catch (ClickHouseException e) {
switch (e.getErrorCode()) {
case ClickHouseException.ERROR_SESSION_NOT_FOUND:
throw new ClickHouseTransactionException(
"Invalid transaction due to session not found or timed out", e.getCause(), this);
case ClickHouseTransactionException.ERROR_INVALID_TRANSACTION:
case ClickHouseTransactionException.ERROR_UNKNOWN_STATUS_OF_TRANSACTION:
throw new ClickHouseTransactionException(e.getErrorCode(), e.getMessage(), e.getCause(), this);
default:
break;
}
throw e;
}
return result;
}
/**
* Gets current transaction ID.
*
* @return non-null transaction ID
*/
public XID getId() {
return id.get();
}
/**
* Gets server of the transaction.
*
* @return non-null server
*/
public ClickHouseNode getServer() {
return server;
}
/**
* Gets session id of the transaction.
*
* @return non-empty session id
*/
public String getSessionId() {
return sessionId;
}
/**
* Gets transaction state, one of {@link #NEW}, {@link #ACTIVE},
* {@link #COMMITTED}, {@link #ROLLED_BACK}, or {@link #FAILED}.
*
* @return transaction state
*/
public int getState() {
return state.get();
}
/**
* Gets transaction timeout in seconds.
*
* @return transaction timeout in seconds, zero or negative number means
* {@code default_session_timeout} as defined on server
*/
public int getTimeout() {
return timeout;
}
/**
* Checks if the transaction is implicit or not.
*
* @return true if it's an implicit transaction; false otherwise
*/
public boolean isImplicit() {
return implicit;
}
/**
* Checks whether the transation's state is {@link #NEW}.
*
* @return true if the state is {@link #NEW}; false otherwise
*/
public boolean isNew() {
return state.get() == NEW;
}
/**
* Checks whether the transation's state is {@link #ACTIVE}.
*
* @return true if the state is {@link #ACTIVE}; false otherwise
*/
public boolean isActive() {
return state.get() == ACTIVE;
}
/**
* Checks whether the transation's state is {@link #COMMITTED}.
*
* @return true if the state is {@link #COMMITTED}; false otherwise
*/
public boolean isCommitted() {
return state.get() == COMMITTED;
}
/**
* Checks whether the transation's state is {@link #ROLLED_BACK}.
*
* @return true if the state is {@link #ROLLED_BACK}; false otherwise
*/
public boolean isRolledBack() {
return state.get() == ROLLED_BACK;
}
/**
* Checks whether the transation's state is {@link #FAILED}.
*
* @return true if the state is {@link #FAILED}; false otherwise
*/
public boolean isFailed() {
return state.get() == FAILED;
}
/**
* Aborts the transaction.
*/
public void abort() {
log.debug("Abort %s", this);
int currentState = state.get();
if (currentState == NEW) {
log.debug("Skip since it's a new transaction which hasn't started yet");
return;
}
id.updateAndGet(x -> {
try (ClickHouseResponse response = ClickHouseClient.newInstance(server.getProtocol()).read(server)
.query("KILL TRANSACTION WHERE tid=" + x.asTupleString()).executeAndWait()) {
// ignore
} catch (ClickHouseException e) {
log.warn("Failed to abort transaction %s", x.asTupleString());
} finally {
state.compareAndSet(currentState, FAILED);
}
return x;
});
log.debug("Aborted transaction: %s", this);
}
/**
* Starts a new transaction. Same as {@code begin(Collections.emptyMap())}.
*
* @throws ClickHouseException when failed to begin new transaction
*/
public void begin() throws ClickHouseException {
begin(Collections.emptyMap());
}
/**
* Starts a new transaction with optional server settings. It's a no-op when
* calling against an {@link #ACTIVE} transaction.
*
* @param settings optional server settings
* @throws ClickHouseException when failed to begin new transaction
*/
public void begin(Map settings) throws ClickHouseException {
log.debug("Begin %s", this);
int currentState = state.get();
if (currentState == ACTIVE) {
log.debug("Skip since the transaction has been started already");
return;
} else if (currentState == FAILED) {
throw new ClickHouseTransactionException(
"Cannot restart a failed transaction - please roll back or create a new transaction",
this);
}
try {
id.updateAndGet(x -> {
boolean success = false;
XID txId = null;
try {
// reuse existing transaction if any
txId = XID.of(issue(QUERY_SELECT_TX_ID, false, Collections.emptyMap()).getValue(0).asTuple());
if (XID.EMPTY.equals(txId)) {
issue("BEGIN TRANSACTION", true, settings);
txId = XID.of(issue(QUERY_SELECT_TX_ID).getValue(0).asTuple());
}
if (XID.EMPTY.equals(txId)) {
throw new ClickHouseTransactionException(
ClickHouseTransactionException.ERROR_UNKNOWN_STATUS_OF_TRANSACTION,
"Failed to start new transaction", this);
}
success = state.compareAndSet(currentState, ACTIVE);
return txId;
} catch (ClickHouseException e) {
throw new IllegalStateException(e);
} finally {
if (txId != null && !success) {
state.compareAndSet(currentState, FAILED);
}
}
});
log.debug("Began new transaction: %s", this);
} catch (IllegalStateException e) {
if (e.getCause() instanceof ClickHouseException) {
throw (ClickHouseException) e.getCause();
} else {
throw e;
}
}
}
/**
* Commits the transaction. Same as {@code commit(Collections.emptyMap())}.
*
* @throws ClickHouseException when failed to commit the transaction
*/
public void commit() throws ClickHouseException {
commit(Collections.emptyMap());
}
/**
* Commits the transaction with optional server settings. It's a no-op when
* calling against a {@link #COMMITTED} transaction.
*
* @param settings optional server settings
* @throws ClickHouseException when failed to commit the transaction
*/
public void commit(Map settings) throws ClickHouseException {
log.debug("Commit %s", this);
int currentState = state.get();
if (currentState == COMMITTED) {
log.debug("Skip since the transaction has been committed already");
return;
} else if (currentState != ACTIVE) {
throw new ClickHouseTransactionException(
ClickHouseUtils.format("Cannot commit inactive transaction(state=%s)", NAMES[currentState]), this);
}
try {
id.updateAndGet(x -> {
boolean success = false;
try {
ensureTransactionId();
issue(COMMAND_COMMIT, true, settings);
success = state.compareAndSet(currentState, COMMITTED);
return x;
} catch (ClickHouseException e) {
throw new IllegalStateException(e);
} finally {
if (!success) {
state.compareAndSet(currentState, FAILED);
}
}
});
} catch (IllegalStateException e) {
if (e.getCause() instanceof ClickHouseException) {
throw (ClickHouseException) e.getCause();
} else {
throw e;
}
}
}
/**
* Rolls back the transaction. Same as {@code rollback(Collections.emptyMap())}.
*
* @throws ClickHouseException when failed to roll back the transaction
*/
public void rollback() throws ClickHouseException {
rollback(Collections.emptyMap());
}
/**
* Rolls back the transaction with optional server settings. It's a no-op when
* calling against a {@link #NEW} or {@link #ROLLED_BACK} transaction.
*
* @param settings optional server settings
* @throws ClickHouseException when failed to roll back the transaction
*/
public void rollback(Map settings) throws ClickHouseException {
log.debug("Roll back %s", this);
int currentState = state.get();
if (currentState == NEW) {
log.debug("Skip since the transaction has not started yet");
return;
} else if (currentState == ROLLED_BACK) {
log.debug("Skip since the transaction has been rolled back already");
return;
} else if (currentState != ACTIVE && currentState != FAILED) {
throw new ClickHouseTransactionException(
ClickHouseUtils.format("Cannot roll back inactive transaction(state=%s)", NAMES[currentState]),
this);
}
try {
id.updateAndGet(x -> {
boolean success = false;
try {
ensureTransactionId();
issue(COMMAND_ROLLBACK, true, settings);
success = state.compareAndSet(currentState, ROLLED_BACK);
return x;
} catch (ClickHouseException e) {
throw new IllegalStateException(e);
} finally {
if (!success) {
state.compareAndSet(currentState, FAILED);
}
}
});
} catch (IllegalStateException e) {
if (e.getCause() instanceof ClickHouseException) {
throw (ClickHouseException) e.getCause();
} else {
throw e;
}
}
}
/**
* Sets transaction snapshot with optional server settings. Same as
* {@code snapshot(snapshotVersion, Collections.emptyMap())}.
*
* @param snapshotVersion snapshot version
* @throws ClickHouseException when failed to set transaction snapshot
*/
public void snapshot(long snapshotVersion) throws ClickHouseException {
snapshot(snapshotVersion, Collections.emptyMap());
}
/**
* Sets transaction snapshot with optional server settings, only works for
* {@link #ACTIVE} transaction. Use {@code snapshot(CSN_EVERYTHING_VISIBLE)} to
* read uncommitted data.
*
* @param snapshotVersion snapshot version
* @param settings optional server settings
* @throws ClickHouseException when failed to set transaction snapshot
*/
public void snapshot(long snapshotVersion, Map settings) throws ClickHouseException {
log.debug("Set snapshot %d for %s", snapshotVersion, this);
int currentState = state.get();
if (currentState != ACTIVE) {
throw new ClickHouseTransactionException(
ClickHouseUtils.format("Cannot set snapshot version for inactive transaction(state=%s)",
NAMES[currentState]),
this);
}
try {
id.updateAndGet(x -> {
boolean success = false;
try {
ensureTransactionId();
issue("SET TRANSACTION SNAPSHOT " + snapshotVersion, true, settings);
success = true;
return x;
} catch (ClickHouseException e) {
throw new IllegalStateException(e);
} finally {
if (!success) {
state.compareAndSet(currentState, FAILED);
}
}
});
} catch (IllegalStateException e) {
if (e.getCause() instanceof ClickHouseException) {
throw (ClickHouseException) e.getCause();
} else {
throw e;
}
}
}
@Override
public int hashCode() {
final int prime = 31;
int result = prime + server.getBaseUri().hashCode();
result = prime * result + sessionId.hashCode();
result = prime * result + timeout;
result = prime * result + id.get().hashCode();
result = prime * result + state.get();
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
} else if (obj == null || getClass() != obj.getClass()) {
return false;
}
ClickHouseTransaction other = (ClickHouseTransaction) obj;
return server.isSameEndpoint(other.server) && sessionId.equals(other.sessionId)
&& timeout == other.timeout && id.get().equals(other.id.get()) && state.get() == other.state.get();
}
@Override
public String toString() {
return new StringBuilder().append("ClickHouseTransaction [id=").append(id.get().asTupleString())
.append(", session=").append(sessionId).append(", timeout=").append(timeout).append(", state=")
.append(NAMES[state.get()]).append(", server=").append(server.getBaseUri()).append("]@")
.append(hashCode()).toString();
}
}