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Fix #289: Add alternative execution for counting queries in lock service #292

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merged 2 commits into from
May 9, 2024
Merged

Fix #289: Add alternative execution for counting queries in lock service #292

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bdde9cc
Add alternative execution for counting queries in lock service
maximevw May 4, 2024
f7f6802
Remove build folder and update .gitignore
maximevw May 4, 2024
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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -5,3 +5,4 @@
.classpath
.project
.settings/
/build
48 changes: 26 additions & 22 deletions src/main/java/liquibase/ext/cassandra/lockservice/LockServiceCassandra.java
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Expand Up @@ -21,6 +21,8 @@

import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;
import java.util.Map;

public class LockServiceCassandra extends StandardLockService {

Expand Down Expand Up @@ -62,19 +64,6 @@ public boolean acquireLock() throws LockException {
// another node was faster
return false;
}
if ((rowsUpdated == -1) && (database instanceof MSSQLDatabase)) {
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Thanks for removing the trash here.


Scope.getCurrentScope().getLog(this.getClass()).info("Database did not return a proper row count (Might have NOCOUNT enabled)");
database.rollback();
Sql[] sql = SqlGeneratorFactory.getInstance().generateSql(
new LockDatabaseChangeLogStatement(), database
);
if (sql.length != 1) {
throw new UnexpectedLiquibaseException("Did not expect " + sql.length + " statements");
}
rowsUpdated = executor.update(new RawSqlStatement("EXEC sp_executesql N'SET NOCOUNT OFF " +
sql[0].toSql().replace("'", "''") + "'"));
}
if (rowsUpdated > 1) {
throw new LockException("Did not update change log lock correctly");
}
Expand Down Expand Up @@ -142,11 +131,11 @@ public boolean isDatabaseChangeLogLockTableCreated() {
boolean hasChangeLogLockTable;
try {
Statement statement = ((CassandraDatabase) database).getStatement();
statement.executeQuery("SELECT ID from " + getChangeLogLockTableName());
statement.executeQuery("SELECT ID FROM " + getChangeLogLockTableName());
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statement.close();
hasChangeLogLockTable = true;
} catch (SQLException e) {
Scope.getCurrentScope().getLog(getClass()).info("No " + getChangeLogLockTableName() + " available in cassandra.");
Scope.getCurrentScope().getLog(getClass()).info("No " + getChangeLogLockTableName() + " available in Cassandra.");
hasChangeLogLockTable = false;
} catch (DatabaseException e) {
e.printStackTrace();
Expand All @@ -163,9 +152,8 @@ public boolean isDatabaseChangeLogLockTableInitialized(final boolean tableJustCr
Executor executor = Scope.getCurrentScope().getSingleton(ExecutorService.class).getExecutor("jdbc", database);

try {
isDatabaseChangeLogLockTableInitialized = executor.queryForInt(
new RawSqlStatement("SELECT COUNT(*) FROM " + getChangeLogLockTableName())
) > 0;
isDatabaseChangeLogLockTableInitialized = executeCountQueryWithAlternative(executor,
"SELECT COUNT(*) FROM " + getChangeLogLockTableName()) > 0;
} catch (LiquibaseException e) {
if (executor.updatesDatabase()) {
throw new UnexpectedLiquibaseException(e);
Expand All @@ -185,10 +173,9 @@ private boolean isLocked(Executor executor) throws DatabaseException {

private boolean isLockedByCurrentInstance(Executor executor) throws DatabaseException {
final String lockedBy = NetUtil.getLocalHostName() + " (" + NetUtil.getLocalHostAddress() + ")";
return executor.queryForInt(
new RawSqlStatement("SELECT COUNT(*) FROM " + getChangeLogLockTableName() + " where " +
"LOCKED = TRUE AND LOCKEDBY = '" + lockedBy + "' ALLOW FILTERING")
) > 0;
return executeCountQueryWithAlternative(executor,
"SELECT COUNT(*) FROM " + getChangeLogLockTableName() + " WHERE " +
"LOCKED = TRUE AND LOCKEDBY = '" + lockedBy + "' ALLOW FILTERING") > 0;
}

private String getChangeLogLockTableName() {
Expand All @@ -198,4 +185,21 @@ private String getChangeLogLockTableName() {
return database.getDatabaseChangeLogLockTableName();
}
}

private int executeCountQueryWithAlternative(final Executor executor, final String query) throws DatabaseException {
if (!query.contains("SELECT COUNT(*)")) {
throw new UnexpectedLiquibaseException("Invalid count query: " + query);
}
try {
return executor.queryForInt(new RawSqlStatement(query));
} catch (DatabaseException e) {
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Nice workaround!

// If the count query failed (for example, because counting rows is not implemented - see issue #289 with
// AWS Keyspaces where aggregate functions like COUNT are not supported:
// https://docs.aws.amazon.com/keyspaces/latest/devguide/cassandra-apis.html#cassandra-functions), try to
// execute the same query without the COUNT function then programmatically count returned rows.
final String altQuery = query.replace("SELECT COUNT(*)", "SELECT *");
final List<Map<String, ?>> rows = executor.queryForList(new RawSqlStatement(altQuery));
return rows.size();
}
}
}
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