MariaDbSequenceHandler.java
/*
** Module : MariaDbSequenceHandler.java
** Abstract : Static class that handles sequence functions and statements from Progress / OpenEdge 10.x.
**
** Copyright (c) 2022-2025, Golden Code Development Corporation.
**
** -#- -I- --Date-- ----------------------------------------Description---------------------------------------
** 001 OM 20220817 Created initial version with basic support only.
** OM 20221013 Fixed the query for sequences lookup.
** CA 20221014 In MariaDB, the current value is private per connection -there is no state being preserved
** at the database server for current value, it 'select previous value' always return NULL if
** 'next value' has never been called for this sequence, in this connection. For this reason,
** current value is determined by getting the next value, subtracting one, and adjusting the
** sequence value again.
** CA 20221019 When populating 'sequences' registry, 'safeContains' must use physical database name, and
** not the ldbname.
** OM 20221025 Improve sequence compatibility with 4GL.
** 002 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 003 OM 20230623 Sequences use separate SQL session/connection to avoid deadlock caused by MDEV-13713.
** 004 OM 20241128 Multi-tenant runtime support: selected the proper persistence context, eventually
** based on [sharedDb] parameter.
** 005 OM 20250110 Added sequence support for multi-tenant databases.
*/
/*
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** published by the Free Software Foundation, either version 3 of the
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**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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**
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** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
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*/
package com.goldencode.p2j.persist.sequence;
import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.persist.orm.*;
import com.goldencode.p2j.util.ErrorManager;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.logging.*;
import java.sql.*;
import java.util.*;
import java.util.logging.*;
/**
* MariaDb implementation of sequences using a native SQL sequence primitives queries. Each primitive tries to
* execute exactly one database query (except NEXT-VALUE, where the output is checked to match the P4GL
* jump-to INITIAL value instead of MIN-VALUE).
*/
public class MariaDbSequenceHandler
extends SequenceHandler
{
/** Central Logger. */
private static final CentralLogger LOG = CentralLogger.get(MariaDbSequenceHandler.class);
/** The list of sequences grouped by databases. It uses lazy initialization. */
private HashMap<String, Set<String>> sequences = null;
/**
* The only constructor takes the name of the database as argument. It is passed on to super class.
*
* @param ldbName
* The database logical name on which this handler will work with.
*/
public MariaDbSequenceHandler(String ldbName)
{
super(ldbName);
}
/**
* Queries the current value of a sequence.
* <p>
* This method should be called only in a safe environment, where the database-level lock for
* access to sequences has already been acquired.
*
* @param seqName
* The name of the sequence.
* @param ldbName
* The database to which the sequence belongs to. It is assumed it is not null and valid.
* @param tenantId
* The tenant id. If present (not null) it is checked. If not it is computed as
* {@code tenant-id(ldbName}).
*
* @return the current value of the sequence
*/
@Override
protected int64 safeGetCurrentValue(String seqName, String ldbName, Long tenantId)
{
Sequence seq = SequenceManager.getSequence(ldbName, seqName);
if (seq == null)
{
ErrorManager.recordOrThrowError(2913, "Unknown sequence expression " + seqName.toUpperCase());
return new int64();
}
// in MariaDB, sequence 'previous value' is kept per connection. It is also unreliable because, as
// the name suggests it is the last value returned. If the sequence was reset the value is incorrect
Persistence persistence = ConnectionManager.getPersistence(ldbName);
if (tenantId != null)
{
int crtTenant = persistence.getContext(Persistence.PRIVATE_CTX).getTenantId();
if (crtTenant != tenantId)
{
// NOTE: super-tenants are not implemented yet so we raise this unconditionally, for the moment:
ErrorManager.recordOrThrowError(15956);
// Only super-tenants may use a tenant-id other than their own in a sequence function. (15956)
return new int64();
}
}
String getNextValQuery = persistence.getDialect().getSequenceNextValString(seqName);
// We need to get the NEXT VALUE and then set the current value to prevValue - increment
int64 nextVal = getResultValue(executeSQL(getNextValQuery,
persistence.getDatabase(!seq.isMultiTenant()), true));
if (nextVal.isUnknown())
{
// that failed too ?
return new int64();
}
long currentValue = nextVal.longValue() - seq.getIncrement();
safeSetValue(seqName, ldbName, currentValue, tenantId);
return new int64(currentValue);
}
/**
* Computes and returns the next value of a sequence.
* <p>
* This method should be called only in a safe environment, where the database-level lock for
* access to sequences has already been acquired.
*
* @param seqName
* The name of the sequence.
* @param ldbName
* The database to which the sequence belongs to. It is assumed it is not {@code null} and valid.
* @param tenantId
* The tenant id. If present (not null) it is checked. If not it is computed as
* {@code tenant-id(ldbName}).
*
* @return the next value of the sequence or unknown value (?) if sequence/database not found
* or the sequence is not cycling and has passed the maximum/minimum value.
*/
@Override
protected int64 safeGetNextValue(String seqName, String ldbName, Long tenantId)
{
Sequence seq = SequenceManager.getSequence(ldbName, seqName);
if (seq == null)
{
ErrorManager.recordOrThrowError(2913, "Unknown sequence expression " + seqName.toUpperCase());
return new int64();
}
Persistence persistence = ConnectionManager.getPersistence(ldbName);
if (tenantId != null)
{
int crtTenant = persistence.getContext(Persistence.PRIVATE_CTX).getTenantId();
if (crtTenant != tenantId)
{
// NOTE: super-tenants are not implemented yet so we raise this unconditionally, for the moment:
ErrorManager.recordOrThrowError(15956);
// Only super-tenants may use a tenant-id other than their own in a sequence function. (15956)
return new int64();
}
}
String getNextValQuery = persistence.getDialect().getSequenceNextValString(seqName);
int64 resultValue = getResultValue(executeSQL(getNextValQuery,
persistence.getDatabase(!seq.isMultiTenant()), true));
// MariaDb is different from Progress when cycling:
// it will make the counter jump from MAX_VALUE to MIN_VALUE (and the reverse)
// instead, 4GL will jump back to INITIAL_VALUE
if (seq.isCycle())
{
// in a cycling sequence resultValue is never null/unknown
long crtVal = resultValue.longValue();
// did the cycle jump occurred?
if (seq.getIncrement() > 0 && crtVal == seq.getMin())
{
// if this is a nop, skip it
long ret = seq.getInitial();
if (crtVal != ret)
{
safeSetValue(seqName, ldbName, ret, tenantId);
return new int64(ret);
}
}
}
return resultValue;
}
/**
* Initialize (reset) the current value of a sequence.
* <p>
* This method should be called only in a safe environment, where the database-level lock for
* access to sequences has already been acquired.
*
* @param seqName
* The name of the sequence.
* @param ldbName
* The database to which the sequence belongs to.
* It is assumed it is not null and valid.
* @param newVal
* The value the sequence will be reset to.
* @param tenantId
* The tenant id. If present (not null) it is checked. If not it is computed as
* {@code tenant-id(ldbName}).
*/
@Override
protected void safeSetValue(String seqName, String ldbName, long newVal, Long tenantId)
{
Sequence seq = SequenceManager.getSequence(ldbName, seqName);
if (seq == null)
{
ErrorManager.recordOrThrowError(3133,
"SYSTEM ERROR: Sequence " + seqName.toUpperCase() + " not found");
return;
}
if (seq.getMin() > newVal || newVal > seq.getMax())
{
ErrorManager.recordOrThrowError(3132,
"Cannot set sequence " + seq.getLegacyName().toUpperCase() + " beyond its max/min values");
return;
}
Persistence persistence = ConnectionManager.getPersistence(ldbName);
if (tenantId != null)
{
int crtTenant = persistence.getContext(Persistence.PRIVATE_CTX).getTenantId();
if (crtTenant != tenantId)
{
// NOTE: super-tenants are not implemented yet so we raise this unconditionally, for the moment:
ErrorManager.recordOrThrowError(15956);
// Only super-tenants may use a tenant-id other than their own in a sequence function. (15956)
return;
}
}
Database db = persistence.getDatabase(!seq.isMultiTenant());
executeSQL("ALTER SEQUENCE " + seqName + " RESTART WITH ?", db, false, newVal); // expect [retVal] to be 0.
executeSQL("SELECT SETVAL(" + seqName + ", ?, TRUE)", db, true, newVal);
}
/**
* Test whether the database contains a sequence. This is useful to identify the correct
* database/sequences when a 4GL static function / statement is called without the database
* parameter.
* <p>
* This method should be called only in a safe environment, where the database-level lock for
* access to sequences has already been acquired.
*
* @param seqName
* The name of the sequence.
* @param ldbName
* The database to which the sequence belongs to. If is null then the first connected
* database is assumed.
*
* @return <code>true</code> if the sequence is defined in the database
*/
@Override
protected boolean safeContains(String seqName, String ldbName)
{
// lazy initialization
if (sequences == null)
{
sequences = new HashMap<>();
}
// make sure the structure is initialized for this database:
Set<String> crtSeqList = sequences.get(ldbName);
if (crtSeqList == null)
{
// create the list
crtSeqList = new HashSet<>();
sequences.put(ldbName, crtSeqList);
Persistence persistence = ConnectionManager.getPersistence(ldbName);
try
{
String catalog = persistence.getSession(Persistence.META_CTX).getConnection().getCatalog();
ScrollableResults<String> rs = persistence.executeSQLQuery(
"SELECT table_name FROM information_schema.tables " +
"WHERE table_type = 'SEQUENCE' AND table_schema = ?",
Persistence.META_CTX,
new Object[] { catalog });
while (rs.next())
{
crtSeqList.add(rs.get(0, String.class));
}
}
catch (PersistenceException | SQLException pe)
{
if (LOG.isLoggable(Level.WARNING))
{
LOG.log(Level.WARNING,
"Failed to get sequence list from " + ldbName + ": " + pe.getMessage());
}
return false;
}
}
// now check whether the sequence is in database
return crtSeqList.contains(seqName);
}
/**
* Execute a SQL statement and optionally return the result as a single value.
*
* @param sqlStmt
* The SQL statement to be executed.
* @param db
* The {@code Database} on which the statement will be executed.
* @param select
* Flags a SELECT statement. The statement will be executed as a query and the first result will
* be returned as unique value.
* @param params
* An optional set of parameters for the statement.
*
* @return In case of a SELECT statement the value is the unique (first) column in first row, or
* {@code null} is the query provided an empty result set.
* In case of not SELECT statements, the result is always {@code null}.
*/
private static Object executeSQL(String sqlStmt, Database db, boolean select, Object... params)
{
try (Session s = new Session(db))
{
PreparedStatement preparedStatement = s.getConnection().prepareStatement(sqlStmt);
for (int i = 0; i < params.length; i++)
{
preparedStatement.setObject(i + 1, params[i]);
}
if (select)
{
SQLExecutor.FunctionWithException<PreparedStatement, ResultSet> f = PreparedStatement::executeQuery;
ResultSet rs = SQLExecutor.getInstance().execute(db, sqlStmt, f, preparedStatement);
return rs.next() ? rs.getObject(1) : null;
}
else
{
SQLExecutor.FunctionWithException<PreparedStatement, Integer> f = PreparedStatement::executeUpdate;
SQLExecutor.getInstance().execute(db, sqlStmt, f, preparedStatement);
return null; // to be ignored
}
}
catch (SQLException | PersistenceException e)
{
return null;
}
}
}