Examples with In org.h2.dev.util.BinaryArithmeticStream.In used on opensource projects

Example 46 with In

use of org.h2.dev.util.BinaryArithmeticStream.In in project h2database by h2database.

the class FunctionAlias method getMethodSignature.

private static String getMethodSignature(Method m) {
    StatementBuilder buff = new StatementBuilder(m.getName());
    buff.append('(');
    for (Class<?> p : m.getParameterTypes()) {
        // do not use a space here, because spaces are removed
        // in CreateFunctionAlias.setJavaClassMethod()
        buff.appendExceptFirst(",");
        if (p.isArray()) {
            buff.append(p.getComponentType().getName()).append("[]");
        } else {
            buff.append(p.getName());
        }
    }
    return buff.append(')').toString();
}

Example 47 with In

use of org.h2.dev.util.BinaryArithmeticStream.In in project h2database by h2database.

the class BackupCommand method backupTo.

private void backupTo(String fileName) {
    Database db = session.getDatabase();
    if (!db.isPersistent()) {
        throw DbException.get(ErrorCode.DATABASE_IS_NOT_PERSISTENT);
    }
    try {
        Store mvStore = db.getMvStore();
        if (mvStore != null) {
            mvStore.flush();
        }
        String name = db.getName();
        name = FileUtils.getName(name);
        try (OutputStream zip = FileUtils.newOutputStream(fileName, false)) {
            ZipOutputStream out = new ZipOutputStream(zip);
            db.flush();
            if (db.getPageStore() != null) {
                String fn = db.getName() + Constants.SUFFIX_PAGE_FILE;
                backupPageStore(out, fn, db.getPageStore());
            }
            // synchronize on the database, to avoid concurrent temp file
            // creation / deletion / backup
            String base = FileUtils.getParent(db.getName());
            synchronized (db.getLobSyncObject()) {
                String prefix = db.getDatabasePath();
                String dir = FileUtils.getParent(prefix);
                dir = FileLister.getDir(dir);
                ArrayList<String> fileList = FileLister.getDatabaseFiles(dir, name, true);
                for (String n : fileList) {
                    if (n.endsWith(Constants.SUFFIX_LOB_FILE)) {
                        backupFile(out, base, n);
                    }
                    if (n.endsWith(Constants.SUFFIX_MV_FILE) && mvStore != null) {
                        MVStore s = mvStore.getStore();
                        boolean before = s.getReuseSpace();
                        s.setReuseSpace(false);
                        try {
                            InputStream in = mvStore.getInputStream();
                            backupFile(out, base, n, in);
                        } finally {
                            s.setReuseSpace(before);
                        }
                    }
                }
            }
            out.close();
        }
    } catch (IOException e) {
        throw DbException.convertIOException(e, fileName);
    }
}

Example 48 with In

use of org.h2.dev.util.BinaryArithmeticStream.In in project h2database by h2database.

the class Function method calculatePrecisionAndDisplaySize.

private void calculatePrecisionAndDisplaySize() {
    switch(info.type) {
        case ENCRYPT:
        case DECRYPT:
            precision = args[2].getPrecision();
            displaySize = args[2].getDisplaySize();
            break;
        case COMPRESS:
            precision = args[0].getPrecision();
            displaySize = args[0].getDisplaySize();
            break;
        case CHAR:
            precision = 1;
            displaySize = 1;
            break;
        case CONCAT:
            precision = 0;
            displaySize = 0;
            for (Expression e : args) {
                precision += e.getPrecision();
                displaySize = MathUtils.convertLongToInt((long) displaySize + e.getDisplaySize());
                if (precision < 0) {
                    precision = Long.MAX_VALUE;
                }
            }
            break;
        case HEXTORAW:
            precision = (args[0].getPrecision() + 3) / 4;
            displaySize = MathUtils.convertLongToInt(precision);
            break;
        case LCASE:
        case LTRIM:
        case RIGHT:
        case RTRIM:
        case UCASE:
        case LOWER:
        case UPPER:
        case TRIM:
        case STRINGDECODE:
        case UTF8TOSTRING:
        case TRUNCATE:
            precision = args[0].getPrecision();
            displaySize = args[0].getDisplaySize();
            break;
        case RAWTOHEX:
            precision = args[0].getPrecision() * 4;
            displaySize = MathUtils.convertLongToInt(precision);
            break;
        case SOUNDEX:
            precision = 4;
            displaySize = (int) precision;
            break;
        case DAY_NAME:
        case MONTH_NAME:
            // day and month names may be long in some languages
            precision = 20;
            displaySize = (int) precision;
            break;
        default:
            DataType type = DataType.getDataType(dataType);
            precision = type.defaultPrecision;
            displaySize = type.defaultDisplaySize;
    }
}

Example 49 with In

use of org.h2.dev.util.BinaryArithmeticStream.In in project h2database by h2database.

the class Function method getValueWithArgs.

private Value getValueWithArgs(Session session, Expression[] args) {
    Value[] values = new Value[args.length];
    if (info.nullIfParameterIsNull) {
        for (int i = 0; i < args.length; i++) {
            Expression e = args[i];
            Value v = e.getValue(session);
            if (v == ValueNull.INSTANCE) {
                return ValueNull.INSTANCE;
            }
            values[i] = v;
        }
    }
    Value v0 = getNullOrValue(session, args, values, 0);
    Value resultSimple = getSimpleValue(session, v0, args, values);
    if (resultSimple != null) {
        return resultSimple;
    }
    Value v1 = getNullOrValue(session, args, values, 1);
    Value v2 = getNullOrValue(session, args, values, 2);
    Value v3 = getNullOrValue(session, args, values, 3);
    Value v4 = getNullOrValue(session, args, values, 4);
    Value v5 = getNullOrValue(session, args, values, 5);
    Value result;
    switch(info.type) {
        case ATAN2:
            result = ValueDouble.get(Math.atan2(v0.getDouble(), v1.getDouble()));
            break;
        case BITAND:
            result = ValueLong.get(v0.getLong() & v1.getLong());
            break;
        case BITGET:
            result = ValueBoolean.get((v0.getLong() & (1L << v1.getInt())) != 0);
            break;
        case BITOR:
            result = ValueLong.get(v0.getLong() | v1.getLong());
            break;
        case BITXOR:
            result = ValueLong.get(v0.getLong() ^ v1.getLong());
            break;
        case MOD:
            {
                long x = v1.getLong();
                if (x == 0) {
                    throw DbException.get(ErrorCode.DIVISION_BY_ZERO_1, getSQL());
                }
                result = ValueLong.get(v0.getLong() % x);
                break;
            }
        case POWER:
            result = ValueDouble.get(Math.pow(v0.getDouble(), v1.getDouble()));
            break;
        case ROUND:
            {
                double f = v1 == null ? 1. : Math.pow(10., v1.getDouble());
                double middleResult = v0.getDouble() * f;
                int oneWithSymbol = middleResult > 0 ? 1 : -1;
                result = ValueDouble.get(Math.round(Math.abs(middleResult)) / f * oneWithSymbol);
                break;
            }
        case TRUNCATE:
            {
                if (v0.getType() == Value.TIMESTAMP) {
                    result = ValueTimestamp.fromDateValueAndNanos(((ValueTimestamp) v0).getDateValue(), 0);
                } else if (v0.getType() == Value.DATE) {
                    result = ValueTimestamp.fromDateValueAndNanos(((ValueDate) v0).getDateValue(), 0);
                } else if (v0.getType() == Value.TIMESTAMP_TZ) {
                    ValueTimestampTimeZone ts = (ValueTimestampTimeZone) v0;
                    result = ValueTimestampTimeZone.fromDateValueAndNanos(ts.getDateValue(), 0, ts.getTimeZoneOffsetMins());
                } else if (v0.getType() == Value.STRING) {
                    ValueTimestamp ts = ValueTimestamp.parse(v0.getString(), session.getDatabase().getMode());
                    result = ValueTimestamp.fromDateValueAndNanos(ts.getDateValue(), 0);
                } else {
                    double d = v0.getDouble();
                    int p = v1 == null ? 0 : v1.getInt();
                    double f = Math.pow(10., p);
                    double g = d * f;
                    result = ValueDouble.get(((d < 0) ? Math.ceil(g) : Math.floor(g)) / f);
                }
                break;
            }
        case HASH:
            result = ValueBytes.getNoCopy(getHash(v0.getString(), v1.getBytesNoCopy(), v2.getInt()));
            break;
        case ENCRYPT:
            result = ValueBytes.getNoCopy(encrypt(v0.getString(), v1.getBytesNoCopy(), v2.getBytesNoCopy()));
            break;
        case DECRYPT:
            result = ValueBytes.getNoCopy(decrypt(v0.getString(), v1.getBytesNoCopy(), v2.getBytesNoCopy()));
            break;
        case COMPRESS:
            {
                String algorithm = null;
                if (v1 != null) {
                    algorithm = v1.getString();
                }
                result = ValueBytes.getNoCopy(CompressTool.getInstance().compress(v0.getBytesNoCopy(), algorithm));
                break;
            }
        case DIFFERENCE:
            result = ValueInt.get(getDifference(v0.getString(), v1.getString()));
            break;
        case INSERT:
            {
                if (v1 == ValueNull.INSTANCE || v2 == ValueNull.INSTANCE) {
                    result = v1;
                } else {
                    result = ValueString.get(insert(v0.getString(), v1.getInt(), v2.getInt(), v3.getString()), database.getMode().treatEmptyStringsAsNull);
                }
                break;
            }
        case LEFT:
            result = ValueString.get(left(v0.getString(), v1.getInt()), database.getMode().treatEmptyStringsAsNull);
            break;
        case LOCATE:
            {
                int start = v2 == null ? 0 : v2.getInt();
                result = ValueInt.get(locate(v0.getString(), v1.getString(), start));
                break;
            }
        case INSTR:
            {
                int start = v2 == null ? 0 : v2.getInt();
                result = ValueInt.get(locate(v1.getString(), v0.getString(), start));
                break;
            }
        case REPEAT:
            {
                int count = Math.max(0, v1.getInt());
                result = ValueString.get(repeat(v0.getString(), count), database.getMode().treatEmptyStringsAsNull);
                break;
            }
        case REPLACE:
            {
                if (v0 == ValueNull.INSTANCE || v1 == ValueNull.INSTANCE || v2 == ValueNull.INSTANCE && database.getMode().getEnum() != Mode.ModeEnum.Oracle) {
                    result = ValueNull.INSTANCE;
                } else {
                    String s0 = v0.getString();
                    String s1 = v1.getString();
                    String s2 = (v2 == null) ? "" : v2.getString();
                    if (s2 == null) {
                        s2 = "";
                    }
                    result = ValueString.get(StringUtils.replaceAll(s0, s1, s2), database.getMode().treatEmptyStringsAsNull);
                }
                break;
            }
        case RIGHT:
            result = ValueString.get(right(v0.getString(), v1.getInt()), database.getMode().treatEmptyStringsAsNull);
            break;
        case LTRIM:
            result = ValueString.get(StringUtils.trim(v0.getString(), true, false, v1 == null ? " " : v1.getString()), database.getMode().treatEmptyStringsAsNull);
            break;
        case TRIM:
            result = ValueString.get(StringUtils.trim(v0.getString(), true, true, v1 == null ? " " : v1.getString()), database.getMode().treatEmptyStringsAsNull);
            break;
        case RTRIM:
            result = ValueString.get(StringUtils.trim(v0.getString(), false, true, v1 == null ? " " : v1.getString()), database.getMode().treatEmptyStringsAsNull);
            break;
        case SUBSTR:
        case SUBSTRING:
            {
                String s = v0.getString();
                int offset = v1.getInt();
                if (offset < 0) {
                    offset = s.length() + offset + 1;
                }
                int length = v2 == null ? s.length() : v2.getInt();
                result = ValueString.get(substring(s, offset, length), database.getMode().treatEmptyStringsAsNull);
                break;
            }
        case POSITION:
            result = ValueInt.get(locate(v0.getString(), v1.getString(), 0));
            break;
        case XMLATTR:
            result = ValueString.get(StringUtils.xmlAttr(v0.getString(), v1.getString()), database.getMode().treatEmptyStringsAsNull);
            break;
        case XMLNODE:
            {
                String attr = v1 == null ? null : v1 == ValueNull.INSTANCE ? null : v1.getString();
                String content = v2 == null ? null : v2 == ValueNull.INSTANCE ? null : v2.getString();
                boolean indent = v3 == null ? true : v3.getBoolean();
                result = ValueString.get(StringUtils.xmlNode(v0.getString(), attr, content, indent), database.getMode().treatEmptyStringsAsNull);
                break;
            }
        case REGEXP_REPLACE:
            {
                String regexp = v1.getString();
                String replacement = v2.getString();
                if (database.getMode().regexpReplaceBackslashReferences) {
                    if ((replacement.indexOf('\\') >= 0) || (replacement.indexOf('$') >= 0)) {
                        StringBuilder sb = new StringBuilder();
                        for (int i = 0; i < replacement.length(); i++) {
                            char c = replacement.charAt(i);
                            if (c == '$') {
                                sb.append('\\');
                            } else if (c == '\\' && ++i < replacement.length()) {
                                c = replacement.charAt(i);
                                sb.append(c >= '0' && c <= '9' ? '$' : '\\');
                            }
                            sb.append(c);
                        }
                        replacement = sb.toString();
                    }
                }
                String regexpMode = v3 == null || v3.getString() == null ? "" : v3.getString();
                int flags = makeRegexpFlags(regexpMode);
                try {
                    result = ValueString.get(Pattern.compile(regexp, flags).matcher(v0.getString()).replaceAll(replacement), database.getMode().treatEmptyStringsAsNull);
                } catch (StringIndexOutOfBoundsException e) {
                    throw DbException.get(ErrorCode.LIKE_ESCAPE_ERROR_1, e, replacement);
                } catch (PatternSyntaxException e) {
                    throw DbException.get(ErrorCode.LIKE_ESCAPE_ERROR_1, e, regexp);
                } catch (IllegalArgumentException e) {
                    throw DbException.get(ErrorCode.LIKE_ESCAPE_ERROR_1, e, replacement);
                }
                break;
            }
        case RPAD:
            result = ValueString.get(StringUtils.pad(v0.getString(), v1.getInt(), v2 == null ? null : v2.getString(), true), database.getMode().treatEmptyStringsAsNull);
            break;
        case LPAD:
            result = ValueString.get(StringUtils.pad(v0.getString(), v1.getInt(), v2 == null ? null : v2.getString(), false), database.getMode().treatEmptyStringsAsNull);
            break;
        case ORA_HASH:
            result = ValueLong.get(oraHash(v0.getString(), v1 == null ? null : v1.getInt(), v2 == null ? null : v2.getInt()));
            break;
        case TO_CHAR:
            switch(v0.getType()) {
                case Value.TIME:
                case Value.DATE:
                case Value.TIMESTAMP:
                case Value.TIMESTAMP_TZ:
                    result = ValueString.get(ToChar.toCharDateTime(v0, v1 == null ? null : v1.getString(), v2 == null ? null : v2.getString()), database.getMode().treatEmptyStringsAsNull);
                    break;
                case Value.SHORT:
                case Value.INT:
                case Value.LONG:
                case Value.DECIMAL:
                case Value.DOUBLE:
                case Value.FLOAT:
                    result = ValueString.get(ToChar.toChar(v0.getBigDecimal(), v1 == null ? null : v1.getString(), v2 == null ? null : v2.getString()), database.getMode().treatEmptyStringsAsNull);
                    break;
                default:
                    result = ValueString.get(v0.getString(), database.getMode().treatEmptyStringsAsNull);
            }
            break;
        case TO_DATE:
            result = ToDateParser.toDate(v0.getString(), v1 == null ? null : v1.getString());
            break;
        case TO_TIMESTAMP:
            result = ToDateParser.toTimestamp(v0.getString(), v1 == null ? null : v1.getString());
            break;
        case ADD_MONTHS:
            result = DateTimeFunctions.dateadd("MONTH", v1.getInt(), v0);
            break;
        case TO_TIMESTAMP_TZ:
            result = ToDateParser.toTimestampTz(v0.getString(), v1 == null ? null : v1.getString());
            break;
        case TRANSLATE:
            {
                String matching = v1.getString();
                String replacement = v2.getString();
                result = ValueString.get(translate(v0.getString(), matching, replacement), database.getMode().treatEmptyStringsAsNull);
                break;
            }
        case H2VERSION:
            result = ValueString.get(Constants.getVersion(), database.getMode().treatEmptyStringsAsNull);
            break;
        case DATE_ADD:
            result = DateTimeFunctions.dateadd(v0.getString(), v1.getLong(), v2);
            break;
        case DATE_DIFF:
            result = ValueLong.get(DateTimeFunctions.datediff(v0.getString(), v1, v2));
            break;
        case DATE_TRUNC:
            result = DateTimeFunctions.truncateDate(v0.getString(), v1);
            break;
        case EXTRACT:
            result = DateTimeFunctions.extract(v0.getString(), v1);
            break;
        case FORMATDATETIME:
            {
                if (v0 == ValueNull.INSTANCE || v1 == ValueNull.INSTANCE) {
                    result = ValueNull.INSTANCE;
                } else {
                    String locale = v2 == null ? null : v2 == ValueNull.INSTANCE ? null : v2.getString();
                    String tz = v3 == null ? null : v3 == ValueNull.INSTANCE ? null : v3.getString();
                    if (v0 instanceof ValueTimestampTimeZone) {
                        tz = DateTimeUtils.timeZoneNameFromOffsetMins(((ValueTimestampTimeZone) v0).getTimeZoneOffsetMins());
                    }
                    result = ValueString.get(DateTimeFunctions.formatDateTime(v0.getTimestamp(), v1.getString(), locale, tz), database.getMode().treatEmptyStringsAsNull);
                }
                break;
            }
        case PARSEDATETIME:
            {
                if (v0 == ValueNull.INSTANCE || v1 == ValueNull.INSTANCE) {
                    result = ValueNull.INSTANCE;
                } else {
                    String locale = v2 == null ? null : v2 == ValueNull.INSTANCE ? null : v2.getString();
                    String tz = v3 == null ? null : v3 == ValueNull.INSTANCE ? null : v3.getString();
                    java.util.Date d = DateTimeFunctions.parseDateTime(v0.getString(), v1.getString(), locale, tz);
                    result = ValueTimestamp.fromMillis(d.getTime());
                }
                break;
            }
        case NULLIF:
            result = database.areEqual(v0, v1) ? ValueNull.INSTANCE : v0;
            break;
        // system
        case NEXTVAL:
            {
                Sequence sequence = getSequence(session, v0, v1);
                SequenceValue value = new SequenceValue(sequence);
                result = value.getValue(session);
                break;
            }
        case CURRVAL:
            {
                Sequence sequence = getSequence(session, v0, v1);
                result = ValueLong.get(sequence.getCurrentValue());
                break;
            }
        case CSVREAD:
            {
                String fileName = v0.getString();
                String columnList = v1 == null ? null : v1.getString();
                Csv csv = new Csv();
                String options = v2 == null ? null : v2.getString();
                String charset = null;
                if (options != null && options.indexOf('=') >= 0) {
                    charset = csv.setOptions(options);
                } else {
                    charset = options;
                    String fieldSeparatorRead = v3 == null ? null : v3.getString();
                    String fieldDelimiter = v4 == null ? null : v4.getString();
                    String escapeCharacter = v5 == null ? null : v5.getString();
                    Value v6 = getNullOrValue(session, args, values, 6);
                    String nullString = v6 == null ? null : v6.getString();
                    setCsvDelimiterEscape(csv, fieldSeparatorRead, fieldDelimiter, escapeCharacter);
                    csv.setNullString(nullString);
                }
                char fieldSeparator = csv.getFieldSeparatorRead();
                String[] columns = StringUtils.arraySplit(columnList, fieldSeparator, true);
                try {
                    result = ValueResultSet.get(csv.read(fileName, columns, charset));
                } catch (SQLException e) {
                    throw DbException.convert(e);
                }
                break;
            }
        case LINK_SCHEMA:
            {
                session.getUser().checkAdmin();
                Connection conn = session.createConnection(false);
                ResultSet rs = LinkSchema.linkSchema(conn, v0.getString(), v1.getString(), v2.getString(), v3.getString(), v4.getString(), v5.getString());
                result = ValueResultSet.get(rs);
                break;
            }
        case CSVWRITE:
            {
                session.getUser().checkAdmin();
                Connection conn = session.createConnection(false);
                Csv csv = new Csv();
                String options = v2 == null ? null : v2.getString();
                String charset = null;
                if (options != null && options.indexOf('=') >= 0) {
                    charset = csv.setOptions(options);
                } else {
                    charset = options;
                    String fieldSeparatorWrite = v3 == null ? null : v3.getString();
                    String fieldDelimiter = v4 == null ? null : v4.getString();
                    String escapeCharacter = v5 == null ? null : v5.getString();
                    Value v6 = getNullOrValue(session, args, values, 6);
                    String nullString = v6 == null ? null : v6.getString();
                    Value v7 = getNullOrValue(session, args, values, 7);
                    String lineSeparator = v7 == null ? null : v7.getString();
                    setCsvDelimiterEscape(csv, fieldSeparatorWrite, fieldDelimiter, escapeCharacter);
                    csv.setNullString(nullString);
                    if (lineSeparator != null) {
                        csv.setLineSeparator(lineSeparator);
                    }
                }
                try {
                    int rows = csv.write(conn, v0.getString(), v1.getString(), charset);
                    result = ValueInt.get(rows);
                } catch (SQLException e) {
                    throw DbException.convert(e);
                }
                break;
            }
        case SET:
            {
                Variable var = (Variable) args[0];
                session.setVariable(var.getName(), v1);
                result = v1;
                break;
            }
        case FILE_READ:
            {
                session.getUser().checkAdmin();
                String fileName = v0.getString();
                boolean blob = args.length == 1;
                try {
                    long fileLength = FileUtils.size(fileName);
                    final InputStream in = FileUtils.newInputStream(fileName);
                    try {
                        if (blob) {
                            result = database.getLobStorage().createBlob(in, fileLength);
                        } else {
                            Reader reader;
                            if (v1 == ValueNull.INSTANCE) {
                                reader = new InputStreamReader(in);
                            } else {
                                reader = new InputStreamReader(in, v1.getString());
                            }
                            result = database.getLobStorage().createClob(reader, fileLength);
                        }
                    } finally {
                        IOUtils.closeSilently(in);
                    }
                    session.addTemporaryLob(result);
                } catch (IOException e) {
                    throw DbException.convertIOException(e, fileName);
                }
                break;
            }
        case FILE_WRITE:
            {
                session.getUser().checkAdmin();
                result = ValueNull.INSTANCE;
                String fileName = v1.getString();
                try {
                    FileOutputStream fileOutputStream = new FileOutputStream(fileName);
                    try (InputStream in = v0.getInputStream()) {
                        result = ValueLong.get(IOUtils.copyAndClose(in, fileOutputStream));
                    }
                } catch (IOException e) {
                    throw DbException.convertIOException(e, fileName);
                }
                break;
            }
        case TRUNCATE_VALUE:
            {
                result = v0.convertPrecision(v1.getLong(), v2.getBoolean());
                break;
            }
        case XMLTEXT:
            if (v1 == null) {
                result = ValueString.get(StringUtils.xmlText(v0.getString()), database.getMode().treatEmptyStringsAsNull);
            } else {
                result = ValueString.get(StringUtils.xmlText(v0.getString(), v1.getBoolean()), database.getMode().treatEmptyStringsAsNull);
            }
            break;
        case REGEXP_LIKE:
            {
                String regexp = v1.getString();
                String regexpMode = v2 == null || v2.getString() == null ? "" : v2.getString();
                int flags = makeRegexpFlags(regexpMode);
                try {
                    result = ValueBoolean.get(Pattern.compile(regexp, flags).matcher(v0.getString()).find());
                } catch (PatternSyntaxException e) {
                    throw DbException.get(ErrorCode.LIKE_ESCAPE_ERROR_1, e, regexp);
                }
                break;
            }
        case VALUES:
            result = session.getVariable(args[0].getSchemaName() + "." + args[0].getTableName() + "." + args[0].getColumnName());
            break;
        case SIGNAL:
            {
                String sqlState = v0.getString();
                if (sqlState.startsWith("00") || !SIGNAL_PATTERN.matcher(sqlState).matches()) {
                    throw DbException.getInvalidValueException("SQLSTATE", sqlState);
                }
                String msgText = v1.getString();
                throw DbException.fromUser(sqlState, msgText);
            }
        default:
            throw DbException.throwInternalError("type=" + info.type);
    }
    return result;
}

Example 50 with In

use of org.h2.dev.util.BinaryArithmeticStream.In in project h2database by h2database.

the class Session method unlockReadLocks.

/**
 * Unlock all read locks. This is done if the transaction isolation mode is
 * READ_COMMITTED.
 */
public void unlockReadLocks() {
    if (database.isMultiVersion()) {
        // MVCC: keep shared locks (insert / update / delete)
        return;
    }
    // locks is modified in the loop
    for (int i = 0; i < locks.size(); i++) {
        Table t = locks.get(i);
        if (!t.isLockedExclusively()) {
            synchronized (database) {
                t.unlock(this);
                locks.remove(i);
            }
            i--;
        }
    }
}