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提交 c04541fe authored 作者: noelgrandin's avatar noelgrandin
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Fix the combination of updating a table which contains an LOB, and reading from… 

Fix the combination of updating a table which contains an LOB, and reading from the LOB at the same time.
Previously it would throw an exception, now it works.
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h2/src/docsrc/html/changelog.html
浏览文件 @ c04541fe
......@@ -53,6 +53,8 @@ Change Log
</li><li>Add sufficient ClientInfo support to our javax.sql.Connection implementation to make WebSphere happy.
</li><li>Issue 482: class LobStorageBackend$LobInputStream does not override the method InputStream.available().
</li><li>Fix corruption resulting from a mix of the "WRITE_DELAY=0" option and "SELECT DISTINCT" queries
</li><li>Fix the combination of updating a table which contains an LOB, and reading from the LOB at the same time.
Previously it would throw an exception, now it works.
</li></ul>
<h2>Version 1.3.172 (2013-05-25)</h2>
......
h2/src/main/org/h2/store/LobStorageBackend.java
浏览文件 @ c04541fe
......@@ -185,24 +185,21 @@ public class LobStorageBackend implements LobStorageInterface {
/**
* Read a block of data from the given LOB.
*
* @param lob the lob id
* @param seq the block sequence number
* @param block the block number
* @return the block (expanded if stored compressed)
*/
byte[] readBlock(long lob, int seq) throws SQLException {
byte[] readBlock(long block) throws SQLException {
// we have to take the lock on the session
// before the lock on the database to prevent ABBA deadlocks
synchronized (conn.getSession()) {
synchronized (database) {
String sql = "SELECT COMPRESSED, DATA FROM " + LOB_MAP + " M " +
"INNER JOIN " + LOB_DATA + " D ON M.BLOCK = D.BLOCK " +
"WHERE M.LOB = ? AND M.SEQ = ?";
String sql = "SELECT COMPRESSED, DATA FROM " + LOB_DATA + " WHERE BLOCK = ?";
PreparedStatement prep = prepare(sql);
prep.setLong(1, lob);
prep.setInt(2, seq);
prep.setLong(1, block);
ResultSet rs = prep.executeQuery();
if (!rs.next()) {
throw DbException.get(ErrorCode.IO_EXCEPTION_1, "Missing lob entry: "+ lob + "/" + seq).getSQLException();
throw DbException.get(ErrorCode.IO_EXCEPTION_1, "Missing lob entry, block: " + block)
.getSQLException();
}
int compressed = rs.getInt(1);
byte[] buffer = rs.getBytes(2);
......@@ -316,28 +313,13 @@ public class LobStorageBackend implements LobStorageInterface {
@Override
public InputStream getInputStream(long lobId, byte[] hmac, long byteCount) throws IOException {
init();
if (byteCount == -1) {
synchronized (conn.getSession()) {
synchronized (database) {
try {
String sql = "SELECT BYTE_COUNT FROM " + LOBS + " WHERE ID = ?";
PreparedStatement prep = prepare(sql);
prep.setLong(1, lobId);
ResultSet rs = prep.executeQuery();
if (!rs.next()) {
throw DbException.get(ErrorCode.IO_EXCEPTION_1, "Missing lob: " + lobId).getSQLException();
}
byteCount = rs.getLong(1);
reuse(sql, prep);
init();
return new LobInputStream(lobId, byteCount);
} catch (SQLException e) {
throw DbException.convertToIOException(e);
}
}
}
}
return new LobInputStream(lobId, byteCount);
}
private ValueLobDb addLob(InputStream in, long maxLength, int type) {
try {
......@@ -585,9 +567,15 @@ public class LobStorageBackend implements LobStorageInterface {
public class LobInputStream extends InputStream {
/**
* The size of the lob.
* Data from the LOB_MAP table. We cache this to prevent other updates
* to the table that contains the LOB column from changing the data under us.
*/
private final long length;
private final long[] lobMapBlocks;
/**
* index into the lobMapBlocks array.
*/
private int lobMapIndex = 0;
/**
* The remaining bytes in the lob.
......@@ -602,22 +590,52 @@ public class LobStorageBackend implements LobStorageInterface {
/**
* The position within the buffer.
*/
private int pos;
private int bufferPos;
/**
* The lob id.
*/
private final long lob;
/**
* The lob sequence id.
*/
private int seq;
public LobInputStream(long lobId, long byteCount) throws SQLException {
public LobInputStream(long lob, long byteCount) {
this.lob = lob;
// we have to take the lock on the session
// before the lock on the database to prevent ABBA deadlocks
synchronized (conn.getSession()) {
synchronized (database) {
if (byteCount == -1) {
String sql = "SELECT BYTE_COUNT FROM " + LOBS + " WHERE ID = ?";
PreparedStatement prep = prepare(sql);
prep.setLong(1, lobId);
ResultSet rs = prep.executeQuery();
if (!rs.next()) {
throw DbException.get(ErrorCode.IO_EXCEPTION_1, "Missing lob entry: " + lobId).getSQLException();
}
byteCount = rs.getLong(1);
reuse(sql, prep);
}
this.remainingBytes = byteCount;
this.length = byteCount;
String sql = "SELECT COUNT(*) FROM " + LOB_MAP + " WHERE LOB = ?";
PreparedStatement prep = prepare(sql);
prep.setLong(1, lobId);
ResultSet rs = prep.executeQuery();
if (!rs.next()) {
throw DbException.get(ErrorCode.IO_EXCEPTION_1, "Missing lob entry: " + lobId).getSQLException();
}
int lobMapCount = rs.getInt(1);
reuse(sql, prep);
this.lobMapBlocks = new long[lobMapCount];
sql = "SELECT BLOCK FROM " + LOB_MAP + " WHERE LOB = ? ORDER BY SEQ";
prep = prepare(sql);
prep.setLong(1, lobId);
rs = prep.executeQuery();
int i = 0;
while (rs.next()) {
this.lobMapBlocks[i] = rs.getLong(1);
i++;
}
reuse(sql, prep);
}
}
}
@Override
......@@ -627,29 +645,23 @@ public class LobStorageBackend implements LobStorageInterface {
return -1;
}
remainingBytes--;
return buffer[pos++] & 255;
return buffer[bufferPos++] & 255;
}
@Override
public long skip(long n) throws IOException {
if (n <= 0) {
return 0;
}
long remaining = n;
remaining -= skipSmall(remaining);
if (remaining > BLOCK_LENGTH) {
long toPos = length - remainingBytes + remaining;
try {
long[] seqPos = skipBuffer(lob, toPos);
if (seqPos == null) {
remaining -= super.skip(remaining);
return n - remaining;
}
seq = (int) seqPos[0];
long p = seqPos[1];
remainingBytes = length - p;
remaining = toPos - p;
} catch (SQLException e) {
throw DbException.convertToIOException(e);
while (remaining > BLOCK_LENGTH) {
remaining -= BLOCK_LENGTH;
remainingBytes -= BLOCK_LENGTH;
lobMapIndex++;
}
pos = 0;
bufferPos = 0;
buffer = null;
}
fillBuffer();
......@@ -659,9 +671,9 @@ public class LobStorageBackend implements LobStorageInterface {
}
private int skipSmall(long n) {
if (n > 0 && buffer != null && pos < buffer.length) {
int x = MathUtils.convertLongToInt(Math.min(n, buffer.length - pos));
pos += x;
if (buffer != null && bufferPos < buffer.length) {
int x = MathUtils.convertLongToInt(Math.min(n, buffer.length - bufferPos));
bufferPos += x;
remainingBytes -= x;
return x;
}
......@@ -694,9 +706,9 @@ public class LobStorageBackend implements LobStorageInterface {
break;
}
int len = (int) Math.min(length, remainingBytes);
len = Math.min(len, buffer.length - pos);
System.arraycopy(buffer, pos, buff, off, len);
pos += len;
len = Math.min(len, buffer.length - bufferPos);
System.arraycopy(buffer, bufferPos, buff, off, len);
bufferPos += len;
read += len;
remainingBytes -= len;
off += len;
......@@ -706,15 +718,16 @@ public class LobStorageBackend implements LobStorageInterface {
}
private void fillBuffer() throws IOException {
if (buffer != null && pos < buffer.length) {
if (buffer != null && bufferPos < buffer.length) {
return;
}
if (remainingBytes <= 0) {
return;
}
try {
buffer = readBlock(lob, seq++);
pos = 0;
buffer = readBlock(lobMapBlocks[lobMapIndex]);
lobMapIndex++;
bufferPos = 0;
} catch (SQLException e) {
throw DbException.convertToIOException(e);
}
......
h2/src/test/org/h2/test/db/TestLob.java
浏览文件 @ c04541fe
......@@ -80,6 +80,7 @@ public class TestLob extends TestBase {
testTempFilesDeleted(false);
testAddLobRestart();
testLobServerMemory();
testUpdatingLobRow();
if (config.memory) {
return;
}
......@@ -1447,4 +1448,24 @@ public class TestLob extends TestBase {
return new ByteArrayInputStream(buff);
}
}
/** test the combination of updating a table which contains an LOB, and reading from the LOB at the same time */
private void testUpdatingLobRow() throws Exception {
deleteDb("lob");
Connection conn = getConnection("lob");
Statement stat = conn.createStatement();
stat.execute("create table test(id int primary key, name clob, counter int)");
stat.execute("insert into test(id, name) select x, space(100000) from system_range(1, 3)");
ResultSet rs = stat.executeQuery("select name from test where id = 1");
rs.next();
Reader r = rs.getClob("name").getCharacterStream();
Random random = new Random();
char[] tmp = new char[256];
while ( r.read(tmp) > 0) {
stat.execute("update test set counter = " + random.nextInt(1000) + " where id = 1");
}
r.close();
conn.close();
}
}
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