/* (non-Javadoc)
* @see org.apache.hadoop.hbase.TableDescriptors#getTableDescriptor(byte[])
*/
@Override
public HTableDescriptor get(final String tablename) throws IOException {
invocations++;
if (HTableDescriptor.ROOT_TABLEDESC.getNameAsString().equals(tablename)) {
cachehits++;
return HTableDescriptor.ROOT_TABLEDESC;
}
if (HTableDescriptor.META_TABLEDESC.getNameAsString().equals(tablename)) {
cachehits++;
return HTableDescriptor.META_TABLEDESC;
}
// .META. and -ROOT- is already handled. If some one tries to get the descriptor for
// .logs, .oldlogs or .corrupt throw an exception.
if (HConstants.HBASE_NON_USER_TABLE_DIRS.contains(tablename)) {
throw new IOException("No descriptor found for table = " + tablename);
}
// Look in cache of descriptors.
TableDescriptorModtime cachedtdm = this.cache.get(tablename);
if (cachedtdm != null) {
// Check mod time has not changed (this is trip to NN).
if (getTableInfoModtime(this.fs, this.rootdir, tablename) <= cachedtdm.getModtime()) {
cachehits++;
return cachedtdm.getTableDescriptor();
}
}
TableDescriptorModtime tdmt = null;
try {
tdmt = getTableDescriptorModtime(this.fs, this.rootdir, tablename);
} catch (NullPointerException e) {
LOG.debug("Exception during readTableDecriptor. Current table name = " + tablename, e);
} catch (IOException ioe) {
LOG.debug("Exception during readTableDecriptor. Current table name = " + tablename, ioe);
}
if (tdmt == null) {
LOG.warn(
"The following folder is in HBase's root directory and "
+ "doesn't contain a table descriptor, "
+ "do consider deleting it: "
+ tablename);
} else {
this.cache.put(tablename, tdmt);
}
return tdmt == null ? null : tdmt.getTableDescriptor();
}
/**
* Checks if the specified table exists. Looks at the META table hosted on the specified server.
*
* @param catalogTracker
* @param tableName table to check
* @return true if the table exists in meta, false if not
* @throws IOException
*/
public static boolean tableExists(CatalogTracker catalogTracker, String tableName)
throws IOException {
if (tableName.equals(HTableDescriptor.ROOT_TABLEDESC.getNameAsString())
|| tableName.equals(HTableDescriptor.META_TABLEDESC.getNameAsString())) {
// Catalog tables always exist.
return true;
}
final byte[] tableNameBytes = Bytes.toBytes(tableName);
// Make a version of ResultCollectingVisitor that only collects the first
CollectingVisitor<HRegionInfo> visitor =
new CollectingVisitor<HRegionInfo>() {
private HRegionInfo current = null;
@Override
public boolean visit(Result r) throws IOException {
this.current = parseHRegionInfoFromCatalogResult(r, HConstants.REGIONINFO_QUALIFIER);
if (this.current == null) {
LOG.warn("No serialized HRegionInfo in " + r);
return true;
}
if (!isInsideTable(this.current, tableNameBytes)) return false;
// Else call super and add this Result to the collection.
super.visit(r);
// Stop collecting regions from table after we get one.
return false;
}
@Override
void add(Result r) {
// Add the current HRI.
this.results.add(this.current);
}
};
fullScan(catalogTracker, visitor, getTableStartRowForMeta(tableNameBytes));
// If visitor has results >= 1 then table exists.
return visitor.getResults().size() >= 1;
}
@Test
public void testCreateBadTables() throws IOException {
String msg = null;
try {
this.admin.createTable(HTableDescriptor.ROOT_TABLEDESC);
} catch (IllegalArgumentException e) {
msg = e.toString();
}
assertTrue(
"Unexcepted exception message " + msg,
msg != null
&& msg.startsWith(IllegalArgumentException.class.getName())
&& msg.contains(HTableDescriptor.ROOT_TABLEDESC.getNameAsString()));
msg = null;
try {
this.admin.createTable(HTableDescriptor.META_TABLEDESC);
} catch (IllegalArgumentException e) {
msg = e.toString();
}
assertTrue(
"Unexcepted exception message " + msg,
msg != null
&& msg.startsWith(IllegalArgumentException.class.getName())
&& msg.contains(HTableDescriptor.META_TABLEDESC.getNameAsString()));
// Now try and do concurrent creation with a bunch of threads.
final HTableDescriptor threadDesc = new HTableDescriptor("threaded_testCreateBadTables");
threadDesc.addFamily(new HColumnDescriptor(HConstants.CATALOG_FAMILY));
int count = 10;
Thread[] threads = new Thread[count];
final AtomicInteger successes = new AtomicInteger(0);
final AtomicInteger failures = new AtomicInteger(0);
final HBaseAdmin localAdmin = this.admin;
for (int i = 0; i < count; i++) {
threads[i] =
new Thread(Integer.toString(i)) {
@Override
public void run() {
try {
localAdmin.createTable(threadDesc);
successes.incrementAndGet();
} catch (TableExistsException e) {
failures.incrementAndGet();
} catch (IOException e) {
throw new RuntimeException("Failed threaded create" + getName(), e);
}
}
};
}
for (int i = 0; i < count; i++) {
threads[i].start();
}
for (int i = 0; i < count; i++) {
while (threads[i].isAlive()) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// continue
}
}
}
// All threads are now dead. Count up how many tables were created and
// how many failed w/ appropriate exception.
assertEquals(1, successes.get());
assertEquals(count - 1, failures.get());
}