Calling close on HTable (it's there contrary to your claim) only calls a
flushCommits to ensure no data is kept in the write buffer (not your case).
We added a shutdownHook to make sure that when the JVM exists it closes the
connection to zookeeper.
There is a hard limit of client connection per IP for each member of the
zookeeper quorum, you maybe hitting that limit. From conf/hbase-default.xml:
<property>
<name>hbase.zookeeper.property.maxClientCnxns</name>
<value>30</value>
<description>Property from ZooKeeper's config zoo.cfg.
Limit on number of concurrent connections (at the socket level) that a
single client, identified by IP address, may make to a single member of
the ZooKeeper ensemble. Set high to avoid zk connection issues running
standalone and pseudo-distributed.
</description>
</property>
You may want to play with that.
J-D
2010/2/5 <y_823...@tsmc.com>
> Hi,
> I didn't see any code about close HTable, just scaner.close.
> Finish running HBase client program in a container then I restart HBase;
> I found there's message zookeeper.ClientCnxn: Server connection successful
> in my
> container console.
> I think that maybe I didn't close that table.
> By adding table.close; I hope that mesage "Server connection successful"
> would not appear again,
> but it's not.
> I guess there are still up to 2000 clients' connection to Hbase without
> closing.
> After that, I can't query data from hbase any more.
> Any suggestions?
>
>
> HTable table = new HTable(config, "myLittleHBaseTable");
>
> // To add to a row, use Put. A Put constructor takes the name of the
> row
> // you want to insert into as a byte array. In HBase, the Bytes class
> has
> // utility for converting all kinds of java types to byte arrays. In
> the
> // below, we are converting the String "myLittleRow" into a byte array
> to
> // use as a row key for our update. Once you have a Put instance, you
> can
> // adorn it by setting the names of columns you want to update on the
> row,
> // the timestamp to use in your update, etc.If no timestamp, the server
> // applies current time to the edits.
> Put p = new Put(Bytes.toBytes("myLittleRow"));
>
> // To set the value you'd like to update in the row 'myLittleRow',
> specify
> // the column family, column qualifier, and value of the table cell
> you'd
> // like to update. The column family must already exist in your table
> // schema. The qualifier can be anything. All must be specified as
> byte
> // arrays as hbase is all about byte arrays. Lets pretend the table
> // 'myLittleHBaseTable' was created with a family 'myLittleFamily'.
> p.add(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"),
> Bytes.toBytes("Some Value"));
>
> // Once you've adorned your Put instance with all the updates you want
> to
> // make, to commit it do the following (The HTable#put method takes the
> // Put instance you've been building and pushes the changes you made
> into
> // hbase)
> table.put(p);
>
> // Now, to retrieve the data we just wrote. The values that come back
> are
> // Result instances. Generally, a Result is an object that will package
> up
> // the hbase return into the form you find most palatable.
> Get g = new Get(Bytes.toBytes("myLittleRow"));
> Result r = table.get(g);
> byte [] value = r.getValue(Bytes.toBytes("myLittleFamily"),
> Bytes.toBytes("someQualifier"));
> // If we convert the value bytes, we should get back 'Some Value', the
> // value we inserted at this location.
> String valueStr = Bytes.toString(value);
> System.out.println("GET: " + valueStr);
>
> // Sometimes, you won't know the row you're looking for. In this case,
> you
> // use a Scanner. This will give you cursor-like interface to the
> contents
> // of the table. To set up a Scanner, do like you did above making a
> Put
> // and a Get, create a Scan. Adorn it with column names, etc.
> Scan s = new Scan();
> s.addColumn(Bytes.toBytes("myLittleFamily"),
> Bytes.toBytes("someQualifier"));
> ResultScanner scanner = table.getScanner(s);
> try {
> // Scanners return Result instances.
> // Now, for the actual iteration. One way is to use a while loop like
> so:
> for (Result rr = scanner.next(); rr != null; rr = scanner.next()) {
> // print out the row we found and the columns we were looking for
> System.out.println("Found row: " + rr);
> }
>
> // The other approach is to use a foreach loop. Scanners are
> iterable!
> // for (Result rr : scanner) {
> // System.out.println("Found row: " + rr);
> // }
> } finally {
> // Make sure you close your scanners when you are done!
> // Thats why we have it inside a try/finally clause
> scanner.close();
> }
>
>
>
>
>
> Fleming Chiu(邱宏明)
> 707-6128
> y_823...@tsmc.com
> 週一無肉日吃素救地球(Meat Free Monday Taiwan)
>
>
>
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