|
@@ -481,7 +481,7 @@ document.write("Last Published: " + document.lastModified);
|
|
|
<em>znode</em>. Znodes maintain a stat structure that
|
|
|
includes version numbers for data changes, acl changes. The stat
|
|
|
structure also has timestamps. The version number, together with the
|
|
|
- timestamp allow ZooKeeper to validate the cache and to coordinate
|
|
|
+ timestamp, allows ZooKeeper to validate the cache and to coordinate
|
|
|
updates. Each time a znode's data changes, the version number increases.
|
|
|
For instance, whenever a client retrieves data, it also receives the
|
|
|
version of the data. And when a client performs an update or a delete,
|
|
@@ -582,7 +582,7 @@ document.write("Last Published: " + document.lastModified);
|
|
|
</p>
|
|
|
|
|
|
|
|
|
-<p>Every change to a a node will cause an increase to one of the
|
|
|
+<p>Every change to a node will cause an increase to one of the
|
|
|
version numbers of that node. The three version numbers are version
|
|
|
(number of changes to the data of a znode), cversion (number of
|
|
|
changes to the children of a znode), and aversion (number of changes
|
|
@@ -927,7 +927,7 @@ document.write("Last Published: " + document.lastModified);
|
|
|
<strong>Added in 3.2.0 -- SessionMovedException</strong>. There is an internal
|
|
|
exception that is generally not seen by clients called the SessionMovedException.
|
|
|
This exception occurs because a request was received on a connection for a session
|
|
|
- which has be reestablished on a different server. The normal cause of this error is
|
|
|
+ which has been reestablished on a different server. The normal cause of this error is
|
|
|
a client that sends a request to a server, but the network packet gets delayed, so
|
|
|
the client times out and connects to a new server. When the delayed packet arrives at
|
|
|
the first server, the old server detects that the session has moved, and closes the
|
|
@@ -936,7 +936,7 @@ document.write("Last Published: " + document.lastModified);
|
|
|
condition can be seen is when two clients try to reestablish the same connection using
|
|
|
a saved session id and password. One of the clients will reestablish the connection
|
|
|
and the second client will be disconnected (causing the pair to attempt to re-establish
|
|
|
- it's connection/session indefinitely).</p>
|
|
|
+ its connection/session indefinitely).</p>
|
|
|
<p>
|
|
|
<strong>Updating the list of servers</strong>. We allow a client to
|
|
|
update the connection string by providing a new comma separated list of host:port pairs,
|
|
@@ -1047,13 +1047,13 @@ document.write("Last Published: " + document.lastModified);
|
|
|
|
|
|
</ul>
|
|
|
<p>Watches are maintained locally at the ZooKeeper server to which the
|
|
|
- client is connected. This allows watches to be light weight to set,
|
|
|
+ client is connected. This allows watches to be lightweight to set,
|
|
|
maintain, and dispatch. When a client connects to a new server, the watch
|
|
|
will be triggered for any session events. Watches will not be received
|
|
|
while disconnected from a server. When a client reconnects, any previously
|
|
|
registered watches will be reregistered and triggered if needed. In
|
|
|
general this all occurs transparently. There is one case where a watch
|
|
|
- may be missed: a watch for the existance of a znode not yet created will
|
|
|
+ may be missed: a watch for the existence of a znode not yet created will
|
|
|
be missed if the znode is created and deleted while disconnected.</p>
|
|
|
<a name="sc_WatchGuarantees"></a>
|
|
|
<h3 class="h4">What ZooKeeper Guarantees about Watches</h3>
|
|
@@ -1649,7 +1649,7 @@ authProvider.2=com.f.MyAuth2
|
|
|
have been applied. On some failures (communication errors,
|
|
|
timeouts, etc) the client will not know if the update has
|
|
|
applied or not. We take steps to minimize the failures, but the
|
|
|
- only guarantee is only present with successful return codes.
|
|
|
+ guarantee is only present with successful return codes.
|
|
|
(This is called the <em>monotonicity condition</em> in Paxos.)</p>
|
|
|
|
|
|
</li>
|
|
@@ -1672,7 +1672,7 @@ authProvider.2=com.f.MyAuth2
|
|
|
</dt>
|
|
|
<dd>
|
|
|
<p>The clients view of the system is guaranteed to be up-to-date
|
|
|
- within a certain time bound. (On the order of tens of seconds.)
|
|
|
+ within a certain time bound (on the order of tens of seconds).
|
|
|
Either system changes will be seen by a client within this bound, or
|
|
|
the client will detect a service outage.</p>
|
|
|
</dd>
|
|
@@ -1975,7 +1975,7 @@ authProvider.2=com.f.MyAuth2
|
|
|
<li>
|
|
|
|
|
|
<p>Include ZooKeeper header: #include
|
|
|
- <zookeeper/zookeeper.h</p>
|
|
|
+ <zookeeper/zookeeper.h></p>
|
|
|
|
|
|
</li>
|
|
|
|