> On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/if/hive_metastore.thrift, line 347 > > <https://reviews.apache.org/r/738/diff/1/?file=18685#file18685line347> > > > > Having separate calls for sending request and response messages looks > > unnecessary. A sendMessage() function with separate request and response > > message types should work just as well, and will help to avoid confusion -- > > otherwise I think people will assume that receiveMessage is a polling call. > > > > This is starting to look like a general purpose messaging/rpc > > framework. Is that the intent? > >
>> A sendMessage() function with separate request and response message types >> should work just as well. That is correct. But semantically they are different. In sendMessage() user is just notifying Metastore of an event and is not bothered of return value. recvMessage() user is asking for a response for his message. This distinction is further enforced by return types. We could just have one api sendMessage() for both as you suggested, but having distinct apis for sending and receiving makes it easier for client to understand the semantics. >> This is starting to look like a general purpose messaging/rpc framework. Well general purpose rpc framework would be much more sophisticated. I am not aiming for that. > On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/if/hive_metastore.thrift, line 348 > > <https://reviews.apache.org/r/738/diff/1/?file=18685#file18685line348> > > > > Identifying the message type using an integer seems brittle. This won't > > work if you have more than one application that is firing events at the > > metastore. There are two other alternatives that I thought of before settling on this one. 1) Add specific apis for different message types. This would have made doing this generic api redundant but then this will result in application specific apis in the metastore. E.g., in HCatalog we want to send a message for "set of partitions" telling Metastore to mark them as done. What does finalizePartition() mean in metastore api when Metastore itself is not aware of this concept as this is application specific. This would be confusing. 2) Use enums instead of integer. This will result in similar problem as above though on a lower scale. Enums give compile time safety so we have to define them in Metastore code. Defining application specific enums doesnt look like a good idea because of similar reasons. > On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/HiveMetaStore.java, > > line 3126 > > <https://reviews.apache.org/r/738/diff/1/?file=18694#file18694line3126> > > > > So the event model is that each event may be handled by at most one > > event handler? Yes. > On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/HiveMetaStore.java, > > line 3134 > > <https://reviews.apache.org/r/738/diff/1/?file=18694#file18694line3134> > > > > Please add some DEBUG or TRACE level logging here that indicates which > > handler consumed a particular event, or if an event was unserviceable. Will add logging. > On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/HiveMetaStore.java, > > line 3149 > > <https://reviews.apache.org/r/738/diff/1/?file=18694#file18694line3149> > > > > Semantically this function looks more like "sendRequest" than > > "receiveMessage" (and "sendMessage" looks more like "fireEvent"). Same as my very first comment. > On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/HiveMetaStore.java, > > line 3151 > > <https://reviews.apache.org/r/738/diff/1/?file=18694#file18694line3151> > > > > Checkstyle: you need a space between control flow tokens and open > > parens. > > will roll this in. > On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/IMetaStoreClient.java, > > line 640 > > <https://reviews.apache.org/r/738/diff/1/?file=18696#file18696line640> > > > > Nice to have: javadoc. Will add. > On 2011-05-25 03:43:30, Carl Steinbach wrote: > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/MetaStoreEventListener.java, > > line 86 > > <https://reviews.apache.org/r/738/diff/1/?file=18697#file18697line86> > > > > canProcessSendMessage() looks like a redundant call. Is there any > > reason that this can't be be rolled into processSendMessage()? > > Event model is every event is handled by atmost one handler. If we roll this in processSendMsg() then we have to make this method return boolean which will tell whether this event got serviced by this handler or not. Then how will it communicate back the actual return value. In case of sendMsg() this is fine, but recvMsg() returns a valid value which is then need to be returned to a client. So, we first ask handler if it can handle the message and then expect a valid return value in processRecvMsg() call. - Ashutosh ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/738/#review713 ----------------------------------------------------------- On 2011-05-12 21:03:29, Ashutosh Chauhan wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/738/ > ----------------------------------------------------------- > > (Updated 2011-05-12 21:03:29) > > > Review request for hive and Carl Steinbach. > > > Summary > ------- > > Updated patch to include missing ASF license and generated thrift code. > > > This addresses bug HIVE-2147. > https://issues.apache.org/jira/browse/HIVE-2147 > > > Diffs > ----- > > trunk/metastore/if/hive_metastore.thrift 1102450 > trunk/metastore/src/gen/thrift/gen-cpp/ThriftHiveMetastore.h 1102450 > trunk/metastore/src/gen/thrift/gen-cpp/ThriftHiveMetastore.cpp 1102450 > > trunk/metastore/src/gen/thrift/gen-cpp/ThriftHiveMetastore_server.skeleton.cpp > 1102450 > > trunk/metastore/src/gen/thrift/gen-javabean/org/apache/hadoop/hive/metastore/api/ThriftHiveMetastore.java > 1102450 > > trunk/metastore/src/gen/thrift/gen-php/hive_metastore/ThriftHiveMetastore.php > 1102450 > > trunk/metastore/src/gen/thrift/gen-py/hive_metastore/ThriftHiveMetastore-remote > 1102450 > trunk/metastore/src/gen/thrift/gen-py/hive_metastore/ThriftHiveMetastore.py > 1102450 > trunk/metastore/src/gen/thrift/gen-rb/thrift_hive_metastore.rb 1102450 > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/HiveMetaStore.java > 1102450 > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/HiveMetaStoreClient.java > 1102450 > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/IMetaStoreClient.java > 1102450 > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/MetaStoreEventListener.java > 1102450 > > trunk/metastore/src/java/org/apache/hadoop/hive/metastore/events/MessageEvent.java > PRE-CREATION > > trunk/metastore/src/test/org/apache/hadoop/hive/metastore/DummyListener.java > 1102450 > > trunk/metastore/src/test/org/apache/hadoop/hive/metastore/TestMetaStoreEventListener.java > 1102450 > > Diff: https://reviews.apache.org/r/738/diff > > > Testing > ------- > > Updated TestMetaStoreEventListener to test new api. > > > Thanks, > > Ashutosh > >
