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  1 karl  1.1.2.1         Using the CIM/XML Pull Operations
  2               
  3               STATUS
  4               
  5 karl  1.1.2.4 <<< The TODO section is being maintained during the review and checkin process
  6 karl  1.1.2.1 to keep track of problems, errors, notes, etc.  Must be deleted before
  7               checkin to head of tree. Please feel free to add notes, etc in this
  8               section as you review/test.>>>>>>
  9               
 10 karl  1.1.2.4 TODO list:
 11 karl  1.1.2.3    1. Binary operation from OOP.  Need to add counter to binary
 12                     protocol to be able to count objects in response. Generates
 13                     warnings in things like messageserializer and does not work with
 14                     OOP right now.
 15 karl  1.1.2.4    2. OpenExecQuery - Code is incorrect in that it used InstancesWithPath
 16                     where the spec is instances with no path.  Need new function to wrap
 17                     getInstanceElement(withoutPathElement) in XmlReader.  Note that
 18                     Alternate is to put flag on InstancesWith Path to say no path
 19                  3. Code for Pull part of OpenQueryInstancesRequest a) should be part of
 20                     the common CIMOperationRequestDispatcher execCommon code.
 21                  4. The changes to WQLCIMOperationRequestDispatcher and CQL... for handling
 22                     pull not completed so we feed the responses back to the EnmerationContext
 23                     queues
 24 karl  1.1.2.7    3. Lots of minor TODOs, diagnostics, etc.
 25 karl  1.1.2.4    4. External runtime variables. Decide this as part of PEP. The variables
 26                     exist in CIMOperationRequestDispatcher but not in CIMConfig.  The primary
 27                     ones to consider are:
 28                     a. System maxObjectCount.  Setting some maximum size on what a pull
 29                         client can request (i.e. the maximum size of the maxObjectCount on
 30                         Open... and pull operations.
 31                     b. Pull interoperationTimeout (max times between operations). This is
 32                         the maximum number of seconds on the operationTimeout parameter of the
 33                         Open operations
 34                     c. Maximum size of the responseCache before it starts backing up
 35                         responses to the providers.
 36 karl  1.1.2.3    5. Decision on EnumerationContext timeout (separate thread or just
 37 karl  1.1.2.4       checks during other operations). Can we, in fact really keep the 
 38                     enumeration context table and queue under control without monitoring
 39                     with a separate thread. We must monitor for:
 40                     a. Client operation that stop requesting (i.e. inter operation time
 41                         exceeds operationTimeout). Note that if it simply exceeds the time
 42                         the next operation does the cleanup.  The issue is those clients that
 43                         simply stop and do not either close or go to completion.
 44                     b. We should protect against providers that no not every finish delivering
 45                         or take to long between deliveries.  This does not exist in Pegasus
 46                         today
 47 karl  1.1.2.8    6. Clean up code in Dispatcher. Want to at least reduce the code for the
 48                     Open Operations to a set of templates so we know that the code is the
 49                     same for all operations.  Right now the existing operations enum, assoc,
 50                     etc. are all in templates but not the open operations.  Note that the
 51                     pull is a single template for both pullInstances and pullInstancePaths.
 52                     However, we might be able to reduce this to a single function by adding
 53                     a new level to CIMMessage.h (CommonPullResponse)
 54 karl  1.1.2.3    7. Extension to avoid double move of objects in CIMResponseData (one
 55                     into enumerationContext queue and second to new cimResponseData for
 56                     response.  Want to avoid second move by extending Open/Pull response
 57                     messages to include count and CIMResponse data to count objects out
 58                     of queue when converting (avoids the second move).  Big issue here
 59                     with binary data since need to extend format to count it.
 60 karl  1.1.2.8    8. NEXT TASKS: 
 61                     a. get the pull operations rather than a template into a single
 62                     function by creating a new CIMPullResponse message in CIMMessage.h that
 63                     contains the pull data.  Then we can use a single function to process all
 64                     pull operations.
 65 karl  1.1.2.9       b. test the enumeration timeout thread
 66 karl  1.1.2.8       c. New Mergout to bring up to to date again.
 67 karl  1.1.2.11       d. Sort out issues with statisticalData since it really does not work
 68                         with Open and Pull operations
 69 karl  1.1.2.10 
 70                29 September 2013. CVS update.
 71                1. Modified calls to statisticalData.cpp to a) directly call with request
 72                   type, b) incorporate the open, pull, etc. messages.  However, since these
 73                   are not part of the CIM class, we must do something special with them.
 74                2. Corrected OOP interface to enable new flag to indicate internal operations
 75                   and set host, etc.
 76                3. Add code to CQLOperationsDispatcher and WQLOperationDispatcher to clean
 77                   up CIMResponseDataCounter after filtering.
 78                4. Modified ProviderAgent to set Host info for some pull operations.
 79                5. Added new flag to CIMBinMsgSerializer and Deserializer.
 80 karl  1.1.2.8  
 81 karl  1.1.2.9  17 September 2013 CVS update (Actually two different updates over 3 days)
 82                1. Clean up some issues in CIMMessage.h and CIMMessage.cpp
 83                2. Extend OpenExecQuery to WQL and CQL processors but return not complete
 84                3. Remove memory leak in EnumerationContext and EnumerationContextTable
 85                   handling.
 86                4. Created template functions for much of the pull operations.
 87                5. Reversed order of queryLanguage and query (and changed names to match
 88                   execQuery) in client and server.  Note that these are the execQuery
 89                   WQL and CQL filters and NOT FQL filters.
 90                6. Some code cleanup in dispatcher
 91                7. Today, passes all tests in pullop but issue in alltests. For some reason
 92                   not finding CIMObjectManager instance. Also, leaves enumeration contexts
 93                   if client terminates since cleanup thread not operating.
 94 karl  1.1.2.11 8. XML from OOP not correctly processed.
 95 karl  1.1.2.9  
 96 karl  1.1.2.8  14 September 2013 CVS update
 97                Merged out up to 25 August.  Cleaned up all operations and standardized code.
 98                At this point the non pull operations code is in a set of templates but the
 99                pull is not yet.
100                Fixed a significant number of problems so that it appears that the operations
101                except for OpenExecQuery run stably, at least with the pullop test program.
102                Note that there is a problem in that the Interop control provider is not
103                returning its singleton wbemserver object for some reason.  Causes a test
104                failure
105 karl  1.1.2.7  
106                Fixed for 16 June CVS Update
107                   1. Cleaned up the enumerationContext and Table release functions and tested
108                      to confirm that we do not lose memory in either normal sequences or
109                      sequences that close early. Cleaned up pullop and added more tests
110 karl  1.1.2.8  Taged Before: PREAUG25UPDATE and after POSTAUG25UPDATE
111 karl  1.1.2.4  
112                Fixed for 9 June CVS update
113                   1. Cleaned up code for OpenQueryInstances.  Note that this is incomplete.
114                      No support in WQL or CQL Operations
115                   2. 
116                
117                What was fixed for 5 June checkin.
118 karl  1.1.2.3     1. Extended ResponseTest MOF for for both CMPI and C++ subclasses
119                   2. Fixed issues with pullop.
120                   3. Fixed temp issue with CIMResponseData size by putting in mutex. That
121                      is not a permanent fix but it gets around issue probably in the control
122                      of the move logic that meant counts were off.
123                   4. Fixed issues in Dispatcher so that associator code works. Still messy
124                      code in the dispatcher.
125                   5. Changed name of Enumerationtable.h & cpp to EnumerationContextTable.*
126                   6  Changed name of ResponseStressTest module, classes, etc.
127                
128                TAG: TASK_PEP317_5JUNE_2013_2
129                
130 karl  1.1.2.2  2 June 2013
131 karl  1.1.2.1  
132                Issues  - KS
133                1. have not installed the binary move in CIMResponseData. Please run
134                with OPP off.
135                2. Some problem in the processing so we are getting server crashes.
136                Right no I am guessing that this is in the binaryCodec and am going to
137                expand the test tools to allow testing through the localhost.
138                
139                3. Still way to many TODO and KS comments and KS_TEMPS.  Removing bit by bit.
140                
141                4. Env variable connection for the config parameters not installed.
142                
143                5. Issue with the threaded timer.  For some reason during tests it
144                eventually calls the timer thread with trash for the parm (which is
145                pointer to the EnumerationTable object). Caught because we do a valid
146                test at beginning of the function.
147                
148 karl  1.1.2.2  6. Still using the templates in CIMOperationRequestDispatcher to simplify
149                the handle... processing.  
150                
151                7. I think I have a way around the double move of objects in the
152                EnumerationContext so that the outputter will just take a defined number
153                of objects directly from the gathering cache and save the second move.
154                
155                8. Not yet passing all tests but getting closer now.
156                
157                9. Created a tag before this commit TASK_PEP317_1JUNE_2013.
158                
159                10. Next Tag will be TASK_PEP317_2_JUNE_2013 in the task branch
160                
161                
162 karl  1.1.2.1  ===========================================
163                
164                OVERVIEW:
165                
166                The operation extensions for pull operations defined in the DMTF specification
167                DSP0200 V 1.4 were implemented in Pegasus effective Pegasus version 2.11
168                including Client and Server.
169                
170                These operations extend the CIM/XML  individual operations to operation
171                sequences where the server must maintain state between operations in a
172                sequence and the client must execute multiple operations to get the full
173                set of instances or instance paths.
174                
175                The following new CIM/XML operations as defined in DSP0200 are included;
176                
177                    -OpenEnumerateInstances
178                    -openEnumerateInstancePaths
179                    -OpenReferenceInstances
180                    -OpenReferenceInstancePaths
181                    -OpenAssociatiorInstances
182                    -OpenAssociatorInstancePaths
183 karl  1.1.2.1      -PullInstancesWithPath
184                    -PullInstancePaths
185                    -CloseEnumeration
186                    -EnumerationCount
187 karl  1.1.2.2       OpenExecQuery
188 karl  1.1.2.1  
189                The following  operations have not been implemented in this version of Pegasus:
190                
191                    -OpenQueryInstances
192                
193                The following limitations on the implementation exist;
194                
195                1. The filterQueryLanguage and filterQuery parameters are processed by
196                   the Pegasus client but the server returns error if there is any data in
197 karl  1.1.2.2     either parameter. This work does not include the development of the
198                   query language.  Note that a separate effort to extend Pegasus to use
199                   the DMTF FQL query language is in process.
200 karl  1.1.2.1  
201                2. The input parameter continueOnError is processed correctly by the client
202                   but the Pegasus server only provides for false since the server does not
203                   include logic to continue processing responses after an error is
204                   encountered. 
205                   This is consistent with the statement in the specification that use of 
206                   this functionality is optional and the fact that the DMTF agrees that all 
207                   of the issues of continuing after errors have not been clarified.  
208                
209                3. The operation enumerationCount is not processed by the server today since
210                   a) really getting the count would be the same cost as the corresponding
211                   enumeration, b) the server does not include a history or estimating
212                   mechanism for this to date.
213 karl  1.1.2.2     NOTE: After a through review as part of the development of the next version
214                   of CMPI we have concluded that this operation is probably not worth the
215                   effort.  Since it is optional, Pegasus will only return the unknown status
216                   at this point
217 karl  1.1.2.1  
218                Since the concept of sequences of operations linked together (open, pull, close)
219                is a major extension to the original CIM/XML operation concept of completely
220                independent operations several new pieces of functionality are implemented
221                to control interOperationTimeouts, counts of objects to be returned, etc.
222                
223                TBD - Review this
224                
225                CLIENT
226                
227                The new operations follow the same pattern as the APIs for existing operations
228                in that:
229                
230                1. All errors are handled as CIMException and Exception
231                
232                2. The means of inputting parameters are the same except that there are
233                   significantly more input parameters with the open operations and for the 
234                   first time operations return parameters as well as objects in the 
235                   response.  Specifically the open and pull operations return values for 
236                   enumerationContext which is the identity for a pull sequence and 
237                   endOfSequence which is the marker the server sends in open and pull 
238 karl  1.1.2.1     responses when it has no more objects to send.
239                
240                The significant differences include:
241                
242                1. Processing of parameters on responses (i.e. the endOfSequence and
243                   enumerationContext parameters are returned for open and pull operations).
244                
245                2. Numeric arguments (Uint32 and Uint64 include the option of NULL in some
246                   cases so they are packaged inside classes Uint32Arg and Uint64Arg in the
247                   client api.
248                
249                3. The association and reference operations ONLY process instances.  They do
250                   not include the capability to return classes like reference and associator
251                   do and therefore return CIMInstance rather than CIMObject.
252                
253                4. Paths are returned in all cases (i.e OpenEnumerateInstances and
254                   PullInstancesWithPath where they were not with EnumeratInstances.
255                
256                5. The client must maintain state between operations in a sequence (using
257                   the enumerationContext parameter).
258                
259 karl  1.1.2.1  TBD- Are there more differences.
260                
261                
262                SERVER
263                
264                The Pegasus server attempts to always deliver the requested number of objects
265                for any open or pull request (the specification allows for the server to
266                deliver less than the requested number of objects and specifically to return
267                zero objects on open).  We felt that it was worth any extra cost in processing
268                to provide the client with exactly what it had requested.
269                
270                The pegasus server always closes an enumeration sequence upon receipt of any
271                error from the providers, repository, etc. Therefore the server will reject
272 karl  1.1.2.2  any request that has continueOnError = true;
273                
274                Expansion to allow the continue on error may be added in a future version.
275                In any case, the whole purpose of the continue on error is really to allow
276                input from good providers to be mixed with providers that return errors so
277                that generally this would mean simply changing the logic in the return mechanism 
278                to not shutdown when an error is received from any given provider.
279                
280                Generally we do not believe that the providers need to do much more in the
281                future to support the continueOnError other than possibly allowing the provider
282                to continue processing after it has received an error.
283 karl  1.1.2.1  
284                PROVIDERS
285                
286                This implementation requires NO changes to the existing providers.  The
287                provider APIs operate just as they do with the original operations.
288                
289                Because the server processing is different however, there may be some
290                behavior differences primarily because the client now controls the speed of
291                delivery of objects.
292                
293                In previous versions of Pegasus, the server attempts to deliver objects as
294                rapidly as then can be put on the network.  In the case of HTTP chunked requests
295                they are delivered in chunks of about 100 objects. The primary delay for the
296                providers was the processing of each segment through the server.  The server
297                is blocked so that no other segment can proceed through the server until that
298                segment is processed and sent on the network.
299                In the case of non-chunkedresponses, they are completely gathered in the serve
300                and then delivered as one non-chunked response. There were no delays for the
301                providers, just lots of possible memory use in the server.
302                
303                The responses from providers (delivered through the deliver(...) interface are
304 karl  1.1.2.1  gathered into segments of about 100 objects and this group of objects is moved
305                through the server to be delivered to the client.
306                
307                However with the inclusion of the pull operations,   The segments of objects
308                from the providers are cached in the server response path until the 
309                maxObjectCount for that request (open or pull) and that number returned in a
310                non-chunked response. Thus, if the client is slow to issue pull requests,
311                the providers might be delayed at some point to reduce memory usage in the
312                server (the delay appears as slow response tothe deliver operation).
313                
314                In other words, the time to process large sets of responses from the provider
315                now depends on the speed of handling the client.
316                
317                It is important to remember in developing providers that the Pegasus server
318                can most efficiently process responses if they are passed from the provider
319                to the server individually or in small arrays of objects rather than the
320                provider gathering very large arrays of objects and sending them to the
321                server.
322                
323 karl  1.1.2.2  NEXT GENERATION PROVIDERS
324                KS_TODO
325                
326 karl  1.1.2.1  CONFIGURATION PARAMETERS
327                
328                The server includes several configuration parameters to set limits on the
329                processing of pull operations.  All of these configuration parameters are
330                compile time parameters rather than runtime.
331                
332                1. Maximum value of minimum interoperation time.  This parameter defines the
333                maximum time allowed between the return of an open or pull response and 
334                the receipt of the next pull or a close operation before the server may 
335                close the enumeration.  The specification allows the server to set a 
336                maximum interoperation time and refuse open requests that with requested 
337                operationTimeout greater than that time.  
338                CIM_ERR_INVALID_OPERATION_TIMEOUT
339                
340                This value is set with the Pegasus environment variable
341                PEGASUS_PULL....
342                
343                2. Maximum objects returned in a single open or pull operation.  The server
344                can set a maximum limit on the number of objects that can be returned in
345                a single open or pull oepration with the maxObjectCount parameter.
346                
347 karl  1.1.2.1  3. Whether the server allows 0 as an interoperation timeout value. The value
348                zero is s special value for the interoperationTimeout in that it tells the
349                server to not timeout any enumeration sequence.
350                
351                With this value for interoperationTimeout, the only way to close an 
352                enumeration sequence is to complete all of the pulls or issue the close.  
353                If for some reason the sequence is not completed, that enumeration context 
354                would remain open indefinitly.  Since in Pegasus any open enumeration 
355                context uses resources (the context object and any provider resposnes that 
356                have not yet been issued in a response) it would appear that most 
357                platforms would not want to allow the existence of enumeration contexts 
358                that cannot be closed by the server.  
359                
360                4, maximum consecutive pull requests with 0 maxObjectCount.  The use of the
361                pull operation with maxObjectCount set to zero could be used to keep an
362                enumeration context open indefinitly (this tells the server to restart the
363                interoperationTimeout but not send any objects in the response). Therefore the
364                specification allows for the server setting maximum limits on this behavior
365                and returning the error CIM_ERR_SERVER_LIMITS_EXCEEDED if this limit is
366                exceeded.
367                Note that this is maximum CONSECUTIVE pulls so that issuing a pull with
368 karl  1.1.2.1  a non-zero count resets this counter.
369                
370                KS-TBD - Is this really logical since we can still block by just issuing
371                lots of zero request and an occansional request for one object.
372                
373                Pegaus sets the value of this limit to 1000 and allows the implementer to
374                modify it with the PEGASUS_MAXIMUM_ZERO_OBJECTCOUNT environment variable.
375                
376                5. Default operationTimeout - 
377                
378                The default of this parameter is to refuse operat
379                
380                In the current release of Pegasus these are all compile time parameters.
381 karl  1.1.2.11 
382                
383                NOTES On working with task branch.
384                
385                Merge out Process
386                
387                   To keep our TASK branch in sync with the current head of tree we need
388                   to do a regular merge out.  the TaskMakefile contains the makefile
389                   procedures to do this efficiently.  NOTE: Following these procedures is
390                   important in that you are merging out new material each time you do
391                   the merge out.  If you were just to repeatedly merge out, you would be
392                   merging previously merged changes a second time causing a real mess.
393                
394                    Start with new directory and put TaskMakefile above pegasus (needed so you
395                    have this file for the initial operations.  
396                
397                      make -f TaskMakefile branch_merge_out BNAME=PEP317-pullop  ## takes a long time
398                
399                   This checks out current head, merges it into task branch and sets tags
400                   for the mergeout.  Note that at the end of this step this work is
401                   part of the TASK... branch.
402 karl  1.1.2.11 
403                   NOW check for conflicts, errors, etc. that resulted from the merge.
404                   Look for conflict flags, compare the results (I use linux merge as a
405                   good graphic compare tool) and build and test. When you are satisfied
406                   that the merge out is clean, you can commit the results to the TASK...
407                   branch
408                   
409                   To commit the work to  this into Task branch
410                
411                      make -f mak/TaskMakefile branch_merge_out_commit BNAME=PEP317-pullop
412                
413                  or manually commit and finish as follows
414                
415                    cvs commit
416                    make -f mak/TaskMakefile  branch_merge_out_finish BNAME=PEP317-pullop
417                
418                ## This last step is important since it cleans up temporary tags to prepare
419                   you for the next checkout
420                   
421                COMPARE TASKBRANCH WITH HEAD
422                
423 karl  1.1.2.11     In a new pegasus work space do same as above for merge out.
424                
425                    make -f TaskMakefile BNAME=PEP317-pullop
426                
427                    This produces a result which is all of the head merged into the branch.
428                    A diff of this is all the new changes to the head of tree that you will
429                    include into the merge.
430                

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