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Using the CIM/XML Pull Operations

Using the CIM/XML Pull Operations and FQL query Language

STATUS

Date: 12 November 2014

<<< The TODO section is being maintained during the review and checkin process

to keep track of problems, errors, notes, etc. Must be deleted before

checkin to head of tree. Please feel free to add notes, etc in this

section as you review/test.>>>>>>

TODO list:

1. Binary operation from OOP. Need to add counter to binary

protocol to be able to count objects in response. Generates

warnings in things like messageserializer and does not work with

OOP right now. Fixed by converting to XML. Concluded that we do not

need to do this. The binary response is not really used often

in the current environment So double mapping it is not a major issue.

Leave this as FUTURE

2. OpenExecQuery - Code is incomplete in that it does not include the

return from the exec query function to the aggregator yet. Code for Pull

part of OpenQueryInstancesRequest a) should be part of the common

CIMOperationRequestDispatcher execCommon code. DONE, not tested. 29 May

3. The changes to WQLCIMOperationRequestDispatcher and CQL... for handling

pull not completed so we feed the responses back to the EnmerationContext

queues. DONE Not tested 29 May

4. Minor TODOs, diagnostics, etc. still in the code

5. Extension to avoid double move of objects in CIMResponseData (one

into enumerationContext queue and second to new cimResponseData for

response. Want to avoid second move by extending Open/Pull response

messages to include count and CIMResponse data to count objects out

of queue when converting (avoids the second move). This would mean

extending the output writers to allow the count field to be supplied

so they would only create output for up to the count supplied.(Make

this future beyond bug 9676)

6. Add more static tests (currently only OpenEnumerateInstances and

OpenEnumerateInstanceNames covered).

Low priority because most of this except exact XML covered in other

tests. note that we can only add very limited tests since a) no

way to test multiple operations in sequence(i.e. open/pull) and

cannot be sure how many responses will come back in all cases even

for open.

7. Clean up the CIMOperationRequestDecoder.cpp rejectCIMException

further since there is some overlap. VERY Low priority.

8. Correct issue between operations and HTTP where we are sending

trailers with exceptions. Modify response mechanisms so that we

set non-chunked for all responses where we send error responses to

avoid the trailers.

9. It would be more efficient in dispatcher to always use exception for

rejects and change the _reject functions so that they never return

when they reject. This is VERY LOW PRIORITY and primarily saves

a few lines of code in the reject functions and their calls. Means we

would code.

_rejectIfEnumerationToBroad(...)

_rejectIfThisParameterIncorrect(...)

instead of

if (_rejectIfEnum...)

{

return true

}

It would mean that the method trace for the handlers would not return

an exit if we rejected. VERY LOW PRIORITY

10. There are still a couple of template functions around the task of

distributing requests to the multiple providers.

In fact there are two similiar but different templates for

the associators(i.e. assoc, ref, etc.) functions and the parallel

openAssoc functions. It would be nice to consolidate that logic and

further to try to create a non-template form for those functions. LOW

PRIORITY.

11. External runtime variables. This bug leaves these variables as

internal to CIMOperationRequestDispatcher.cpp.

See bug 9819 for the changes to externalize these variables, both

the runtime and buildtime variables. The Work group discussion

documents what the variables are and how they tie to statistics info.

See the OpenPegasus Wiki, Pull operations work group.

12. Not directly related to pull but now over half the code in

WQLOperationRequestDispatcher.cpp and CQLOperationRequestDispatcher

handle functions is just duplicated. Need to create a common function

and eliminate the duplicated code

13. Left almost duplicate createContext function in EnumerationContextTab.

Clean up code

NEXT TASKS:

a. finish 8, 11 2,3 above ( Finish by about 1 June)

29 May 2014

1. Correct issue in cimcli that was causing rejects of open operations when

there were no filters requested. The standard default is WQL in cimcli

so we overrode this for the pull operations.

2. Clean up OpenQueryInstances in CIMMessage.h and CIMMessage.cpp.

3. Modify CIMOperationRequestDispatcher and

EnumerationContextTable.CreateContext to pass request rather than request

parameters.

4. Remove a number of diagnostic messages. Note that there are still some.

They are marked KS_TODO with with note to remove before checkin. They are

all traces and validations.

5. Correct error in inclusion of execinfo.h include in CIMOperationRequestDis.

found by Ji Lee.

6. Cleaned up execQuery and extended it for OpenQueryInstances. ExecQuery

tested but have not tested OpenQueryInstances yet. One more checkin and we

should be able to close 2,3 above (OpenQueryInstances).

26 May 2014

1. Remove a number of diagnostics.

2. Make cache size in EnumerationContextTable dynamic and remove function

to set default values. MaximumEnums set from Dispatcher on constructor for

EnumerationContextTable and table size set to 1/2 of maximum number of

open contexts.

3. Clean up some statistics in EnumerationContextTable

4. Correct error in query and queryLanguage parameters in cimcli in that

the default for queryLanguage is WQL but must be "" for pull operations.

If WQL found they set it to "".

9 May 2104

1. Converted several template functions in CIMOperationRequestDispatcher

to real functions

2. Added intermediate CIMMessage for CIMPullOperationRequestMessage since

all of the pulls have exactly the same data. This allowed us to

convert the template function processPullRequest from template to

real function

3. Added intermediate CIMMessage for CIMOpenOperationRequestMessage betweeh\n

all of the Opens and the CIMRequestData message. This will allow

common code to test all of these variables in all 6

CIMOperationRequestDispatcher handleOpen... functions

3. Added variable in CIMOperationRequestDispatcher handleEnqueue to make

releasing the original request conditional on return from the handle...

for open... and pull... handlers.

This allowed us to drop one place where we were creating a new request msg

for the delayed response and use the original request. This meant that

we could convert the issueOpenOrPullResponse from template function to

real function.

4. Moved open and pull constructors in CIMMessage.h to CIMMessage.cpp. NOTE:

openQueryInstances not moved. Will do when we get this funciton running.

5. Added test for correct namespace in pull operations. Note that it is

never really used but since supplied with request, we test to be sure it is

same as open request namespace. added internationalized exception for this.

6. We should probably add same test to close just as an input parameter

validation.

6. Modified processPullRequest to close the enumeration context if

incorrect response type received. Before we just returned exception and

left context open for next request. Closing is much more logical since the

client really did send an erronous request.

7. Modified PullErrors to correctly test above changed in behavior.

8. Removed a significant number of diagnostic messages.

9. Added query and querylanguage parameters to cimcli.

4 May 2014

1. Clean interface with EnumerationContext timeout thread

2. Remove more diagnostics

3. Correct issue with enumerationContext Release that was causing

failures during nightly tests.

2 May 2014

1. Remove Diagnostics from ResponseData.cpp

2. Correct setup and start of EnumerationContextTimerThread

3. Change limit on max number of enum contexts to be set from Dispatcher.

4. Increase size of hashtable for enum contexts.

5. Corrected issue causing failures in removeContext. Now runs through nightly

tests most of the time.

1 May 2014

1. Cleanup of code and variable names.

2. Removed namespace variable from EnumerationContext. It was never used.

3. Added test for max number of open enumerations. Right now it is fixed

and set about 100. Note that this is tied to the size of hash table

so that there is a issue with more dynamic setting of max and the

hash table size.

4. Removed several unused functions.

5. Found one possible issue causing thread conflict but not the core one

yet.

30 April

1. Added exception response to dispatcher for Limits exceeded on

CreateEnumerationContext. Returns Exceeded server limits CIMException.

2. Fixed possible deadlock where we were not unlocking EnumerationContext

under error condition

27 April - mergeout to head of tree

1. Mergeout of the code to the head of tree. Documented that mergeout in

the bug

27 April 2014

1. Clean up in a number of areas, mostly just code without changing

functionality.

2. Modified CIMMessage.h slightly to clarify names of the pull intermediate

messages (the common open and pull response);

3. Removed a number of diagnostics from CIMResponseData

4. Added new function to ResponseStressTestProvider to be able to terminate

output after a defined number of objects with a CIMException.

5. Removed a number of other TODOs

6. Corrected a couple of errors in the server message bundle.

7. Modified ResponseEncoder to only output the error for pull errors.

It was errounously outputting the EndOfSequence, EnumerationContext and

the error. This way, only the error is sent which is spec.

8. Removed number of TODOs and cleaned up a couple of others.

9. Added static tests for OpenEnumerateInstanceNames.

10. Modified a number of the temporary diagnostics to be permanent by

changing them to PEGASUS_DEBUG_ASSERTs

22 April 2014

1. Clean up some messages.

2. Still trying to find issue that randomly keeps messages in timeout

queue long after they have been closed and returned.

3. Fixed memory loss error.

4. Added zero reject for OperationTimeout because that effectively disables

the whole timeout mechanism so that enumerations could be started, never

completed by the client and would just hang around in memory. That

would be a significant DDOS attack (start very large enum with no

timeout) and never do pulls after open.

21 April 2014

1. Reorganized code in CIMOperationRequestDecoder.cpp ...Iparam classes.

Cleaned up the rejectCIMException code.

2. Cleanup some issues in the EnumerationContextTimeout Thread.

3. Fixed issue in pullop where it was using zero as default for default

operation timeout where it should have been NULL, the DMTF specified

default.

4. Enabled the test to reject 0 as operation timeout on a request and but

controled by a #define in CIMOperationRequestDispatcher.cpp

5. Added test for excessive new OperationContext entries in table.

18 April 2014

1. Internationalize remaining messages in CIMOperationRequestDecoder.cpp and

clean up the decoders for some of the messages so they use the

...Iparam classes. Note that we did not clean up all of the old message

decoders, just the new ones and we did not clean up the Count message

since it is deprecated. TODO clean these up so the decoder is really

consistent.

2. Enabled the EnumerationContext Timer and removed code for alternate

non-thread solution.

17 April 2014

1. Reorganized the lock/unlock for handling the EnumerationContext because

there were thread windows (i.e. using the context after it was released

by other thread).

2. Modified code for the InteroperationTimerThread and deleted old code that

allowed this whole thread to by bypassed.

3. Internationalized a number of CIMOperationRequestDispatcher CIMException

response messages.

4. Fixed stress tests in Client/tests/pullop that were getting timeout. The

issue was not the pull code but that fact that the idle client timeout

appears to be measureing to the end of the operation and the operation

was taking more than 40 seconds which is the default timeout. The idle

timeout takes no account of the fact that chunks are being regularly

delivered.

5. Several minor code changes.

NOTE: At this point the code passes extensive tests of the pull operations

both in OOP and none OOP mode (but with lots of diagnostics that may

be affecting timing).

10 April 2014

1. Fix issues causing failure with repeated pull operations.

2. Consolidate some of the CIMOperationRequestDispatcher.cpp template code

7 April 2104

MergeOut of head of tree.

7 April 2014

1. Permanently fixed issue with getting correct number of objects on response.

This was introduced when did a temp fix to the OOP processing, in particular

removed the condition variable wait in the CIMOperationDispatcher handle

functions for opens and pulls. This moved the functionality to kick off

open and pull responses to the provider threads if there are not enough

objects when the handle is processed. Also added a variable to allow us to

test with either a) responses are required to satisfy the original

request size or) b, responses are required only to return some objects.

We will add statistics to see which of these works best.

2. Modified WsmProcessor EnumerationContext class since the name conflicts

with the pull Operation EnumerationContext class.

3. Created a new intermediate level of CIMMessage, the CIMPullResponseData

Message so that all of the open and Pull responses can use common code

since there are only two variables (endOfSequence and EnumerationContext)

and they are common across all the open and pull responses.

4. Removed a number of diagnostics.

5. Cleaned up the Dispcatcher so that the open and pulls have common response

code and that code can be used from the dispatcher handle functions and

the provider response functions.

31 March 2014 - Checkin

1. Fixed issues in OOP processing of pull operations, in particular

issues with cimxml output format when processed through the

*InternalXmlEncoder functions.

2. Clean up some of the internalXml functionality

3. Found issues causing timeout with a particular provider. The issue

is that the dispatcher and monitor end up using the same thread so the

condition variable in the dispatcher thread stops the monitor. Turned

off the conditionVariable in getCache for the moment which means that

we get number of responses for open... with 0 objects before the

providers can begin to respond. This is only for test.

4. Added some statistics for enumerations and display the statistics

when we close the server (same as cache statistics)

12 March 2014 - Mergeout and Mergein

1. Mergeout to head of tree for this date and mergein for patch update

to bug 9676

2. Extensions to pullop tests program and tests.

3. Added some diagnostics in looking for OOP issue.

4. Removed a number of diagnostics messages and cleaned up code in

dispatcher to simplify pull operation processing.

15 December 2013

1. Mergeout and mergein up to 15 December 2013

2. Clean up issues from tests documented in bug 9676 last week.

3. Clean up some code in dispatcher

4. Remove the filter function from ResponseStressc++Provider.

21 November 2013

1. Mergeout from head of tree to 21 November 2013.

18 November 2013

1. Cleanup of a bunch of minor errors and completion of all of the code for

the openQueryInstances except for the PullInstances in Dispatcher and

the aggregator function.

2. OpenqueryInstances added to cimcli.

13 October 2013 CVS branch update.

1. Integrated bug 9786 into the branch. Note that we need to test the

generated statistics.

2. Mergeout executed to update to head of tree as of 8:00 am 13 October 2013.

3. Cleaned up several errors in OOP processing. Note that there is at least

one issue left when we to a pull on ManagedElement in at least one of the

namespaces.

4. Cleaned up some of the outstanding diagnostic code

5. Generally passes all tests except for one test of pullop where it is trying

to pull enum instances CIM_ManagedElement from a particular namespace.

NOTE: I did not make comments here for changes in October despite the fact

that I did 2 mergouts, number of fixes, and a mergein.

30 September 2013 - CVS Update

Mergeout head of tree up to 29 September 2013.

29 September 2013. CVS update.

1. Modified calls to statisticalData.cpp to a) directly call with request

type, b) incorporate the open, pull, etc. messages. However, since these

are not part of the CIM class, we must do something special with them.

See bug 9785 for full solution to this issue.

2. Corrected OOP interface to enable new flag to indicate internal operations

and set host, etc.

3. Add code to CQLOperationsDispatcher and WQLOperationDispatcher to clean

up CIMResponseDataCounter after filtering.

4. Modified ProviderAgent to set Host info for some pull operations.

5. Added new flag to CIMBinMsgSerializer and Deserializer.

17 September 2013 CVS update (Actually two different updates over 3 days)

1. Clean up some issues in CIMMessage.h and CIMMessage.cpp

2. Extend OpenExecQuery to WQL and CQL processors but return not complete

3. Remove memory leak in EnumerationContext and EnumerationContextTable

handling.

4. Created template functions for much of the pull operations.

5. Reversed order of queryLanguage and query (and changed names to match

execQuery) in client and server. Note that these are the execQuery

WQL and CQL filters and NOT FQL filters.

6. Some code cleanup in dispatcher

7. Today, passes all tests in pullop but issue in alltests. For some reason

not finding CIMObjectManager instance. Also, leaves enumeration contexts

if client terminates since cleanup thread not operating.

8. XML from OOP not correctly processed.

14 September 2013 CVS update

Merged out up to 25 August. Cleaned up all operations and standardized code.

At this point the non pull operations code is in a set of templates but the

pull is not yet.

Fixed a significant number of problems so that it appears that the operations

except for OpenExecQuery run stably, at least with the pullop test program.

Note that there is a problem in that the Interop control provider is not

returning its singleton wbemserver object for some reason. Causes a test

failure

Fixed for 16 June CVS Update

1. Cleaned up the enumerationContext and Table release functions and tested

to confirm that we do not lose memory in either normal sequences or

sequences that close early. Cleaned up pullop and added more tests

Taged Before: PREAUG25UPDATE and after POSTAUG25UPDATE

Fixed for 9 June CVS update

1. Cleaned up code for OpenQueryInstances. Note that this is incomplete.

No support in WQL or CQL Operations

What was fixed for 5 June checkin.

1. Extended ResponseTest MOF for for both CMPI and C++ subclasses

2. Fixed issues with pullop.

3. Fixed temp issue with CIMResponseData size by putting in mutex. That

is not a permanent fix but it gets around issue probably in the control

of the move logic that meant counts were off.

4. Fixed issues in Dispatcher so that associator code works. Still messy

code in the dispatcher.

5. Changed name of Enumerationtable.h & cpp to EnumerationContextTable.*

6 Changed name of ResponseStressTest module, classes, etc.

TAG: TASK_PEP317_5JUNE_2013_2

2 June 2013

Issues - KS

- Still way to many TODO and KS comments and KS_TEMPS. Removing bit by bit.

- Runtime variable connection for the config parameters not installed. That

has been made into a separate bug (see bug 9819)

5. Issue with the threaded timer. For some reason during tests it

eventually calls the timer thread with trash for the parm (which is

pointer to the EnumerationTable object). Caught because we do a valid

test at beginning of the function.

6. Still using the templates in CIMOperationRequestDispatcher to simplify

the handle... processing.

7. I think I have a way around the double move of objects in the

EnumerationContext so that the outputter will just take a defined number

of objects directly from the gathering cache and save the second move.

8. Not yet passing all tests but getting closer now. The major test that is

causing an error today is the execution of a full enumeration with the

forceProviders = true. This causes a client timeout sometimes.

STATUS

The client pull operations and FQL query language are incorporated into

OpenPegasus 2.14. consistent and compatible with the DMTF specifications for

the pull operations (DMTF DSP0200 v 1.4, and DMTF DSP0212 v 1.01.

This readme defines the characteristics, limitations,

etc. for that implementation.

===========================================

OVERVIEW:

The operation extensions for pull operations defined in the DMTF specification

DSP0200 V 1.4 were implemented in Pegasus effective Pegasus version 2.11

DSP0200 V 1.4 were implemented in OpenPegasus effective version 2.14

including Client and Server.

These operations extend the CIM/XML individual operations to operation

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The following new CIM/XML operations as defined in DSP0200 are included;

-OpenEnumerateInstances

-openEnumerateInstances

-openEnumerateInstancePaths

-OpenReferenceInstances

-openReferenceInstances

-OpenReferenceInstancePaths

-openReferenceInstancePaths

-OpenAssociatiorInstances

-openAssociatiorInstances

-OpenAssociatorInstancePaths

-openAssociatorInstancePaths

-OpenQueryInstances

-openQueryInstances

-PullInstancesWithPath

-pullInstancesWithPath

-PullInstancePaths

-pullInstancePaths

-PullInstances

-pullInstances

-CloseEnumeration

-closeEnumeration

-EnumerationCount

-enumerationCount (deprecated by DMTF and incomplete)

OpenExecQuery

The following operations have not been implemented in this version of Pegasus:

-OpenQueryInstances

The following limitations on the implementation exist;

1. The filterQueryLanguage and filterQuery parameters are processed by

the Pegasus client but the server returns error if there is any data in

either parameter. This work does not include the development of the

query language. Note that a separate effort to extend Pegasus to use

the DMTF FQL query language is in process.

2. The input parameter continueOnError is processed correctly by the client

but the Pegasus server only provides for false since the server does not

include logic to continue processing responses after an error is

encountered.

This is consistent with the statement in the specification that use of

this functionality is optional and the fact that the DMTF agrees that all

of the issues of continuing after errors have not been clarified.

3. The operation enumerationCount is not processed by the server today since

a) really getting the count would be the same cost as the corresponding

enumeration, b) the server does not include a history or estimating

mechanism for this to date.

NOTE: After a through review as part of the development of the next version

of CMPI we have concluded that this operation is probably not worth the

effort. Since it is optional, Pegasus will only return the unknown status

at this point

Since the concept of sequences of operations linked together (open, pull, close)

is a major extension to the original CIM/XML operation concept of completely

independent operations several new pieces of functionality are implemented

to control interOperationTimeouts, counts of objects to be returned, etc.

to control interOperation timeouts, counts of objects to be returned, etc.

NOTE: More detailed information on the pull operations is contained in:

1. The OpenPegasus wiki (pull operations work group)

2. The pull operations PEP (preliminary today)

3. Presentations in the OpenPegasus wiki, in particular in the

pull operations workgroup documentation at:

TBD - Review this

https://wiki.opengroup.org/pegasus-wiki/doku.php?id=dev:workgroups:pulloperationsupportworkgroup:pull_operation_support_work_group

CLIENT

OPENPEGASUS CLIENT

The new operations follow the same pattern as the APIs for existing operations

in that:

1. All errors are handled as CIMException and Exception

1. All errors are handled as CIMException and Exception the same as the

original client operations. Note, however, that there are additional

CIMStatusCodes for the new operations.

2. The means of inputting parameters are the same except that there are

significantly more input parameters with the open operations and for the

first time operations return parameters as well as objects in the

response. Specifically the open and pull operations return values for

enumerationContext which is the identity for a pull sequence and

the enumerationContext argument which is the identity for a pull sequence and

endOfSequence which is the marker the server sends in open and pull

the endOfSequence argument which is the marker the server sends in open and

responses when it has no more objects to send.

pull responses when it has no more objects to send.

The significant differences include:

The significant differences between the open... and original enumerate,

associator, and reference operations includes:

1. Processing of parameters on responses (i.e. the endOfSequence and

enumerationContext parameters are returned for open and pull operations).

1. The new pull client operations typically require multiple client operations

to retrieve a complete set of data (ex. openEnumerateInstances and

pullInstancesWithPath) are equivalent to the old enumerateInstances

client request. While the whole collection of responses might be returned

on the open if the maxObjectCount argument is set larger than the the number

of objects in the total response, depending on the speed of delivery of

objects from providers, the response might still not deliver everything

in the initial response. The client code writer should always assume that

multiple requests will be required.

2. Processing of parameters on responses (i.e. the endOfSequence and

enumerationContext arguments are returned for open and pull operations)

These return arguments are used to control the loop retrieving data

for an enumeration sequence (ex. the sequence of OpenEnumerateInstances

and PullInstancesWithPath that represents a complete enumeration

sequence). The sequence continues until the server responds with

EndOfSequence is true, and the enumerationContext is the identifier

for the sequence.

2. Numeric arguments (Uint32 and Uint64 include the option of NULL in some

3. Numeric arguments (Uint32 and Uint64) include the option of NULL in some

cases so they are packaged inside classes Uint32Arg and Uint64Arg in the

client api.

client API.

3. The association and reference operations ONLY process instances. They do

4. The openAsociatorInstances and openReferenceInstances operations ONLY

not include the capability to return classes like reference and associator

process instances. They do not include the capability to return classes

do and therefore return CIMInstance rather than CIMObject.

as reference and associator requests do and therefore return CIMInstance

rather than CIMObject.

4. Paths are returned in all cases (i.e OpenEnumerateInstances and

5. Paths are returned for the instance operations as part of the returned

PullInstancesWithPath where they were not with EnumeratInstances.

instances (ex. openEnumerateInstances and pullInstancesWithPath) where

they were not with EnumerateInstances.

5. The client must maintain state between operations in a sequence (using

6. The client must maintain state between operations in an enumeration

the enumerationContext parameter).

sequence (using the enumerationContext parameter returned with open

and pull responses). The client must always return the last

enumerationContext received as the server may modify the

enumerationContext for each response in an enumeration sequence.

TBD- Are there more differences.

The client API is defined in the header file:

pegasus/src/Pegasus/Client/CIMCLient.h

SERVER

The Pegasus server attempts to always deliver the requested number of objects

OPENPEGASUS SERVER

for any open or pull request (the specification allows for the server to

deliver less than the requested number of objects and specifically to return

zero objects on open). We felt that it was worth any extra cost in processing

to provide the client with exactly what it had requested.

The pegasus server always closes an enumeration sequence upon receipt of any

The OpenPegasus server attempts to always deliver at least some objects

in a response. It does not wait to deliver the exact number requested but

waits to deliver at least some. The sever will wait about 15 seconds to

deliver and if there is nothing delivered from the providers it will then

return a response with zero objects in it so that the client does not

timeout. This would only occur if the providers are extremely slow (i.e.

greater than 15 seconds) in preparing response objects to be delivered.

The OpenPegasus server always closes an enumeration sequence upon receipt of any

error from the providers, repository, etc. Therefore the server will reject

any request that has continueOnError = true;

any request that has the continueOnError argument = true;

Expansion to allow the continue on error may be added in a future version.

In any case, the whole purpose of the continue on error is really to allow

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future to support the continueOnError other than possibly allowing the provider

to continue processing after it has received an error.

PROVIDERS

OPENPEGASUS PROVIDERS

This implementation requires NO changes to the existing providers. The

This implementation (OpenPegasus version 2.14) requires NO changes to the

provider APIs operate just as they do with the original operations.

existing providers. The provider APIs operate just as they do with the

original operations.

Because the server processing is different however, there may be some

behavior differences primarily because the client now controls the speed of

delivery of objects.

In previous versions of Pegasus, the server attempts to deliver objects as

In previous versions of Pegasus, the server attempted to deliver objects as

rapidly as then can be put on the network. In the case of HTTP chunked requests

they are delivered in chunks of about 100 objects. The primary delay for the

providers was the processing of each segment through the server. The server

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and then delivered as one non-chunked response. There were no delays for the

providers, just lots of possible memory use in the server.

The responses from providers (delivered through the deliver(...) interface are

The responses from providers (delivered through the deliver(...) interface) are

gathered into segments of about 100 objects and this group of objects is moved

through the server to be delivered to the client.

However with the inclusion of the pull operations, The segments of objects

However with the inclusion of the pull operations, the segments (CIMResponseData

from the providers are cached in the server response path until the

objects containing the instance or path objects) from the providers are cached

maxObjectCount for that request (open or pull) and that number returned in a

in the server response cache until the next pull request and that number

non-chunked response. Thus, if the client is slow to issue pull requests,

is returned in the response to that pull. Thus, if the client is slow to issue

the providers might be delayed at some point to reduce memory usage in the

pull requests, the providers might be delayed at some point to reduce memory

server (the delay appears as slow response tothe deliver operation).

usage in the server (the delay appears as slow response to the deliver operation).

In other words, the time to process large sets of responses from the provider

now depends on the speed of handling the client.

It is important to remember in developing providers that the Pegasus server

It is important to remember in developing providers that the OpenPegasus server

can most efficiently process responses if they are passed from the provider

to the server individually or in small arrays of objects rather than the

provider gathering very large arrays of objects and sending them to the

server.

NEXT GENERATION PROVIDERS

FQL (FILTER QUERY LANGUAGE)

KS_TODO

The FQL implementation is complete in accord with the DMTF

specification DSP 0212 except for a few issues including:

1. The regex for the LIKE operation is the same as CQL basic. It provides

only the following special characters "." and "*".

2. The implementation does not include the comparison of

embeddedInstances functionality.

3. The implementation does not include the handling of Uint8[] as

strings.

4. Since the cimserver provides the filtering, it can only filter properties

that are returned from the providers. Therefore all of the properties in

the filter MUST BE included in any property list provided with the request.

For more details on the FQL implementation see the readme.txt in the

directory pegasus/src/Pegasus/FQL.

OpenPegasus will remove these limitations in a future version.

The FQL implementation includes a large set of sample queries in the

directory:

pegasus/src/Pegasus/FQL/tests/Parser

including both good and error generating queries.

==================================================================

LIMITATIONS IN OPENPEGASUS 2.14

1. The openQueryInstances does not allow requesting the class on response

(i.e. the returnQueryResultClass argument must be false in this version).

Since OpenPegasus is actively proposing that this argument be deprecated

we will see what happens in future releases.

2. The openEnumerateInstanceNames, openAssociatorNames, and openReferenceNames

do not allow use of the query filter. This is because:

a. The intention is to deprecate these operations completely and remove

them in a future versionof both the specificatons and OpenPegasus.

b. They require that the server call the providers with the corresponding

enumerate, associators, references to get the full instances to

filter and then remap this to the corresponding Names operation.

We propose that if the user wants just the paths, this can be achieved

with the instances operation with the propertylist set empty which

requests that the server return no properties.

3. The filterQuery filtering is done by the server, not the providers in this

version of OpenPegasus. This will be modified in a future version of

OpenPegasus when the provider API extensions for the pull operations

have been resolved. Version 2.1 of the CMPI specification will resolve

this issue. However, this has imposed another limitation as mentioned above,

the properties that are part of the filter MUST BE included in any

propertyList in the request. OpenPegasus does not check to be sure that

all properties in the filter are also in the request and would therefore

try to filter the response on non-existent properties.

4. The input parameter continueOnError is processed correctly by the client

but the Pegasus server only provides code for 'false' value, since the server

does not include logic to continue processing responses after an error is

encountered.

This is consistent with the statement in the specification that use of

this functionality is optional and the fact that the DMTF agrees that all

of the issues of continuing after errors have not been clarified.

5. The operation enumerationCount is not processed by the server today since

a) Getting the count would be the same cost as the corresponding

enumeration, b) the server does not include a history or estimating

mechanism for this to date.

NOTE: After a through review as part of the development of the next version

of CMPI we have concluded that this operation is probably not worth the

effort. Since it is optional, Pegasus will only return the unknown status

at this point. Further it is the intention of the DMTF to deprecate this

function.

CONFIGURATION PARAMETERS

===================================================================

PULL OPERATION CONFIGURATION PARAMETERS

The server includes several configuration parameters to set limits on the

processing of pull operations. All of these configuration parameters are

processing of pull operations.

compile time parameters rather than runtime.

1. Maximum value of minimum interoperation time. This parameter defines the

RUNTIME CONFIGURATION PARAMETERS

maximum time allowed between the return of an open or pull response and

the receipt of the next pull or a close operation before the server may

1. Maximum value of interoperation time (pullOperationsMaxTimeout) -

close the enumeration. The specification allows the server to set a

This parameter defines the maximum time allowed between the return of an open

maximum interoperation time and refuse open requests that with requested

or pull response and the receipt of the next pull or a close operation before

operationTimeout greater than that time.

the server may close the enumeration.

CIM_ERR_INVALID_OPERATION_TIMEOUT

The specification allows the server to set a maximum interoperation time and

refuse open requests that with requested operationTimeout greater than that

This value is set with the Pegasus environment variable

time.

PEGASUS_PULL....

2. Maximum number of objects returned in a single open or pull operation

2. Maximum objects returned in a single open or pull operation. The server

(pullOperationsMaxObjectCount) - The server can set a maximum limit on the

can set a maximum limit on the number of objects that can be returned in

number of objects that can be returned in a single open or pull operation

a single open or pull oepration with the maxObjectCount parameter.

with the maxObjectCount parameter. This parameter sets the maximum limit.

The absolute maximum allowed without recompiling (and changing a value in

3. Whether the server allows 0 as an interoperation timeout value. The value

Common/Constants.h) is 10000.

zero is s special value for the interoperationTimeout in that it tells the

server to not timeout any enumeration sequence.

3. Default operationTimeout (pullOperationsdefaultTimeout) - If the client

does not specify an operation timeout in the open request, the server uses

the value defined by this runtime configuration variable. The default

is 30 seconds.

STATISTICS

The server does maintain some statistics on the pull operations and outputs

these to the console when the server is shutdown. In this version there

is no way to output these statistics other than to the console and at

shutdown.

COMPILE TIME CONFIGURATION PARAMETERS

1. Whether the server allows 0 as an interoperation timeout value - The value

zero is a special value for the interoperationTimeout in that it tells the

server to not timeout the enumeration sequence. This should never be used

as it allows a client to open enumeration sequences that will not be

cleaned up if the client does not properly terminate them. There is a

compile time variable in CIMOperationRequestDispatcher that would allow this

to be set so 0 interoperation is allowed but we recommend that it never

be used since it removes a significant component of the server management

of enumerationContext information.

With this value for interoperationTimeout, the only way to close an

enumeration sequence is to complete all of the pulls or issue the close.

If for some reason the sequence is not completed, that enumeration context

would remain open indefinitly. Since in Pegasus any open enumeration

would remain open indefinitely. Since in Pegasus any open enumeration

context uses resources (the context object and any provider resposnes that

context uses resources (the context object and any provider responses that

have not yet been issued in a response) it would appear that most

platforms would not want to allow the existence of enumeration contexts

that cannot be closed by the server.

4, maximum consecutive pull requests with 0 maxObjectCount. The use of the

2. Maximum consecutive pull requests with 0 maxObjectCount - The use of the

pull operation with maxObjectCount set to zero could be used to keep an

enumeration context open indefinitly (this tells the server to restart the

enumeration context open indefinitely (this tells the server to restart the

interoperationTimeout but not send any objects in the response). Therefore the

specification allows for the server setting maximum limits on this behavior

and returning the error CIM_ERR_SERVER_LIMITS_EXCEEDED if this limit is

exceeded.

Note that this is maximum CONSECUTIVE pulls so that issuing a pull with

a non-zero count resets this counter.

KS-TBD - Is this really logical since we can still block by just issuing

Pegasus sets the value of this limit to 1000 and allows the implementer to

lots of zero request and an occansional request for one object.

modify it by compiling with the PEGASUS_MAXIMUM_ZERO_OBJECTCOUNT define in

CIMOperationRequestDispatcher.cpp modified.

Pegaus sets the value of this limit to 1000 and allows the implementer to

modify it with the PEGASUS_MAXIMUM_ZERO_OBJECTCOUNT environment variable.

3. Time to wait for next response from providers - In the case where providers

are responding very slowly, the goal is to generate responses with

5. Default operationTimeout -

zero instances at regular intervals to allow the client to keep the

enumeration context alive. This wait time is set by a compile time define

The default of this parameter is to refuse operat

(PEGASUS_PULL_MAX_OPERATION_WAIT_SEC)in pegasus/src/Pegasus/Common/Constants.h

and is set to 15 seconds in the current release.

In the current release of Pegasus these are all compile time parameters.

4. Time to wait before killing off an enumeration context that is blocked

by missing provider responses. In the rare case where providers do not complete

their responses to the server there is a compile-time counter that trys to

clean up the providers and finally just kill the enumeration sequence after

a defined number of consecutive pulls that return zero objects.

The limit is defined in pegasus/src/Pegasus/Constants.h

NOTE: The development team is trying to consolidate all such constants and

#define definitions that control overall server characteristics but are not

runtime parameters in Constants.h

===================================================================

TESTING PULL OPERATIONS

The pull operations are tested primarily with two client programs in the

directory Pegasus/Client/tests

1. pullop and it corresponding Makefile provide extensive tests of the

pull operations and comparison of the results with the corresponding non

pull operations.

2. PullErrors tests a number of error scenarios with the pull operations.

3. cimcli has been extended to allow execution of the pull operations with new

operations that parallel the existing operations:

enumerateinstances(ei) - corresponding is pullenumerateInstances(pei)

ni -> pni enumerateInstanceNames

r -> pr references

rn -> prn referenceNames

a -> pa associators

ar -> par associatorNames

NOTES On working with task branch.

These execute complete pull sequences (open, pull) with cimcli options

to control parameters like maxObjectCount, interoperation Timeout, etc.

Merge out Process

To keep our TASK branch in sync with the current head of tree we need

=============================================================

to do a regular merge out. the TaskMakefile contains the makefile

TODO LIST - Post 2.14 release

procedures to do this efficiently. NOTE: Following these procedures is

1. Binary operation from OOP. Need to add counter to binary

important in that you are merging out new material each time you do

protocol to be able to count objects in response. Generates

the merge out. If you were just to repeatedly merge out, you would be

warnings in things like messageserializer and does not work with

merging previously merged changes a second time causing a real mess.

OOP right now. Fixed by converting to XML. Concluded that we do not

need to do this. The binary response is not really used often

Start with new directory and put TaskMakefile above pegasus (needed so you

in the current environment So double mapping it is not a major issue.

have this file for the initial operations.

Leave this as FUTURE

2. Minor TODOs, diagnostics, etc. still in the code. Reduced almost to

make -f TaskMakefile branch_merge_out BNAME=PEP317-pullop ## takes a long time

none now. We are leaving some in as PEGASUS_DEBUG

3. Extension to avoid double move of objects in CIMResponseData (one

This checks out current head, merges it into task branch and sets tags

into enumerationContext queue and second to new CIMResponseData for

for the mergeout. Note that at the end of this step this work is

response. Want to avoid second move by extending open/pull response

part of the TASK... branch.

messages to include count and CIMResponse data to count objects out

of queue when converting (avoids the second move). This would mean

NOW check for conflicts, errors, etc. that resulted from the merge.

extending the output writers to allow the count field to be supplied

Look for conflict flags, compare the results (I use linux merge as a

so they would only create output for up to the count supplied.(Make

good graphic compare tool) and build and test. When you are satisfied

this future beyond bug 9676). This is fairly extensive because it

that the merge out is clean, you can commit the results to the TASK...

extends beyond CIMResponseData to SCMO and XML writers where the

branch

XmlWriters used by encodeXmlResponse would have to have counters

added. Then instead of copying on getCache we would simply pass the

To commit the work to this into Task branch

cache and count on and the writer would take and remove.

4. Add more static tests (currently only OpenEnumerateInstances and

make -f mak/TaskMakefile branch_merge_out_commit BNAME=PEP317-pullop

OpenEnumerateInstanceNames covered).

5. Correct issue between operations and HTTP where we are sending

or manually commit and finish as follows

trailers with exceptions. Modify response mechanisms so that we

set non-chunked for all responses where we send error responses to

cvs commit

avoid the trailers. NOTE: There should be now a bug on this in general

make -f mak/TaskMakefile branch_merge_out_finish BNAME=PEP317-pullop

where we would want to send an initial error without the trailer. Should

have always done that.

## This last step is important since it cleans up temporary tags to prepare

6. It would be more efficient in dispatcher to always use exception for

you for the next checkout

rejects and change the _reject functions so that they never return

when they reject. This is VERY LOW PRIORITY and primarily saves

COMPARE TASKBRANCH WITH HEAD

a few lines of code in the reject functions and their calls. Means we

would code.

In a new pegasus work space do same as above for merge out.

_rejectIfEnumerationToBroad(...);

_rejectIfThisParameterIncorrect(...);

make -f TaskMakefile BNAME=PEP317-pullop

This produces a result which is all of the head merged into the branch.

instead of

A diff of this is all the new changes to the head of tree that you will

if (_rejectIfEnum...)

include into the merge.

{

return true

}

It would mean that the method trace for the handlers would not return

an exit if we rejected. VERY LOW PRIORITY. Possibly FUTURE. No behavior

change, just more compact source code but it messes with the method

trace logic.

7. There are still a couple of template functions around the task of

distributing requests to the multiple providers.

In fact there are two similar but different templates for

the associators(i.e. assoc, ref, etc.) functions and the parallel

openAssoc functions. It would be nice to consolidate that logic and

further to try to create a non-template form for those functions. LOW

PRIORITY

8. Trace functions in CIMResponseData,h & cpp should be PEGASUS_DEBUG.

Same for trace function in EnumerationContext and

EnumerationContextTable

9. Question. We added trace in CIMRequestOperationDispatcher.cpp if

query enum is recevied with no object path. However, since this is

a provider problem should we be doing something other than a trace

(ex. log) since traces are often not really used and they do generate

lots of data whereby something like this could get lost. Also, need

to review what level of trace if we keep trace.

10. Better statistics keeping for open, etc. through cimperf.

11. Incorporate a simple test of pull operations into the TestClient

12. Define a simpler iteration interface for the client so that

the client does not have to directly control the open, pull, etc.

operations.

13. Map properties in the FQL Filter to properties in any property list

provided.

14. Output statistical information on a regular basis rather than just

as server shutdown and to the log or somewhere else than just the

console.

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