[Buffer] Fix the bug that buffer configuration will cause failed logs during warm restart.

[steven-guo-ec]

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• What I do: Let BufferMgr not execute the entries which are already in APPL_DB after a warm restart.

• Why I did it: After warm start, the BufferMgr will set entries into APPL_DB which already exist. It will cause bufferorch to do a modification event. But, currently, modifying the buffer configuration is not supported in SAI, and it will print error messages. The error messages will cause test cases to fail.

• How I verify it: With this enhancement, the syslog will not appear the error messages about Buffer during a warm restart.

[stephenxs]

@steven-guo-ec can you please elaborate on which buffer attributes are not supported in SAI? IMO buffer orch will not set create-only attributes

[prsunny]

Please add VS tests

[steven-guo-ec]

SAI_BUFFER_POOL_ATTR_SIZE and SAI_BUFFER_PROFILE_ATTR_BUFFER_SIZE is not supported to set after they were created, they can be configured only when creating them.

[stephenxs]

SAI_BUFFER_POOL_ATTR_SIZE and SAI_BUFFER_PROFILE_ATTR_BUFFER_SIZE is not supported to set after they were created, they can be configured only when creating them.

Thanks. But this does not comply with SAI definition. Check SAI_BUFFER_POOL_ATTR_SIZE and SAI_BUFFER_PROFILE_ATTR_RESERVED_BUFFER_SIZE for details. So IMO this should be fixed by vendor SAI.