Hi Neel, I just realized another issue.
Adding a default will not result in the default getting added to old-instances at runtime. This is because there is no way to inform the OI/Appliers of this change. But at cluster restart, the old instances are recreated by the loader and will get the new default set. During loading there is no OI and so There is no risk of OI diverging from imm config state. The OI attaches After loading and will presumably then read the data. In any case, the same behavior exists today for the case where an appliaiton Sets an attribute value to nuil where that attribute has a default value defined in the Class. The attribute will stay null unitl the "next" cluster restart. At such a cluster Restart the attribute will get reset to the default value. This semantic on default values is not documented. On he other hand no one has complained about this... /AndersBJ -----Original Message----- From: Anders Bjornerstedt [mailto:anders.bjornerst...@ericsson.com] Sent: den 17 juli 2014 15:54 To: Neelakanta Reddy Cc: opensaf-devel@lists.sourceforge.net Subject: Re: [devel] [PATCH 1 of 1] MM: Allow class schema change to add attribute default [#895] Hi Neel, Neelakanta Reddy wrote: > HI AndersBj, > > Reviewed and tested the patch. > > comments: > change variable has to be set to true when any attributes are getting > changed in schema upgrade. Yes I missed that. will send a new patch. /AndersBj > > more comments inline > > Thanks, > Neel. > > On Wednesday 16 July 2014 08:23 PM, Anders Bjornerstedt wrote: >> osaf/services/saf/immsv/README | 24 >> +++++++++++++++++++++--- >> osaf/services/saf/immsv/immnd/ImmModel.cc | 2 +- >> 2 files changed, 22 insertions(+), 4 deletions(-) >> >> >> This enhancement removes the restriction of not allowing a class >> schema change to add a default to an attribute definition. (Note: >> Removing a default is still not allowed as it is inherrently not >> backwards compatible.) >> >> Only new instances of the class will get the default assigned when no >> value is provided for the attribute at object-create time. >> >> Old instances with a null-value for the attribute will still have a >> null-value for that attribute even after the schema change. A general >> rule for schema changes is that the immsv never alters the value of >> existing attributes as part of a schema change. Doing so would >> require the OI to be notified, which is not realistic since the >> shcema change is not performed as a CCB. >> >> This feature is only functional after an upgrade to 4.5 has completed. >> >> diff --git a/osaf/services/saf/immsv/README >> b/osaf/services/saf/immsv/README >> --- a/osaf/services/saf/immsv/README >> +++ b/osaf/services/saf/immsv/README >> @@ -484,6 +484,10 @@ CHANGE of an existing attribute if it is >> New instances of the class will get the new default, >> old instances retain the old value. >> + * Adding default-value for an attribute (config or runtime). >> + New instances of the class will get the new default, >> + old instances retain the null value. >> + >> * Adding 'multivalued' flag for an attribute (config or runtime). >> * Adding 'writable' flag for an attribute (config). >> @@ -494,7 +498,7 @@ CHANGE of an existing attribute if it is >> All other changes, such as change of attribute type, removal of >> default, -addition of default, etc are not allowed. >> +etc are not allowed. >> There is no API change. The existing saImmOmClassCreate_2 call is >> used >> to insert the new class version. The standard behavior is to reject >> @@ -1842,7 +1846,6 @@ not to create deadlock cycles between th >> be resolved by the timeout of the synchronous admin-ops, so the >> problem would be lack >> of progress on some task, not a permanently hung set of processes. >> - >> Attribute 'longDnsAllowed' added to class 'OpensafImm' (4.5) >> =========================================================== >> https://sourceforge.net/p/opensaf/tickets/897 >> @@ -1869,10 +1872,25 @@ The xml file should be used for upgradin >> upgraded to OpenSAF 4.5 and that system must be capable of >> supporting long DNs. >> +Allow schema change to add attribute default (4.5) >> +================================================== >> +https://sourceforge.net/p/opensaf/tickets/895 >> + >> +The restriction of not allowing a default value to be added to an >> attribute that >> +previously had no default, has been removed. Only new instances of >> the class will >> +get the default assigned when no value is provided for the attribute >> at object-create >> +time. Old instances with a null-value for the attribute will still >> have a null-value >> +for that attribute even after the schema change. A general rule for >> schema changes >> +is that the immsv never alters the value of existing attributes as >> part of a schema >> +change. Doing so would require the OI to be notified, which is not >> realistic since >> +the shcema change is not performed as a CCB. >> +This new feature is only available after an upgrade to OpensAF 4.5 >> has completed. >> + >> + >> Notes on upgrading from OpenSAF 4.[1,2,3,4] to OpenSAF 4.5 >> ========================================================== >> Several enhancements in OpenSAF4.5 add new message types or add new >> imm server states -for ccb handling (#798, #799, #16). During a >> rolling upgrade from an earlier OpenSAF >> +for ccb handling (#798, #799, #16, #895). During a rolling upgrade >> from an earlier OpenSAF >> release to the 4.5 release there will be nodes executing the older >> release concurrently >> with nodes executing OpenSAF 4.5. Nodes executing the earlier >> release will not >> recognize new message types originating from nodes executing 4.5 >> and messages from diff --git >> a/osaf/services/saf/immsv/immnd/ImmModel.cc >> b/osaf/services/saf/immsv/immnd/ImmModel.cc >> --- a/osaf/services/saf/immsv/immnd/ImmModel.cc >> +++ b/osaf/services/saf/immsv/immnd/ImmModel.cc >> @@ -3727,7 +3727,7 @@ ImmModel::notCompatibleAtt(const std::st >> } >> } >> - if(oldAttr->mDefaultValue.empty() && >> !newAttr->mDefaultValue.empty()) { >> + if(oldAttr->mDefaultValue.empty() && >> !newAttr->mDefaultValue.empty() && !protocol45Allowed()) { >> LOG_NO("Impossible upgrade, attribute %s:%s adds >> default value", >> className.c_str(), attName.c_str()); >> return true; > if(oldAttr->mDefaultValue.empty() && !newAttr->mDefaultValue.empty()){ > if(!protocol45Allowed()) { > LOG_NO("Impossible upgrade, attribute %s:%s adds > default value", > className.c_str(), attName.c_str()); > return true; > } else { > change=true; > } > } > > > ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? 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