Full_Name: Magne Land Version: 2.3.43 OS: RHEL 5.1 64-bit URL: ftp://ftp.openldap.org/incoming/ Submission from: (NULL) (72.37.244.20) Currently the man page of slapo-unique says "enforce uniqueness", which I find misleading. Would it be possible to change it to say "makes the best effort to enforce uniqueness" or something to that effect?
moved from Incoming to Documentation
> Full_Name: Magne Land > Version: 2.3.43 > OS: RHEL 5.1 64-bit > URL: ftp://ftp.openldap.org/incoming/ > Submission from: (NULL) (72.37.244.20) > > > Currently the man page of slapo-unique says "enforce uniqueness", which I find > misleading. > Would it be possible to change it to say "makes the best effort to enforce > uniqueness" or something to that effect? > > It would need more words than that to comment on what exactly happens i.e. why it is a "best effort".
Hi, Please see this thread for background info: http://www.openldap.org/lists/openldap-software/200901/msg00112.html To me, something is either guaranteed or not. And I think "enforce" means something that is guaranteed. In this case, the uniqueness is not guaranteed, therefore it is not enforced. Regards, Magne Land On 1/28/09 2:33 PM, "Gavin Henry" <openldap-its@OpenLDAP.org> wrote: > Full_Name: Magne Land > Version: 2.3.43 > OS: RHEL 5.1 64-bit > URL: ftp://ftp.openldap.org/incoming/ > Submission from: (NULL) (72.37.244.20) > > > Currently the man page of slapo-unique says "enforce uniqueness", which I find > misleading. > Would it be possible to change it to say "makes the best effort to enforce > uniqueness" or something to that effect? > > It would need more words than that to comment on what exactly happens i.e. why it is a "best effort".
--On January 28, 2009 10:39:41 PM +0000 Magne.Land@citrix.com wrote: > Hi, > Please see this thread for background info: > http://www.openldap.org/lists/openldap-software/200901/msg00112.html > > To me, something is either guaranteed or not. And I think "enforce" means > something that is guaranteed. In this case, the uniqueness is not > guaranteed, therefore it is not enforced. Set up slapo-accesslog on your master. Then uniqueness is guaranteed. --Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration
----- quanah@zimbra.com wrote: > --On January 28, 2009 10:39:41 PM +0000 Magne.Land@citrix.com wrote: > > > Hi, > > Please see this thread for background info: > > > http://www.openldap.org/lists/openldap-software/200901/msg00112.html > > > > To me, something is either guaranteed or not. And I think "enforce" > means > > something that is guaranteed. In this case, the uniqueness is not > > guaranteed, therefore it is not enforced. > > Set up slapo-accesslog on your master. Then uniqueness is > guaranteed. We don't document this requirement in slapo-unique.5 though. -- Kind Regards, Gavin Henry. Managing Director. T +44 (0) 1224 279484 M +44 (0) 7930 323266 F +44 (0) 1224 824887 E ghenry@suretecsystems.com Open Source. Open Solutions(tm). http://www.suretecsystems.com/ Suretec Systems is a limited company registered in Scotland. Registered number: SC258005. Registered office: 13 Whiteley Well Place, Inverurie, Aberdeenshire, AB51 4FP. Subject to disclaimer at http://www.suretecgroup.com/disclaimer.html
quanah@zimbra.com wrote: > --On January 28, 2009 10:39:41 PM +0000 Magne.Land@citrix.com wrote: > >> Hi, >> Please see this thread for background info: >> http://www.openldap.org/lists/openldap-software/200901/msg00112.html >> >> To me, something is either guaranteed or not. And I think "enforce" means >> something that is guaranteed. In this case, the uniqueness is not >> guaranteed, therefore it is not enforced. > > Set up slapo-accesslog on your master. Then uniqueness is guaranteed. Are you sure about this? I didn't look in detail to the code, so I can't tell whether serializing writes that way will cause the desired behavior, since slapo-unique is using internal writes. As Gavin says,. if this is the case then it should be at least documented, and not only in slapo-unique, but also for any overlay/module that does internal writes. p. Ing. Pierangelo Masarati OpenLDAP Core Team SysNet s.r.l. via Dossi, 8 - 27100 Pavia - ITALIA http://www.sys-net.it ----------------------------------- Office: +39 02 23998309 Mobile: +39 333 4963172 Fax: +39 0382 476497 Email: ando@sys-net.it -----------------------------------
ando@sys-net.it wrote: > quanah@zimbra.com wrote: >> --On January 28, 2009 10:39:41 PM +0000 Magne.Land@citrix.com wrote: >> >>> Hi, >>> Please see this thread for background info: >>> http://www.openldap.org/lists/openldap-software/200901/msg00112.html >>> >>> To me, something is either guaranteed or not. And I think "enforce" means >>> something that is guaranteed. In this case, the uniqueness is not >>> guaranteed, therefore it is not enforced. >> Set up slapo-accesslog on your master. Then uniqueness is guaranteed. > > Are you sure about this? I didn't look in detail to the code, so I > can't tell whether serializing writes that way will cause the desired > behavior, since slapo-unique is using internal writes. Huh? slapo-unique only does internal searches. The writes are all user ops, and accesslog will serialize all of them. > As Gavin says,. > if this is the case then it should be at least documented, and not only > in slapo-unique, but also for any overlay/module that does internal writes. -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/
----- hyc@symas.com wrote: > ando@sys-net.it wrote: > > quanah@zimbra.com wrote: > >> --On January 28, 2009 10:39:41 PM +0000 Magne.Land@citrix.com > wrote: > >> > >>> Hi, > >>> Please see this thread for background info: > >>> > http://www.openldap.org/lists/openldap-software/200901/msg00112.html > >>> > >>> To me, something is either guaranteed or not. And I think > "enforce" means > >>> something that is guaranteed. In this case, the uniqueness is not > >>> guaranteed, therefore it is not enforced. > >> Set up slapo-accesslog on your master. Then uniqueness is > guaranteed. > > > > Are you sure about this? I didn't look in detail to the code, so I > > can't tell whether serializing writes that way will cause the > desired > > behavior, since slapo-unique is using internal writes. > > Huh? slapo-unique only does internal searches. The writes are all user > ops, > and accesslog will serialize all of them. So, where does this leave us? -- Kind Regards, Gavin Henry. Managing Director. T +44 (0) 1224 279484 M +44 (0) 7930 323266 F +44 (0) 1224 824887 E ghenry@suretecsystems.com Open Source. Open Solutions(tm). http://www.suretecsystems.com/ Suretec Systems is a limited company registered in Scotland. Registered number: SC258005. Registered office: 13 Whiteley Well Place, Inverurie, Aberdeenshire, AB51 4FP. Subject to disclaimer at http://www.suretecgroup.com/disclaimer.html
--On Thursday, January 29, 2009 3:48 PM +0000 ghenry@suretecsystems.com wrote: >> Huh? slapo-unique only does internal searches. The writes are all user >> ops, >> and accesslog will serialize all of them. > > So, where does this leave us? If you want guaranteed atomic writes, use slapo-accesslog on your master to serialize them. --Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration
Ok, so this should be in the man page. Where else should this be listed that affects other overlays? ------Original Message------ From: Quanah Gibson-Mount Sender: To: Gavin Henry To: openldap-its@openldap.org Subject: Re: slapo-unique man page misleading (ITS#5908) Sent: 30 Jan 2009 19:04 --On Thursday, January 29, 2009 3:48 PM +0000 ghenry@suretecsystems.com wrote: >> Huh? slapo-unique only does internal searches. The writes are all user >> ops, >> and accesslog will serialize all of them. > > So, where does this leave us? If you want guaranteed atomic writes, use slapo-accesslog on your master to serialize them. --Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration -- Kind Regards, Gavin Henry. Managing Director. T +44 (0) 1224 279484 M +44 (0) 7930 323266 F +44 (0) 1224 824887 E ghenry@suretecsystems.com Open Source. Open Solutions(tm). http://www.suretecsystems.com/ Suretec Systems is a limited company registered in Scotland. Registered number: SC258005. Registered office: 13 Whiteley Well Place, Inverurie, Aberdeenshire, AB51 4FP. Subject to disclaimer at http://www.suretecgroup.com/disclaimer.html
--On Friday, January 30, 2009 7:08 PM +0000 Gavin Henry <ghenry@suretecsystems.com> wrote: > Ok, so this should be in the man page. Where else should this be listed > that affects other overlays? Eh, I'm not sure it should be in the man page. The point is, if you ever want guaranteed atomic writes, you have to use slapo-accesslog to serialize them. That's an issue that affects other LDAP servers as well. AS Pierangelo said: There is no guarantee of DSA-wide or even database-wide atomicity in write operations, including internal ones. This was never even intended to be in place. This is a known design limitation not only of slapo-unique, but also of slapd (and, I'd say, of LDAP itself). --Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration
Ok, but we should mention this somewhere like in the admin guide perhaps. ------Original Message------ From: Quanah Gibson-Mount Sender: To: Gavin Henry To: openldap-its@openldap.org Subject: Re: slapo-unique man page misleading (ITS#5908) Sent: 30 Jan 2009 19:13 --On Friday, January 30, 2009 7:08 PM +0000 Gavin Henry <ghenry@suretecsystems.com> wrote: > Ok, so this should be in the man page. Where else should this be listed > that affects other overlays? Eh, I'm not sure it should be in the man page. The point is, if you ever want guaranteed atomic writes, you have to use slapo-accesslog to serialize them. That's an issue that affects other LDAP servers as well. AS Pierangelo said: There is no guarantee of DSA-wide or even database-wide atomicity in write operations, including internal ones. This was never even intended to be in place. This is a known design limitation not only of slapo-unique, but also of slapd (and, I'd say, of LDAP itself). --Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration -- Kind Regards, Gavin Henry. Managing Director. T +44 (0) 1224 279484 M +44 (0) 7930 323266 F +44 (0) 1224 824887 E ghenry@suretecsystems.com Open Source. Open Solutions(tm). http://www.suretecsystems.com/ Suretec Systems is a limited company registered in Scotland. Registered number: SC258005. Registered office: 13 Whiteley Well Place, Inverurie, Aberdeenshire, AB51 4FP. Subject to disclaimer at http://www.suretecgroup.com/disclaimer.html
> Ok, but we should mention this somewhere like in the admin guide perhaps. > > ------Original Message------ > From: Quanah Gibson-Mount > Sender: > To: Gavin Henry > To: openldap-its@openldap.org > Subject: Re: slapo-unique man page misleading (ITS#5908) > Sent: 30 Jan 2009 19:13 > > --On Friday, January 30, 2009 7:08 PM +0000 Gavin Henry > <ghenry@suretecsystems.com> wrote: > >> Ok, so this should be in the man page. Where else should this be listed >> that affects other overlays? > > Eh, I'm not sure it should be in the man page. The point is, if you ever > want guaranteed atomic writes, you have to use slapo-accesslog to serialize > them. That's an issue that affects other LDAP servers as well. > > AS Pierangelo said: > > > There is no guarantee of DSA-wide or even database-wide atomicity in write > operations, including internal ones. This was never even intended to be in > place. This is a known design limitation not only of slapo-unique, but > also of slapd (and, I'd say, of LDAP itself). > Should this be in the Admin Guide? I can't think of a place for it at the moment. Should we suspend the ITS until there is a right place? Thanks.
With Issue#9264 it is now possible to do full locking with slapo-unique if in single master, which resolves this issue. With multi-provider, there can never be a fixed guarantee if two conflicting write operations come into two different providers at near the same time. This sort of limitation with MPR is already well documented however. *** This issue has been marked as a duplicate of issue 9264 ***