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Sync question
by Singley, Norman 21 Nov '16

21 Nov '16

Hi folks - Just a quick question I couldn't quite find the answer to in the oldap documentation. We have a multi-master oldap with three nodes. One node is on a physical machine, and we are planning on doing a physical to virtual migration soon. All three nodes are part of a DNS round robin. We will take the physical node out of the DNS round robin, do the migration and bring the virtual back in. My question regards synchronization. We are using "refreshandpersist" for syncrepl. For the hour or so it takes to do the migration, users will be changing Passwords - that should be the only oldap changes made in that time. Will the password changes that get written to the two existing nodes sync over to the third node when we bring it back up, or will they be lost and we would be out of sync? Thanks for any clarification. Norman Singley Directory Services University of Montana 406 243 6799 Norman.singley(a)mso.umt.edu

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Can't add "same" mail attribute with different cases.
by Patrick Zacharias 21 Nov '16

21 Nov '16

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Re: reusing transactions in LMDB
by Howard Chu 21 Nov '16

21 Nov '16

Tim Uckun wrote: > Hi. > > Sorry for being so dense but... > The document says > > The transaction handle is freed. It and its cursors must not be used again > after this call, except with mdb_cursor_renew(). > > > I am still very confused about reusing transactions. Keep reading. > If I commit or abort a read write transaction I can't reuse the transaction > but I can re use the cursor? In the cursor documentation it says > > Cursors that are only used in read-only transactions may be re-used, to avoid > unnecessary malloc/free overhead. > > So this indicates only read only cursors can be reused right? Yes. > > So can you confirm my understanding? This is what I get from reading the docs. > > A transaction can either be read write or read only. > > If a transaction is read only you can commit or abort the transaction and then > re-open it again for further use. No. Once a transaction is committed or aborted it is freed and cannot be reused. Period, end of story. Both the commit() and abort() docs are quite explicit about this. > If a transaction is read write then it can't be used again after you commit or > abort the transaction. > > > > > > On Tue, Nov 22, 2016 at 3:17 PM, Howard Chu <hyc(a)symas.com > <mailto:hyc@symas.com>> wrote: > > Tim Uckun wrote: > > > > No. You can perform multiple write operations in a single transaction. > > > But once the commit has been called the next write operation has to be > a newly > opened transaction right? The write transactions can't be re-opened. > > http://lmdb.tech/doc/group__mdb.html#ga846fbd6f46105617ac9f4d76476f6597 > <http://lmdb.tech/doc/group__mdb.html#ga846fbd6f46105617ac9f4d76476f6597> > -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/

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Re: Repairing a lmdb database
by Howard Chu 21 Nov '16

21 Nov '16

Tim Uckun wrote: > The language is Crystal which is still a very young language. It does not have > threading at this time so there should be no issues with mutexes. While > writing the code I never opened up a database but did repeatedly open up the > environment and if the app ran into an error while coding didn't properly > close the environment. I didn't ask about languages, I asked about OS and LMDB version. LMDB uses mutexes internally to serialize write transactions. > > Howard while I have you on the line.... > > The documentation says to be very careful about closing databases and says > it's not normally necessary. I am going to omit those calls from my wrapper. > Is this OK? I will probably omit a bunch of other calls too at least from the > first release but I want to make sure I don't omit anything crucial. Probably a good idea to omit dbi_close. > > Thanks. > > On Tue, Nov 22, 2016 at 7:42 AM, Howard Chu <hyc(a)symas.com > <mailto:hyc@symas.com>> wrote: > > Tim Uckun wrote: > > Hi All. > > I am writing a wrapper for Lmdb for the Crystal language. During the > process > of writing my code started hanging when attempting to open a > transaction. At > first I thought I was calling the C functions wrong but it turned out > to be > some sort of a corruption in the database itself. I deleted the database > directory and the code started working fine again. > > > Sounds like you're not using robust mutexes. Just a guess, since you > didn't provide any info about your OS / platform or LMDB version. > > -- > -- Howard Chu > CTO, Symas Corp. http://www.symas.com > Director, Highland Sun http://highlandsun.com/hyc/ > Chief Architect, OpenLDAP http://www.openldap.org/project/ > <http://www.openldap.org/project/> > > -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/

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Re: reusing transactions in LMDB
by Howard Chu 21 Nov '16

21 Nov '16

Tim Uckun wrote: > > > No. You can perform multiple write operations in a single transaction. > > > But once the commit has been called the next write operation has to be a newly > opened transaction right? The write transactions can't be re-opened. > http://lmdb.tech/doc/group__mdb.html#ga846fbd6f46105617ac9f4d76476f6597 -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/

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Re: reusing transactions in LMDB
by Howard Chu 21 Nov '16

21 Nov '16

Tim Uckun wrote: > Another question regarding my wrapper for lmdb. > > The comments say it's possible to reuse read only transactions but says > nothing about reusing the read write transactions. Does this mean every write > operation needs a fresh transaction? No. You can perform multiple write operations in a single transaction. > Is there any downsides to not > implementing the reuse functions for the wrapper? There is a performance gain from reusing read transactions. > I figure the use case is > quite limited and frankly I would have to manage all the transaction pointers > to make sure they were being used property. > > Also I noticed that every call to mdb_txn_id returns 1 even for different > transactions. Is this normal? http://lmdb.tech/doc/group__internal.html#a26512036328af11cdaeb6c9880859290 > Thanks. -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/

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Re: Repairing a lmdb database
by Howard Chu 21 Nov '16

21 Nov '16

Tim Uckun wrote: > Hi All. > > I am writing a wrapper for Lmdb for the Crystal language. During the process > of writing my code started hanging when attempting to open a transaction. At > first I thought I was calling the C functions wrong but it turned out to be > some sort of a corruption in the database itself. I deleted the database > directory and the code started working fine again. Sounds like you're not using robust mutexes. Just a guess, since you didn't provide any info about your OS / platform or LMDB version. -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/

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RE: Sync question
by Quanah Gibson-Mount 21 Nov '16

21 Nov '16

--On Monday, November 21, 2016 6:20 PM +0000 "Singley, Norman" <Norman.Singley(a)mso.umt.edu> wrote: > That's what I thought. Thanks. We are actually running 2.4.36 at the > moment. You may wish to read over <http://www.openldap.org/software/release/changes.html> then. Regards, Quanah -- Quanah Gibson-Mount Product Architect Symas Corporation Packaged, certified, and supported LDAP solutions powered by OpenLDAP: <http://www.symas.com>

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Re: Re: Can't add "same" mail attribute with different cases.
by Quanah Gibson-Mount 21 Nov '16

21 Nov '16

--On Thursday, November 17, 2016 11:27 PM +0100 Patrick Zacharias <LittleFighter19(a)web.de> wrote: > The gerrit devs (if I recall correctly) argued that this behavior is > intentional as due to the standard, mails can be case sensitive and get > to different recipients. I would stop using a product written by developers who are so clearly clueless. Zero part of the internet is going to work with them if they treat email as case specific. I would in fact point to rfc1274, which SPECIFICALLY notes that the "mail" attribute is NOT case sensitive. 9.3.3. RFC 822 Mailbox The RFC822 Mailbox attribute type specifies an electronic mailbox attribute following the syntax specified in RFC 822. Note that this attribute should not be used for greybook or other non-Internet order mailboxes. rfc822Mailbox ATTRIBUTE WITH ATTRIBUTE-SYNTAX caseIgnoreIA5StringSyntax (SIZE (1 .. ub-rfc822-mailbox)) ::= {pilotAttributeType 3} I also suggest reading RFC822, section 3.4.7: 3.4.7. CASE INDEPENDENCE Except as noted, alphabetic strings may be represented in any combination of upper and lower case. The only syntactic units August 13, 1982 - 14 - RFC #822 Standard for ARPA Internet Text Messages which requires preservation of case information are: - text - qtext - dtext - ctext - quoted-pair - local-part, except "Postmaster" When matching any other syntactic unit, case is to be ignored. For example, the field-names "From", "FROM", "from", and even "FroM" are semantically equal and should all be treated ident- ically. > Now I'd like to know if it possible to modify the scheme that way so that > mail works case sensitive (because that's also what the standard says). No. > Or if there is a way to force the creation of entries with the "same" > value No. --Quanah -- Quanah Gibson-Mount Product Architect Symas Corporation Packaged, certified, and supported LDAP solutions powered by OpenLDAP: <http://www.symas.com>

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Re: Sync question
by Quanah Gibson-Mount 21 Nov '16

21 Nov '16

--On Friday, November 18, 2016 4:49 PM +0000 "Singley, Norman" <Norman.Singley(a)mso.umt.edu> wrote: > My question regards synchronization. We are using > "refreshandpersist" for syncrepl. For the hour or so it takes to do > the migration, users will be changing Passwords – that should be the > only oldap changes made in that time. Will the password changes that get > written to the two existing nodes sync over to the third node when we > bring it back up, or will they be lost and we would be out of sync? The third node should "catch up" with the other masters. I will assume you're running the current OpenLDAP release (2.4.44). --Quanah -- Quanah Gibson-Mount Product Architect Symas Corporation Packaged, certified, and supported LDAP solutions powered by OpenLDAP: <http://www.symas.com>

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