December 2013 - openldap-bugs

(ITS#7775) LMDB terminates Postfix daemon process without logfile record

by wietse＠porcupine.org

Full_Name: Wietse Venema Version: All LMDB versions OS: Linux, BSD URL: ftp://ftp.openldap.org/incoming/ Submission from: (NULL) (70.104.130.26) Subject: LMDB terminates Postfix daemon process without logfile record The LMDB library uses assert() which will abort() the program after writing a message to stderr. In the case of the Postfix MTA, the symptom is a that a daemon process falls out of the sky without logfile record. - This frustrates sysadmins (no logfile message). - This frustrates my efforts to make Postfix automatically recover from non-catastrophic error. In many cases the database is only a cache, a mere optimization. I want the option to just blow it away when LMDB has a problem with it. - Library modules should not abort programs after error. They should return an error result such as EINVAL, or use some other strategy that leaves control with the application. - Writing diagnostics to stderr is not useful for daemon programs in the general case. To fix this problem I suggest that LMDB provide way to notify the application that it was unable to complete a request, so that the application can make proper arrangements. A few alternatives: - When a request fails, return a distinct error code such as MDB_PANIC, and allow the application to look up the text for the error. - Invoke an application call-back function with the error code and problem description text. If the error code is MDB_PANIC then the application knows that it needs to make final arrangements. The second option preserves 100% backwards compatibility. The first option may cause functions to return a result that they didn't return previously. Wietse

9 years, 8 months

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Re: (ITS#7773) slapo-constraint falsely restricts modrdn with count 1

by pierangelo.masarati＠polimi.it

On 12/28/2013 01:52 PM, michael(a)stroeder.com wrote: > Full_Name: > Version: 2.4.38 > OS: > URL: > Submission from: (NULL) (212.227.35.93) > > > Sometimes it's useful to restrict an existing attribute type declared > multi-valued to a single value with slapo-constraint to avoid modifying the > standard schema. > > Example: > > constraint_attribute > uid > count 1 > restrict="ldap:///ou=example??sub?(objectClass=account)" > > Unfortunately when using uid in the RDN one cannot rename the entry anymore even > when deleteoldrdn is set to true. > > slapo-constraint should handle this case exactly like SINGLE-VALUE RDN > attributes are handled. Should be fixed in git master. Nothing specific to rename; rather, slapo-constraint was not handling internal modifications like softadd/softdel. p. -- Pierangelo Masarati Associate Professor Dipartimento di Scienze e Tecnologie Aerospaziali Politecnico di Milano

9 years, 8 months

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(ITS#7773) slapo-constraint falsely restricts modrdn with count 1

by michael＠stroeder.com

Full_Name: Version: 2.4.38 OS: URL: Submission from: (NULL) (212.227.35.93) Sometimes it's useful to restrict an existing attribute type declared multi-valued to a single value with slapo-constraint to avoid modifying the standard schema. Example: constraint_attribute uid count 1 restrict="ldap:///ou=example??sub?(objectClass=account)" Unfortunately when using uid in the RDN one cannot rename the entry anymore even when deleteoldrdn is set to true. slapo-constraint should handle this case exactly like SINGLE-VALUE RDN attributes are handled.

9 years, 8 months

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Re: (ITS#7665) LMDB: Documentation issue or mistake: MDB_NOMETASYNC vs MDB_CREATE

by h.b.furuseth＠usit.uio.no

Salvador Ortiz writes: > The documentation states that the Environment's flags should not overlap with > the Database's ones, but MDB_NOMETASYNC and MDB_CREATE share the same value. That doc is a current implementation detail for liblmdb developers adding new flags. I should not have put it in ldmb.h. I'll drop it and add an #if/#error check in mdb.c instead. -- Hallvard

9 years, 8 months

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Re: (ITS#7682) LMDB: [PATCH] mdb_env_copy should retry open() if O_DIRECT fails

by hyc＠symas.com

h.b.furuseth(a)usit.uio.no wrote: > This was fixed in LMDB 0.9.9, except: If both O_DIRECT and > F_NOCACHE are #defined, both are used. Looks a bit strange. > Maybe just one should be used in that case. (Which?) Also I'm > still wondering if env_open needs to fail if F_NOCACHE fails. > > Anyway, maybe it should be something like this. The "else {}" > is in case O_DIRECT is an unsupported dummy definiton: Isn't that in the wrong order then? What you suggest here will use O_DIRECT even if it's a dummy. I don't see any reason to fail the operation. They just want to make a copy/backup; even if the optimization of avoiding pollution of the buffer cache can't be done, they still want the copy to happen. > #ifdef O_DIRECT > if ((rc = fcntl(newfd, F_GETFL)) != -1) > (void) fcntl(newfd, F_SETFL, rc | O_DIRECT); > else > #endif > { > #ifdef F_NOCACHE /* __APPLE__ */ > (void) fcntl(newfd, F_NOCACHE, 1); > #endif > } > -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/

9 years, 9 months

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(ITS#7772) liblmdb sub-page growth when adding existing data

by h.b.furuseth＠usit.uio.no

Full_Name: Hallvard B Furuseth Version: mdb.master, 4c8f57615c5ca7b014c038e59c1045182e74f5ad OS: Linux x86_64 URL: ftp://ftp.openldap.org/incoming/Hallvard-Furuseth-growth-131223.c Submission from: (NULL) (81.191.45.35) Submitted by: hallvard A non-LEAF2 sub-page grows if you put() a data item which already exists. The space remains unused while the sub-page exists. (A LEAF2 page grows reusable space, and only if it is full.) Demo program enclosed. Edit mdb.c to set mdb_debug=1 and build with -DMDB_DEBUG. Watch the 1st DPRINTF() in mdb_node_add(): bash$ ./a.out 2>&1 | perl -lne '/add to (.*) key size/ && print $1' leaf page 2 index 0, data size 404 # node with 1st item leaf page 2 index 0, data size 840 # convert to sub-page for 2nd item leaf sub-page 2 index 0, data size 0 leaf sub-page 2 index 1, data size 0 leaf page 2 index 0, data size 1250 # space for re-adding 2nd item leaf page 2 index 0, data size 1660 # space for re-adding 2nd item leaf page 2 index 0, data size 48 # ...too big, moved to sub-DB. Fix: lmdb could position cursor+xcursor fully before spill/touch, with an MDB_GET_BOTH variant which returns different codes for "no such key" and "no such data". And position it before MDB_MULTIPLE loops up. The current comparisons to see if the data item exists, go away. Maybe mdb_cursor_put() gets split in several functions, since much of the work in the recursive put()s will be unneeded.

9 years, 9 months

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(ITS#7771) liblmdb cursor issues

by h.b.furuseth＠usit.uio.no

Full_Name: Hallvard B Furuseth Version: mdb.master, 4c8f57615c5ca7b014c038e59c1045182e74f5ad OS: Linux x86_64 URL: ftp://ftp.openldap.org/incoming/Hallvard-Furuseth-131222.c Submission from: (NULL) (2001:700:100:556::233) Submitted by: hallvard mdb_cursor_put() doc bug in lmdb.h: "If the function fails for any reason, the state of the cursor will be unchanged." That's quite untrue. To do that, the function must backup the cursor before moving it. (What is a "failure" anyway - are MDB_KEYEXIST and MDB_NOTFOUND failures?) Cursor tracking issues with MDB_DUPSORT: Cursor tracking sometimes ignores xcursors referring to sub-pages, yet code which uses an xcursor does not always fix that first. The enclosed program has several crashes. I.e. lots more code needs something like if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf); before using an xcursor. I tried that everywhere before using xcursors: That helped, but it was not enough. E.g. after mdb_cursor_del() calls mdb_node_shrink(), it tracks cursors in the same sub-page but not nearby sub-pages. Also the fix suggested above means readers do more work that writers did not. Maybe instead all code which modified a database, should fix or invalidate that DB's cursors before returning (even at failure).

9 years, 9 months

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Re: (ITS#7682) LMDB: [PATCH] mdb_env_copy should retry open() if O_DIRECT fails

by h.b.furuseth＠usit.uio.no

I wrote: > still wondering if env_open needs to fail if F_NOCACHE fails. Oops - env_copy, not env_open. -- Hallvard

9 years, 9 months

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Re: (ITS#7682) LMDB: [PATCH] mdb_env_copy should retry open() if O_DIRECT fails

by h.b.furuseth＠usit.uio.no

This was fixed in LMDB 0.9.9, except: If both O_DIRECT and F_NOCACHE are #defined, both are used. Looks a bit strange. Maybe just one should be used in that case. (Which?) Also I'm still wondering if env_open needs to fail if F_NOCACHE fails. Anyway, maybe it should be something like this. The "else {}" is in case O_DIRECT is an unsupported dummy definiton: #ifdef O_DIRECT if ((rc = fcntl(newfd, F_GETFL)) != -1) (void) fcntl(newfd, F_SETFL, rc | O_DIRECT); else #endif { #ifdef F_NOCACHE /* __APPLE__ */ (void) fcntl(newfd, F_NOCACHE, 1); #endif } -- Hallvard

9 years, 9 months

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Re: (ITS#7515) Nested liblmdb transaction bugs

by h.b.furuseth＠usit.uio.no

The remaining issues were fixed in LMDB 0.9.9. Closing this ITS. -- Hallvard

9 years, 9 months

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openldap-bugs December 2013