openldap-bugs October 2023

openldap-bugs@openldap.org

2 participants
212 discussions

[Issue 10054] New: Value size limited to 2,147,479,552 bytes
by openldap-its＠openldap.org 12 Jul '26

12 Jul '26

https://bugs.openldap.org/show_bug.cgi?id=10054 Issue ID: 10054 Summary: Value size limited to 2,147,479,552 bytes Product: LMDB Version: unspecified Hardware: x86_64 OS: Linux Status: UNCONFIRMED Keywords: needs_review Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: louis(a)meilisearch.com Target Milestone: --- Hello, According to the documentation[0], a database that is not using `MDB_DUPSORT` can store values up to `0xffffffff` bytes (around 4GB). In practice, under Linux, the actual limit is `0x7ffff000` though (2^31 - 4096, so around 2GB). This is due to the write loop in `mdb_page_flush`. The `wsize` value determining how many bytes will be written can be as big as `4096*dp->mp_pages`[1], and the number of overflow pages grows with the size of the value put inside the DB. The `wsize` is not split in smaller chunks in the case where there are many overflow pages to write, and as a result the call to `pwrite`[2] does not perform a full write, but only a "short" write of 2147479552 bytes (the maximum allowed on a call to `pwrite` on Linux[3]). This would be OK if the short write condition was handled by looping and performing another `pwrite` with the rest of the data, but instead `EIO` is returned[4]. There seems to be a related, but different issue on macOS when trying to `pwrite` more the 2^31 bytes, that was already reported[5]. This issue was reported to me by a Meilisearch user because it causes their database indexing to fail[6]. I had to investigate a bit because their setup was peculiar (high number of documents in their database) and the `EIO` error code is not very descriptive of the underlying issue. I join a C reproducer of the issue that attempts to add a 2147479553 bytes value to the DB and fails with `EIO` (decreasing `nb_items` to a smaller value such as `2107479552` does succeed)[7]. Thank you for making LMDB! Louis Dureuil. [0]: https://github.com/LMDB/lmdb/blob/mdb.master/libraries/liblmdb/lmdb.h#LL284… [1]: https://github.com/LMDB/lmdb/blob/mdb.master/libraries/liblmdb/mdb.c#LL3770… [2]: https://github.com/LMDB/lmdb/blob/mdb.master/libraries/liblmdb/mdb.c#L3820 [3]: https://stackoverflow.com/questions/70368651/why-cant-linux-write-more-than… [4]: https://github.com/LMDB/lmdb/blob/mdb.master/libraries/liblmdb/mdb.c#L3840 [5]: https://bugs.openldap.org/show_bug.cgi?id=9736 [6]: https://github.com/meilisearch/meilisearch/issues/3654 [7]: https://github.com/dureuill/lmdb_3654/tree/main -- You are receiving this mail because: You are on the CC list for the issue.

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[Bug 9223] New: Add support for incremental backup
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=9223 Bug ID: 9223 Summary: Add support for incremental backup Product: LMDB Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: quanah(a)openldap.org Target Milestone: --- For LMDB 1.0, add support for incremental backups -- You are receiving this mail because: You are on the CC list for the bug.

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[Issue 9496] New: Some writes missing from database
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=9496 Issue ID: 9496 Summary: Some writes missing from database Product: LMDB Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: igfoo(a)github.com Target Milestone: --- With the attached test program, some of my database writes appear not to actually be written to the database. For example, a run may look like this: $ ./run.sh All done. All finished 1802 test.txt foo_200 is missing bar_200 is missing foo_404 is missing bar_404 is missing foo_407 is missing bar_407 is missing The script that I am using to run the program is below. This is using mdb.master 52bc29ee2efccf09c650598635cd42a50b6ecffe on Linux, with an ext4 filesystem. Is this an LMDB bug, or is there a bug in my code? Thanks Ian #!/bin/sh set -e if ! [ -d lmdb ] then rm -rf lmdb git clone https://github.com/LMDB/lmdb.git INSTALL_DIR="`pwd`/inst" cd lmdb/libraries/liblmdb make install prefix="$INSTALL_DIR" cd ../../.. fi gcc -Wall -Werror -Iinst/include loop.c inst/lib/liblmdb.a -o loop -pthread rm -f test.db test.db-lock ./loop echo "All finished" mdb_dump -np test.db > test.txt wc -l test.txt for i in `seq 100 999` do if ! grep -q "foo_$i" test.txt then echo "foo_$i is missing" fi if ! grep -q "bar_$i" test.txt then echo "bar_$i is missing" fi done -- You are receiving this mail because: You are on the CC list for the issue.

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[Issue 9619] New: mdb_env_copy2 with MDB_CP_COMPACT in mdb.master3 produces corrupt mdb file
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=9619 Issue ID: 9619 Summary: mdb_env_copy2 with MDB_CP_COMPACT in mdb.master3 produces corrupt mdb file Product: LMDB Version: 0.9.29 Hardware: All OS: Windows Status: UNCONFIRMED Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: kriszyp(a)gmail.com Target Milestone: --- When copying an LMDB database with mdb_env_copy2 with the MDB_CP_COMPACT with mdb.master3, the resulting mdb file seems to be corrupt and when using it in LMDB, I get segmentation faults. Copying without the compacting flag seems to work fine. I apologize, I know this is not a very good issue report, as I haven't had a chance to actually narrow this down to a more reproducible/isolated case, or look for how to patch. I thought I would report in case there are any ideas on what could cause this. The segmentation faults always seem to be memory write faults (as opposed to try fault on trying to read). Or perhaps the current backup/copying functionality is eventually going to be replaced by incremental backup/copying anyway (https://twitter.com/hyc_symas/status/1315651814096875520). I'll try to update this if I get a chance to investigate more, but otherwise feel free to ignore/consider low-priority since the work around is easy. -- You are receiving this mail because: You are on the CC list for the issue.

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[Issue 10024] New: MDB_PREVSNAPSHOT broken
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=10024 Issue ID: 10024 Summary: MDB_PREVSNAPSHOT broken Product: LMDB Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Keywords: needs_review Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: markus(a)objectbox.io Target Milestone: --- It seems that the patch #9496 had a negative side effect on MDB_PREVSNAPSHOT. In certain cases, when opening the DB using MDB_PREVSNAPSHOT, the previous (2nd latest) commit is not selected. Instead, reads show that the latest commit was selected voiding the effect of MDB_PREVSNAPSHOT. I observed this in our test cases a while back. Today, I was finally able to reproduce it and debug into it. When creating the transaction to read the data, I debugged into mdb_txn_renew0. Here, ti (MDB_txninfo; env->me_txns) was non-NULL. However, ti->mti_txnid was 0 (!) and thus txn->mt_txnid was set to 0. That's the reason for always selecting the first (index 0) meta page inside mdb_txn_renew0: meta = env->me_metas[txn->mt_txnid & 1]; This line occurs twice (once for read txn and once for write txn; it affects both txn types). Thus, the chances of MDB_PREVSNAPSHOT selecting the correct meta page is 50-50. It's only correct if the first meta page (index 0) is the older one. I believe that this is related to #9496 because the patch, that was provided there, removed the initialization of "env->me_txns->mti_txnid" in mdb_env_open2. This would explain why txn->mt_txnid inside mdb_txn_renew0 was set to 0. I can confirm that adding back the following two lines back in fixes MDB_PREVSNAPSHOT: if (env->me_txns) env->me_txns->mti_txnid = meta.mm_txnid; The said patch including the removal of these two lines was applied in the commit(s) "ITS#9496 fix mdb_env_open bug from #8704" (Howard Chu on 09.04.21). I hope this information is useful to find a suitable fix. Please let me know if you have questions. Also, I'd be happy to help confirming a potential fix with our test suite. -- You are receiving this mail because: You are on the CC list for the issue.

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[Bug 9224] New: Add support for PREPARE/2-phase commit
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=9224 Bug ID: 9224 Summary: Add support for PREPARE/2-phase commit Product: LMDB Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: quanah(a)openldap.org Target Milestone: --- In LMDB, add support for PREPARE/2-phase commits -- You are receiving this mail because: You are on the CC list for the bug.

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[Issue 9769] New: Patch new feature batch get
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=9769 Issue ID: 9769 Summary: Patch new feature batch get Product: LMDB Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Keywords: needs_review Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: rouzier(a)gmail.com Target Milestone: --- Created attachment 859 --> https://bugs.openldap.org/attachment.cgi?id=859&action=edit New functionality mdb_cursor_get_batch New functionality mdb_cursor_get_batch mdb_cursor_get_batch retrieves a page worth of key/values. This is to reduce the number of function calls when doing a scan of the database. -- You are receiving this mail because: You are on the CC list for the issue.

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[Issue 9291] New: Detection of corrupted database files
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=9291 Issue ID: 9291 Summary: Detection of corrupted database files Product: LMDB Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: markus(a)objectbox.io Target Milestone: --- Let's assume we have to deal with a corrupted database for whatever reason (e.g. broken hardware or file system). Current behavior seems to be mostly undefined, which is understandable as it's not known what is broken (e.g. there are no checksums). For example, I'm seeing a SIGBUS in mdb_page_touch because the cursor's top page (mp) is pointing to invalid memory (0x7f99cf004000) during a commit: mdb_page_touch mdb.c:2772 mdb_page_search mdb.c:6595 mdb_freelist_save mdb.c:3575 mdb_txn_commit mdb.c:4060 Cursor data at that point: mc_snum = 1, mc_top = 0; myki[0] = 0 A SIGBUS is troublesome as it crashes the process, and I wonder if there are other ways to detect such inconsistencies. If that be possible there could be user-specific handling in place. E.g. a user might start a new database file. This issue was reported by our users, which also provided DB files: https://github.com/objectbox/objectbox-java/issues/859 I did not find a lot of consistency checks besides MDB_PAGE_NOTFOUND and MDB_CORRUPTED. Also, I think there's no current way to thoroughly check a DB file (e.g. like fsck for the DB file)? My first idea other than checksums was to walk through the branch pages from the root and check if the referenced pages are within reasonable bounds. Also check the page content (e.g. nodes, flags). Additionally (optionally?), it should be possible to check that the key values are actually sorted. So, it boils down to 3 points in summary: 1.) If there no way to check the DB file for consistency yet(?), which approach do you think would make sense? There might be two modes; one for a through check through all data, and a quick check that does not take long and could be e.g. done when opening the DB. Goal is to avoid process crashes and let users handle the situation. 2.) In general, is it possible to add more consistency checks in regular DB operations? 3.) Could the the particular situation (for which I provided the stack trace) detected (e.g. is myki[0] = 0 legal here?) I'd be happy to provide a patch if you provide some direction where you want to take that. -- You are receiving this mail because: You are on the CC list for the issue.

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[Issue 9539] New: ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(env, 0)
by openldap-its＠openldap.org 30 Jun '26

30 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=9539 Issue ID: 9539 Summary: ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(env, 0) Product: LMDB Version: 0.9.28 Hardware: x86_64 OS: Windows Status: UNCONFIRMED Severity: normal Priority: --- Component: liblmdb Assignee: bugs(a)openldap.org Reporter: igfoo(a)github.com Target Milestone: --- On Windows, with the attached program and the commands below, I am getting ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(env, 0) on the latest 0.9.28 release. The program works as expected on mdb.master. git clone https://github.com/LMDB/lmdb.git cd lmdb git reset --hard LMDB_0.9.28 cd .. call "c:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars64.bat" cl -Femain.exe -Ilmdb/libraries/liblmdb main.c lmdb/libraries/liblmdb/mdb.c lmdb/libraries/liblmdb/midl.c Advapi32.lib cl -Feloop.exe -Ilmdb/libraries/liblmdb loop.c lmdb/libraries/liblmdb/mdb.c lmdb/libraries/liblmdb/midl.c Advapi32.lib .\main.exe Example output: Loop 300000 400000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 500000 600000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 200000 300000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 400000 500000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 600000 700000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 100000 200000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 700000 800000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 900000 1000000 starting. Got ERROR_USER_MAPPED_FILE from mdb_env_set_mapsize(0). Loop 800000 900000 starting. Loop 800000 900000 done. Non-zero 0 exit code 1. Non-zero 1 exit code 1. Non-zero 2 exit code 1. Non-zero 3 exit code 1. Non-zero 4 exit code 1. Non-zero 5 exit code 1. Non-zero 6 exit code 1. Non-zero 8 exit code 1. All done. -- You are receiving this mail because: You are on the CC list for the issue.

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[Issue 10026] New: Refresh handling can skip entries (si_dirty not managed properly)
by openldap-its＠openldap.org 23 Jun '26

23 Jun '26

https://bugs.openldap.org/show_bug.cgi?id=10026 Issue ID: 10026 Summary: Refresh handling can skip entries (si_dirty not managed properly) Product: OpenLDAP Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Keywords: needs_review Severity: normal Priority: --- Component: overlays Assignee: bugs(a)openldap.org Reporter: ondra(a)mistotebe.net Target Milestone: --- Take MPR plain syncrepl with 3+ providers. When a provider's own syncrepl session transitions to persist and a it starts a new parallel session towards another host, that session always has to start as a refresh. If that refresh serves entries to us, our handling of si_dirty is not consistent: - if the existing persist session serves some of these entries to us, we can "forget" to pass the others to a newly connected consumer - same if the refresh is abandoned and we start refreshing from a different provider that might be behind what we were being served (again our consumers could suffer) - if we restart, si_dirty is forgotten and our consumers suffer even worse We might need to be told (at the beginning of the refresh?) what the end state we're going for is, so we can keep si_dirty on until then. And somehow persist that knowledge in the DB... -- You are receiving this mail because: You are on the CC list for the issue.

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openldap-bugs October 2023