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...
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https://bugs.openldap.org/show_bug.cgi?id=9343
Issue ID: 9343
Summary: Expand ppolicy policy configuration to allow URL
filter
Product: OpenLDAP
Version: 2.5
Hardware: All
OS: All
Status: UNCONFIRMED
Severity: normal
Priority: ---
Component: overlays
Assignee: bugs(a)openldap.org
Reporter: quanah(a)openldap.org
Target Milestone: ---
Currently, ppolicy only supports a single global default policy, and past that
any policies must be manually added to a given user entry if they are supposed
to have something other than the default policy.
Also, some sites want no default policy, and only a specific subset to have a
policy applied to them.
For both of these cases, it would be helpful if it were possible to configure a
policy to apply to a set of users via a URL similar to the way we handle
creating groups of users in dynlist
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https://bugs.openldap.org/show_bug.cgi?id=9667
Issue ID: 9667
Summary: 2.6 to 2.7 upgrade documentation
Product: OpenLDAP
Version: unspecified
Hardware: All
OS: All
Status: UNCONFIRMED
Keywords: needs_review
Severity: normal
Priority: ---
Component: documentation
Assignee: bugs(a)openldap.org
Reporter: quanah(a)openldap.org
Target Milestone: ---
Need to document any upgrade information for going from 2.6 to 2.7
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https://bugs.openldap.org/show_bug.cgi?id=10358
Issue ID: 10358
Summary: syncrepl can revert an entry's CSN
Product: OpenLDAP
Version: unspecified
Hardware: All
OS: All
Status: UNCONFIRMED
Keywords: needs_review
Severity: normal
Priority: ---
Component: slapd
Assignee: bugs(a)openldap.org
Reporter: ondra(a)mistotebe.net
Target Milestone: ---
Created attachment 1080
--> https://bugs.openldap.org/attachment.cgi?id=1080&action=edit
Debug log of an instance of this happening
There is a sequence of operations which can force a MPR node to apply changes
out of order (essentially reverting an operation). Currently investigating
which part of the code that should have prevented this has let it slip.
A sample log showing how this happened is attached.
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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
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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
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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
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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.
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https://bugs.openldap.org/show_bug.cgi?id=10395
Issue ID: 10395
Summary: Support multiple readers on uncommitted changes
Product: LMDB
Version: unspecified
Hardware: All
OS: All
Status: UNCONFIRMED
Keywords: needs_review
Severity: normal
Priority: ---
Component: liblmdb
Assignee: bugs(a)openldap.org
Reporter: renault.cle(a)gmail.com
Target Milestone: ---
Created attachment 1086
--> https://bugs.openldap.org/attachment.cgi?id=1086&action=edit
A patch to support multiple readers on uncommitted changes
Hello,
The attached patch is not meant to be merged immediately into LMDB. Still, it
demonstrates how I added a helpful feature to the key-value store: reading
uncommitted changes from multiple transactions. I am conscious that the patch
still requires some work and uses non-C99 features, i.e., atomics are C11,
which could be a blocker for it to be merged upstream. I would also be
delighted to merge these changes under a flag/define to ensure we don't impact
other users with non-C99 stuff.
The main feature we need at Meilisearch is to read uncommitted changes from
multiple threads, compute parallel post-processing of different data structures
[1], and speed up the search requests. We could have done the post-processing
in a following transaction by opening multiple read transactions, but this
would mean that the post-processed data structure would not include newly
inserted or modified document IDs. Both data structures would be desync.
Regarding the design choice, I decided to follow the same design as the nested
write transactions: use the parent argument of the mdb_txn_begin [2], and allow
the MDB_RDONLY flag, which was disallowed when the parent argument was non-NULL
[3]. I find it clear enough that, by calling the mdb_txn_begin function with
these arguments, you can call it multiple times (I need to update the doc) to
obtain nested read-only transactions from the parent write transaction.
ret = mdb_txn_begin(env, parent_txn, MDB_RDONLY, new_nested_rtxn);
Note that this early proposal lacks security and error handling. The generated
transactions are fake-read-only and actually write transactions that share the
underlying parent allocations and data structures. This is unsafe and must be
changed or reviewed carefully, but most importantly, we need to add read-only
capabilities to these transactions to disallow writes. Using a Rust wrapper on
top of LMDB, I wrapped the fake read-only transactions into ReadTxn, which
disallows any writes at compile time. However, I haven't checked the conflict
database creations or openings.
The main issues I encountered were concurrent free of the main shared data
structures when the different threads owning the transactions were dropping the
transactions simultaneously. So, I decided to implement the equivalent of an
ARC to free resources only when the last nested transaction was freed.
I can share numbers about how this feature improves the post-processing by
4x-9x or from 1200s to 120s [1]. You can look at this PR, which I would be
happy to merge once an improved version of this patch lands on LMDB upstream.
I would be very happy if you could guide me a bit on how I could improve this
patch to make it mergeable into LMDB. We want to contribute useful features
like this to LMDB and not keep a deviant fork. LMDB works great; we are happy
about it, and its performance is predictable.
Have a lovely week,
kero
[1]: https://github.com/meilisearch/meilisearch/pull/5307
[2]:
https://github.com/LMDB/lmdb/blob/14d6629bc8a9fe40d8a6bee1bf71c45afe7576b6/…
[3]:
https://github.com/LMDB/lmdb/blob/14d6629bc8a9fe40d8a6bee1bf71c45afe7576b6/…
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https://bugs.openldap.org/show_bug.cgi?id=10428
Issue ID: 10428
Summary: Make larger key sizes available at compile time
Product: LMDB
Version: unspecified
Hardware: All
OS: All
Status: UNCONFIRMED
Keywords: needs_review
Severity: normal
Priority: ---
Component: liblmdb
Assignee: bugs(a)openldap.org
Reporter: marlowsd(a)gmail.com
Target Milestone: ---
I discovered that I can increase the key size to 1982 bytes with the following
patch
```
***************
*** 1053,1059 ****
#define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
/** ITS#7713, change PAGEBASE to handle 65536 byte pages */
! #define PAGEBASE ((MDB_DEVEL) ? PAGEHDRSZ : 0)
/** Number of nodes on a page */
#define NUMKEYS(p) ((MP_LOWER(p) - (PAGEHDRSZ-PAGEBASE)) >> 1)
--- 1054,1061 ----
#define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
/** ITS#7713, change PAGEBASE to handle 65536 byte pages */
! #define PAGEBASE PAGEHDRSZ
! // #define PAGEBASE ((MDB_DEVEL) ? PAGEHDRSZ : 0)
/** Number of nodes on a page */
#define NUMKEYS(p) ((MP_LOWER(p) - (PAGEHDRSZ-PAGEBASE)) >> 1)
```
and then passing `-DMDB_MAXKEYSIZE=0` at compile time. I didn't want to use
`MDB_DEVEL` because this is for a production use case.
Is this feature ready to be widely used? If so, could it be given a
compile-time (or run-time) flag please?
Background: this is for Glean
(https://github.com/facebookincubator/Glean/pull/663), this page explains our
DB structure https://glean.software/docs/implementation/db/.
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