Correction, with the flags MDB_RESERVE|MDB_APPENDDUP
Here is the stack from gdb :
Program received signal SIGSEGV, Segmentation fault.
mdb_node_del (mc=mc@entry=0x7fffffffdb10, ksize=ksize@entry=0) at mdb.c:7183
7183 mp->mp_ptrs[j] = mp->mp_ptrs[i];
(gdb) bt
#0 mdb_node_del (mc=mc@entry=0x7fffffffdb10, ksize=ksize@entry=0)
at mdb.c:7183
#1 0x00007ffff7bd06e2 in mdb_cursor_put (mc=0x7fffffffdb10,
key=0x7fffffffd8d0, data=0x7fffffffd8c0, flags=<optimized out>)
at mdb.c:6698
#2 0x00007ffff7bd0f8e in mdb_cursor_put (mc=0x7fffffffd980,
key=0x7fffffffdd70, data=0x7fffffffdda0, flags=<optimized out>)
at mdb.c:6757
#3 0x00007ffff7bd29b2 in mdb_put (txn=<optimized out>, dbi=<optimized
out>,
key=0x7fffffffdd70, data=0x7fffffffdda0, flags=327680) at mdb.c:8611
#4 0x0000000000400dea in main (argc=1, argv=0x7fffffffded8)
at test_lmdb_appenddup.c:59
On 21 August 2015 at 19:25, Simon Majou <[email protected]> wrote:
> And in the case where I want to append data in a DUPSORT database, is
> there a way to write directly in the persisted page ?
> I tried with the flags MDB_RESERVE|MDB_APPEND but it fails.
>
> On 18 August 2015 at 15:41, Simon Majou <[email protected]> wrote:
>
>> Oh ok it makes sense now. Thank you for the heads up
>>
>> On 18 August 2015 at 15:36, Howard Chu <[email protected]> wrote:
>>
>>> Simon Majou wrote:
>>>
>>>> This is version 0.9.16
>>>>
>>>> I used sample-bdb.txt for instance, with the DUP_SORT option, and the
>>>> mdb_put
>>>> with the MDB_RESERVED flags, and execute it 2 times. The first run
>>>> (creation)
>>>> is ok, the second (update) gets the seg fault.
>>>>
>>>
>>> DUPSORT and RESERVED are incompatible. RESERVED means you're not
>>> providing a data value, only a length. DUPSORT sorts *values* - since you
>>> didn't provide a valid value, it probably chased a pointer off into space.
>>>
>>>
>>>> I ran it in gdb and got the stack :
>>>> #0 mdb_cursor_set (mc=mc@entry=0x7fffffffdb40, key=key@entry
>>>> =0x7fffffffdda0,
>>>> data=data@entry=0x7fffffffd800, op=op@entry=MDB_SET,
>>>> exactp=exactp@entry=0x7fffffffd7f0) at mdb.c:5867
>>>> #1 0x00007ffff7bd024c in mdb_cursor_put (mc=0x7fffffffdb40,
>>>> key=0x7fffffffdda0, data=0x7fffffffd8f0, flags=32768) at mdb.c:6391
>>>> #2 0x00007ffff7bd095f in mdb_cursor_put (mc=0x7fffffffd9b0,
>>>> key=0x7fffffffdd90, data=0x7fffffffdda0, flags=<optimized out>)
>>>> at mdb.c:6780
>>>> #3 0x00007ffff7bd29b2 in mdb_put (txn=<optimized out>, dbi=<optimized
>>>> out>,
>>>> key=0x7fffffffdd90, data=0x7fffffffdda0, flags=65536) at mdb.c:8611
>>>> #4 0x0000000000400ccf in main (argc=1, argv=0x7fffffffded8) at
>>>> sample-mdb.c:43
>>>>
>>>> It seems the mp_lower value of the page is set to 0 instead of a value
>>>> inside
>>>> the page.
>>>>
>>>> On 18 August 2015 at 13:58, Howard Chu <[email protected] <mailto:
>>>> [email protected]>>
>>>> wrote:
>>>>
>>>> Simon Majou wrote:
>>>>
>>>> Hello,
>>>>
>>>> I wonder, why do I get a Segmentation fault when I use mdb_put
>>>> with
>>>> MDB_RESERVE on a key that already exists ?
>>>>
>>>>
>>>> Have no idea. Provide some more details and maybe we can guess.
>>>>
>>>> LMDB version? stack trace from SEGV? What's the size of the existing
>>>> record, what's the size of the new record? Show sample code that
>>>> demonstrates the problem?
>>>>
>>>> --
>>>> -- Howard Chu
>>>> CTO, Symas Corp. http://www.symas.com
>>>> Director, Highland Sun http://highlandsun.com/hyc/
>>>> Chief Architect, OpenLDAP http://www.openldap.org/project/
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> Best regards,
>>>>
>>>> Simon
>>>>
>>>
>>>
>>> --
>>> -- Howard Chu
>>> CTO, Symas Corp. http://www.symas.com
>>> Director, Highland Sun http://highlandsun.com/hyc/
>>> Chief Architect, OpenLDAP http://www.openldap.org/project/
>>>
>>
>>
>>
>> --
>>
>> Best regards,
>>
>> Simon
>>
>
>
>
> --
>
> Best regards,
>
> Simon
>
--
Best regards,
Simon
