Crash on recovery attempt in HamsterDB 2.1.6

[Julian Graham]

Hi Christoph et al.,

I'm testing an integration between my application and the HamsterDB C API (2.1.6), and I'm seeing some puzzling behavior. When I do the following things...

1. Create a new environment and local database with the `HAM_ENABLE_TRANSACTIONS' flag set

2. Begin a transaction

3. Insert multiple keys with `ham_db_insert'

4. Commit the transaction

5. Exit without cleaning up the environment (e.g., via `SIGKILL')

...I wind up with an un-openable environment. That is to say, if I later attempt to open the environment via `ham_env_open' (and `HAM_ENABLE_TRANSACTIONS', I get `HAM_NEEDS_RECOVERY'. If I add the `HAM_AUTO_RECOVERY' flag, my process crashes with:

  ASSERT FAILED in file blob_manager_disk.cc, line 357:

  "old_blob_header.get_self() == old_blobid"

  Aborted (core dumped)

What am I doing wrong? It might be worth noting that this only happens when multiple keys are inserted as part of the transaction described above. I've attached a small C program that captures my use case and can be used to reproduce the behavior I'm seeing. (Run "a.out -i" followed by "a.out -r".)

Thanks,

Julian

[Christoph Rupp]

Hi Julian,

thanks for the code. I think i know what's going on. 2.1.6 (and older versions) try to log as little as possible to reduce I/O, and it seems they were too aggressive and ignored  I'm going to look into it and send you a message till today evening (CET).

Best regards
Christoph

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[Christoph Rupp]

Hi Julian,

the bug was already fixed - you can pull the sources from github. The branch is "topic/next":
https://github.com/cruppstahl/hamsterdb/tree/topic/next

2.1.6 and older versions did log as little as possible in order to save I/O. 2.1.7 is logging more pessimistically. (It has other logging optimizations, and logging should be equally fast if not faster than in 2.1.6.)

Shame on me that i did not realize that this issue was so critical. I'm going to release a new version in a few days. "topic/next" is an unstable branch, but things should work well enough for integration testing.

Also, i'll create a unittest from your sample.

Best regards
Christoph

[Julian Graham]

Hi Christoph,

Thanks for the quick response! 

On Sunday, March 23, 2014 10:51:11 AM UTC-4, Christoph Rupp wrote:

the bug was already fixed - you can pull the sources from github. The branch is "topic/next":

https://github.com/cruppstahl/hamsterdb/tree/topic/next

 

I've done some light testing with the code on "topic/next," and my application is working much better. I eagerly await the release of 2.1.7.  :)

Regards,

Julian