https://bugs.openldap.org/show_bug.cgi?id=10529

--- Comment #1 from Howard Chu hyc@openldap.org --- (In reply to christopher@gmerlin.de from comment #0)

When testing the OCaml bindings with lmdb 1.0 I encountered this assertion failure: at src/mdb.c:7588: Assertion 'root > 1' failed in mdb_page_search()")

It was triggered by:

• start transaction
• add new key-value
• commit transaction
• rollback transaction
• start read only transaction
• try to get any key -> assertion failure

Will look into this later.

On another note I notice that this fails with MDB_CANT_ROLLBACK:

• start transaction
• commit ¡EMPTY! transaction

Committing an empty transaction is a no-op. The txnID doesn't advance.

• rollback transaction -> MDB_CANT_ROLLBACK

There is nothing to roll back in that case.

Of course this is a nonsensical transaction. But nevertheless maybe this case should be mentioned in the documentation, too.

https://bugs.openldap.org/show_bug.cgi?id=10529

--- Comment #2 from Howard Chu hyc@openldap.org --- (In reply to christopher@gmerlin.de from comment #0)

When testing the OCaml bindings with lmdb 1.0 I encountered this assertion failure: at src/mdb.c:7588: Assertion 'root > 1' failed in mdb_page_search()")

It was triggered by:

• start transaction
• add new key-value
• commit transaction
• rollback transaction
• start read only transaction
• try to get any key -> assertion failure

Unable to reproduce. On a freshly created DB, where these steps are the very first transaction in the environment, the rollback yields MDB_CANT_ROLLBACK because the txnid is 1 and it can't rollback to txnid 0 (which is not a valid txnid).

On a freshly created DB, where other data was added in txnid 1, and these steps are performed using txnid 2, the rollback succeeds and the subsequent readonly txn works fine.

Please provide the actual code to reproduce your issue.

https://bugs.openldap.org/show_bug.cgi?id=10529

--- Comment #4 from christopher@gmerlin.de christopher@gmerlin.de --- I added a c program to reproduce the failure. Originally I hit this failure when running tests on the ocaml bindings.

The backtrace looks like this:

Got <blub> mdb.c:7588: Assertion 'root > 1' failed in mdb_page_search()

Program received signal SIGABRT, Aborted. 0x00007ffff7e4995c in ?? () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) bt #0 0x00007ffff7e4995c in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #1 0x00007ffff7df4cc2 in raise () from /lib/x86_64-linux-gnu/libc.so.6 #2 0x00007ffff7ddd4ac in abort () from /lib/x86_64-linux-gnu/libc.so.6 #3 0x000055555555671d in mdb_assert_fail (env=0x5555555792a0, expr_txt=0x55555557490d "root > 1", func=0x555555574b90 <__func__.13> "mdb_page_search", file=0x5555555747d4 "mdb.c", line=7588) at mdb.c:1995 #4 0x00005555555617d7 in mdb_page_search (mc=0x7fffffffdc90, key=0x5555555794b0, flags=0) at mdb.c:7588 #5 0x0000555555561664 in mdb_page_search (mc=0x7fffffffe0d0, key=0x0, flags=2) at mdb.c:7553 #6 0x0000555555568003 in mdb_cursor_init (mc=0x7fffffffe0d0, txn=0x55555557db00, dbi=2, mx=0x7fffffffded0) at mdb.c:9662 #7 0x000055555556205a in mdb_get (txn=0x55555557db00, dbi=2, key=0x7fffffffe290, data=0x7fffffffe280) at mdb.c:7763 #8 0x0000555555573af2 in main () at test.c:87

I hope you can reproduce this now.

https://bugs.openldap.org/show_bug.cgi?id=10529

--- Comment #6 from christopher@gmerlin.de christopher@gmerlin.de --- Created attachment 1179 --> https://bugs.openldap.org/attachment.cgi?id=1179&action=edit Expanded test program

https://bugs.openldap.org/show_bug.cgi?id=10529

--- Comment #8 from christopher@gmerlin.de christopher@gmerlin.de --- You are right, mdb_strerror() would have been more correct. But in this case it makes no difference.

I tested with again with this program against commit 6c1fc84aa979e00f5e505409138a49ceed69ac4f.

as probably expected mdb_get() after the rollback fails with 22(Invalid argument) instead of assertion failure because the dbi handle got invalidated. In my opinion this still es unexpected behaviour because the rollback has the side-effect of invalidating a dbi handle that was opened in another previous transaction.

Trying opening the dbi again fails with the old assertion failure:

Got <blub> on line 56 test: mdb_get(txn, dbi, &k, &v) on line 83 failed with 22 (Invalid argument) Got <(null)> on line 84 openldap-mdb.master3/libraries/liblmdb/mdb.c:7615: Assertion 'root > 1' failed in mdb_page_search()

Program received signal SIGABRT, Aborted. 0x00007ffff7e4995c in ?? () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) bt #0 0x00007ffff7e4995c in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #1 0x00007ffff7df4cc2 in raise () from /lib/x86_64-linux-gnu/libc.so.6 #2 0x00007ffff7ddd4ac in abort () from /lib/x86_64-linux-gnu/libc.so.6 #3 0x000055555555670d in mdb_assert_fail (env=0x55555557a2a0, expr_txt=0x55555557593d "root > 1", func=0x555555575bc0 <__func__.13> "mdb_page_search", file=0x5555555757d8 "openldap-mdb.master3/libraries/liblmdb/mdb.c", line=7615) at openldap-mdb.master3/libraries/liblmdb/mdb.c:1997 #4 0x0000555555561850 in mdb_page_search (mc=0x7fffffffdfd0, key=0x7fffffffe170, flags=0) at openldap-mdb.master3/libraries/liblmdb/mdb.c:7615 #5 0x00005555555632f8 in mdb_cursor_set (mc=0x7fffffffdfd0, key=0x7fffffffe170, data=0x7fffffffe160, op=MDB_SET, exactp=0x7fffffffdf9c) at openldap-mdb.master3/libraries/liblmdb/mdb.c:8149 #6 0x0000555555570b3b in mdb_dbi_open (txn=0x55555557b710, name=0x555555575dc2 "double txn_abort", flags=262152, dbi=0x7fffffffe21c) at openldap-mdb.master3/libraries/liblmdb/mdb.c:12332 #7 0x0000555555573f0a in main () at test.c:91

https://bugs.openldap.org/show_bug.cgi?id=10529

--- Comment #10 from christopher@gmerlin.de christopher@gmerlin.de --- Perfect! Now the test suite of the ocaml bindings completely passes as well.

https://bugs.openldap.org/show_bug.cgi?id=10529

Quanah Gibson-Mount quanah@openldap.org changed:

What |Removed |Added ---------------------------------------------------------------------------- Resolution|TEST |FIXED Status|RESOLVED |VERIFIED