Re: LMDB: issue with mdb_cursor_del

[timur.kristof@gmail.com]

Hi Leonid,


> 1) With MDB_WRITEMAP the mdb_mid2l_append() will be used.
> Internally mdb_mid2l_append() don't check for duplicated, but just
> append a given page number to the list.
> Therefore when database opens with MDB_WRITEMAP this bug leads to
> duplicates inside the dirty-list and then (seems) to database
> corruption.
> 
> 2) Without MDB_WRITEMAP the mdb_mid2l_insert() will be used.
> Internally mdb_mid2l_insert() made insertion into a sorted list, so
> it
> checks for duplicates and returns -1 for such case.
> Therefore when database opens without MDB_WRITEMAP this bug leads
> only
> to assertion failure, or nothing if assertions checking was disabled.

Yes, that's exactly what I said.
That simply allowing -1 would fix the problem for the non-writemap
case, because then there is no duplicate. Right?

- Timur