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Re: BadRSlotError: mdb_txn_begin: MDB_BAD_RSLOT: Invalid reuse of reader locktable slot
- To: Luke Kenneth Casson Leighton <firstname.lastname@example.org>
- Subject: Re: BadRSlotError: mdb_txn_begin: MDB_BAD_RSLOT: Invalid reuse of reader locktable slot
- From: Howard Chu <email@example.com>
- Date: Thu, 11 Sep 2014 12:01:55 +0100
- Cc: "OpenLDAPfirstname.lastname@example.org" <OpenLDAPemail@example.com>
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Luke Kenneth Casson Leighton wrote:
garbage collection occurs periodically, at any time the interpreter
feels like it
(afaik). so, the scenario under consideration is therefore that a
cursor gets closed
at random points, well after its txn has been closed.
however if the c api is reflected in the python layer then correspondingly the
cursor could not interfere with a txn.
the only other possibility under consideration is that the python
process has been
killed unexpectedly (kill -9) and has left the database in an abnormal state.
Not possible; the database structure is inherently incorruptible. kill -9
won't do anything to it.
looking at the application logs that i have available (qty one only
at the moment)
i do note that the application appears to have just undergone a restart...
You're talking about a database being accessed by only a single process; the
lock table is reinitialized whenever a process opens it and no other processes
already have it open. As such, no locktable elements from a previous crash
will ever affect the running process.
i'll have to have a closer look but would that be causing any problems (esp
with the arguments to speed up access such as sync=False etc.)
Nope. sync is irrelevant for application-level crashes, all the data goes into
the OS buffer cache regardless. sync=False will likely leave you a corrupted
database if the OS or hardware crashes, but not if the application process
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/