My mistake, "PRAGMA lock_status" is only a valid command if you compile
with -DSQLITE_DEBUG. And you're also right that your unused databases
are being locked because you are using "BEGIN EXCLUSIVE". See here:
d...@computer2:~/work/experimental/bld$ ./sqlite3 abc
SQLite version 3.6.10
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> create table t1(a, b, c);
sqlite> attach 'def' AS def;
sqlite> create table def.def(d, e, f);
sqlite> begin;
sqlite> insert into def values(1, 2, 3);
sqlite> pragma lock_status;
main|unlocked
temp|closed
def|reserved
sqlite> commit;
sqlite> begin exclusive;
sqlite> insert into def values(1, 2, 3);
sqlite> pragma lock_status;
main|exclusive
temp|closed
def|exclusive
sqlite> commit;
sqlite> begin exclusive;
sqlite> pragma lock_status;
main|exclusive
temp|closed
def|exclusive
sqlite> commit;
Dan.
On Jan 30, 2009, at 1:54 AM, Chris Eich wrote:
> I can't get it this (undocumented <http://www.sqlite.org/pragma.html>)
> pragma to do anything for me:
>
> $ sqlite3 db/emu.db
> SQLite version 3.6.3
> Enter ".help" for instructions
> Enter SQL statements terminated with a ";"
> sqlite> attach 'db/binned-eich.db' as binned;
> sqlite> begin exclusive;
> sqlite> pragma lock_status;
> sqlite> select complete,count(*) from binned.device_perf_interval
> group by
> complete;
> 0|34
> 1|145399
> sqlite> pragma lock_status;
> sqlite> update binned.device_perf_interval set complete=2 where
> complete=1;
> sqlite> pragma lock_status;
> sqlite>
> [1]+ Stopped sqlite3 db/emu.db
> $ ls -lc db/{emu,binned-eich}.db*
> -rw-r--r-- 1 ceich ceich 16400384 Jan 29 10:47 db/binned-eich.db
> -rw-r--r-- 1 ceich ceich 9379912 Jan 29 10:47 db/binned-eich.db-
> journal
> -rw-r--r-- 1 ceich ceich 77824 Dec 24 14:56 db/emu.db
> -rw-r--r-- 1 ceich ceich 512 Jan 29 10:46 db/emu.db-journal
>
> But I did notice my code was doing a BEGIN EXCLUSIVE. Would this
> cause an
> unmodified database to be locked anyway?
>
> Chris
>
> On Thu, Jan 29, 2009 at 2:02 AM, Dan <danielk1...@gmail.com> wrote:
>
>>
>> On Jan 29, 2009, at 3:13 AM, Chris Eich wrote:
>>
>>> I have read http://sqlite.org/atomiccommit.html which seems to imply
>>> that
>>> all db files in a transaction are locked at the same level as the
>>> transaction progresses (i.e. all Reserved, then all Exclusive, ...).
>>> This
>>> makes sense when all the files are being changed, but I have a use
>>> case
>>> where I am only modifying one of the attached databases and would
>>> like to
>>> leave the main database unlocked.
>>
>> That should happen automatically.
>>
>> You can use "PRAGMA lock_status" to query the locks held on each
>> file at any time.
>>
>> Dan.
>>
>> _______________________________________________
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>> sqlite-users@sqlite.org
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>>
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