On 31.10.2013 16:43, Robert Haas wrote:
Let me say this again: the dynamic shared memory code *does* clean up
after itself. If you kill -9 the postmaster and all of its children,
you'll orphan the main shared memory segment and any dynamic shared
memory segments that exist. There is nothing we can do about that.
When you restart the postmaster, both the main shared memory segment
and any dynamic shared memory segments orphaned by the previous kill
will be cleaned up. I spent a lot of time trying to make sure that
the handling of dynamic shared memory segments is, in all cases, as
parallel to the handling of the main shared memory segment as
possible. There should be no cases where the main shared memory
segment gets cleaned up and the dynamic shared memory segments do not.
1. initdb -D data1
2. initdb -D data2
3. postgres -D data1
4. killall -9 postgres
5. postgres -D data2
The system V shmem segment orphaned at step 4 will be cleaned up at step
5. The DSM segment will not.
BTW, 9.3 actually made the situation a lot better for the main memory
segment. You only leak the small interlock shmem segment, the large
mmap'd block does get automatically free'd when the last process using
it exits.
- Heikki
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