Re: Zedstore - compressed in-core columnar storage

> When doing update operation, for each tuple being modified,
> *tuplebuffers_insert()* says that there is no entry for the relation
> being modified in the hash table although it was already added when
> the first tuple in the table was updated. Why is it so?

Currently, when doing an update, it will actually flush the tuple
buffers every time we update a tuple. As a result, we only ever spool
up one tuple at a time. This is a good place to put in an optimization
like was implemented for insert, but I haven't gotten around to
looking into that yet.

The memory leak is actually happening because it isn't freeing the
attbuffers after flushing. Alexandra Wang and I have a working
branch[1] where we tried to plug the leak by freeing the attbuffers,
but it has exposed an issue with triggers that I need to understand
before I push the fix into the main zedstore branch.

I don't like our solution of freeing the buffers either, because they
could easily be reused. I'm going to take a stab at making that better
before merging in the fix.

[1] https://github.com/l-wang/postgres-1/tree/zedstore-fix-memory-issues