Re: CREATE INDEX and HOT - revised design

On 3/28/07, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>
>
>
> Set it at the end, not the beginning.

At the end of what ? It does not help to set it at the end of CREATE
INDEX because the transaction may not commit immediately. In
the meantime, many new transactions may start with
transaction id > xcreate. All these transactions can see the old
tuple (which we did not index) and can also see the index once
CREATE INDEX commits.

If you are indexing a table that hasn't just been created by you, set
> the xcreate field on pg_index at the *end* of the build using
> ReadNewTransactionId(). Any xid less than that sees the index as
> invalid. If you created the table in this transaction (i.e.
> createSubId != 0) then set xcreate to creating xid.

Why do we need to handle the case where table is created in
the same transaction ? Neither the table nor the index is visible
until we commit. So thats a simple case.

Thanks,
Pavan

--

EnterpriseDB http://www.enterprisedb.com