"Dann Corbit" <[EMAIL PROTECTED]> writes: > How would this work with MVCC? > >> > Whenever a commit occurs, the pending inserts are totaled into the sum > and the pending deletes are subtracted. It can be a list in memory or > whatever. Maybe you are referring to the old (expired) rows begin > stored until vacuum? Perhaps I really don't understand your question or > the issues involved. Why does MVCC complicate issues? > <<
Because the row count depends on what transactions have committed when yours starts. Also, you will see the count(*) reflecting INSERTs in your transaction, but others won't until you commit. So there is no well-defined concept of cardinality under MVCC--it depends on which rows are visible to which transactions. -Doug -- Doug McNaught Wireboard Industries http://www.wireboard.com/ Custom software development, systems and network consulting. Java PostgreSQL Enhydra Python Zope Perl Apache Linux BSD... ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
