| Subject | Re: [Firebird-general] Re: History of Interbase's failure to make it to the big time. |
|---|---|
| Author | Ann W. Harrison |
| Post date | 2005-10-19T15:13:10Z |
plinehan wrote:
explaining their new, not yet released, MVCC. Postgres was
designed for write-once media, so it always left old record
versions behind. One of their Russian developers adapted that
mechanism to provide repeatable read and recognize update
conflicts.
The PostgreSQL MVCC is very like MGA except
Their record versions are (or were then) linked from oldest
to newest. Firebird goes from newest to oldest.
Their back versions are not compressed
They keep both the id of the transaction that created the
record version and the id of the transaction that replaced
it.
>I was at a conference in late October of 2000 and Tom Lane was
>>- PostgreSQL have MVCC since ... (don't know).
explaining their new, not yet released, MVCC. Postgres was
designed for write-once media, so it always left old record
versions behind. One of their Russian developers adapted that
mechanism to provide repeatable read and recognize update
conflicts.
The PostgreSQL MVCC is very like MGA except
Their record versions are (or were then) linked from oldest
to newest. Firebird goes from newest to oldest.
Their back versions are not compressed
They keep both the id of the transaction that created the
record version and the id of the transaction that replaced
it.