> How is PGSQL Locking compared with Oracle's MVCC? How PGSQL handles
> concurreny and how it differs with Oracle's Multi-Version Concurrency
> Control (MVCC)?
In PostgreSQL, old rows remain in the table until the table is vacuumed.
In Oracle, old rows are kept in the 'undo table space' until - well,
until
the undo table space runs out and they are recycled. Depends.
I have never heard this referred to as 'MVCC'.
Locking and concurrency work pretty similar in both - at least as far
as the behaviour is concerned.
Yours,
Laurenz Albe
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