RPK wrote:
I want to know whether MVCC has cons also. Is it heavy on resources? How PGSQL MVCC relates with SQL Server 2005 new Snapshot Isolation.
Speaking as an end-user, I can give only one I've ever seen, which is performance. Because of MVCC, Postgres's write performance (insert and update) appears on my systems to be almost exactly linear to row size. Inserting 1000 rows into a table with row size 100 characters takes twice as long as inserting 1000 rows into a table with row size 50 characters.
This tends to be more of an issue for me because my system materializes derived information in columns, so my tables are more fat to begin with, and so this hits me harder.
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