Hey guys,
I have a bunch of queries I need to convert from SQL Server. The queries have a NOLOCK option on each table which is supposed to improve concurrency on a busy system...
Can I do this in Vertica? Is it necessary?
Thank you,
Deb
NOLOCK option in Vertica
Moderator: NorbertKrupa
Re: NOLOCK option in Vertica
Hello,
Vertica support read commited isolation level on its table by defauls.
This means only the latest commited data will be read in your select statements(queries).
This allows new data to be loaded while concurrent queries are running.
Also, Vertica has no option matching NOLOCK and Vertica uses shared lock for select operations by default.
So this should not affect the perfomance if you don't mention it in your queries.
Vertica support read commited isolation level on its table by defauls.
This means only the latest commited data will be read in your select statements(queries).
This allows new data to be loaded while concurrent queries are running.
Also, Vertica has no option matching NOLOCK and Vertica uses shared lock for select operations by default.
So this should not affect the perfomance if you don't mention it in your queries.
Re: NOLOCK option in Vertica
Thank you, nnani!
So I'll just remove all the NOLOCK commands from my scripts.
Cool.
So I'll just remove all the NOLOCK commands from my scripts.
Cool.