"Pavan Deolasee" <pavan.deolasee@gmail.com> wrote:
> In a typical scenario, user might create a table and load data in the table as
> part of a single transaction (e.g pg_restore). In this case, it would help if we
> create the tuples in the *frozen* state to avoid any wrap-around related issues
> with the table.
Sounds cool. I recommended users to do VACUUM FREEZE just after initial
loading, but we can avoid it with your method.
> Without this, very large read-only tables would require one round of
> complete freezing if there are lot of transactional activities in the other parts
> of the database. And when that happens, it would generate lots of unnecessary
> IOs on these large tables.
To make things worse, the freezing day comes at once because the first restore
is done in a single or near transactions; The wraparound timings of many
tables are aligned at the same time. Freezing copy will be the solution.
Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center
