I am working for a client who is interested
in migrating from Oracle to Postgres. Their database is currently ~20TB
in size, and is growing. The biggest table in this database is effectively
a BLOB store and currently has around 1 billion rows.
From reading around Postgres, there
are a couple of limits which are concerning in terms of being able to migrate
this database. We are not up against these limits just yet, but it is likely
that they will be a potential blocker within the next few years.
1) Table can be maximum of 32TB (http://www.postgresql.org/about/)
2) When storing bytea or text datatypes
there is a limit of 4 billion entries per table (https://wiki.postgresql.org/wiki/BinaryFilesInDB)
With both of these, are they hard limits
or can they be worked around with partitioning of tables? Could we set
the table up in such a way that each child table was limited, but there
was no limit on the number of children?
With point two, does this mean that
any table with a bytea datatype is limited to 4 billion rows (which would
seem in conflict with the "unlimited rows" shown by http://www.postgresql.org/about)?
If we had rows where the bytea was a "null" entry would they
contribute towards this total or is it 4 billion non-null entries?
Thanks.
