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The scenario is as follows:
We have a data warehouse type application that relies on the Oracle job scheduler and a Chain. This chain is responsible for generating materialized views (caches) that are to be queried against based on data that exists in the primary tables. For the sake of discussion the materialized views are :
select * from Cats,
select * from Dogs,
select * from Humans

During this cache creation process there are arbitrary tasks that are constantly populating the Cats, Dogs, and Humans tables. My question is:

Given the above scenario is it possible for the creation of the materialized views (a read statement) to block during the insertion of new records from an abritrary program (these are bound by a transaction). I believe that there should be zero conflict, but I want to bring this question to more experienced DBAs.

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up vote 2 down vote accepted

No, the reading of your cats, dogs and humans tables wont block other processes that are inserting in them.

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That is what I thought, because reads should never be blocked. Some of my peers seem to disagree. – Woot4Moo Nov 9 '12 at 16:46
@Woot4Moo:… - "a reader never blocks a writer [...] a writer never blocks a reader" – Mat Nov 9 '12 at 16:55
@Mat thanks for that link! – Woot4Moo Nov 9 '12 at 19:24

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