Just think about this: to move a table across the network you can either (a) make a physical copy, and this includes data, indexes, triggers, transaction caches, and whatever the DBMS keeps in store for that table, or (b) copy just the data as SQL statements or as exportable text, but then the receiving DBMS should rebuild the indexes.

Instead, to calculate a CRC you have just a table scan.

Therefore you should compare the time needed to calculate a SHA twice per record (one for the record and one to apply it to a global SHA) versus the time needed to pass all the above mentioned stuff over the network.

I put my bet on SHA. :)

In reply to Re^6: Comparing tables over multiple servers by rnahi
in thread Comparing tables over multiple servers by mnlight

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