I'm working on upgrading 7.4 to 8.0 at the moment via Slony 1.0.5
(modified to handle a group size larger than 100).

Since I ran into large issues due to the initial data copy (an 8 day
transaction), I decided to try creating one set per table, and merging
them as it went along. This mostly worked.

The initial data copy was done in small chunks.

The problem is that when copying multiple sets from a single source to a
single destination, the query plan does an index scan based on the
Origin key id, and nothing else (no transaction range is included).

This is made far worse by the forced index scan.

See below for the query and the plan.

        http://rbt.urbandb.com/slonyplan

This is what I'm left with until it gets through the various MERGE_SET
events.

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