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Timeline for Using JOIN keyword or not

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May 22, 2011 at 16:07 comment added Denis de Bernardy You've slightly misunderstood those docs, however. Firstly, there actually are three thresholds. One fires the GEQO as you pointed out; the other two (from and join collapse limits) end up making the planer stick to picking applicable indexes rather than re-organizing the join order. Secondly and just as importantly, the queries are rewritten as they are parsed. This results in the first of the example queries getting parsed into the exact same query tree as that of the second one -- the thresholds then let PG know if it should try to re-order the joins or not.
May 22, 2011 at 2:04 history answered SingleNegationElimination CC BY-SA 3.0