[Python-Dev] Compact ordered dict is not ordered for split table. (was: PEP XXX: Compact ordered dict (original) (raw)

INADA Naoki songofacandy at gmail.com
Sun Jun 26 07:25:36 EDT 2016

Another idea (though it has several issues and seems like a step backward): a split-table dict can have a separate iteration list, indexing into the entry table. There are ways to share iteration lists, and make it so that adding the same keys in the same order each time results in the same iteration list each time, but this costs overhead. There might be ways of reducing the overhead, or the overhead might be replacing bigger overhead, but we should decide if the behavior is what we want in the first place.

I'll test some ideas. But for now, I'll update http://bugs.python.org/issue27350 to stop key sharing when order is different. (a. deletion is not allowed, and insertion order must be same). It may reduce key sharing rate, but total memory usage must not increase so much thanks to compact dict.

I did it. issue27350 is now ordered for key sharing dict, too.

-- INADA Naoki <songofacandy at gmail.com>

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