[Openmcl-devel] Hash Table anomaly -- hash-table-size decreases - wondering how this can happen

Madhu enometh at meer.net
Sun Jan 4 03:29:56 PST 2015

* Glenn Iba <CAL+m5F4=B=YcwdYKz4Aut+=HtjcCP4HAjMQMaj=e3UNjk9Z7XQ at mail.gmail.com> :
Wrote on Sat, 3 Jan 2015 02:47:37 -0500:

| I'm doing some large searches in CCL, and have been using large
| hash-tables, but I"m perplexed that the hash-table-size is getting
| mysteriously decreased.  Can anyone explain how this is possible?

Apologies to the OP for a some incorrect emails, which I sent without
understanding the "lock-free" algorithms used in level-0/l0-hash.lisp. I
still haven't been able to understand them.

You could try creating your hash-tables with :LOCK-FREE NIL to use the
original algorithms which may avoid this problem.

The resizing seems unconditional in LOCK-FREE-REHASH, which is forced,
when GROW-THRESHOLD becomes 0, which eventually happens when the hash
vector is filled up --- regardless of the hash-table-count.---Madhu

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