| From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
|---|---|
| To: | Beena Emerson <memissemerson(at)gmail(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: pg_trgm Memory Allocation logic |
| Date: | 2015-03-09 12:54:56 |
| Message-ID: | 20150309125456.GK3291@alvh.no-ip.org |
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| Lists: | pgsql-hackers |
Beena Emerson wrote:
> In the pg_trgm module, within function generate_trgm, the memory for trigrams
> is allocated as follows:
>
> trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) *3);
>
> I have been trying to understand why this is so because it seems to be
> allocating more space than that is required.
Maybe it's considering a worst-case for multibyte characteres? I don't
really know if trgm supports multibyte, but I assume it does. If it
does, then probably the trigrams consist of chars, not bytes.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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