Re: Prefix support for synonym dictionary

From: Teodor Sigaev <teodor(at)sigaev(dot)ru>
To: Jeff Davis <pgsql(at)j-davis(dot)com>
Cc: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>, Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Prefix support for synonym dictionary
Date: 2009-08-06 15:58:49
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> 1. The docs should be clarified a little. For instance, it should have a
> link back to the definition of a prefix search (12.3.2). I included my
> doc suggestions as an attachment.
Thank you, merged

> 2. dsynonym_init() uses findwrd() in a slightly confusing (and perhaps
> fragile) way. After calling findwrd(), the "end" pointer is pointing at
> either the end of the string, or the *; depending on whether the string
> ends in * and whether flags is NULL. I only mention this because I had
> to take a more careful look to see what was happening. Perhaps add a
> comment to make it more clear?
Add comments:
* Finds the next whitespace-delimited word within the 'in' string.
* Returns a pointer to the first character of the word, and a pointer
* to the next byte after the last character in the word (in *end).
* Character '*' at the end of word will not be threated as word
* charater if flags is not null.
static char *
findwrd(char *in, char **end, uint16 *flags)

> 3. The patch looks for the special byte '*'. I think that's fine,
> because we depend on the files being in UTF-8 encoding, where it's the
> same byte. However, I thought it was worth mentioning in case we want to
> support other encodings for text search files later.

tsearch_readline() converts file's UTF8 encoding into server encoding. pgsql
supports only encoding which are a superset of ASCII. So it's safe to use
asterisk with any encodings

Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru

Attachment Content-Type Size
synonym_prefix-0.2.gz application/x-tar 2.4 KB

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