Re: Updated tsearch documentation - Mailing list pgsql-hackers

On Sun, 17 Jun 2007, Bruce Momjian wrote:

> I have completed my first pass over the tsearch documentation:
>
>     http://momjian.us/expire/fulltext/HTML/sql.html
>
> They are from section 14 and following.
>
> I have come up with a number of questions that I placed in SGML comments
> in these files:
>
>     http://momjian.us/expire/fulltext/SGML/
>
> Teodor/Oleg, let me know when you want to go over my questions.

Below are my answers (marked as )


Comments to editorial work of Bruce Momjian.

fulltext-intro.sgml:

it is useful to have a predefined list of lexemes.

>Bruce, here should be list of types of lexemes !


</para></listitem>

<!--
SEEMS UNNECESSARY
It useless to attempt normalize <type>email address</type> using
morphological dictionary of russian language, but looks reasonable to pick
out <type>domain name</type> and be able to search for <type>domain
name</type>.
-->

>I dont' understand where did you get this para :)

fulltext-opfunc.sgml:

All of the following functions that accept a configuration argument can
use either an integer <!-- why an integer --> or a textual configuration
name to select a configuration.

> originally it was integer id, probably better use <type>oid</type>


This returns the query used for searching an index. It can be used to test
for an empty query. The <command>SELECT</> below returns <literal>'T'</>,
<!-- lowercase? --> which corresponds to an empty query since GIN indexes
do not support negate queries (a full index scan is inefficient):

> capital case. This looks cumbersome, probably querytree() should
> just return NULL.

The integer option controls several behaviors which is done using bit-wise
fields and <literal>|</literal> (for example, <literal>2|4</literal>):
<!-- why so complex? -->

> to avoid 2 arguments

its <replaceable>id</replaceable> or <replaceable>ts_name</replaceable>; <!-- n
if none is specified that the current configuration is used.

> I don't understand this question

<para>
<!-- why?  -->
Note that the cascade dropping of the <function>headline</function> function
cause dropping of the <literal>parser</literal> used in fulltext configuration
<replaceable>tsname</replaceable>.
</para>

> hmm, probably it should be reversed - cascade dropping of the parser cause
> dropping of the headline function.

In example below, <literal>fulltext_idx</literal> is
a GIN index:<!-- why isn't this automatic -->

> It's explained above. The problem is that current index api doesn't allow
> to say if search was lossy or exact, so to preserve performance of
> GIN index we had to introduce @@@ operator, which is the same as @@, but
> lossy.

nly the <token>lword</token> lexeme, then a <acronym>TZ</acronym>
definition like ' one 1:11' will not work since lexeme type
<token>digit</token> is not assigned to the <acronym>TZ</acronym>.
<!-- what do these numbers mean? -->
</para>

> nothing special, just numbers for example.

<function>ts_debug</> displays information about every token of
<replaceable class="PARAMETER">document</replaceable> as produced by the
parser and processed by the configured dictionaries using the configuration
specified by <replaceable class="PARAMETER">cfgname</replaceable> or
<replaceable class="PARAMETER">oid</replaceable>. <!-- no need for oid

> don't understand this comment. ts_debug accepts cfgname or its oid



    Regards,        Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83