On Wed, 20 Jun 2007, Bruce Momjian wrote:
Oleg Bartunov wrote:
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 )
OK.
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 !
Agreed. Are the list of lexemes parser-specific?
yes, it it parser which defines types of lexemes.
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>
Uh, my question is why are you allowing specification as an integer/oid
when the name works just fine. I don't see the value in allowing
numbers here.
for compatibility reason. Hmm, indeed, i don't recall where oid's could be
important.
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.
Agreed.
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
But I don't see why you would want to set two of those values --- they
seem mutually exclusive, e.g.
1 divides the rank by the 1 + logarithm of the document length
2 divides the rank by the length itself
I assume you do either one, not both.
but what's about others variants ?
What I missed is the definition of extent.
From http://www.sai.msu.su/~megera/wiki/NewExtentsBasedRanking
Extent is a shortest and non-nested sequence of words, which satisfy a query.
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
Same issue as above --- why allow a number here when the name works just
fine. We don't allow tables to be specified by number, so why
configurations?
<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.
Agreed.
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.
Well, then we have to fix the API. Telling users to use a different
operator based on what index is defined is just bad style.
This was raised by Heikki and we discussed it a bit in Ottawa, but it's
unclear if it's doable for 8.3. @@@ operator is in rare use, so we could
say it will be improved in future versions.
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>
OK, I changed it to be clearer.
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
Again, no need for oid.
We need to decide if we need oids as user-visible argument. I don't see
any value, probably Teodor think other way.
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: [EMAIL PROTECTED], http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?
http://archives.postgresql.org
