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><H1
CLASS="SECT1"
><A
NAME="TEXTSEARCH-DEBUGGING"
>12.8. Testing and Debugging Text Search</A
></H1
><P
> The behavior of a custom text search configuration can easily become
confusing. The functions described
in this section are useful for testing text search objects. You can
test a complete configuration, or test parsers and dictionaries separately.
</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="TEXTSEARCH-CONFIGURATION-TESTING"
>12.8.1. Configuration Testing</A
></H2
><P
> The function <CODE
CLASS="FUNCTION"
>ts_debug</CODE
> allows easy testing of a
text search configuration.
</P
><PRE
CLASS="SYNOPSIS"
>ts_debug([<SPAN
CLASS="OPTIONAL"
> <TT
CLASS="REPLACEABLE"
><I
>config</I
></TT
> <TT
CLASS="TYPE"
>regconfig</TT
>, </SPAN
>] <TT
CLASS="REPLACEABLE"
><I
>document</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>alias</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>description</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>token</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>dictionaries</I
></TT
> <TT
CLASS="TYPE"
>regdictionary[]</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>dictionary</I
></TT
> <TT
CLASS="TYPE"
>regdictionary</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>lexemes</I
></TT
> <TT
CLASS="TYPE"
>text[]</TT
>)
returns setof record</PRE
><P
> <CODE
CLASS="FUNCTION"
>ts_debug</CODE
> displays information about every token of
<TT
CLASS="REPLACEABLE"
><I
>document</I
></TT
> as produced by the
parser and processed by the configured dictionaries. It uses the
configuration specified by <TT
CLASS="REPLACEABLE"
><I
>config</I
></TT
>,
or <TT
CLASS="VARNAME"
>default_text_search_config</TT
> if that argument is
omitted.
</P
><P
> <CODE
CLASS="FUNCTION"
>ts_debug</CODE
> returns one row for each token identified in the text
by the parser. The columns returned are
<P
></P
></P><UL
COMPACT="COMPACT"
><LI
STYLE="list-style-type: disc"
><P
> <TT
CLASS="REPLACEABLE"
><I
>alias</I
></TT
> <TT
CLASS="TYPE"
>text</TT
> — short name of the token type
</P
></LI
><LI
STYLE="list-style-type: disc"
><P
> <TT
CLASS="REPLACEABLE"
><I
>description</I
></TT
> <TT
CLASS="TYPE"
>text</TT
> — description of the
token type
</P
></LI
><LI
STYLE="list-style-type: disc"
><P
> <TT
CLASS="REPLACEABLE"
><I
>token</I
></TT
> <TT
CLASS="TYPE"
>text</TT
> — text of the token
</P
></LI
><LI
STYLE="list-style-type: disc"
><P
> <TT
CLASS="REPLACEABLE"
><I
>dictionaries</I
></TT
> <TT
CLASS="TYPE"
>regdictionary[]</TT
> — the
dictionaries selected by the configuration for this token type
</P
></LI
><LI
STYLE="list-style-type: disc"
><P
> <TT
CLASS="REPLACEABLE"
><I
>dictionary</I
></TT
> <TT
CLASS="TYPE"
>regdictionary</TT
> — the dictionary
that recognized the token, or <TT
CLASS="LITERAL"
>NULL</TT
> if none did
</P
></LI
><LI
STYLE="list-style-type: disc"
><P
> <TT
CLASS="REPLACEABLE"
><I
>lexemes</I
></TT
> <TT
CLASS="TYPE"
>text[]</TT
> — the lexeme(s) produced
by the dictionary that recognized the token, or <TT
CLASS="LITERAL"
>NULL</TT
> if
none did; an empty array (<TT
CLASS="LITERAL"
>{}</TT
>) means it was recognized as a
stop word
</P
></LI
></UL
><P>
</P
><P
> Here is a simple example:
</P><PRE
CLASS="SCREEN"
>SELECT * FROM ts_debug('english','a fat cat sat on a mat - it ate a fat rats');
alias | description | token | dictionaries | dictionary | lexemes
-----------+-----------------+-------+----------------+--------------+---------
asciiword | Word, all ASCII | a | {english_stem} | english_stem | {}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | fat | {english_stem} | english_stem | {fat}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | cat | {english_stem} | english_stem | {cat}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | sat | {english_stem} | english_stem | {sat}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | on | {english_stem} | english_stem | {}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | a | {english_stem} | english_stem | {}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | mat | {english_stem} | english_stem | {mat}
blank | Space symbols | | {} | |
blank | Space symbols | - | {} | |
asciiword | Word, all ASCII | it | {english_stem} | english_stem | {}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | ate | {english_stem} | english_stem | {ate}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | a | {english_stem} | english_stem | {}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | fat | {english_stem} | english_stem | {fat}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | rats | {english_stem} | english_stem | {rat}</PRE
><P>
</P
><P
> For a more extensive demonstration, we
first create a <TT
CLASS="LITERAL"
>public.english</TT
> configuration and
Ispell dictionary for the English language:
</P
><PRE
CLASS="PROGRAMLISTING"
>CREATE TEXT SEARCH CONFIGURATION public.english ( COPY = pg_catalog.english );
CREATE TEXT SEARCH DICTIONARY english_ispell (
TEMPLATE = ispell,
DictFile = english,
AffFile = english,
StopWords = english
);
ALTER TEXT SEARCH CONFIGURATION public.english
ALTER MAPPING FOR asciiword WITH english_ispell, english_stem;</PRE
><PRE
CLASS="SCREEN"
>SELECT * FROM ts_debug('public.english','The Brightest supernovaes');
alias | description | token | dictionaries | dictionary | lexemes
-----------+-----------------+-------------+-------------------------------+----------------+-------------
asciiword | Word, all ASCII | The | {english_ispell,english_stem} | english_ispell | {}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | Brightest | {english_ispell,english_stem} | english_ispell | {bright}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | supernovaes | {english_ispell,english_stem} | english_stem | {supernova}</PRE
><P
> In this example, the word <TT
CLASS="LITERAL"
>Brightest</TT
> was recognized by the
parser as an <TT
CLASS="LITERAL"
>ASCII word</TT
> (alias <TT
CLASS="LITERAL"
>asciiword</TT
>).
For this token type the dictionary list is
<TT
CLASS="LITERAL"
>english_ispell</TT
> and
<TT
CLASS="LITERAL"
>english_stem</TT
>. The word was recognized by
<TT
CLASS="LITERAL"
>english_ispell</TT
>, which reduced it to the noun
<TT
CLASS="LITERAL"
>bright</TT
>. The word <TT
CLASS="LITERAL"
>supernovaes</TT
> is
unknown to the <TT
CLASS="LITERAL"
>english_ispell</TT
> dictionary so it
was passed to the next dictionary, and, fortunately, was recognized (in
fact, <TT
CLASS="LITERAL"
>english_stem</TT
> is a Snowball dictionary which
recognizes everything; that is why it was placed at the end of the
dictionary list).
</P
><P
> The word <TT
CLASS="LITERAL"
>The</TT
> was recognized by the
<TT
CLASS="LITERAL"
>english_ispell</TT
> dictionary as a stop word (<A
HREF="textsearch-dictionaries.html#TEXTSEARCH-STOPWORDS"
>Section 12.6.1</A
>) and will not be indexed.
The spaces are discarded too, since the configuration provides no
dictionaries at all for them.
</P
><P
> You can reduce the width of the output by explicitly specifying which columns
you want to see:
</P><PRE
CLASS="SCREEN"
>SELECT alias, token, dictionary, lexemes
FROM ts_debug('public.english','The Brightest supernovaes');
alias | token | dictionary | lexemes
-----------+-------------+----------------+-------------
asciiword | The | english_ispell | {}
blank | | |
asciiword | Brightest | english_ispell | {bright}
blank | | |
asciiword | supernovaes | english_stem | {supernova}</PRE
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="TEXTSEARCH-PARSER-TESTING"
>12.8.2. Parser Testing</A
></H2
><P
> The following functions allow direct testing of a text search parser.
</P
><PRE
CLASS="SYNOPSIS"
>ts_parse(<TT
CLASS="REPLACEABLE"
><I
>parser_name</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>, <TT
CLASS="REPLACEABLE"
><I
>document</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>tokid</I
></TT
> <TT
CLASS="TYPE"
>integer</TT
>, OUT <TT
CLASS="REPLACEABLE"
><I
>token</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>) returns <TT
CLASS="TYPE"
>setof record</TT
>
ts_parse(<TT
CLASS="REPLACEABLE"
><I
>parser_oid</I
></TT
> <TT
CLASS="TYPE"
>oid</TT
>, <TT
CLASS="REPLACEABLE"
><I
>document</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>tokid</I
></TT
> <TT
CLASS="TYPE"
>integer</TT
>, OUT <TT
CLASS="REPLACEABLE"
><I
>token</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>) returns <TT
CLASS="TYPE"
>setof record</TT
></PRE
><P
> <CODE
CLASS="FUNCTION"
>ts_parse</CODE
> parses the given <TT
CLASS="REPLACEABLE"
><I
>document</I
></TT
>
and returns a series of records, one for each token produced by
parsing. Each record includes a <TT
CLASS="VARNAME"
>tokid</TT
> showing the
assigned token type and a <TT
CLASS="VARNAME"
>token</TT
> which is the text of the
token. For example:
</P><PRE
CLASS="SCREEN"
>SELECT * FROM ts_parse('default', '123 - a number');
tokid | token
-------+--------
22 | 123
12 |
12 | -
1 | a
12 |
1 | number</PRE
><P>
</P
><PRE
CLASS="SYNOPSIS"
>ts_token_type(<TT
CLASS="REPLACEABLE"
><I
>parser_name</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>, OUT <TT
CLASS="REPLACEABLE"
><I
>tokid</I
></TT
> <TT
CLASS="TYPE"
>integer</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>alias</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>, OUT <TT
CLASS="REPLACEABLE"
><I
>description</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>) returns <TT
CLASS="TYPE"
>setof record</TT
>
ts_token_type(<TT
CLASS="REPLACEABLE"
><I
>parser_oid</I
></TT
> <TT
CLASS="TYPE"
>oid</TT
>, OUT <TT
CLASS="REPLACEABLE"
><I
>tokid</I
></TT
> <TT
CLASS="TYPE"
>integer</TT
>,
OUT <TT
CLASS="REPLACEABLE"
><I
>alias</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>, OUT <TT
CLASS="REPLACEABLE"
><I
>description</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>) returns <TT
CLASS="TYPE"
>setof record</TT
></PRE
><P
> <CODE
CLASS="FUNCTION"
>ts_token_type</CODE
> returns a table which describes each type of
token the specified parser can recognize. For each token type, the table
gives the integer <TT
CLASS="VARNAME"
>tokid</TT
> that the parser uses to label a
token of that type, the <TT
CLASS="VARNAME"
>alias</TT
> that names the token type
in configuration commands, and a short <TT
CLASS="VARNAME"
>description</TT
>. For
example:
</P><PRE
CLASS="SCREEN"
>SELECT * FROM ts_token_type('default');
tokid | alias | description
-------+-----------------+------------------------------------------
1 | asciiword | Word, all ASCII
2 | word | Word, all letters
3 | numword | Word, letters and digits
4 | email | Email address
5 | url | URL
6 | host | Host
7 | sfloat | Scientific notation
8 | version | Version number
9 | hword_numpart | Hyphenated word part, letters and digits
10 | hword_part | Hyphenated word part, all letters
11 | hword_asciipart | Hyphenated word part, all ASCII
12 | blank | Space symbols
13 | tag | XML tag
14 | protocol | Protocol head
15 | numhword | Hyphenated word, letters and digits
16 | asciihword | Hyphenated word, all ASCII
17 | hword | Hyphenated word, all letters
18 | url_path | URL path
19 | file | File or path name
20 | float | Decimal notation
21 | int | Signed integer
22 | uint | Unsigned integer
23 | entity | XML entity</PRE
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="TEXTSEARCH-DICTIONARY-TESTING"
>12.8.3. Dictionary Testing</A
></H2
><P
> The <CODE
CLASS="FUNCTION"
>ts_lexize</CODE
> function facilitates dictionary testing.
</P
><PRE
CLASS="SYNOPSIS"
>ts_lexize(<TT
CLASS="REPLACEABLE"
><I
>dict</I
></TT
> <TT
CLASS="TYPE"
>regdictionary</TT
>, <TT
CLASS="REPLACEABLE"
><I
>token</I
></TT
> <TT
CLASS="TYPE"
>text</TT
>) returns <TT
CLASS="TYPE"
>text[]</TT
></PRE
><P
> <CODE
CLASS="FUNCTION"
>ts_lexize</CODE
> returns an array of lexemes if the input
<TT
CLASS="REPLACEABLE"
><I
>token</I
></TT
> is known to the dictionary,
or an empty array if the token
is known to the dictionary but it is a stop word, or
<TT
CLASS="LITERAL"
>NULL</TT
> if it is an unknown word.
</P
><P
> Examples:
</P><PRE
CLASS="SCREEN"
>SELECT ts_lexize('english_stem', 'stars');
ts_lexize
-----------
{star}
SELECT ts_lexize('english_stem', 'a');
ts_lexize
-----------
{}</PRE
><P>
</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
> The <CODE
CLASS="FUNCTION"
>ts_lexize</CODE
> function expects a single
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>token</I
></SPAN
>, not text. Here is a case
where this can be confusing:
</P><PRE
CLASS="SCREEN"
>SELECT ts_lexize('thesaurus_astro','supernovae stars') is null;
?column?
----------
t</PRE
><P>
The thesaurus dictionary <TT
CLASS="LITERAL"
>thesaurus_astro</TT
> does know the
phrase <TT
CLASS="LITERAL"
>supernovae stars</TT
>, but <CODE
CLASS="FUNCTION"
>ts_lexize</CODE
>
fails since it does not parse the input text but treats it as a single
token. Use <CODE
CLASS="FUNCTION"
>plainto_tsquery</CODE
> or <CODE
CLASS="FUNCTION"
>to_tsvector</CODE
> to
test thesaurus dictionaries, for example:
</P><PRE
CLASS="SCREEN"
>SELECT plainto_tsquery('supernovae stars');
plainto_tsquery
-----------------
'sn'</PRE
><P>
</P
></BLOCKQUOTE
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