pgestraier/trunk/README.pod

=head1 pgestraier - search Hyper Estraier indexes from PostgreSQL

This package is essentially PostgreSQL C function which calls Hyper Estraier
API and returns results in user defined format.

=head1 Why is it written?

Aside from providing single API to query your RDBMS and full text index
(using any language that has PostgreSQL client libraries), real power is
hidden in ability to join results from full text index and structured data
in RDBMS.

=head1 How to install

Installation should be simple. However, you will have to have following
software already installed before you try this function:

=over

=item *

PostgreSQL (tested with versions 7.4 and 8.0) with development libraries

=item *

Hyper Estraier (tested with various versions, recommended 1.2.4 of newer)

=back

To run tests you will also need:

=over

=item *

working perl installation

=item *

perl modules C<DBI>, C<DBD::Pg>, C<Test::More> and optionally C<Search::Estraier>

=item *

C<trivia.list.gz> from Internet Movie Database in C<data/> directory

=item *

PostgreSQL database C<test> with permissions for current user

=item *

Hyper Estraier node C<trivia> with permissions for C<admin> user.

=back

If you have all that, you should be able to type

  make

and see sample results. You will be asked your password once (via sudo) to
install C<pgest.so> shared library in system-wide location so that PostgreSQL
could access it.

=head2 Create sample index using Hyper Estraier perl bindings

Perl bindings for Hyper Estraier are available at CPAN:

L<http://search.cpan.org/~dpavlin/Search-Estraier/>


After installing C<Search::Estraier> you can create index using following commands:

  cd data
  make index
  cd ..

To run tests (which require that you have estcmd in your $PATH) issue

  make test

See also included file C<test.sql> for more examples of usage.

=head1 Usage of pgest from SQL

C<pgest> PostgreSQL function tries to mimic usage of normal database tables (with support for attribute filtering, limit and offset) in following way:

        SELECT
                -- columns to return (defined later)
                id,title,size
        FROM pgest(
                -- node URI, login, password and depth of search
                'http://localhost:1978/node/trivia', 'admin', 'admin', 42,
                -- query
                'blade runner',
                -- additional attributes, use NULL or '' to disable
                -- multiple attributes conditions can be separated by {{!}}
                '@title ISTRINC blade',
                -- order results by
                '@title STRA',
                -- limit, use NULL or 0 to disable
                null,
                -- offset, use NULL or 0 to disable
                null,
                -- attributes to return as columns
                ARRAY['@id','@title','@size']
        ) AS (
                -- specify names and types of returned attributes
                id text, title text, size text
        );

You should note that Hyper Estraier uses UTF-8 encoding, while your
PostgreSQL installation might use different encoding. To fix that, use
C<convert> function in PostgreSQL to convert encodings.

=head2 Using index via C<estmaster> server process

This is default and recommended way to use C<pgest> functionality. In this
case, C<pgest> will use node API and access index through C<estmaster>
process which should be running on (local or remote) machine. 

This will remove database opening overhead, at a cost of (small) additional network
traffic. However, you can have Hyper Estraier C<estmaster> process running on
different machine or update index while doing searches, so benefits of this
approach are obvious.

=head2 Accessing database directly

B<Please note that direct access to database is depreciated.> As such, it's
not stated in example, and it's kept just for backward compatibility, but it
will probably be removed in future versions of C<pgest>.

If you want to access database directly (without running C<estmaster> process), you
have to replace node URI, login, password and depth with full path to database file.

Have in mind that C<postgres> user under which PostgreSQL is running must
have read permission on Hyper Estraier database files.

This will work a bit faster on really small indexes. However, when your
index grows bigger, you might consider using node API to remove overhead of
database opening on each query.

=head1 Who wrote this?

Hyper Estraier is written by Mikio Hirabayashi.

Perl bindings for Hyper Estraier are written by MATSUNO Tokuhiro.

PostgreSQL is written by hackers calling themselves PostgreSQL Global
Development Group.

This small C function is written by Dobrica Pavlinusic, dpavlin@rot13.org.
1	dpavlin	33	=head1 pgestraier - search Hyper Estraier indexes from PostgreSQL
2	dpavlin	23
3			This package is essentially PostgreSQL C function which calls Hyper Estraier
4			API and returns results in user defined format.
5
6	dpavlin	33	=head1 Why is it written?
7	dpavlin	23
8			Aside from providing single API to query your RDBMS and full text index
9			(using any language that has PostgreSQL client libraries), real power is
10			hidden in ability to join results from full text index and structured data
11			in RDBMS.
12
13	dpavlin	33	=head1 How to install
14	dpavlin	23
15			Installation should be simple. However, you will have to have following
16			software already installed before you try this function:
17
18	dpavlin	33	=over
19	dpavlin	23
20	dpavlin	33	=item *
21
22	dpavlin	43	PostgreSQL (tested with versions 7.4 and 8.0) with development libraries
23	dpavlin	33
24			=item *
25
26	dpavlin	54	Hyper Estraier (tested with various versions, recommended 1.2.4 of newer)
27	dpavlin	33
28			=back
29
30	dpavlin	23	To run tests you will also need:
31
32	dpavlin	33	=over
33	dpavlin	23
34	dpavlin	33	=item *
35
36			working perl installation
37
38			=item *
39
40	dpavlin	54	perl modules C<DBI>, C<DBD::Pg>, C<Test::More> and optionally C<Search::Estraier>
41	dpavlin	33
42			=item *
43
44	dpavlin	49	C<trivia.list.gz> from Internet Movie Database in C<data/> directory
45	dpavlin	33
46			=item *
47
48	dpavlin	43	PostgreSQL database C<test> with permissions for current user
49	dpavlin	33
50	dpavlin	43	=item *
51
52			Hyper Estraier node C<trivia> with permissions for C<admin> user.
53
54	dpavlin	33	=back
55
56	dpavlin	23	If you have all that, you should be able to type
57
58			make
59
60			and see sample results. You will be asked your password once (via sudo) to
61	dpavlin	43	install C<pgest.so> shared library in system-wide location so that PostgreSQL
62	dpavlin	23	could access it.
63
64	dpavlin	54	=head2 Create sample index using Hyper Estraier perl bindings
65	dpavlin	29
66	dpavlin	54	Perl bindings for Hyper Estraier are available at CPAN:
67	dpavlin	29
68	dpavlin	54	L<http://search.cpan.org/~dpavlin/Search-Estraier/>
69	dpavlin	29
70
71	dpavlin	54	After installing C<Search::Estraier> you can create index using following commands:
72	dpavlin	42
73	dpavlin	29	cd data
74	dpavlin	54	make index
75	dpavlin	29	cd ..
76
77	dpavlin	23	To run tests (which require that you have estcmd in your $PATH) issue
78
79			make test
80
81	dpavlin	54	See also included file C<test.sql> for more examples of usage.
82	dpavlin	23
83	dpavlin	42	=head1 Usage of pgest from SQL
84
85	dpavlin	54	C<pgest> PostgreSQL function tries to mimic usage of normal database tables (with support for attribute filtering, limit and offset) in following way:
86	dpavlin	42
87			SELECT
88			-- columns to return (defined later)
89			id,title,size
90			FROM pgest(
91	dpavlin	54	-- node URI, login, password and depth of search
92	dpavlin	49	'http://localhost:1978/node/trivia', 'admin', 'admin', 42,
93	dpavlin	42	-- query
94			'blade runner',
95			-- additional attributes, use NULL or '' to disable
96			-- multiple attributes conditions can be separated by {{!}}
97			'@title ISTRINC blade',
98			-- order results by
99			'@title STRA',
100			-- limit, use NULL or 0 to disable
101			null,
102			-- offset, use NULL or 0 to disable
103			null,
104			-- attributes to return as columns
105			ARRAY['@id','@title','@size']
106			) AS (
107			-- specify names and types of returned attributes
108			id text, title text, size text
109			);
110
111	dpavlin	54	You should note that Hyper Estraier uses UTF-8 encoding, while your
112			PostgreSQL installation might use different encoding. To fix that, use
113			C<convert> function in PostgreSQL to convert encodings.
114
115			=head2 Using index via C<estmaster> server process
116
117			This is default and recommended way to use C<pgest> functionality. In this
118			case, C<pgest> will use node API and access index through C<estmaster>
119			process which should be running on (local or remote) machine.
120
121			This will remove database opening overhead, at a cost of (small) additional network
122			traffic. However, you can have Hyper Estraier C<estmaster> process running on
123			different machine or update index while doing searches, so benefits of this
124			approach are obvious.
125
126	dpavlin	42	=head2 Accessing database directly
127
128	dpavlin	54	B<Please note that direct access to database is depreciated.> As such, it's
129			not stated in example, and it's kept just for backward compatibility, but it
130			will probably be removed in future versions of C<pgest>.
131	dpavlin	42
132	dpavlin	54	If you want to access database directly (without running C<estmaster> process), you
133			have to replace node URI, login, password and depth with full path to database file.
134
135	dpavlin	42	Have in mind that C<postgres> user under which PostgreSQL is running must
136			have read permission on Hyper Estraier database files.
137
138			This will work a bit faster on really small indexes. However, when your
139			index grows bigger, you might consider using node API to remove overhead of
140			database opening on each query.
141
142	dpavlin	33	=head1 Who wrote this?
143	dpavlin	23
144			Hyper Estraier is written by Mikio Hirabayashi.
145
146	dpavlin	42	Perl bindings for Hyper Estraier are written by MATSUNO Tokuhiro.
147
148	dpavlin	23	PostgreSQL is written by hackers calling themselves PostgreSQL Global
149			Development Group.
150
151			This small C function is written by Dobrica Pavlinusic, dpavlin@rot13.org.