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.

For simple real-life example which address problem
I<where like '%foo%' is slow>
see L<Tutorial>.

=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 C<estmaster> running with permissions for C<admin> user
to create C<trivia> node.

=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	=head1 pgestraier - search Hyper Estraier indexes from PostgreSQL
2
3	This package is essentially PostgreSQL C function which calls Hyper Estraier
4	API and returns results in user defined format.
5
6	=head1 Why is it written?
7
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	For simple real-life example which address problem
14	I<where like '%foo%' is slow>
15	see L<Tutorial>.
16
17	=head1 How to install
18
19	Installation should be simple. However, you will have to have following
20	software already installed before you try this function:
21
22	=over
23
24	=item *
25
26	PostgreSQL (tested with versions 7.4 and 8.0) with development libraries
27
28	=item *
29
30	Hyper Estraier (tested with various versions, recommended 1.2.4 of newer)
31
32	=back
33
34	To run tests you will also need:
35
36	=over
37
38	=item *
39
40	working perl installation
41
42	=item *
43
44	perl modules C<DBI>, C<DBD::Pg>, C<Test::More> and optionally C<Search::Estraier>
45
46	=item *
47
48	C<trivia.list.gz> from Internet Movie Database in C<data/> directory
49
50	=item *
51
52	PostgreSQL database C<test> with permissions for current user
53
54	=item *
55
56	Hyper Estraier C<estmaster> running with permissions for C<admin> user
57	to create C<trivia> node.
58
59	=back
60
61	If you have all that, you should be able to type
62
63	make
64
65	and see sample results. You will be asked your password once (via sudo) to
66	install C<pgest.so> shared library in system-wide location so that PostgreSQL
67	could access it.
68
69	=head2 Create sample index using Hyper Estraier perl bindings
70
71	Perl bindings for Hyper Estraier are available at CPAN:
72
73	L<http://search.cpan.org/~dpavlin/Search-Estraier/>
74
75
76	After installing C<Search::Estraier> you can create index using following commands:
77
78	cd data
79	make index
80	cd ..
81
82	To run tests (which require that you have estcmd in your $PATH) issue
83
84	make test
85
86	See also included file C<test.sql> for more examples of usage.
87
88	=head1 Usage of pgest from SQL
89
90	C<pgest> PostgreSQL function tries to mimic usage of normal database tables (with support for attribute filtering, limit and offset) in following way:
91
92	SELECT
93	-- columns to return (defined later)
94	id,title,size
95	FROM pgest(
96	-- node URI, login, password and depth of search
97	'http://localhost:1978/node/trivia', 'admin', 'admin', 42,
98	-- query
99	'blade runner',
100	-- additional attributes, use NULL or '' to disable
101	-- multiple attributes conditions can be separated by {{!}}
102	'@title ISTRINC blade',
103	-- order results by
104	'@title STRA',
105	-- limit, use NULL or 0 to disable
106	null,
107	-- offset, use NULL or 0 to disable
108	null,
109	-- attributes to return as columns
110	ARRAY['@id','@title','@size']
111	) AS (
112	-- specify names and types of returned attributes
113	id text, title text, size text
114	);
115
116	You should note that Hyper Estraier uses UTF-8 encoding, while your
117	PostgreSQL installation might use different encoding. To fix that, use
118	C<convert> function in PostgreSQL to convert encodings.
119
120	=head2 Using index via C<estmaster> server process
121
122	This is default and recommended way to use C<pgest> functionality. In this
123	case, C<pgest> will use node API and access index through C<estmaster>
124	process which should be running on (local or remote) machine.
125
126	This will remove database opening overhead, at a cost of (small) additional network
127	traffic. However, you can have Hyper Estraier C<estmaster> process running on
128	different machine or update index while doing searches, so benefits of this
129	approach are obvious.
130
131	=head2 Accessing database directly
132
133	B<Please note that direct access to database is depreciated.> As such, it's
134	not stated in example, and it's kept just for backward compatibility, but it
135	will probably be removed in future versions of C<pgest>.
136
137	If you want to access database directly (without running C<estmaster> process), you
138	have to replace node URI, login, password and depth with full path to database file.
139
140	Have in mind that C<postgres> user under which PostgreSQL is running must
141	have read permission on Hyper Estraier database files.
142
143	This will work a bit faster on really small indexes. However, when your
144	index grows bigger, you might consider using node API to remove overhead of
145	database opening on each query.
146
147	=head1 Who wrote this?
148
149	Hyper Estraier is written by Mikio Hirabayashi.
150
151	Perl bindings for Hyper Estraier are written by MATSUNO Tokuhiro.
152
153	PostgreSQL is written by hackers calling themselves PostgreSQL Global
154	Development Group.
155
156	This small C function is written by Dobrica Pavlinusic, dpavlin@rot13.org.