mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-21 08:29:39 +08:00
5fcb079858
hard-to-maintain textual examples currently in the SGML docs. From Sergey Karpov.
42 lines
1.1 KiB
Plaintext
42 lines
1.1 KiB
Plaintext
Dictionary for integers
|
|
=======================
|
|
|
|
The motivation for this example dictionary is to control the indexing of
|
|
integers (signed and unsigned), and, consequently, to minimize the number of
|
|
unique words which greatly affect the performance of searching.
|
|
|
|
* Configuration
|
|
|
|
The dictionary accepts two options:
|
|
|
|
- The MAXLEN parameter specifies the maximum length (number of digits)
|
|
allowed in an integer word. The default value is 6.
|
|
|
|
- The REJECTLONG parameter specifies if an overlength integer should be
|
|
truncated or ignored. If REJECTLONG=FALSE (default), the dictionary returns
|
|
the first MAXLEN digits of the integer. If REJECTLONG=TRUE, the
|
|
dictionary treats an overlength integer as a stop word, so that it will
|
|
not be indexed.
|
|
|
|
* Usage
|
|
|
|
1. Compile and install
|
|
|
|
2. Load dictionary
|
|
|
|
psql mydb < dict_int.sql
|
|
|
|
3. Test it
|
|
|
|
mydb# select ts_lexize('intdict', '12345678');
|
|
ts_lexize
|
|
-----------
|
|
{123456}
|
|
|
|
4. Change its options as you wish
|
|
|
|
mydb# ALTER TEXT SEARCH DICTIONARY intdict (MAXLEN = 4, REJECTLONG = true);
|
|
ALTER TEXT SEARCH DICTIONARY
|
|
|
|
That's all.
|