KingbaseES 内置的缺省的分词解析器采用空格分词，因为中文的词语之间没有空格分割，所以这种方法并不适用于中文。要支持中文的全文检索需要额外的中文分词插件：zhparser and sys_jieba，其中zhparser 支持 GBK 和 UTF8 字符集，sys_jieba 支持 UTF8 字符集。

1、tsvector

test=# SELECT to_tsvector('English','Try not to become a man of success, but rather try to become a man of value');

to_tsvector

'becom':4,13 'man':6,15 'rather':10 'success':8 'tri':1,11 'valu':17
(1 row)

test=# SELECT to_tsvector('simple','Try not to become a man of success, but rather try to become a man of value');

to_tsvector

'a':5,14 'become':4,13 'but':9 'man':6,15 'not':2 'of':7,16 'rather':10 'success':8 'to':3,12 'try':1,11 'value':17
(1 row)

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value');

to_tsvector

'a':5,14 'become':4,13 'but':9 'man':6,15 'not':2 'of':7,16 'rather':10 'success':8 'to':3,12 'try':1,11 'value':17
(1 row)

这里可以看到，如果词干分析器是english ，会采取词干标准化的过程；而simple 只是转换成小写。默认是 simple。

test=# show default_text_search_config;

default_text_search_config

pg_catalog.simple
(1 row)

2、标准化过程

标准化过程会完成以下操作：

1. 总是把大写字母换成小写的
2. 也经常移除后缀（比如英语中的s,es和ing等），这样可以搜索同一个字的各种变体，而不是乏味地输入所有可能的变体。
3. 数字表示词位在原始字符串中的位置，比如“man"出现在第6和15的位置上。
4. to_tesvetor的默认配置的文本搜索是“英语“。它会忽略掉英语中的停用词（stopword，译注：也就是am is are a an等单词)。

3、tsvector搜索

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ 'become';

?column?

t
(1 row)

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ 'becom';

?column?

f
(1 row)

test=# select 'become'::tsquery,to_tsquery('become'),to_tsquery('english','become');
tsquery | to_tsquery | to_tsquery
----------+------------+------------
'become' | 'become' | 'becom'
(1 row)

to_tsquery 也会进行标准化转换，在搜索时必须用 to_tsquery，确保数据不会因为标准化转换而搜索不到。

4、逻辑操作

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ to_tsquery('become');

?column?

t
(1 row)

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ to_tsquery('!become');

?column?

f
(1 row)

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ to_tsquery('tri & become');

?column?

t
(1 row)

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ to_tsquery('Try & !becom');

?column?

f
(1 row)

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ to_tsquery('Try | !become');

?column?

t
(1 row)

5、可以用 :* 表示某词开始字符

test=# SELECT to_tsvector('Try not to become a man of success, but rather try to become a man of value') @@ to_tsquery('bec:*');

?column?

t
(1 row)

6、其他语言支持

test=# SELECT to_tsvector('simple','Try not to become a man of success, but rather try to become a man of value');

to_tsvector

'a':5,14 'become':4,13 'but':9 'man':6,15 'not':2 'of':7,16 'rather':10 'success':8 'to':3,12 'try':1,11 'value':17
(1 row)

test=# SELECT to_tsvector('english','Try not to become a man of success, but rather try to become a man of value') ;

to_tsvector

'becom':4,13 'man':6,15 'rather':10 'success':8 'tri':1,11 'valu':17
(1 row)
^
test=# SELECT to_tsvector('french','Try not to become a man of success, but rather try to become a man of value') ;

to_tsvector

'a':5,14 'becom':4,13 'but':9 'man':6,15 'not':2 'of':7,16 'rath':10 'success':8 'to':3,12 'try':1,11 'valu':17
(1 row)
^
test=# SELECT to_tsvector('french'::regconfig,'Try not to become a man of success, but rather try to become a man of value') ;

to_tsvector

'a':5,14 'becom':4,13 'but':9 'man':6,15 'not':2 'of':7,16 'rath':10 'success':8 'to':3,12 'try':1,11 'valu':17
(1 row)

simple并不忽略禁用词表，它也不会试着去查找单词的词根。使用simple时，空格分割的每一组字符都是一个语义；simple 只做了小写转换；对于数据来说，simple文本搜索配置项很实用。

在开始介绍中文检索前，我们先来看个例子：

test=# select to_tsvector('人大金仓致力于提供高可靠的数据库产品');

to_tsvector

'人大金仓致力于提供高可靠的数据库产品':1

因为内置的分词器是按空格分割的，而中文间没有空格，因此，整句话就被看做一个分词。

1、创建中文搜索插件

create extension zhparser;
create text search configuration zhongwen_parser (parser = zhparser);
alter text search configuration zhongwen_parser add mapping for n,v,a,i,e,l,j with simple;

上面 for 后面的字母表示分词的token，上面的token映射只映射了名词(n)，动词(v)，形容词(a)，成语(i)，叹词(e)，缩写(j) 和习用语(l)6种，这6种以外的token全部被屏蔽。词典使用的是内置的simple词典。具体的token 如下：

test=# select ts_token_type('zhparser');

ts_token_type

(97,a,adjective)
(98,b,differentiation)
(99,c,conjunction)
(100,d,adverb)
(101,e,exclamation)
(102,f,position)
(103,g,root)
(104,h,head)
(105,i,idiom)
(106,j,abbreviation)
(107,k,tail)
(108,l,tmp)
(109,m,numeral)
(110,n,noun)
(111,o,onomatopoeia)
(112,p,prepositional)
(113,q,quantity)
(114,r,pronoun)
(115,s,space)
(116,t,time)
(117,u,auxiliary)
(118,v,verb)
(119,w,punctuation)
(120,x,unknown)
(121,y,modal)
(122,z,status)
(26 rows)

2、查看pg_ts_config

创建text search configuration 后，可以在视图pg_ts_config 看到如下信息：

test=# select * from pg_ts_config;
oid | cfgname | cfgnamespace | cfgowner | cfgparser
-------+-----------------+--------------+----------+-----------
3748 | simple | 11 | 10 | 3722
13265 | arabic | 11 | 10 | 3722
13267 | danish | 11 | 10 | 3722
13269 | dutch | 11 | 10 | 3722
13271 | english | 11 | 10 | 3722
13273 | finnish | 11 | 10 | 3722
13275 | french | 11 | 10 | 3722
13277 | german | 11 | 10 | 3722
13279 | hungarian | 11 | 10 | 3722
13281 | indonesian | 11 | 10 | 3722
13283 | irish | 11 | 10 | 3722
13285 | italian | 11 | 10 | 3722
13287 | lithuanian | 11 | 10 | 3722
13289 | nepali | 11 | 10 | 3722
13291 | norwegian | 11 | 10 | 3722
13293 | portuguese | 11 | 10 | 3722
13295 | romanian | 11 | 10 | 3722
13297 | russian | 11 | 10 | 3722
13299 | spanish | 11 | 10 | 3722
13301 | swedish | 11 | 10 | 3722
13303 | tamil | 11 | 10 | 3722
13305 | turkish | 11 | 10 | 3722
16390 | parser_name | 2200 | 10 | 16389
24587 | zhongwen_parser | 2200 | 10 | 16389

3、使用中文分词

test=# select to_tsvector('zhongwen_parser','人大金仓致力于提供高可靠的数据库产品');

to_tsvector

'产品':7 '人大':1 '可靠':5 '提供':3 '数据库':6 '致力于':2 '高':4

4、contains 函数

test=# \df+ contains
List of functions
Schema | Name | Result data type | Argument data types | Type | Volatility | Parallel | Owner | Security | Access privileges | Language | Source code
| Description
--------+----------+------------------+---------------------+------+------------+----------+--------+----------+-------------------+----------+------------------------------------------+-------------
sys | contains | boolean | text, text | func | immutable | safe | system | invoker | | sql | select to_tsvector($1) @@ to_tsquery($2) |
sys | contains | boolean | text, text, integer | func | immutable | safe | system | invoker | | sql | select to_tsvector($1) @@ to_tsquery($2) |
sys | contains | boolean | text, tsquery | func | immutable | safe | system | invoker | | sql | select $1::tsvector @@ $2 |
sys | contains | boolean | tsvector, text | func | immutable | safe | system | invoker | | sql | select $1 @@ $2::tsquery |
sys | contains | boolean | tsvector, tsquery | func | immutable | safe | system | invoker | | sql | select $1 @@ $2 |

默认contains 函数使用的是空格分词解析器，因此，无法使用contains 进行中文判断

test=# select contains('人大金仓致力于提供高可靠的数据库产品','产品');

contains

f