案例说明：

在执行表数据查询时，出现下图所示错误，索引故障导致表无法访问，后重建索引问题解决。本案例复现了此类故障解决过程。

适用版本：

KingbaseES V8R3/R6

一、创建测试环境

# 表结构信息prod=# \d+ test1                                   Table "public.test1" Column|  Type   |Collation| Nullable |Default| Storage  | Stats target | Description--------+---------+-----------+----------+---------+----------+--------------+------------- id     |integer||notnull|| plain    || v_name |varchar|||| extended ||Indexes:    "test1_pkey" PRIMARY KEY, btree (id)    "test1_name_ind" btree (v_name)Access method: heap # 插入测试数据prod=# insertinto test1 values (generate_series(1,10000),'usr'||generate_series(1,10000));INSERT010000prod=# selectcount(*) from test1; count-------10000(1row) # 查看索引应用prod=# explain analyze select*from  test1 where v_name='usr2';                                                      QUERY PLAN----------------------------------------------------------------------------------------------------------------------- Index Scan using test1_name_ind on test1  (cost=0.29..8.30rows=1 width=11) (actual time=0.023..0.024rows=1 loops=1)   Index Cond: ((v_name)::text ='usr2'::text) Planning Time: 0.055 ms Execution Time: 0.038 ms(4rows)
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二、模拟数据文件故障

1、查看索引文件存储路径

prod=# select pg_relation_filepath('test1_name_ind'); pg_relation_filepath---------------------- base/16385/26800(1row)
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2、模拟数据文件被破坏

[kingbase@node102 data]$ ls -lh  base/16385/26800-rw------- 1 kingbase kingbase 240K Nov 1715:01 base/16385/26800 [kingbase@node102 data]$ dd if=/dev/zero of=/data/kingbase/v8r6_c6/data/base/16385/26800 bs=8k count=22+0 records in2+0 records out16384 bytes (16 kB) copied, 0.000147959 s, 111 MB/s [kingbase@node102 data]$ ls -lh  base/16385/26800-rw------- 1 kingbase kingbase 16K Nov 1715:04 base/16385/26800# 如下所示索引故障导致表访问错误prod=# select * from  test1;ERROR:  index "test1_name_ind" contains unexpected zero page at block 0HINT:  Please REINDEX it.
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三、重建索引解决故障

1、查看表索引信息

prod=# \d+ test1;                                   Table"public.test1"Column |  Type   | Collation | Nullable | Default | Storage  | Stats target | Description--------+---------+-----------+----------+---------+----------+--------------+------------- id     | integer |           | not null |         | plain    |              | v_name | varchar |           |          |         | extended |              |Indexes:    "test1_pkey"PRIMARYKEY, btree (id)    "test1_name_ind" btree (v_name)Access method: heap
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2、重建索引

# 索引重建prod=# reindex index test1_name_ind;REINDEX #如下所示，重建索引后表数据访问正常prod=# select*from  test1 limit 3; id | v_name----+--------1| usr1  2| usr2  3| usr3(3rows) prod=# select*from  test1 where v_name='usr2'; id | v_name----+--------2| usr2(1row) prod=# explain analyze select*from  test1 where v_name='usr2';                                                      QUERY PLAN----------------------------------------------------------------------------------------------------------------------- Index Scan using test1_name_ind on test1  (cost=0.29..8.30rows=1 width=11) (actual time=0.023..0.024rows=1 loops=1)   Index Cond: ((v_name)::text ='usr2'::text) Planning Time: 0.055 ms Execution Time: 0.038 ms(4rows)
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四、总结

对于KingbaseES数据库，索引块的损坏会影响到表数据的正常访问，对于索引块故障处理比较简单，直接重建索引一般都可以解决此类问题。