#td-engine
Вопрос:
У меня есть кластер TDeninge с 4 узлами. и я создал базу данных с некоторыми данными. Но когда я попытался изменить реплику этой базы данных с 1 на 3, мне показалось, что изменение не может быть отражено немедленно.
taos> select count(*) from meters;
count(*) |
========================
10000000000 |
Query OK, 1 row(s) in set (61.782195s)
taos> show vgroups;
vgId | tables | status | onlines | v1_dnode | v1_status | compacting |
==========================================================================================
3 | 1000 | ready | 1 | 1 | master | 0 |
4 | 1000 | ready | 1 | 1 | master | 0 |
5 | 1000 | ready | 1 | 1 | master | 0 |
6 | 1000 | ready | 1 | 1 | master | 0 |
7 | 1000 | ready | 1 | 1 | master | 0 |
8 | 1000 | ready | 1 | 1 | master | 0 |
9 | 1000 | ready | 1 | 1 | master | 0 |
10 | 1000 | ready | 1 | 1 | master | 0 |
11 | 1000 | ready | 1 | 1 | master | 0 |
12 | 1000 | ready | 1 | 1 | master | 0 |
Query OK, 10 row(s) in set (0.001231s)
taos> alter database insertdb replica 3;
Query OK, 0 of 0 row(s) in database (0.051466s)
taos> show vgroups;
vgId | tables | status | onlines | v1_dnode | v1_status | compacting |
==========================================================================================
3 | 1000 | ready | 1 | 1 | master | 0 |
4 | 1000 | ready | 1 | 1 | master | 0 |
5 | 1000 | ready | 1 | 1 | master | 0 |
6 | 1000 | ready | 1 | 1 | master | 0 |
7 | 1000 | ready | 1 | 1 | master | 0 |
8 | 1000 | ready | 1 | 1 | master | 0 |
9 | 1000 | ready | 1 | 1 | master | 0 |
10 | 1000 | ready | 1 | 1 | master | 0 |
11 | 1000 | ready | 1 | 1 | master | 0 |
12 | 1000 | ready | 1 | 1 | master | 0 |
Query OK, 10 row(s) in set (0.001503s)
Через несколько минут это может быть отражено, как показано ниже:
taos> show vgroups;
vgId | tables | status | onlines | v1_dnode | v1_status | v2_dnode | v2_status | v3_dnode | v3_status | compacting |
========================================================================================================================================
3 | 1000 | ready | 3 | 1 | master | 4 | slave | 3 | slave | 0 |
4 | 1000 | ready | 3 | 1 | master | 2 | slave | 4 | slave | 0 |
5 | 1000 | ready | 3 | 1 | master | 3 | slave | 2 | slave | 0 |
6 | 1000 | ready | 3 | 1 | master | 4 | slave | 3 | slave | 0 |
7 | 1000 | ready | 3 | 1 | master | 2 | slave | 4 | slave | 0 |
8 | 1000 | ready | 3 | 1 | master | 3 | slave | 2 | slave | 0 |
9 | 1000 | ready | 3 | 1 | master | 4 | slave | 3 | slave | 0 |
10 | 1000 | ready | 3 | 1 | master | 2 | slave | 4 | slave | 0 |
11 | 1000 | ready | 3 | 1 | master | 3 | slave | 2 | slave | 0 |
12 | 1000 | ready | 3 | 1 | master | 4 | slave | 3 | slave | 0 |
Query OK, 10 row(s) in set (0.001422s)
Почему изменение реплики занимает так много времени для отражения?