- 【TiDB 版本】:4.0.0ga
- 【问题描述】:集群从2.1.3升级到4.0.0后一直无法稳定下来,看监控怀疑是不是gc引起的?
当前的配置:
+--------------------------+--------------------------------------------------------------------------------------+
| VARIABLE_NAME | VARIABLE_VALUE |
+--------------------------+--------------------------------------------------------------------------------------+
| bootstrapped | True |
| tidb_server_version | 47 |
| tikv_gc_leader_uuid | 5ca6ff655dc0002 |
| tikv_gc_leader_desc | host:db04, pid:32075, start at 2020-06-10 10:09:46.88374466 +0800 CST m=+0.930456411 |
| tikv_gc_leader_lease | 20200611-15:45:46 +0800 |
| tikv_gc_run_interval | 10m0s |
| tikv_gc_life_time | 10m0s |
| tikv_gc_last_run_time | 20200611-15:33:46 +0800 |
| tikv_gc_safe_point | 20200610-15:40:01 +0800 |
| tikv_gc_concurrency | 1 |
| system_tz | Asia/Shanghai |
| new_collation_enabled | False |
| tikv_gc_enable | true |
| tikv_gc_auto_concurrency | true |
| tikv_gc_mode | distributed |
+--------------------------+--------------------------------------------------------------------------------------+
当tikv_gc_auto_concurrency为true的时候,tikv_gc_concurrency将不起作用,而会并行的向所有tikv发送gc请求
而tikv的默认设置:
[gc]
## The number of keys to GC in one batch.
# batch-keys = 512
## Max bytes that GC worker can write to rocksdb in one second.
## If it is set to 0, there is no limit.
# max-write-bytes-per-sec = "0"
即tikv gc不会限制io,这样的设计会不会导致gc把集群的IO资源全部占用光了呢?