some system variable default value are different after upgrade

[seiya-annie]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

1. install a v6.0.0 tidb cluster without doing any configuration
2. upgrade to nightly(v6.1.0)
3. check default value of system variable

2. What did you expect to see? (Required)

tidb_committer_concurrency = 128
tidb_enable_auto_analyze=ON
tidb_mem_oom_action = Cancel
tidb_mem_quota_query = 1073741824

3. What did you see instead (Required)

[tidb@101 610]$ diff 610-systemvar_new_install.txt 610-systemvar-upgrade.txt 
492c492
< tidb_committer_concurrency	128
---
> tidb_committer_concurrency	1
503c503
< tidb_enable_auto_analyze	ON
---
> tidb_enable_auto_analyze	OFF
523c523
< tidb_enable_prepared_plan_cache	ON
---
> tidb_enable_prepared_plan_cache	OFF
564c564
< tidb_mem_oom_action	CANCEL
---
> tidb_mem_oom_action	
568c568
< tidb_mem_quota_query	1073741824
---
> tidb_mem_quota_query	0
598c598
< tidb_prepared_plan_cache_size	100
---
> tidb_prepared_plan_cache_size	1000

4. What is your TiDB version? (Required)

Git Commit Hash: 6a02393
Git Branch: heads/refs/tags/v6.1.0-alpha
UTC Build Time: 2022-05-19 15:26:56

[seiya-annie]

tidb config file before upgrade: 600-tidb.txt

[zimulala]

tidb_enable_prepared_plan_cache and tidb_prepared_plan_cache_size changes the default
value because of #34846.

[zimulala]

The other 4 variables(tidb_committer_concurrency, tidb_enable_auto_analyze, tidb_mem_oom_action, tidb_mem_quota_query) are modified after the PR: #34711

[seiya-annie]

cluster topo.yaml 101default.yaml.gz

[zimulala]

The committer-concurrency configuration item was removed(#34368) from the 6.1 configuration file, and the upgrade assigned the value of the committer-concurrency configuration item to tidb_committer_concurrency (ref #34711).
Then when this testing without specifying a configuration file (asked @seiya-annie), the committer-concurrency is zero. So the above phenomenon will occur.

[bb7133]

this testing without specifying a configuration file, the committer-concurrency is zero.

This is not expected and we need to fix it.

[morgo]

The bug can be reproduced by using no config file, and performing an upgrade from 6.0 to master. Here is what is written to the log file in bootstrap v90-91:

[2022/05/20 08:49:18.151 -06:00] [WARN] [bootstrap.go:1839] ["enable-batch-dml is now configured by the system variable tidb_enable_batch_dml. One-time importing the value specified in tidb.toml file"] [value=OFF]
[2022/05/20 08:49:18.152 -06:00] [WARN] [bootstrap.go:1839] ["mem-quota-query is now configured by the system variable tidb_mem_quota_query. One-time importing the value specified in tidb.toml file"] [value=0]
[2022/05/20 08:49:18.152 -06:00] [WARN] [bootstrap.go:1839] ["query-log-max-len is now configured by the system variable tidb_query_log_max_len. One-time importing the value specified in tidb.toml file"] [value="0 10"]
[2022/05/20 08:49:18.152 -06:00] [WARN] [bootstrap.go:1839] ["committer-concurrency is now configured by the system variable tidb_committer_concurrency. One-time importing the value specified in tidb.toml file"] [value=0]
[2022/05/20 08:49:18.152 -06:00] [WARN] [bootstrap.go:1839] ["run-auto-analyze is now configured by the system variable tidb_enable_auto_analyze. One-time importing the value specified in tidb.toml file"] [value=OFF]
[2022/05/20 08:49:18.153 -06:00] [WARN] [bootstrap.go:1839] ["oom-action is now configured by the system variable tidb_mem_oom_action. One-time importing the value specified in tidb.toml file"] [value=]
[2022/05/20 08:49:18.153 -06:00] [WARN] [bootstrap.go:1839] ["prepared-plan-cache.enable is now configured by the system variable tidb_enable_prepared_plan_cache. One-time importing the value specified in tidb.toml file"] [value=OFF]
[2022/05/20 08:49:18.153 -06:00] [WARN] [bootstrap.go:1839] ["prepared-plan-cache.capacity is now configured by the system variable tidb_prepared_plan_cache_size. One-time importing the value specified in tidb.toml file"] [value=1000]
[2022/05/20 08:49:18.153 -06:00] [WARN] [bootstrap.go:1839] ["prepared-plan-cache.memory-guard-ratio is now configured by the system variable tidb_prepared_plan_cache_memory_guard_ratio. One-time importing the value specified in tidb.toml file"] [value=0.1]

So I will modify the bootstraps to better handle incorrect values when no config file is present.