*: add tidb_min_paging_size system variable #36107
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Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/dbf7220f09a4a251b69c74d4ac7d8fac269df10d |
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Please review #36147 before this one. |
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| @@ -1673,6 +1674,10 @@ var defaultSysVars = []*SysVar{ | |||
| metrics.ToggleSimplifiedMode(TiDBOptOn(s)) | |||
| return nil | |||
| }}, | |||
| {Scope: ScopeGlobal | ScopeSession, Name: TiDBMinPagingSize, Value: strconv.Itoa(DefMinPagingSize), Type: TypeUnsigned, MinValue: 1, MaxValue: paging.MaxPagingSize, SetSession: func(s *SessionVars, val string) error { | |||
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If it is only for testing, is it necessary to be a global variable?
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I'm not sure, but I see some other variable use global | session, such as tidb_init_chunk_size, tidb_max_chunk_size
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If you can not come up with a scenario of set global, then no. TiDBInitChunkSize is historical.
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In the benchbot, we can test with this:
python3 main.py gen-benchbot-case --email "xxx@pingcap.com" --token 'tcmsp_XXX' --testbed_size "2xl" \
--bench_type sysbench --bench_sub_types "select_random_ranges" \
--duration=30m --threads 100 \
--arch amd64 \
--versions nightly \
--tidb_urls "http://fileserver.pingcap.net/download/builds/pingcap/tidb-check/pr/80b30c51fb509e267d1fca9ed5122b70ded1a172/centos7/tidb-server.tar.gz" \
--testbed_size "2xl" \
--tidb_configs "{prepared-plan-cache: {enabled: true}}" \
--tidb_globals "set global tidb_enable_paging = 1; set global tidb_min_paging_size = 128;" \
--tidb_globals "set global tidb_enable_paging = 1; set global tidb_min_paging_size = 256;" \
--tidb_globals "set global tidb_enable_paging = 1; set global tidb_min_paging_size = 512;" \
--tidb_globals "set global tidb_enable_paging = 0;"
--tidb_globals requires global variables @xhebox
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This pull request has been accepted and is ready to merge. Commit hash: caff4d7
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/run-mysql-test |
TiDB MergeCI notify🔴 Bad News! New failing [1] after this pr merged.
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* master: (27 commits) executor: parallel cancel mpp query (pingcap#36161) store/copr: adjust the cop cache admission process time for paging (pingcap#36157) log-backup: get can restored global-checkpoint-ts when support v3 checkpoint advance (pingcap#36197) executor: optimize cursor read point get by reading through pessimistic lock cache (pingcap#36149) *: add tidb_min_paging_size system variable (pingcap#36107) planner: handle the expected row count for pushed-down selection in mpp (pingcap#36195) *: support show ddl jobs for sub-jobs (pingcap#36168) table-filter: optimize table pattern message and unit tests (pingcap#36160) domain: fix unstable test TestAbnormalSessionPool (pingcap#36154) executor: check the error returned by `handleNoDelay` (pingcap#36105) log-backup: fix checkpoint display (pingcap#36166) store/mockstore/unistore: fix several issues of coprocessor paging in unistore (pingcap#36147) test: refactor restart test (pingcap#36174) ddl: support rename index and columns for multi-schema change (pingcap#36148) test: remove meaningless test and update bazel (pingcap#36136) planner: Reduce verbosity of logging unknown system variables (pingcap#36013) metrics/grafana: bring back the plan cache miss panel (pingcap#36081) ddl: implement table granularity DDL for SchemaTracker (pingcap#36077) *: bazel use jdk 17 (pingcap#36070) telemetry: add reviewer rule (pingcap#36084) ...
What problem does this PR solve?
Issue Number: close #36106
Problem Summary:
Add a @@tidb_min_paging_size system variable so we can test and turning it.
This variable is not intend to be exposed for the user.
It's just for our internal testing.
What is changed and how it works?
Add a variable, so we can change MinPagingSize dynamically.
This facility makes our testing and turning process easier, we'll do some expirements to find the best default value.
Check List
Tests
Side effects
Documentation
Release note
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