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system variables: add tidb_analyze_version#5824

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TomShawn:analy-varias
Jun 24, 2021
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system variables: add tidb_analyze_version#5824
ti-chi-bot merged 1 commit into
pingcap:masterfrom
TomShawn:analy-varias

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@TomShawn TomShawn commented Jun 22, 2021

What is changed, added or deleted? (Required)

Add the variable which is added in #5781.

Which TiDB version(s) do your changes apply to? (Required)

  • master (the latest development version)
  • v5.1 (TiDB 5.1 versions)
  • v5.0 (TiDB 5.0 versions)
  • v4.0 (TiDB 4.0 versions)
  • v3.1 (TiDB 3.1 versions)
  • v3.0 (TiDB 3.0 versions)
  • v2.1 (TiDB 2.1 versions)

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  • Delete files
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  • Need modification after applied to another branch
  • Might cause conflicts after applied to another branch

@TomShawn TomShawn added translation/from-docs-cn This PR is translated from a PR in pingcap/docs-cn. v5.1 This PR/issue applies to TiDB v5.1. needs-cherry-pick-release-5.1 labels Jun 22, 2021
@TomShawn TomShawn requested a review from qiancai June 22, 2021 09:43
@ti-chi-bot ti-chi-bot added the size/S Denotes a PR that changes 10-29 lines, ignoring generated files. label Jun 22, 2021
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Comment thread statistics.md
# Introduction to Statistics

TiDB uses statistics to decide [which index to choose](/choose-index.md). The `tidb_analyze_version` variable controls the statistics collected by TiDB. Currently, two versions of statistics are supported: `tidb_analyze_version = 1` and `tidb_analyze_version = 2`. In versions before v5.1, the default value of this variable is `1`. In v5.1, the default value of this variable is `2`, which serves as an experimental feature. These two versions include different information in TiDB:
TiDB uses statistics to decide [which index to choose](/choose-index.md). The `tidb_analyze_version` variable controls the statistics collected by TiDB. Currently, two versions of statistics are supported: `tidb_analyze_version = 1` and `tidb_analyze_version = 2`. In versions before v5.1.0, the default value of this variable is `1`. In v5.1.0, the default value of this variable is `2`, which serves as an experimental feature. These two versions include different information in TiDB:
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Suggested change
TiDB uses statistics to decide [which index to choose](/choose-index.md). The `tidb_analyze_version` variable controls the statistics collected by TiDB. Currently, two versions of statistics are supported: `tidb_analyze_version = 1` and `tidb_analyze_version = 2`. In versions before v5.1.0, the default value of this variable is `1`. In v5.1.0, the default value of this variable is `2`, which serves as an experimental feature. These two versions include different information in TiDB:
TiDB uses statistics to decide [which index to choose](/choose-index.md). The `tidb_analyze_version` variable controls the statistics collected by TiDB. Currently, two versions of statistics are supported: `tidb_analyze_version = 1` and `tidb_analyze_version = 2`. In versions before v5.1.0, the default value of this variable is `1`. Starting from v5.1.0, the default value of this variable is `2`, which works as an experimental feature. These two versions include different information in TiDB:

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@TomShawn TomShawn Jun 24, 2021 •
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As confirmed with @winoros, it is better to use "in v5.1.0", because in later versions (after the feature is GA) the behavior might change.

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Yes, the default value and the upgrading behavior may be changed in the later sprint and minor version. So we might not need the Starting from

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Ok. For 5.2, let's check this variable again and see if any update is needed. I've made a note here: https://docs.google.com/spreadsheets/d/1ZUUyLNdvnNRSQBkwavYdAoVp8Zo7kRhPoZhlIhWwZ4o/edit#gid=526167010

Comment thread system-variables.md
- Value options: `1` and `2`
- Default value: `2`
- Controls how TiDB collects statistics.
- In versions before v5.1.0, the default value of this variable is `1`. In v5.1.0, the default value of this variable is `2`, which serves as an experimental feature. For detailed introduction, see [Introduction to Statistics](/statistics.md).
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- In versions before v5.1.0, the default value of this variable is `1`. In v5.1.0, the default value of this variable is `2`, which serves as an experimental feature. For detailed introduction, see [Introduction to Statistics](/statistics.md).
- In versions before v5.1.0, the default value of this variable is `1`. Starting from v5.1.0, the default value of this variable is `2`, which works as an experimental feature. For detailed introduction, see [Introduction to Statistics](/statistics.md).

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qiancai commented Jun 23, 2021

@winoros, could we use this experimental feature in the production environment?

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winoros commented Jun 24, 2021

@qiancai Yes we could. We suggest the old cluster use the old way since this can reduce the possibility that the plan changed when upgrading. For new cluster, we suggest to use the new one.

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ti-chi-bot commented Jun 24, 2021

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@ti-chi-bot ti-chi-bot added the status/LGT1 Indicates that a PR has LGTM 1. label Jun 24, 2021
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TomShawn commented Jun 24, 2021

/merge

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ti-chi-bot commented Jun 24, 2021

@TomShawn: /merge in this pull request requires 2 approval(s).

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TomShawn commented Jun 24, 2021

/remove-status LGT1
/status LGT2

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TomShawn commented Jun 24, 2021

/merge

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ti-chi-bot commented Jun 24, 2021

This pull request has been accepted and is ready to merge.

DetailsCommit hash: 3c2443b

@ti-chi-bot ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Jun 24, 2021
@ti-chi-bot ti-chi-bot merged commit 3770696 into pingcap:master Jun 24, 2021
@TomShawn TomShawn deleted the analy-varias branch June 24, 2021 10:43
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ti-chi-bot commented Jun 24, 2021

In response to a cherrypick label: new pull request created: #5846.

ti-chi-bot added a commit that referenced this pull request Jun 24, 2021
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system variables: add tidb_analyze_version (#5824) (#5846)
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