Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

system-variables: add tiflash_hashagg_preaggregation_mode #18441

Merged
merged 7 commits into from
Aug 19, 2024
Merged

system-variables: add tiflash_hashagg_preaggregation_mode #18441

Changes from 5 commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
79855b9
system-variables: add tiflash_hashagg_preaggregation_mode
guo-shaoge Aug 1, 2024
8c44c26
fix
guo-shaoge Aug 1, 2024
a64e975
fix def
guo-shaoge Aug 6, 2024
d1cf817
refine
guo-shaoge Aug 6, 2024
7d2e8d7
refine
guo-shaoge Aug 7, 2024
8392110
refine wording
Oreoxmt Aug 7, 2024
1e36de3
Apply suggestions from code review
Oreoxmt Aug 14, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions system-variables.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5866,6 +5866,19 @@ For details, see [Identify Slow Queries](/identify-slow-queries.md).

</CustomContent>

### tiflash_hashagg_preaggregation_mode <span class="version-mark">New in v8.3.0</span>

- Scope: SESSION | GLOBAL
- Persists to cluster: Yes
- Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): Yes
- Type: Enumeration
- Default value: `force_preagg`
- Value options: `force_preagg`, `force_streaming`, `auto`
- This variable controls which pre-aggregation strategy is used in the first stage of a two-stage or three-stage HashAgg pushed down to TiFlash:
- `force_preagg`: TiFlash forces pre-aggregation in the first stage of HashAgg, same with behavior prior to version v8.3.0.
- `force_streaming`: TiFlash directly sends data to the next stage of HashAgg without pre-aggregation.
- `auto`: TiFlash automatically selects whether to perform pre-aggregation based on the current workload's aggregation degree.
Oreoxmt marked this conversation as resolved.
Show resolved Hide resolved
Oreoxmt marked this conversation as resolved.
Show resolved Hide resolved

### tikv_client_read_timeout <span class="version-mark">New in v7.4.0</span>

- Scope: SESSION | GLOBAL
Expand Down
Loading