engine=Hybrid improvements #1156

filimonov · 2025-11-19T23:41:06Z

Changelog category (leave one):

Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Added experimental support in the Hybrid table engine to automatically reconcile column-type mismatches across segments via hybrid_table_auto_cast_columns (analyzer only). This allows queries to return consistent headers even when the underlying tables use different physical types.

Documentation entry for user-facing changes

Introduced hybrid_table_auto_cast_columns (requires allow_experimental_analyzer = 1) so Hybrid segments can auto-insert CAST operations and keep their headers aligned when schemas diverge.
Reiterated that engine = Hybrid remains experimental and must be enabled with allow_experimental_hybrid_table.
Updated terminology and wording in the Hybrid docs (tiered → hybrid, layers → segments) for consistency.

CI/CD Options

Exclude tests:

Regression jobs to run:

github-actions · 2025-11-19T23:41:58Z

Workflow [PR], commit [8c0d982]

filimonov · 2025-11-20T07:52:27Z

test failures look unrelated

arthurpassos · 2025-11-20T16:58:43Z

@codex review

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

src/Storages/StorageDistributed.cpp

filimonov · 2025-11-21T20:02:42Z

src/Storages/StorageDistributed.cpp

+                    segment.predicate_ast,
+                    columns_to_cast_ptr,
+                    &metadata_columns,
+                    segment_actual_columns);


unfortunatelly this approach also seem to misbahave.

When doing those rewrites (col -> CAST(col,...) ) it seems like in may potentially affect the order of the columns coming back from the subplans. And when different segments get processed differently the reorder somehow can also be different. And there is a match by positions near converting actions, which then may lead to situation then it try to align / mix together 2 different column. :|

It seems like moving that rewrite out (make it global for the main table) solves the issue (plus reduces the number of query tree traversals)

I've moved that logic to the dedicated Analyzer Pass (which seems to be a more logical place for such global rewrites of the query)...

For the record - it looked like that:

2025.11.21 17:27:03.478289 [ 1817274 ] {82a3c4b5-345b-4373-8591-e731c192f8e6} <Error> executeQuery: Code: 38. DB::Exception: Cannot parse date: value is too short: Cannot parse Date from String: while converting source column `_CAST(__table1.name, 'String'_String)` to destination column `__table1.date`: while executing 'FUNCTION _CAST(_CAST(__table1.name, 'String'_String) :: 2, Date :: 5) -> _CAST(_CAST(__table1.name, 'String'_String), Date) Date : 4'. (CANNOT_PARSE_DATE) (version 25.8.9.20000.altinityantalya) (from 127.0.0.1:39696) (query 1, line 1) (in query: SELECT * FROM test_tiered_watermark ORDER BY id SETTINGS enable_analyzer = 1

Plan

› Expression (Project names) Header: id UInt32 name String date Date value UInt32 Actions: INPUT : 0 -> __table1.id UInt32 : 0 INPUT : 1 -> __table1.name String : 1 INPUT : 2 -> __table1.date Date : 2 INPUT : 3 -> __table1.value UInt32 : 3 ALIAS __table1.id :: 0 -> id UInt32 : 4 ALIAS __table1.name :: 1 -> name String : 0 ALIAS __table1.date :: 2 -> date Date : 1 ALIAS __table1.value :: 3 -> value UInt32 : 2 Positions: 4 0 1 2 Sorting (Merge sorted streams after aggregation stage for ORDER BY) Header: __table1.id UInt32 __table1.name String __table1.date Date __table1.value UInt32 Sort description: __table1.id ASC Union Header: __table1.id UInt32 __table1.name String __table1.date Date __table1.value UInt32 Expression (Change remote column names to local column names) Header: __table1.id UInt32 __table1.name String __table1.date Date __table1.value UInt32 Actions: INPUT : 0 -> _CAST(__table1.id, 'UInt32'_String) UInt32 : 0 INPUT : 1 -> __table1.date Date : 1 INPUT : 2 -> _CAST(__table1.name, 'String'_String) String : 2 INPUT : 3 -> _CAST(__table1.value, 'UInt32'_String) UInt32 : 3 COLUMN Const(String) -> String String : 4 COLUMN Const(String) -> Date String : 5 ALIAS _CAST(__table1.id, 'UInt32'_String) :: 0 -> __table1.id UInt32 : 6 ALIAS _CAST(__table1.value, 'UInt32'_String) :: 3 -> __table1.value UInt32 : 0 FUNCTION _CAST(__table1.date :: 1, String :: 4) -> _CAST(__table1.date, String) String : 3 FUNCTION _CAST(_CAST(__table1.name, 'String'_String) :: 2, Date :: 5) -> _CAST(_CAST(__table1.name, 'String'_String), Date) Date : 4 ALIAS _CAST(__table1.date, String) :: 3 -> __table1.name String : 5 ALIAS _CAST(_CAST(__table1.name, 'String'_String), Date) :: 4 -> __table1.date Date : 3 Positions: 6 5 3 0 ReadFromRemote (Read from remote replica) Header: _CAST(__table1.id, 'UInt32'_String) UInt32 __table1.date Date _CAST(__table1.name, 'String'_String) String _CAST(__table1.value, 'UInt32'_String) UInt32 Expression (Change remote column names to local column names) Header: __table1.id UInt32 __table1.name String __table1.date Date __table1.value UInt32 Actions: INPUT : 0 -> _CAST(__table1.id, 'UInt32'_String) UInt32 : 0 INPUT : 1 -> __table1.date Date : 1 INPUT : 2 -> _CAST(__table1.name, 'String'_String) String : 2 INPUT : 3 -> _CAST(__table1.value, 'UInt32'_String) UInt32 : 3 COLUMN Const(String) -> String String : 4 COLUMN Const(String) -> Date String : 5 ALIAS _CAST(__table1.id, 'UInt32'_String) :: 0 -> __table1.id UInt32 : 6 ALIAS _CAST(__table1.value, 'UInt32'_String) :: 3 -> __table1.value UInt32 : 0 FUNCTION _CAST(__table1.date :: 1, String :: 4) -> _CAST(__table1.date, String) String : 3 FUNCTION _CAST(_CAST(__table1.name, 'String'_String) :: 2, Date :: 5) -> _CAST(_CAST(__table1.name, 'String'_String), Date) Date : 4 ALIAS _CAST(__table1.date, String) :: 3 -> __table1.name String : 5 ALIAS _CAST(_CAST(__table1.name, 'String'_String), Date) :: 4 -> __table1.date Date : 3 Positions: 6 5 3 0 Sorting (Merge sorted streams after aggregation stage for ORDER BY) Header: _CAST(__table1.id, 'UInt32'_String) UInt32 __table1.date Date _CAST(__table1.name, 'String'_String) String _CAST(__table1.value, 'UInt32'_String) UInt32 Sort description: _CAST(__table1.id, 'UInt32'_String) ASC ReadFromRemote (Read from remote replica) Header: _CAST(__table1.id, 'UInt32'_String) UInt32 __table1.date Date _CAST(__table1.name, 'String'_String) String _CAST(__table1.value, 'UInt32'_String) UInt32

maybe, it comes from positional matching here (i'm not sure)

ClickHouse/src/Planner/PlannerJoinTree.cpp

Line 1410 in 25ed9aa

ActionsDAG::MatchColumnsMode::Position,

…d make the expected non-null columns explicit

…vide the required columns

arthurpassos · 2025-11-21T21:29:01Z

@codex review

arthurpassos

To the extents of my knowledge, it looks good. Plus, it is experimental.

chatgpt-codex-connector · 2025-11-21T21:45:05Z

Codex Review: Didn't find any major issues. 🎉

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

… (anyway it works only if experimetal hybrid tables are enabled)

chatgpt-codex-connector bot reviewed Nov 20, 2025

View reviewed changes

src/Storages/StorageDistributed.cpp Outdated Show resolved Hide resolved

ianton-ru reviewed Nov 20, 2025

View reviewed changes

src/Storages/StorageDistributed.cpp Outdated Show resolved Hide resolved

ianton-ru reviewed Nov 20, 2025

View reviewed changes

src/Storages/StorageDistributed.cpp Outdated Show resolved Hide resolved

arthurpassos reviewed Nov 20, 2025

View reviewed changes

filimonov commented Nov 21, 2025

View reviewed changes

filimonov added 22 commits November 21, 2025 21:57

rename files

cd1a38f

rename layers to segments

6ad282e

store headers

5d47f07

more renames

e59a1f3

more renames2

6ac3b3c

test for missing column

abf4a3b

allow using tables from the current database implicitly

3110105

Mark Hybrid experimental

bcb0f1f

almost working draft

a13a1e5

better

0e0e76b

fix merge issue

cac851f

misplaced setting

2f1e11d

better explantation for cached header

6edfd3a

hybrid_table_auto_cast_columns=true

78a9ba1

Tightened buildQueryTreeDistributed to avoid unused default params an…

d48f1bf

…d make the expected non-null columns explicit

redundant move/copy

df02469

better comment for HybridCastVisitor

c152623

better signature, avoid pointer

bb3a5f2

review comments

ac8ad7d

Prevent creation of the Hybrid tables when some segments does not pro…

113cfe6

…vide the required columns

moving the rewrite to a analyzer pass, seem to work much better

eda9305

finishing

2186269

filimonov added 2 commits November 21, 2025 21:57

better

90cbc5e

comment

0896a85

filimonov force-pushed the mf_25.8_hybrid2 branch from ee309f7 to 0896a85 Compare November 21, 2025 21:13

arthurpassos previously approved these changes Nov 21, 2025

View reviewed changes

Get rid of experimatal marker for hybrid_table_auto_cast_columns flag…

6f8377c

… (anyway it works only if experimetal hybrid tables are enabled)

filimonov dismissed arthurpassos’s stale review via 6f8377c November 21, 2025 22:03

arthurpassos approved these changes Nov 21, 2025

View reviewed changes

filimonov and others added 3 commits November 22, 2025 18:11

Trigger CI/CD

87f0a4e

Merge branch 'antalya-25.8' into mf_25.8_hybrid2

6940b68

Merge branch 'antalya-25.8' into mf_25.8_hybrid2

9015f22

svb-alt added antalya antalya-25.8 labels Nov 24, 2025

Merge branch 'antalya-25.8' into mf_25.8_hybrid2

8c0d982

Enmk merged commit 807c012 into antalya-25.8 Nov 25, 2025
403 of 430 checks passed

engine=Hybrid improvements #1156

engine=Hybrid improvements #1156

Uh oh!

Conversation

filimonov commented Nov 19, 2025 • edited by Enmk Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Changelog category (leave one):

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Documentation entry for user-facing changes

CI/CD Options

Exclude tests:

Regression jobs to run:

Uh oh!

github-actions bot commented Nov 19, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

filimonov commented Nov 20, 2025

Uh oh!

arthurpassos commented Nov 20, 2025

Uh oh!

chatgpt-codex-connector bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

filimonov Nov 21, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

filimonov Nov 21, 2025

Choose a reason for hiding this comment

Uh oh!

arthurpassos commented Nov 21, 2025

Uh oh!

arthurpassos left a comment

Choose a reason for hiding this comment

Uh oh!

chatgpt-codex-connector bot commented Nov 21, 2025

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

filimonov commented Nov 19, 2025 •

edited by Enmk

Loading

github-actions bot commented Nov 19, 2025 •

edited

Loading

filimonov Nov 21, 2025 •

edited

Loading