How do I install the Doris Debug Materialized View skill?

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Is Doris Debug Materialized View free to use?

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Who published Doris Debug Materialized View?

apache (@apache) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Doris Debug Materialized View by apache

Name: Doris Debug Materialized View
Author: apache

File contents

Materialized View

Kind comparison

Kind	Code area	Check	Rewrite mechanism
Sync	`MaterializedViewHandler` / rollup	`SHOW ALTER TABLE MATERIALIZED VIEW`	Transparent — planner auto-selects
Async MTMV	`fe/.../mtmv/`	`mv_infos()` RefreshState	CBO-based — EXPLAIN shows if matched

Causes

ID	Cause	Evidence	Kind
A	Sync MV build pending/stuck	`SHOW ALTER TABLE MATERIALIZED VIEW` State≠FINISHED	Sync
B	MTMV refresh failed	`mv_infos()` RefreshState=FAIL	Async
C	MTMV rewrite miss	EXPLAIN shows no MATERIALIZED_REWRITE	Async
D	MTMV data stale	`mv_infos()` LastRefreshTime old	Async
E	MV not selected by planner	EXPLAIN shows TABLE SCAN not MATERIALIZED	Either

10 min triage

-- Sync MV status
SHOW ALTER TABLE MATERIALIZED VIEW FROM db;

-- Async MTMV status
SELECT * FROM mv_infos('database'='db') WHERE Name='mv'\G

-- Check rewrite eligibility
EXPLAIN VERBOSE SELECT ...;

-- Force refresh
REFRESH MATERIALIZED VIEW mv;

-- Enable external MV rewrite (for catalog queries)
SET materialized_view_rewrite_enable_contain_external_table = true;

Cause C — MTMV rewrite miss

Common reasons (see fe/.../mtmv/MTMVService.java rewrite matcher):

Partition misalignment: MV has partition_sync=false and query partition doesn't match → ALTER MATERIALIZED VIEW mv SET ("partition_sync" = "true")
Aggregation granularity: MV groups by (a, b) but query groups by (a) only → MV is not a valid rewrite target
Filter mismatch: MV WHERE clause doesn't cover query WHERE clause → check MV definition
Session var off: SET enable_materialized_view_rewrite = true

-- Debug: force the optimizer to log MV matching
SET enable_materialized_view_rewrite_debug_log = true;
EXPLAIN VERBOSE SELECT ...;  -- check fe/log/fe.audit.log for MV match details

Cause A — Sync MV stuck

-- Cancel stuck build
CANCEL ALTER TABLE MATERIALIZED VIEW FROM db ON table;

-- Check BE compaction queue (MV build competes with compaction)
./scripts/doris-debug be-metrics --be http://$BE:8040 --grep compaction

Source

fe/.../mtmv/MTMVService.java — MTMV lifecycle
fe/.../alter/MaterializedViewHandler.java — sync MV alter
fe/.../materializedview/MaterializedViewRewriter.java — rewrite logic
SessionVariable.java — enable_materialized_view_rewrite, materialized_view_rewrite_enable_contain_external_table

---name: doris-debug-materialized-viewdescription: Use for Doris sync MV (rollup) miss or async MTMV refresh/rewrite issues. Commands: SHOW ALTER TABLE MATERIALIZED VIEW, mv_infos(), EXPLAIN, REFRESH MATERIALIZED VIEW.---# Materialized View## Kind comparison| Kind | Code area | Check | Rewrite mechanism ||------|-----------|-------|-------------------|| Sync | `MaterializedViewHandler` / rollup | `SHOW ALTER TABLE MATERIALIZED VIEW` | Transparent — planner auto-selects || Async MTMV | `fe/.../mtmv/` | `mv_infos()` RefreshState | CBO-based — EXPLAIN shows if matched |## Causes| ID | Cause | Evidence | Kind ||----|-------|----------|------|| A | Sync MV build pending/stuck | `SHOW ALTER TABLE MATERIALIZED VIEW` State≠FINISHED | Sync || B | MTMV refresh failed | `mv_infos()` RefreshState=FAIL | Async || C | MTMV rewrite miss | EXPLAIN shows no MATERIALIZED_REWRITE | Async || D | MTMV data stale | `mv_infos()` LastRefreshTime old | Async || E | MV not selected by planner | EXPLAIN shows TABLE SCAN not MATERIALIZED | Either |## 10 min triage```sql-- Sync MV statusSHOW ALTER TABLE MATERIALIZED VIEW FROM db;-- Async MTMV statusSELECT * FROM mv_infos('database'='db') WHERE Name='mv'\G-- Check rewrite eligibilityEXPLAIN VERBOSE SELECT ...;-- Force refreshREFRESH MATERIALIZED VIEW mv;-- Enable external MV rewrite (for catalog queries)SET materialized_view_rewrite_enable_contain_external_table = true;```## Cause C — MTMV rewrite missCommon reasons (see `fe/.../mtmv/MTMVService.java` rewrite matcher):1. **Partition misalignment**: MV has `partition_sync=false` and query partition doesn't match → `ALTER MATERIALIZED VIEW mv SET ("partition_sync" = "true")`2. **Aggregation granularity**: MV groups by `(a, b)` but query groups by `(a)` only → MV is not a valid rewrite target3. **Filter mismatch**: MV WHERE clause doesn't cover query WHERE clause → check MV definition4. **Session var off**: `SET enable_materialized_view_rewrite = true````sql-- Debug: force the optimizer to log MV matchingSET enable_materialized_view_rewrite_debug_log = true;EXPLAIN VERBOSE SELECT ...; -- check fe/log/fe.audit.log for MV match details```## Cause A — Sync MV stuck```sql-- Cancel stuck buildCANCEL ALTER TABLE MATERIALIZED VIEW FROM db ON table;-- Check BE compaction queue (MV build competes with compaction)./scripts/doris-debug be-metrics --be http://$BE:8040 --grep compaction```## Source- `fe/.../mtmv/MTMVService.java` — MTMV lifecycle- `fe/.../alter/MaterializedViewHandler.java` — sync MV alter- `fe/.../materializedview/MaterializedViewRewriter.java` — rewrite logic- `SessionVariable.java` — `enable_materialized_view_rewrite`, `materialized_view_rewrite_enable_contain_external_table`

Frequently asked questions

Doris Debug Materialized View