xy720 opened a new pull request, #67004:
URL: https://github.com/apache/doris/pull/67004
### What problem does this PR solve?
Assume that mtmv A,B,C,D share same base tables.
We found a lock competition case between them and create new mtmv. Like:
```
T0 T1 T2 T3 T4 T5
T6
│ │ │ │ │ │
│
┌─ Refresh mv_A ────────────────────────────────────────────────┐
│ plan (holds R on mv_A,B,C,D) │ │ W(A) │ BE run │ W(A) │
│ ═══════════════════════════ │ │══════│ │══════│
└──────────────────────────────┘
┌─ Refresh mv_B ────────────────────────────────────────────────┐
│ plan │ │ W(B) │ BE run │ W(B) │
│ ═══ │ │══════│ │══════│
└──────┘
┌─ Refresh mv_C
─────────────────────────────────────────────────┐
│ plan │ │ W(C) │ BE run │ W(C) │
│ ═══ │ │══════│ │══════│
└──────┘
┌─ Refresh mv_D (arrives here)
──────────────────────────────────┐
│ plan: tryReadLock(mv_A) — mv_A currently write-locked
│
│ ════════════ waits ════════════ 60s timeout
│
│ => throw "Failed to get read lock on table:mv_A"
│
└────────────────────────────────────────────────────────────────┘
⋮ (concurrent scheduler keeps firing refresh_E, _F,
...
each shares the base table, each hits the same
wall,
each occupies a worker for a full retry cycle)
⋮ → mtmv worker pool saturates, queue backlog grows
⋮ → mv_A/B/C write-lock windows keep cycling and never
clear the fair-lock queue for read waiters
┌─ CREATE MATERIALIZED VIEW mv_X
─────────────────────┐
│ base table is the same as
A/B/C/D... │
│ tryReadLock(mv_A) — still
contested │
│ ══════════════ waits
══════════════ 60s => error │
└─────────────────────────────────────────────────────┘
```
If there is mv_E,mv_F,mv_G... before create mv_X, the mv_X may be never
created and retry until timeout, throwing MySQL socket read timeout (180s).
### Release note
None
### Check List (For Author)
- Test <!-- At least one of them must be included. -->
- [ ] Regression test
- [ ] Unit Test
- [ ] Manual test (add detailed scripts or steps below)
- [x] No need to test or manual test. Explain why:
- [ ] This is a refactor/code format and no logic has been changed.
- [ ] Previous test can cover this change.
- [ ] No code files have been changed.
- [ ] Other reason <!-- Add your reason? -->
- Behavior changed:
- [x] No.
- [ ] Yes. <!-- Explain the behavior change -->
- Does this need documentation?
- [x] No.
- [ ] Yes. <!-- Add document PR link here. eg:
https://github.com/apache/doris-website/pull/1214 -->
### Check List (For Reviewer who merge this PR)
- [ ] Confirm the release note
- [ ] Confirm test cases
- [ ] Confirm document
- [ ] Add branch pick label <!-- Add branch pick label that this PR should
merge into -->
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