pingcap/tidb

Analyze process should stop once the table is truncated or dropped

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#9,300 opened on Feb 14, 2019

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Description

Description

Bug Report

Please answer these questions before submitting your issue. Thanks!

  1. What did you do?

Constructing a large table whose analyze process would last long. Analyze the table then drop it. Then GC is invoked and sends UnsafeDestroyRange to TiKV to clean up the data of this table. But during the cleanup, the analyze process would read incompletely data which leads to TiKV panic.

  1. What did you expect to see?

Analyze process should stop once the table is truncated or dropped.

  1. What did you see instead?

From TiKV log, we can see that the table is already truncated but the analyze process is still in working.

2019/02/13 20:27:50.999 INFO gc_worker.rs:345: unsafe destroy range start_key: t\200\000\000\000\000\000\000\377\201\000\000\000\000\000\000\000\370, end_key: t\200\000\000\000\000\000\000\377\202\000\000\000\000\000\000\000\370 finished cleaning up all, cost time 2.700992685s
2019/02/13 20:27:55.281 INFO analyze.rs:127: analyze handle column range [start: "t\200\000\000\000\000\000\000\201_r\200\000\000\000\006m\206\312" end: "t\200\000\000\000\000\000\000\201_r\200\000\000\000\006s\027|"]
  1. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

v2.1.1

SIG slack channel

#sig-exec

Score

300

Mentor

  • @lzmhhh123

Contributor guide

Tech stack
go
Domain
backenddatabase
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Go programmingBasic understanding of TiDB architecture
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
The issue describes a bug where the analyze process continues after a table is truncated or dropped, leading to TiKV panic. The logs indicate that the unsafe destroy range is completed but the analyze handle column range is still active. The fix should ensure analyze jobs are cancelled upon table drop/truncation. Relevant files include `gc worker.rs` and `analyze.rs`. The mentor @lzmhhh123 may provide further guidance. A possible approach involves checking table existence before processing analyze ranges or hooking into table drop events.
Analyze process should stop once the table is truncated or dropped · pingcap/tidb#9300 | Good First Issue