server/conn: log more detailed errors (#11731)

[ti-srebot]

cherry-pick #11731 to release-3.0
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/23400

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tidb.git pr/23400:release-3.0-44292d01e9aa

---

What problem does this PR solve?

Print more message to help investigate an bug: when executed some long-time-costing SQL and encountered timeout error, idleTime is relatively small to waitTimeout, e.g.

[2019/08/12 07:43:00.259 +00:00] [INFO] [conn.go:631] ["read packet timeout, close this connection"] [conn=12] [idle=2h11m42.271040483s] [waitTimeout=28800]

What is changed and how it works?

Print original error

Check List

Tests

• Unit test

Code changes

Side effects

Related changes

Release note

• No release note.

[ti-srebot]

/run-all-tests

[ti-srebot]

@lance6716 you're already a collaborator in bot's repo.

[ti-srebot]

No release note, Please follow https://github.com/pingcap/community/blob/master/contributors/release-note-checker.md

[djshow832]

/lgtm

[lysu]

/lgtm

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• djshow832
• lysu

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[lysu]

/run-check_release_note

[lysu]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Details

Commit hash: 38638f2