pingcap/tidb

Incompatible with MySQL 8.0 about decimal truncate

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#10,446 opened on 2019年5月14日

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good first issuepriority/P4type/compatibility

説明

Bug Report

Please answer these questions before submitting your issue. Thanks!

  1. What did you do? If possible, provide a recipe for reproducing the error.
➜  ~ tidiff select 163585273409850809968011255877234629633094624779352518618441553657572897147135360553499480433030391348391690719534799010900398570378470003899837991878694011218651963309356255321688614631601533479175603508137169276827637180801063442877431907302534035121352827985983573079532645288562448964138247704595392364544
MySQL(127.0.0.1:3306)> select 163585273409850809968011255877234629633094624779352518618441553657572897147135360553499480433030391348391690719534799010900398570378470003899837991878694011218651963309356255321688614631601533479175603508137169276827637180801063442877431907302534035121352827985983573079532645288562448964138247704595392364544
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 163585273409850809968011255877234629633094624779352518618441553657572897147135360553499480433030391348391690719534799010900398570378470003899837991878694011218651963309356255321688614631601533479175603508137169276827637180801063442877431907302534035121352827985983573079532645288562448964138247704595392364544 |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 99999999999999999999999999999999999999999999999999999999999999999                                                                                                                                                                                                                                                     |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.003 sec)

TiDB(127.0.0.1:4000)> select 163585273409850809968011255877234629633094624779352518618441553657572897147135360553499480433030391348391690719534799010900398570378470003899837991878694011218651963309356255321688614631601533479175603508137169276827637180801063442877431907302534035121352827985983573079532645288562448964138247704595392364544
Error 1105: line 1 column 316 near ""decimal literal: [types:1690]%s value is out of range in '%s' (total length 316)
  1. What did you expect to see?

The same as MySQL 8.0.

  1. What did you see instead?

See above.

  1. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?
TiDB(127.0.0.1:4000)> select tidb_version()
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                                                                                                                            |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v2.1.8-24-g7b36cdfb6-dirty
Git Commit Hash: 7b36cdfb6e8a4c279fc360ed79cf1c499b553688
Git Branch: failpoint-2.1
UTC Build Time: 2019-04-30 08:26:17
GoVersion: go version go1.12 darwin/amd64
Race Enabled: false
TiKV Min Version: 2.1.0-alpha.1-ff3dd160846b7d1aed9079c389fc188f7f5ea13e
Check Table Before Drop: false |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.007 sec)

コントリビューターガイド

技術スタック
gomysql
領域
databasebackend
Issue 種別
bug
難度新しい貢献者にとっての実装難度です。1 は非常に小さな変更、5 は専門的な作業です。
3
推定時間経験ある貢献者が調査、実装、テスト、pull request 準備にかけるおおよその時間範囲です。
1-2 days
活動状況Issue が今どれだけ取り組みやすいかを示します。新しい、活発、古い、ブロック中、またはメンテナー入力待ちなどです。
stale
明確さ期待される変更、受け入れ条件、次の手順がどれだけ明確かを示します。
mostly clear
前提条件
Go programmingMySQL compatibility knowledge
初心者向け度初回貢献者にどれだけ取り組みやすいかを 1-100 で推定したスコアです。
30
調査方針
Investigate how TiDB parses decimal literals. Compare with MySQL's behavior for large decimal numbers. Look into the parser (likely in `parser` directory) or the evaluation logic in `expression` package. The fix may involve adjusting the decimal type representation or validation to match MySQL's truncation behavior.