executor: fix show database like case sensitive issue#34766 (#34925)

[ti-srebot]

cherry-pick #34925 to release-6.1
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# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/35060

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git push git@github.com:ti-srebot/tidb.git pr/35060:release-6.1-b3d7a8e85fb0

---

Signed-off-by: elijah f1renze.142857@gmail.com

What problem does this PR solve?

Issue Number: close #34766

Problem Summary: show database like should not be case sensitive

What is changed and how it works?

add a filter plannercore.ShowDatabaseExtractor in the ShowExec. It will bring the like expression to the place where to get meta and filter them for getting the right result.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

MySQL root@(none):(none)> CREATE DATABASE `TEST_$1`;
Query OK, 1 row affected
Time: 0.002s
MySQL root@(none):(none)> CREATE DATABASE `test_$2`;
Query OK, 1 row affected
Time: 0.001s
MySQL root@(none):(none)> SHOW DATABASES LIKE "TEST_%";
+------------------+
| Database (TEST%) |
+------------------+
| TEST_$1          |
| test_$2          |
+------------------+

2 rows in set
Time: 0.014s
MySQL root@(none):(none)> SHOW DATABASES LIKE "test_%";
+------------------+
| Database (test%) |
+------------------+
| TEST_$1          |
| test_$2          |
+------------------+
2 rows in set
Time: 0.008s

• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

executor: fix show database like case sensitive issue

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• hawkingrei
• xiongjiwei

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[ti-srebot]

/run-all-tests

[ti-srebot]

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

[hawkingrei]

/run-check_dev

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/e5d32a0002b7ce2879a68decae1bb3bec3737f76

[hawkingrei]

/merge

[ti-chi-bot]

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

Commit hash: 389fe9d

[hawkingrei]

/run-mysql-test

[ti-chi-bot]

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