session, com_stmt: store and restore the params for cursor fetch

[YangKeao]

What problem does this PR solve?

Issue Number: close #40094

Problem Summary:

TiDB cannot handle concurrently running statements. This PR stores and restores the params.

What is changed and how it works?

Store and restore the prepared params in session

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

The following JDBC codes run without panic:

import java.sql.*;

public class Example {
    public static void main(String[] args) throws SQLException, InterruptedException {
        Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:4000/test?useCursorFetch=true&useServerPrepStmts=true&useSSL=false", "root", "");

        conn.setAutoCommit(false); // must set

        conn.prepareStatement("drop table if exists t").execute();
        conn.prepareStatement("create table t (id int auto_increment primary key, id_2 int)").execute();
        conn.prepareStatement("insert into t values (1,1)").execute();
        conn.prepareStatement("insert into t values (2,2)").execute();

        // submit a statement with more arguments:
        PreparedStatement statement1 = conn.prepareStatement("" +
                "select * " +
                "from " +
                "t " +
                "where id = ? and id_2 = ?");
        statement1.setFetchSize(500);
        statement1.setInt(1, 1);
        statement1.setInt(2, 2);
        ResultSet rs_1 = statement1.executeQuery();

        // submit a statement with less arguments:
        PreparedStatement statement2 = conn.prepareStatement("" +
                "select * " +
                "from " +
                "t " +
                "where (id = ?)");
        statement2.setFetchSize(500);
        statement2.setInt(1, 1);
        ResultSet rs_2 = statement2.executeQuery();

        // fetch the result from the first argument
        while (rs_1.next()) {
            int result = rs_1.getInt(1);

            System.out.println(result);
        }
        while (rs_2.next()) {
            int result = rs_2.getInt(1);

            System.out.println(result);
        }

        statement1.close();
        statement2.close();
        conn.commit();
        conn.close();

    }
}

Release note

Fix the issue that the prepared params are lost while executing another statement between EXECUTE and FETCH command.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• bb7133
• tiancaiamao

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[tiancaiamao]

It makes the specific case better, though not a complete fix for the whole related problem.

[YangKeao]

/retest

[bb7133]

LGTM

[tiancaiamao]

/merge

[ti-chi-bot]

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

Commit hash: 1963ef3

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.3: #42238.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.4: #42239.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #42240.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #42241.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.6: #42242.