[IGNITE-21669] Remove sessions from SQL API

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0
• Component/s: sql
• Labels: ignite-3
• Ignite Flags: Docs Required, Release Notes Required
• Assignee: Konstantin Orlov
• Reporter: Igor Sapego
• Created: 04/Mar/24 15:37
• Updated: 04/Sep/24 16:07
• Resolved: 22/Mar/24 15:32

Description

Currently, org.apache.ignite.sql.Session interface does not bring any value, and can be confusing for the users:

• It is simply a property bag and does not hold any other state across queries;
• The same properties can be set on Statement;
• createSession is an extra step for the user;
• Some people, even AI3 developers, look at this API and assume something more, like holding open transactions on the server, etc.

To do:

1. Move query execution methods from Session to IgniteSql;
2. Remove Session interface.

public interface IgniteSql {
   ResultSet<SqlRow> execute(@Nullable Transaction transaction, String query, @Nullable Object... arguments);
   ResultSet<SqlRow> execute(@Nullable Transaction transaction, Statement statement, @Nullable Object... arguments);
   Statement.StatementBuilder statementBuilder();
   ...
}

Usage examples:

// Simple query in one line.
sql.execute(null, "delete from my-table where id = ?", 1);

// Statement.
Statement statement = sql.statementBuilder()
       .query("select foo from bar")
       .pageSize(123)
       .defaultSchema("my-schema")
       .build();

ResultSet<SqlRow> result = sql.execute(null, statement);

// Statement as a template (instead of Session as a common property holder).
Statement statement2 = statement.toBuilder()
       .query("select foo from baz")
       .build();

Issue Links

• incorporates: IGNITE-21544 Amend SQL related thread pools.
• is blocked by: IGNITE-21815 Make client handler to not use Session
• links to: GitHub Pull Request #3464
• links to: PR