Reactive SQL Clients

  • We use vertex reactive SQL clients to access relational databases
  • Reactive SQL client is a high-performance SQL client.
  • The client is fully reactive and non-blocking and can handle many database connections within a single thread.
  • The SQL client focuses on scalability and row overhead, And it has a simple API to execute SQL statements against the database.
  • The vertex reactive SQL client is Currently available for PostgresSQL,MySql, SQL server, And IBM DB2.
  • The reactive SQL client uses multiple databases connections on a single event loop thread.
    • By default, client uses for connections.
    • If we want to override this setting, it is possible to define pool options and specify the amount of database connection per database connection pool.
  • Vertex has support for SQL client templates, which is a syntax to create SQL queries.
    • It supports parameter mapping and row mapping.
    • The database rows Can be mapped easily to Vertex Jason objects over custom objects.
    • The SQL client template library also supports vertex data objects
  • The forquery method is used to execute a query.
    • We define a connection pool.
    • We define SQL query.
    • We map to An entity class.
    • And then, in execute method, we define the query parameters as a collection.
      • The query parameters are replaced in the SQL template.
  • Configuration an our database pool includes defining some connection options With host, port, database, username, and password.
    • We return a PGPool.pool() Object with parameters for Postgres.
    • We return a MySqlPool().pool() Object with parameters for MySql.
  • The SQL client usage is the same for all supported databases.
  • We can configure multiple pool corresponding to different verticals.
    • Each vertical contains one pool and runs on the same event loop thread.
    • Each vertical is bound to one event loop.
  • Vertex also supports JDBC client
    • The JDBC client can be used for blocking JDBC access and uses worker threads.
    • The JDBC client can be used for non-supported relational databases, which are not supported in the reactive SQL client API.
    • The client is deprecated in the vertex version four.
    • We should migrate to reactive SQL client API wherever possible.
  • PGPool
    • Vertex offers a reactive sql client To access relational databases.
    • Most of the web applications use JDBC for relational database access, Which does not fit well in a reactive environment.
    • The reactive SQL client uses multiple database connections on a single event loop thread.
    • Everything is non-blocking and very efficient as the thread context, never changes.
    • It’s also very convenient to use as a vertex is bound to an event loop thread.
    • We should use one reactive database Connection pool for each vertical.
    • By defining the pool options, it is possible to specify how many database connections should be used.
      • By default 4 connections are used per thread.
    • When we scale the rest API vertical up or down, The database connections scale with it.
    • There are no thread Context switches As everything is running in the event loop.
  • SQL client template library
    • We use vertex SQL client template library to convert DB result-set to Java objects.
    • We can use SQL client template library to create sql queries also in an easy way.
    • Documentation Of SQL client template library can be found below

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