Read-replica support with Entity Framework Core and ABP Framework ? #12405

3 Answer(s)

• 

  0

  oguzhanagir created 5 days ago

  Support Team

  Hi kansoftware

  To provide a specific suggestion, would you like to direct all your GET queries to the Replica database, or are you looking to use a repository with a read structure to direct certain read queries to the Replica database? Let me know this distinction, and I can offer a more specific suggestion.

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• 

  0

  kansoftware created 5 days ago

  use a repository with a read structure

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• 

  0

  oguzhanagir created a day ago

  Support Team

  Hi @kansoftware

  Abp uses DbContext internally, so you need to configure your primary database and read replica (read-only) database.

  "ConnectionStrings": {
    "Default": "Server=localhost; Database=MainDb; Trusted_Connection=True; TrustServerCertificate=True;",
    "ReadReplica": "Server=localhost; Database=ReplicaDb; Trusted_Connection=True; TrustServerCertificate=True;"
  }
  

  Update your DB configuration to support a read replica connection.

  public static class YourProjectNameDbContextConfigurer
  {
      public static void Configure(DbContextOptionsBuilder< YourProjectNameDbContext > builder, string primaryConnectionString, string readReplicaConnectionString, bool useReadReplica = false)
      {
          if (useReadReplica)
          {
              builder.UseSqlServer(readReplicaConnectionString); // Use Read Replica for Queries
          }
          else
          {
              builder.UseSqlServer(primaryConnectionString); // Use Primary DB
          }
      }
  }
  

  Modify YourProjectEntityFrameworkModule.cs:
  Example Code

  public override void PreInitialize()
  {
      if (!SkipDbContextRegistration)
      {
          var configuration = AppConfigurations.Get(
              WebContentDirectoryFinder.CalculateContentRootFolder(),
              addUserSecrets: true
          );
          
          var primaryConnectionString = configuration.GetConnectionString("Default");
          var readReplicaConnectionString = configuration.GetConnectionString("ReadReplica");
              
          Configuration.Modules.AbpEfCore().AddDbContext< YourProjectNameDbContext >(options =>
          {
              // Register Primary DB Context (for writes)
              YourProjectNameDbContextConfigurer.Configure(options.DbContextOptions, primaryConnectionString, readReplicaConnectionString, false);
          });
      
          Configuration.Modules.AbpEfCore().AddDbContext< ReadOnlyDbContext >(options =>
          {
              // Register Read-Only DB Context (for reads)
              YourProjectNameDbContextConfigurer.Configure(options.DbContextOptions, primaryConnectionString, readReplicaConnectionString, true);
          });
      }
  }
  

  Since Abp repositories use DbContext internally, we need a separate read-only DbContext.

  public class ReadOnlyDbContext : YourProjectNameDbContext
  {
      public ReadOnlyDbContext(DbContextOptions< ReadOnlyDbContext > options) : base(options) { }
  }
  

  We now route read queries to ReadOnlyDbContext.

  public class ReadOnlyRepository : EfCoreRepositoryBase, IReadOnlyRepository
      where TEntity : class, IEntity
  {
      public ReadOnlyRepository(IDbContextProvider dbContextProvider) : base(dbContextProvider) { }
  
      public override IQueryable GetAll()
      {
          return base.GetAll().AsNoTracking(); // Ensures read-only queries
      }
  }
  

  You can create a ReadOnlyRepository to perform read operations using the designated replica database and use it wherever you need to execute read queries.

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