Optimizing for Performance and Scalability 7.25

TIP

The asynchronous projection and subscription support can in some cases suffer some event "skipping" when transactions that are appending transactions become slower than the StoreOptions.Projections.StaleSequenceThreshold (the default is only 3 seconds).

From initial testing, the Quick append mode seems to stop this problem altogether. This only seems to be an issue with very large data loads.

Marten has several options to potentially increase the performance and scalability of a system that uses the event sourcing functionality:

var builder = Host.CreateApplicationBuilder();
builder.Services.AddMarten(opts =>
{
    opts.Connection("some connection string");

    // Turn on the PostgreSQL table partitioning for
    // hot/cold storage on archived events
    opts.Events.UseArchivedStreamPartitioning = true;

    // Use the *much* faster workflow for appending events
    // at the cost of *some* loss of metadata usage for
    // inline projections
    opts.Events.AppendMode = EventAppendMode.Quick;

    // Little more involved, but this can reduce the number
    // of database queries necessary to process inline projections
    // during command handling with some significant
    // caveats
    opts.Events.UseIdentityMapForInlineAggregates = true;
});

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The archived stream option is further described in the section on Hot/Cold Storage Partitioning.

See the "Rich" vs "Quick" Appends section for more information about the applicability and drawbacks of the "Quick" event appending.

Lastly, see Optimizing FetchForWriting with Inline Aggregates for more information about the UseIdentityMapForInlineAggregates option.