Diagnostics and Instrumentation

Polecat provides several tools for monitoring, debugging, and understanding what's happening in your application.

Session Logging

IPolecatLogger

Implement IPolecatLogger at the store level to create per-session loggers:

public class ConsolePolecatLogger : IPolecatLogger
{
    public IPolecatSessionLogger StartSession(IQuerySession session)
    {
        return new ConsoleSessionLogger();
    }
}

public class ConsoleSessionLogger : IPolecatSessionLogger
{
    public void OnBeforeExecute(string sql)
    {
        Console.WriteLine($"Executing: {sql}");
    }

    public void LogSuccess(string sql)
    {
        Console.WriteLine($"Success: {sql}");
    }

    public void LogFailure(string sql, Exception ex)
    {
        Console.WriteLine($"Failed: {sql} - {ex.Message}");
    }

    public void RecordSavedChanges(IDocumentSession session)
    {
        Console.WriteLine($"Saved changes ({session.RequestCount} requests)");
    }
}

Register the logger:

opts.Logger(new ConsolePolecatLogger());

Request Counting

Track database requests per session:

await using var session = store.LightweightSession();
await session.LoadAsync<User>(id);
Console.WriteLine(session.RequestCount); // 1

SQL Preview

ToSql

Preview the SQL generated by a LINQ query:

var sql = session.Query<User>()
    .Where(x => x.LastName == "Smith")
    .ToSql();

Console.WriteLine(sql);
// SELECT data FROM pc_doc_user WHERE JSON_VALUE(data, '$.lastName') = @p0

Schema Diagnostics

ToDatabaseScript

Generate the complete DDL script for all Polecat tables:

var script = await store.Advanced.ToDatabaseScript();
Console.WriteLine(script);

WriteCreationScriptToFileAsync

Save the schema script to a file:

await store.Advanced.WriteCreationScriptToFileAsync("/path/to/schema.sql");

Data Cleanup

CleanAllDocumentsAsync

Delete all data from all document tables:

await store.Advanced.CleanAllDocumentsAsync();

CleanAsync

Delete all data from a specific document table:

await store.Advanced.CleanAsync<User>();

CleanAllEventDataAsync

Delete all event data (events, streams, progressions):

await store.Advanced.CleanAllEventDataAsync();

WARNING

These cleanup methods permanently delete data. They are intended for testing and development, not production use.