PhoenixmlDb

Logging

Supplying a logger to the embedded database, what is logged without one, the log categories, and the stable event ids

#Logging

The database logs through Microsoft.Extensions.Logging. Both servers route these events into the host's logging, so they reach the console, structured logs and any other configured provider. An embedded application supplies its own logger factory.

#Supplying a logger (embedded)

Set LmdbStorageOptions.LoggerFactory when you open the database:

using Microsoft.Extensions.Logging;
using var loggerFactory = LoggerFactory.Create(b => b.AddConsole().SetMinimumLevel(LogLevel.Information));
var options = LmdbStorageOptions.Default with { LoggerFactory = loggerFactory };
using var db = new DocumentDatabase("./data", options);
                                  

• The database never disposes the factory; it stays yours.

• DocumentDatabase.LoggerFactory is never null.

• Logging can't throw into the database: a provider that throws doesn't affect it.

• Calling AddProvider on the database's factory does nothing, and never changes your own factory.

• The factory isn't part of the options' equality or ToString.

#Without a logger

When no factory is supplied, Information events are dropped, and Warning and above are written to System.Diagnostics.Trace. That includes BackupFailed (1008), which is logged whether or not an OnBackupFailed callback is set, and the cluster warnings 2012 and 2015–2017.

The process-exit errors (1002–1006) are always written to Trace, even when a factory is supplied, because the host's logging may already be shut down when the process exits.

#Categories

#Event ids

Event ids, names and levels are stable once released; message text may change. Filter and alert on the id or name, not the message.

#Storage (1000–1099)

#Indexing (1100–1199)

#Cluster (2000–2099)

PeerRequestFailed (2010) names the request (RequestVote, AppendEntries or TimeoutNow) and the peer. A node that is shutting down doesn't report its own shutdown as a peer failure.

#Server (3000–3099)

The server startup events 3001–3007 are listed in the Server Configuration reference.