mirror of
https://github.com/ppy/osu
synced 2024-12-10 17:12:57 +00:00
165 lines
6.3 KiB
C#
165 lines
6.3 KiB
C#
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
|
|
// See the LICENCE file in the repository root for full licence text.
|
|
|
|
using System.Linq;
|
|
using System.Threading;
|
|
using Microsoft.EntityFrameworkCore.Storage;
|
|
using osu.Framework.Platform;
|
|
using osu.Framework.Statistics;
|
|
|
|
namespace osu.Game.Database
|
|
{
|
|
public class DatabaseContextFactory : IDatabaseContextFactory
|
|
{
|
|
private readonly Storage storage;
|
|
|
|
private const string database_name = @"client";
|
|
|
|
private ThreadLocal<OsuDbContext> threadContexts;
|
|
|
|
private readonly object writeLock = new object();
|
|
|
|
private bool currentWriteDidWrite;
|
|
private bool currentWriteDidError;
|
|
|
|
private int currentWriteUsages;
|
|
|
|
private IDbContextTransaction currentWriteTransaction;
|
|
|
|
public DatabaseContextFactory(Storage storage)
|
|
{
|
|
this.storage = storage;
|
|
recycleThreadContexts();
|
|
}
|
|
|
|
private static readonly GlobalStatistic<int> reads = GlobalStatistics.Get<int>("Database", "Get (Read)");
|
|
private static readonly GlobalStatistic<int> writes = GlobalStatistics.Get<int>("Database", "Get (Write)");
|
|
private static readonly GlobalStatistic<int> commits = GlobalStatistics.Get<int>("Database", "Commits");
|
|
private static readonly GlobalStatistic<int> rollbacks = GlobalStatistics.Get<int>("Database", "Rollbacks");
|
|
|
|
/// <summary>
|
|
/// Get a context for the current thread for read-only usage.
|
|
/// If a <see cref="DatabaseWriteUsage"/> is in progress, the existing write-safe context will be returned.
|
|
/// </summary>
|
|
public OsuDbContext Get()
|
|
{
|
|
reads.Value++;
|
|
return threadContexts.Value;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Request a context for write usage. Can be consumed in a nested fashion (and will return the same underlying context).
|
|
/// This method may block if a write is already active on a different thread.
|
|
/// </summary>
|
|
/// <param name="withTransaction">Whether to start a transaction for this write.</param>
|
|
/// <returns>A usage containing a usable context.</returns>
|
|
public DatabaseWriteUsage GetForWrite(bool withTransaction = true)
|
|
{
|
|
writes.Value++;
|
|
Monitor.Enter(writeLock);
|
|
OsuDbContext context;
|
|
|
|
try
|
|
{
|
|
if (currentWriteTransaction == null && withTransaction)
|
|
{
|
|
// this mitigates the fact that changes on tracked entities will not be rolled back with the transaction by ensuring write operations are always executed in isolated contexts.
|
|
// if this results in sub-optimal efficiency, we may need to look into removing Database-level transactions in favour of running SaveChanges where we currently commit the transaction.
|
|
if (threadContexts.IsValueCreated)
|
|
recycleThreadContexts();
|
|
|
|
context = threadContexts.Value;
|
|
currentWriteTransaction = context.Database.BeginTransaction();
|
|
}
|
|
else
|
|
{
|
|
// we want to try-catch the retrieval of the context because it could throw an error (in CreateContext).
|
|
context = threadContexts.Value;
|
|
}
|
|
}
|
|
catch
|
|
{
|
|
// retrieval of a context could trigger a fatal error.
|
|
Monitor.Exit(writeLock);
|
|
throw;
|
|
}
|
|
|
|
Interlocked.Increment(ref currentWriteUsages);
|
|
|
|
return new DatabaseWriteUsage(context, usageCompleted) { IsTransactionLeader = currentWriteTransaction != null && currentWriteUsages == 1 };
|
|
}
|
|
|
|
private void usageCompleted(DatabaseWriteUsage usage)
|
|
{
|
|
int usages = Interlocked.Decrement(ref currentWriteUsages);
|
|
|
|
try
|
|
{
|
|
currentWriteDidWrite |= usage.PerformedWrite;
|
|
currentWriteDidError |= usage.Errors.Any();
|
|
|
|
if (usages == 0)
|
|
{
|
|
if (currentWriteDidError)
|
|
{
|
|
rollbacks.Value++;
|
|
currentWriteTransaction?.Rollback();
|
|
}
|
|
else
|
|
{
|
|
commits.Value++;
|
|
currentWriteTransaction?.Commit();
|
|
}
|
|
|
|
if (currentWriteDidWrite || currentWriteDidError)
|
|
{
|
|
// explicitly dispose to ensure any outstanding flushes happen as soon as possible (and underlying resources are purged).
|
|
usage.Context.Dispose();
|
|
|
|
// once all writes are complete, we want to refresh thread-specific contexts to make sure they don't have stale local caches.
|
|
recycleThreadContexts();
|
|
}
|
|
|
|
currentWriteTransaction = null;
|
|
currentWriteDidWrite = false;
|
|
currentWriteDidError = false;
|
|
}
|
|
}
|
|
finally
|
|
{
|
|
Monitor.Exit(writeLock);
|
|
}
|
|
}
|
|
|
|
private void recycleThreadContexts()
|
|
{
|
|
// Contexts for other threads are not disposed as they may be in use elsewhere. Instead, fresh contexts are exposed
|
|
// for other threads to use, and we rely on the finalizer inside OsuDbContext to handle their previous contexts
|
|
threadContexts?.Value.Dispose();
|
|
threadContexts = new ThreadLocal<OsuDbContext>(CreateContext, true);
|
|
}
|
|
|
|
protected virtual OsuDbContext CreateContext() => new OsuDbContext(storage.GetDatabaseConnectionString(database_name))
|
|
{
|
|
Database = { AutoTransactionsEnabled = false }
|
|
};
|
|
|
|
public void ResetDatabase()
|
|
{
|
|
lock (writeLock)
|
|
{
|
|
recycleThreadContexts();
|
|
|
|
try
|
|
{
|
|
storage.DeleteDatabase(database_name);
|
|
}
|
|
catch
|
|
{
|
|
// for now we are not sure why file handles are kept open by EF, but this is generally only used in testing
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|