ParameterReplacer performance

So doing some performance profiling recently we’ve noticed that our issues weren’t SQL times but related to the ParameterReplacer class.

Now I’m not saying this class is overly slow - we’re passing in a reasonably big query, but we have noticed that each .When or .WhenWhere appened to the query makes a larger and larger impact than the last one. To the point where one call to ParameterReplacer.Replace is taking over 900ms.

Call to Replace 897.8ms
Expression = ctx.Set().AsSplitQuery().IncludeDeletedWhen(ctx, (Convert(arg_Dynamic_mergedArgs_96aba847-67ac-4181-892e-99d616252ae3.filterType, Nullable`1) == Convert(Lost, Nullable`1))).WhereWhen(i => arg_Dynamic_mergedArgs_96aba847-67ac-4181-892e-99d616252ae3.jobTypes.Contains(i.TypeId), (arg_Dynamic_mergedArgs_96aba847-67ac-4181-892e-99d616252ae3.jobTypes != null)).WhereWhen(i => arg_Dynamic_mergedArgs_96aba847-67ac-4181-892e-99d616252ae3.stages.Contains(i.StageId), (arg_Dynamic_mergedArgs_96aba847-67ac-4181-892e-99d616252ae3.stages != null)).WhereWhen(i => (Convert(i.FactoryId, Nullable`1) == arg_Dynamic_mergedArgs_96aba847-67ac-4181-892e-99d616252ae3.factoryId), arg_Dynamic_mergedArgs_96aba847-67ac-4181-892e-99d616252ae3.factoryId.HasValue).Where(i => True).Where(i => True).Where(i => True).Where(i => True).Where(i => True).Where(i => True).Where(i => True).Where(i => True).Where(i => True).Where(i => True).OrderBy(Param_0 => Param_0.ProdOrder) 

(yes there’s a lotof .Where(i => True) in there, i had actual where whens in there before but noticed it didn’t seem to matter in terms of performance, each .Where(i => True) added a significant impact.)

No specific method seems to take a lot of time it’s just visiting a lot of things.

Thoughts

• Even a tiny fix to the methods on this class would have a large benefit since it seems to go quite deep
• Expressions themselves don’t seem to be cached at all (just the GraphQL doc) maybe there’s something we could do there

Gonna dig in to this deeper.

[lukemurray]

Closing as there were have been improvements. And future changes we’ll check against the benchmarks to make sure things do not regress and hopefully get better.

[bzbetty]

increased the last test to have 20 WhereWhens and it finally seems to be quite slow (~15-20s per run - i’ll post stats once it finishes running).

The query doesn’t seem unreasonable, i did cheap out a bit and just duplicated the queries but I don’t think that many filters is unreasonable in a large project.

(ctx, args) => ctx.Set<Movie>()
                    .AsSplitQuery()
                    .AsNoTracking()
                    .IgnoreQueryFilters()
                    .WhereWhen(i => i.Name == args.Name, !string.IsNullOrWhiteSpace(args.Name))
                    .WhereWhen(i => i.Director.FirstName == args.DirectorName, !string.IsNullOrWhiteSpace(args.DirectorName))
                    .WhereWhen(i => i.Director.Id == args.DirectorId, args.DirectorId.HasValue)
                    .WhereWhen(i => i.Actors.Any(x => x.Id == args.ActorId), !string.IsNullOrWhiteSpace(args.ActorName))
                    .WhereWhen(i => i.Actors.Any(x => x.FirstName == args.ActorName), args.ActorId.HasValue)
                    .WhereWhen(i => i.Rating > args.RatingMin, args.RatingMin.HasValue)
                    .WhereWhen(i => i.Rating < args.RatingMax, args.RatingMax.HasValue)
                    .WhereWhen(i => i.Released > args.ReleasedAfter, args.ReleasedAfter.HasValue)
                    .WhereWhen(i => i.Released < args.ReleasedBefore, args.ReleasedBefore.HasValue)
                    .WhereWhen(i => args.Genres.Contains(i.Genre.Name), args.Genres.Length > 0)
                    .WhereWhen(i => i.Name == args.Name, !string.IsNullOrWhiteSpace(args.Name))
                    .WhereWhen(i => i.Director.FirstName == args.DirectorName, !string.IsNullOrWhiteSpace(args.DirectorName))
                    .WhereWhen(i => i.Director.Id == args.DirectorId, args.DirectorId.HasValue)
                    .WhereWhen(i => i.Actors.Any(x => x.Id == args.ActorId), !string.IsNullOrWhiteSpace(args.ActorName))
                    .WhereWhen(i => i.Actors.Any(x => x.FirstName == args.ActorName), args.ActorId.HasValue)
                    .WhereWhen(i => i.Rating > args.RatingMin, args.RatingMin.HasValue)
                    .WhereWhen(i => i.Rating < args.RatingMax, args.RatingMax.HasValue)
                    .WhereWhen(i => i.Released > args.ReleasedAfter, args.ReleasedAfter.HasValue)
                    .WhereWhen(i => i.Released < args.ReleasedBefore, args.ReleasedBefore.HasValue)
                    .WhereWhen(i => args.Genres.Contains(i.Genre.Name), args.Genres.Length > 0)