Confusing comment and missing rationale blocking Garbage Collection

[guidol-ive]

EPPlus usage

Commercial use (I have a commercial license)

Environment

Windows

Epplus version

8.6.3

Spreadsheet application

Excel

Description

See https://github.com/EPPlusSoftware/EPPlus/blob/develop8/src/EPPlus/ExcelPackageSettings.cs#L41

        /// <summary>
        /// Do not call garbage collection when ExcelPackage is disposed.
        /// </summary>
        public bool DoGarbageCollectOnDispose { get; set; } = true;

Suggestion 1: The summary comment is the exact oppositie of the configured default behaviour. They should align.

But on use, the garbage collection at the end can be heavy in Dispose:

                if (Settings.DoGarbageCollectOnDispose)
                {
                    GC.Collect();
                }

Measured sometimes 500 ms. During that time, all other activity on a multi user application comes to a halt:

It performs a blocking garbage collection of all generations.

according to https://learn.microsoft.com/en-us/dotnet/api/system.gc.collect?view=net-10.0

Sample measurements on our eceltable function to parse Excel of 5 rows:

• Fresh: with GC on: 30 ms, disabled: 3 ms
• During load: with GC on: 500 ms, disabled 2-6 ms.

Suggestion is one of the following:

• configure default to not block all activity
• use different collection level
• change default when multi user environment / server GC (which is different anyway)
• reduce need for full generations GC

Workaround:

1. Once established as a potential blocking of activity, change configuration in code to not do blocking GC.
2. And/or: Use CreateExcelPackage.

[AdrianEPPlus]

We will update the comment so it better reflect the behavior of the property.

As for your other request. If the garbage collection is slow, set the property to false for now. I don't think we will change this for EPPlus 8, as it would be a breaking change. We could have a look at it improving the performance for EPPlus 9.