SourceKitService Consumes CPU and Grinds Xcode to

Question

This is NOT a Beta issue. I am on Xcode 6.0.1, production release. The issue I am having is that when I try to do a Build or Run the code I am working on, Xcode becomes unresponsive for large periods of time and the SourceKitService consumes upwards of 400% of the CPU (according to Activity Monitor). This issue is new as of the last few days, although, oddly, I had been on Xcode 6.0 since it was officially released on Sept 17. I upgraded to 6.0.1 hoping it would contain a fix for this issue.

Any idea as to what the problem could be?

Answer 1

I was facing the same problem after migrating the project to swift 3, find out solution it was taking time because of dictionaries and array created without data type.

Answer 2

This behavior appeared in my project when I accidentally declared a class that inherited from itself. Xcode 8.2.1, using Swift 3.

Answer 3

I spend 4 hours to figure out problems in a long compilation of my project. The first try takes 42 min to compile.

I clear all cache from /Users/myname/Library/Developer/Xcode/DerivedData/ModuleCache/ as was suggested by @LNI, after restart SourceKitService and apply few changes for code:

1) To

    var initDictionary:[String:AnyObject] = [
                    "details" : "",
                    "duration" : serviceDuration,
                    "name" : serviceName,
                    "price" : servicePrice,
                    "typeId" : typeID,
                    "typeName" : typeName,
                    "url" : "",
                    "serviceId" : serviceID,
                    "imageName" : ""
                ]

From

    var initDictionary= [
                    "details" : "",
                    "duration" : serviceDuration,
                    "name" : serviceName,
                    "price" : servicePrice,
                    "typeId" : typeID,
                    "typeName" : typeName,
                    "url" : "",
                    "serviceId" : serviceID,
                    "imageName: "" ]

2) To

            if let elem = obj.property,
                let elem2 = obj.prop2,
                etc
                 {
                 // do stuf here
            }

From

           let value1 = obj.property ?? defaultValue

3)

To

           let serviceImages = images.filter { $0.serviceId == service.id }
           let sorted = serviceImages.sort { $0.sort > $1.sort }

From

            let serviceImages = images.filter { $0.serviceId == service.id }. sort { $0.sort > $1.sort }

As result compile time - 3 min, not so fast but better for 42 min.

As result, before SourceKitService - take ~5,2Gb of memory and after ~0.37Gb

Answer 4

I also had this issue, in my case I was declaring a big array like this:

var myArray: [(String, Bool?)]?
myArray = [("someString", someBool),
("someString", someBool),
("someString", someBool),
("someString", someBool),
("someString", someBool)
.
.
("someString", someBool)]

I solved the problem by adding the items 1 per line instead of all at the same time:

var myArray = [(String, Bool?)]()
myArray.append(("someString", someBool))
myArray.append(("someString", someBool))
myArray.append(("someString", someBool))
myArray.append(("someString", someBool))
myArray.append(("someString", someBool))
.
.
.

this fixed the problem.

Answer 5

I'm having a similar issue with Xcode 8.2.1 - with a section of 1,000+ lines of code commented-out via /* */. Commenting-out the section caused the issue, and removing the commented-out code fixed it.

Answer 6

I resolved another issue that was causing SourceKitService use up to 13GB of memory...

I had String(format line with lots of arguments:

return String(format: "%d,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f", samples.count,sum1.x,sum1.y,sum1.z,sum1.rx,sum1.ry,sum1.rz,sum2.x,sum2.y,sum2.z,sum2.rx,sum2.ry,sum2.rz,sum3.x,sum3.y,sum3.z,sum3.rx,sum3.ry,sum3.rz)

when replaced with this it worked fine (no memory build up and normal CPU consumption)

    var output: String = ""

    output += String(format: "%d,", samples.count)
    output += String(format: "%.3f,%.3f,%.3f,", sum1.x, sum1.y, sum1.z)
    output += String(format: "%.3f,%.3f,%.3f,", sum1.rx, sum1.ry, sum1.rz)
    output += String(format: "%.3f,%.3f,%.3f,", sum2.x, sum2.y, sum2.z)
    output += String(format: "%.3f,%.3f,%.3f,", sum2.rx, sum2.ry, sum2.rz)
    output += String(format: "%.3f,%.3f,%.3f,", sum3.x, sum3.y, sum3.z)
    output += String(format: "%.3f,%.3f,%.3f", sum3.rx, sum3.ry, sum3.rz)

    return output