Core data taking time to insert records with fetching entity & set as relationship

问题

I have 2 entities: Components & SurveyReadingWeb that have a one-to-many relationship. I have saved Components data in core data database; but while saving SurveyReadingWeb -- in a for loop -- I have to fetch Components data entity by passing component id and setting the surveyreadings isComponentexists relationship, like in the code below for 8000 records. This process is taking too much time, nearly 7 minutes. How can I reduce the time?

for item in items {
            autoIncrementId = autoIncrementId + 1
            print("reading items parsed:- \(item.SurveyReadingId), \(autoIncrementId)")

            let reading : SurveyReadingWeb? = NSEntityDescription.insertNewObject(forEntityName: Constants.EntityNames.kSURVEYREADINGWEB, into: self.managedContext) as? SurveyReadingWeb
            reading?.surveyId1 = Int32(autoIncrementId)
            reading?.surveyId = Int32(item.SurveyId) ?? 0
            reading?.readingData = item.CH4
            reading?.surveyDateTime = item.SurveyReadingDateTime
            reading?.latitude = item.Latitude
            reading?.longitude = item.Longitude
            reading?.serialNumber = item.SerialNumber
            reading?.descriptionText = item.Description
            reading?.componentName = item.Description
            reading?.componentId = Int32(item.ComponentId) ?? 0
            reading?.readingTypeId = Int32(item.ReadingTypeID) ?? 0
            reading?.readingTypeDetails = item.ReadingTypeDetails

            reading?.currentLatitude = item.CurrentLatitude
            reading?.currentLongitude = item.CurrentLongitude
            reading?.hdop = item.HDOP
            reading?.vdop = item.VDOP
            reading?.componentDistance = item.ComponentDistance
            reading?.facilityId = Int32(item.ProjectId) ?? 0
            reading?.posted = 1
            reading?.readyToSync = 1

            reading?.isComponentExists = DatabaseManager.sharedManager.getCompNameFromID(compID: Int32(item.ComponentId) ?? 0)
        }
        saveContext()


func getCompNameFromID(compID : Int32) -> Components? {
    var component : Components? = nil
    let fetchRequest : NSFetchRequest<Components> = Components.fetchRequest()
    fetchRequest.predicate = NSPredicate(format: "componentId == %ld", compID)

    do {
        let searchResults = try managedContext.fetch(fetchRequest)
        component =  (searchResults.first) ?? nil
    } catch {
    }
    return component ?? nil
}

回答1:

You can reduce the time dramatically if you add an NSCache instance to cache compID:Components key value pairs.

In getCompNameFromID check if the compID exists in the cache. If yes get the value from the cache (very fast), if not fetch the record and save it for the compID in the cache.

And use the convenient SurveyReadingWeb(context: initializer to get rid of all the ugly question marks, however the performance benefit is rather tiny.

来源：https://stackoverflow.com/questions/62087792/core-data-taking-time-to-insert-records-with-fetching-entity-set-as-relationsh

标签

ios

swift

performance

relationship