Realm file size is too large - swift2

Question

I'm trying to integrate Realm into my project and noticed an issue. I've seen other posts on this, but they were a little over a year ago and have been resolved..
When adding objects to Realm, things are file. But when removing objects, they get removed from the DB, but the file size is still large. If I open the realm file in TextEdit, I can see raw text of old records. Why aren't they getting fully deleted?
Take a look at this screenshot. Zero files in the Realm DB, but the file size is 23 mb.
Thanks.

Answer 1

as bcamur sad,
the Realm file will maintain its size on disk to efficiently reuse
that space for future objects
but there is also written
The extra space will eventually be reused by future writes, or may be
compacted — for example by calling
Realm().writeCopyToPath(_:encryptionKey:).
and
call invalidate to tell Realm that you no longer need any of the
objects that you’ve read from the Realm so far, which frees us from
tracking intermediate versions of those objects. The Realm will update
to the latest version the next time it is accessed

Answer 2

I've also realised that my Realm file size grows too big (and it never decreased) and the solution for me was to initialise my Realm db in the following way:
class RealmManager {
static let shared = RealmManager()
private var realm: Realm?
private init() {
let config = Realm.Configuration(schemaVersion: 1, shouldCompactOnLaunch: { totalBytes, usedBytes in
// totalBytes refers to the size of the file on disk in bytes (data + free space)
// usedBytes refers to the number of bytes used by data in the file
// Compact if the file is over 100MB in size and less than 50% 'used'
let oneHundredMB = 100 * 1024 * 1024
return (totalBytes > oneHundredMB) && (Double(usedBytes) / Double(totalBytes)) < 0.5
})
do {
// Realm is compacted on the first open if the configuration block conditions were met.
realm = try Realm(configuration: config)
} catch let error {
// handle error compacting or opening Realm
print(error)
}
}
}
The key is to add shouldCompactOnLaunch block to my Configuration and please, note that the compaction operation will not be completed till you have another process accessing your realm database (e.g.: an opened db in Realm Studio).
For more information, you can check the following link:
https://realm.io/docs/swift/latest/#compacting-realms

Answer 3

Realm holds on to that space to use later on for new objects:
You can also delete all objects stored in a Realm. Note the Realm file will maintain its size on disk to efficiently reuse that space for future objects.
See this part of documentation

Answer 4

Swift Version 3.0.1
For compact your DB:
func compactRealm() {
let defaultURL = Realm.Configuration.defaultConfiguration.fileURL!
let defaultParentURL = defaultURL.deletingLastPathComponent()
let compactedURL = defaultParentURL.appendingPathComponent("default-compact.realm")
autoreleasepool {
let realm = try! Realm()
try! realm.writeCopy(toFile: compactedURL)
try! FileManager.default.removeItem(at: defaultURL)
try! FileManager.default.moveItem(at: compactedURL, to: defaultURL)
}
}