Key-values that should be deleted are not deleted from disk, even when Close() is called

[stephane-martin]

Hello,

OS: MacOSX
Badger version: 20170624

First process:

• create an empty badger with default options
• insert a key value K1, V1, with a pretty long value (> 20 chars)
• delete K1
• close the badger
• end the program

Second process:

• open the same badger
• try to read K1, V1
• K1, V1 is still present in the badger...

Thank you

[stephane-martin]

Run twice

fmt.Println("testBadger called")
opts := badger.DefaultOptions
dir := "/Users/stef/tmp"
opts.Dir = dir
opts.ValueDir = dir
b, err := badger.NewKV(&opts)
if err != nil {
    fmt.Println("error")
    return
}
key := []byte("key")
item := badger.KVItem{}
b.Get(key, &item)
if item.Value() == nil {
    fmt.Println("non existent key")
    val := []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789FOOBARZOGZOG")
    b.Set(key, val)
    fmt.Println("key value has been inserted")
    b.Get(key, &item)
    fmt.Println("getting the value")
    fmt.Println(string(item.Value()))
    b.Delete(key)
    fmt.Println("key value has been deleted")
    fmt.Println("getting the value again")
    b.Get(key, &item)
    fmt.Println(item.Value())
} else {
    fmt.Println("key exists")
    fmt.Println(string(item.Value()))
}
b.Close()

[pawanrawal]

Hi @stephane-martin, thanks for the bug report. I have submitted a fix and this shouldn't be a problem anymore.

[stephane-martin]

The fix works, thanks!

[manishrjain]

I'm actually not sure why this is the case. If you close cleanly, then Badger should not have to replay the value log, which means the delete markers in value log won't be required.

There's something else going on here, which is causing value log to be replayed even when Badger is closed properly. We should look into why that is happening.

[pawanrawal]

We update valuePointer even if Fid and Offset are 0 and it has length and we replay from end of last entry instead of start so we don't need to have delete markers anymore.