DescendKeys works incorrectly

[jekabolt]

db, _ := buntdb.Open(":memory:")
	db.CreateIndex("name", "*", buntdb.IndexString)
	db.Update(func(tx *buntdb.Tx) error {
		tx.Set("user:1", "Tom", nil)
		tx.Set("user:2", "Tom", nil)
		tx.Set("user:3", "Tom", nil)
		tx.Set("user:4", "Tom", nil)
		tx.Set("user:5", "Tom", nil)
		tx.Set("user:6", "Tom", nil)
		tx.Set("user:7", "Tom", nil)
		tx.Set("user:8", "Tom", nil)
		tx.Set("user:9", "Tom", nil)
		tx.Set("user:10", "Tom", nil)
		tx.Set("user:11", "Tom", nil)
		tx.Set("user:12", "Tom", nil)
		tx.Set("user:13", "Tom", nil)
		tx.Set("user:14", "Tom", nil)
		tx.Set("user:15", "Tom", nil)

		return nil
	})
	db.View(func(tx *buntdb.Tx) error {
		tx.DescendKeys("user:*",
			func(key, value string) bool {
				fmt.Printf("%s: %s\n", key, value)
				return true
			})
		return nil
	})

output

user:9: Tom
user:8: Tom
user:7: Tom
user:6: Tom
user:5: Tom
user:4: Tom
user:3: Tom
user:2: Tom
user:15: Tom
user:14: Tom
user:13: Tom
user:12: Tom
user:11: Tom
user:10: Tom
user:1: Tom

is that correct behavior?

[tidwall]

Yes. This behavior is correct.

The "user:1" is ordered ahead of "user:10" when ascending and ordered behind when descending. This is because the keys in buntdb are in lexicographical order.

A popular option to keep order is to pad the numbers with zeros so that every number is of equal length. user:1 becomes user:0000000001

Makes sure, however, that the length of padded numbers remain the same for all keys.

[jekabolt]

thank you

[gebv]

@jekabolt recently faced a similar problem
Try this project https://github.com/gebv/lex. It is fork. Added go mod and minor code fixes.
It is project looks complete. Maybe as part of other projects (sub packages) there is something more complete.

PS There's a very interesting article https://www.zanopha.com/docs/elen.pdf