Scan does not return all records when using the count param and deleting records while iterating #413
Description
package main
import (
"context"
"fmt"
"log"
"testing"
"github.com/alicebob/miniredis/v2"
"github.com/redis/go-redis/v9"
)
func TestSomething(t *testing.T) {
s := miniredis.RunT(t)
c := redis.NewClient(&redis.Options{Addr: s.Addr()})
for i := range 10 {
c.Set(context.Background(), fmt.Sprintf("foo%d", i), "bar", 0)
}
// iterate 10 records with page size 5
dbSize := c.DBSize(context.Background()).Val()
iter := c.Scan(context.Background(), 0, "foo*", 5).Iterator()
scanned := 0
for iter.Next(context.Background()) {
scanned++
}
log.Printf("%d values, page size 5: %d\n", dbSize, scanned)
// iterate 10 records with page size 5 while deleting records
dbSize = c.DBSize(context.Background()).Val()
iter = c.Scan(context.Background(), 0, "foo*", 5).Iterator()
scanned = 0
for iter.Next(context.Background()) {
c.Del(context.Background(), iter.Val())
scanned++
}
log.Printf("%d values, page size 5, deleting each record: %d\n", dbSize, scanned)
// second iteration is necessary to visit all records
dbSize = c.DBSize(context.Background()).Val()
iter = c.Scan(context.Background(), 0, "foo*", 5).Iterator()
scanned = 0
for iter.Next(context.Background()) {
c.Del(context.Background(), iter.Val())
scanned++
}
log.Printf("%d values, page size 5, deleting each record: %d\n", dbSize, scanned)
}❯ go test -v .
=== RUN TestSomething
2025/09/12 01:50:47 10 values, page size 5: 10
2025/09/12 01:50:47 10 values, page size 5, deleting each record: 5
2025/09/12 01:50:47 5 values, page size 5, deleting each record: 5
--- PASS: TestSomething (0.00s)
PASS
ok github.com/johnmaguire/miniredis-bug-poc 0.168s