SearchFilter misbehaves when data is a lot

Question

I tested the SearchFilter when I had around 10 records , and it was working fine, but I went ahead and tested it when the data records are above 200, it just returning the same data without searching or filtering the data , below is my View file :

class PostList(generics.ListCreateAPIView):
    """Blog post lists"""
    queryset = Post.objects.filter(status=APPROVED)
    serializer_class = serializers.PostSerializer
    authentication_classes = (JWTAuthentication,)
    permission_classes = (PostsProtectOrReadOnly, IsMentorOnly)
    filter_backends = [DjangoFilterBackend, filters.SearchFilter]
    filter_fields = ('title', 'body', 'description',)
    search_fields = (
        '@title',
        '@body',
        '@description',
    )


    def filter_queryset(self, queryset):
        ordering = self.request.GET.get("order_by", None)
        author = self.request.GET.get("author", None)
        if ordering == 'blog_views':
            queryset = queryset.annotate(
                address_views_count=Count('address_views')).order_by(
                '-address_views_count')

        if author:
            queryset = queryset.filter(owner__email=author)

        return queryset

This is how I search :

/api/v1/blogs/?search=an+elephant

But it just returns back all the data instead of filtering.