Large Table Paginator for Django: Scale Django admin pages and avoid timeouts.

admin.py

from django.contrib.admin import ModelAdmin

from .paginator import LargeTablePaginator


class MyTableAdmin(ModelAdmin):
    ...
    large_table_paginator = True
    ...
    
    def get_paginator(  # pylint: disable=too-many-arguments
        self,
        request,
        queryset,
        per_page,
        orphans=0,
        allow_empty_first_page=True,
    ):
        # Always show count locally
        if self.large_table_paginator and not settings.DEBUG:
            return LargeTablePaginator(
                queryset, per_page, orphans, allow_empty_first_page
            )
        return self.paginator(queryset, per_page, orphans, allow_empty_first_page)

    

paginator.py

from django.core.paginator import Paginator
from django.db import connection, transaction, OperationalError
from django.utils.functional import cached_property


class LargeTablePaginator(Paginator):
    """
    # https://gist.github.com/noviluni/d86adfa24843c7b8ed10c183a9df2afe
    Overrides the count method of QuerySet objects to avoid timeouts.
    - Get an estimate instead of actual count when not filtered (this estimate can be stale and hence not fit for
    situations where the count of objects actually matter).
    - If any other exception occured fall back to default behaviour.
    """

    @cached_property
    def count(self):
        """
        Returns an estimated number of objects, across all pages.
        """
        if not self.object_list.query.where:  # type: ignore
            try:
                with connection.cursor() as cursor:
                    # Obtain estimated values (only valid with PostgreSQL)
                    cursor.execute(
                        "SELECT reltuples FROM pg_class WHERE relname = %s",
                        [self.object_list.query.model._meta.db_table],  # type: ignore
                    )
                    estimate = int(cursor.fetchone()[0])
                    return estimate
            except Exception:  # pylint: disable=broad-except
                # If any other exception occurred fall back to default behaviour
                pass
        return super().count