Hybrid Search Date Filter Ignored When No Matching Data in Range?

Support
1

Hi, i’m running into unexpected behavior when combining hybrid search with a date-range filter. When I filter for a range in which no objects exist, the filter seems to be silently dropped and I get back all results—as if no filter were applied. However, when I filter for a range that does contain data, the filter works correctly.

I’m using the Python client and have a class ArtikelChunks with a publishdate property (DateTime). All of my data live in March 2025.

Here a code sample to reproduce:

import datetime
import weaviate
from weaviate.classes.query import Filter
from zoneinfo import ZoneInfo

start_date = datetime.datetime(2025, 5, 1).replace(tzinfo=ZoneInfo("Europe/Berlin"))
end_date   = datetime.datetime(2025, 5, 15).replace(tzinfo=ZoneInfo("Europe/Berlin"))

if start_date.date() == end_date.date():
    next_day = start_date + datetime.timedelta(days=1)
    date_filter = (
        Filter.by_property("publishdate").greater_or_equal(start_date)
        & Filter.by_property("publishdate").less_than(next_day)
    )
else:
    date_filter = (
        Filter.by_property("publishdate").greater_or_equal(start_date)
        & Filter.by_property("publishdate").less_or_equal(end_date)
    )

client = weaviate.connect_to_local(headers={"X-OpenAI-Api-Key": embeddings_api_key})
chunks_collection = client.collections.get("ArtikelChunks")

response = chunks_collection.query.hybrid(
    query="whatever",
    limit=5,
    filters=date_filter,
)

print("Start Date:", start_date)
print("End Date:  ", end_date, "\n")

for o in response.objects:
    print("publishdate:", o.properties.get("publishdate"))

client.close()

Output for May 1–15, 2025 (no data in that window):

Start Date: 2025-05-01 00:00:00+02:00
End Date:   2025-05-15 00:00:00+02:00

publishdate: 2025-03-05 06:23:00+01:00
publishdate: 2025-03-12 14:30:00+01:00
publishdate: 2025-03-18 09:15:00+01:00
publishdate: 2025-03-26 17:50:00+01:00
publishdate: 2025-03-30 22:05:00+01:00

… (all March dates)

Output for Mar 1–15, 2025 (data exists):

Start Date: 2025-03-01 00:00:00+01:00
End Date:   2025-03-15 00:00:00+01:00

publishdate: 2025-03-13 18:46:36+01:00
publishdate: 2025-03-09 18:00:00+01:00
publishdate: 2025-03-14 16:22:09+01:00
publishdate: 2025-03-01 09:02:00+01:00
publishdate: 2025-03-09 19:12:10+01:00

… (correctly only March 1–15)

Questions

  1. Is it expected behavior that when a hybrid query’s filter matches zero objects, the filter is ignored and all objects are returned?
  2. If not, how can I enforce a “no-matches → empty result set” semantic when filtering on a date range with hybrid search?

Any pointers or workarounds would be appreciated.

Server Setup Information

  • Weaviate Server Version: 1.30.0
  • Deployment Method: docker
  • Multi Node? Number of Running Nodes: No, 1 node
  • Client Language and Version: Python client version: 4.12.0
  • Multitenancy?: No
2

Hey Philipp,

there is a known problem in 1.30.0 with keyword search and filters. It has been fixed on 1.30.1.

Could you please upgrade and see if you still encounter the filter issue?

Thank you and sorry for the inconvenience.

Best,
André

1 Like
3

Hi André,

Thanks for the quick response!

I’ve just upgraded to version 1.30.1, and I can confirm that the issue is now resolved. The date-range filter is working as expected—even when no results match, the hybrid query correctly returns an empty result set.

Appreciate the support and the quick fix!

Best regards,
Philipp

2 Likes