# \_plugins/\_asynchronous\_search API does not return partial results for non aggregation query **URL:** \ **Category:** OpenSearch\ **Tags:** troubleshoot\ **Created:** [July 22, 2024, 8:39pm UTC](https://forum.opensearch.org/t/plugins-asynchronous-search-api-does-not-return-partial-results-for-non-aggregation-query/20458 "2024-07-22T20:39:44Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![sxwbc](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@sxwbc](https://forum.opensearch.org/u/sxwbc)\ **Post date:** [July 22, 2024, 8:39pm UTC](https://forum.opensearch.org/t/plugins-asynchronous-search-api-does-not-return-partial-results-for-non-aggregation-query/20458/1 "2024-07-22T20:39:45Z")
**Versions** (relevant - OpenSearch/Dashboard/Server OS/Browser): 2.15.0 **Describe the issue** : I am expecting to see partial results returned when using \_plugins/\_asynchronous\_search endpoint for non aggregation query ```auto POST _plugins/_asynchronous_search/?pretty&wait_for_completion_timeout=1ms&keep_on_completion=true&request_cache=false&index=test-many-shards&track_total_hits=true { "size": 50, "query": { "bool": { "filter": [ { "range": { "ingestDate": { "gte": "now-168h", "lte": "now" } } } ] } } } ``` But looks like it only return the last final result without the intermediate results. Is this the expected behavior in OS? (I have no issue using \_plugins/\_asynchronous\_search/ API to run aggregation query (e.g. with “aggs” field set) and see the partial results get returned at shard level.) **Configuration** : GET \_cat/indices/test-many-shards?v health status index uuid pri rep docs.count docs.deleted store.size pri.store.size green open test-many-shards zy2KfC2qRqOSpR-ZMCkZMw 32 1 17457803 3478897 63.5gb 31.8gb **Relevant Logs or Screenshots** : Some in progress response from \_plugins/\_asynchronous\_search for id FldnODFXRzBhUzRhYjdfbXZFR0tkcVEFNzk0NjAUZkFVazNKQUJOMXVod0dicWJ0Q0QCMjE= ```auto { "id": "FldnODFXRzBhUzRhYjdfbXZFR0tkcVEFNzk0NjAUZkFVazNKQUJOMXVod0dicWJ0Q0QCMjE=", "state": "RUNNING", "start_time_in_millis": 1721680293507, "expiration_time_in_millis": 1721766693507, "response": { "took": 20483, "timed_out": false, "num_reduce_phases": 3, "_shards": { "total": 32, "successful": 15, "skipped": 0, "failed": 0 }, "hits": { "total": { "value": 5049140, "relation": "eq" }, "max_score": null, "hits": [] } } } { "id": "FldnODFXRzBhUzRhYjdfbXZFR0tkcVEFNzk0NjAUZkFVazNKQUJOMXVod0dicWJ0Q0QCMjE=", "state": "RUNNING", "start_time_in_millis": 1721680293507, "expiration_time_in_millis": 1721766693507, "response": { "took": 40764, "timed_out": false, "num_reduce_phases": 7, "_shards": { "total": 32, "successful": 30, "skipped": 0, "failed": 0 }, "hits": { "total": { "value": 11419958, "relation": "eq" }, "max_score": null, "hits": [] } } } ``` As you can see the “hits” field return empty list as partial results even there is some num\_reduce\_phases completed The final response from \_plugins/\_asynchronous\_search for id FldnODFXRzBhUzRhYjdfbXZFR0tkcVEFNzk0NjAUZkFVazNKQUJOMXVod0dicWJ0Q0QCMjE= ```auto { "id": "FldnODFXRzBhUzRhYjdfbXZFR0tkcVEFNzk0NjAUZkFVazNKQUJOMXVod0dicWJ0Q0QCMjE=", "state": "STORE_RESIDENT", "start_time_in_millis": 1721680293507, "expiration_time_in_millis": 1721766693507, "response": { "took": 49259, "timed_out": false, "num_reduce_phases": 8, "_shards": { "total": 32, "successful": 32, "skipped": 0, "failed": 0 }, "hits": { "total": { "value": 12741817, "relation": "eq" }, "max_score": 0, "hits": [ { "_index": "test-many-shards", "_id": "6278716", "_score": 0, "_source": { "ingestDate": "2024-07-18T06:40:37.765+0000", "logDate": "2024-07-18T06:40:35.371+0000", "logTimestamp": 1721284835371, ... ``` As you can see, only the final response contains the results (not paste all records for security purpose) in “hits” field. ---
**Author:** ![sxwbc](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@sxwbc](https://forum.opensearch.org/u/sxwbc)\ **Post date:** [July 26, 2024, 4:49am UTC](https://forum.opensearch.org/t/plugins-asynchronous-search-api-does-not-return-partial-results-for-non-aggregation-query/20458/2 "2024-07-26T04:49:56Z")
Hi OpenSearch team, It will be great if someone can answer my simple question. I am basically expecting a Yes or No answer here. Really appreciated! ---
**Author:** ![mghazaryan](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.opensearch.org/mghazaryan/32/7873_2.png) [@mghazaryan](https://forum.opensearch.org/u/mghazaryan)\ **Post date:** [July 29, 2024, 4:26pm UTC](https://forum.opensearch.org/t/plugins-asynchronous-search-api-does-not-return-partial-results-for-non-aggregation-query/20458/3 "2024-07-29T16:26:07Z")
An engineer with years of experience in full-text search engines here; not an expert in ElasticSearch/OpenSearch, so I can’t provide a definitive “yes” or “no” answer. Instead I’ll try to explain why the behavior you’re encountering may be expected. The decision not to provide partial document hits in the results of an asynchronous search in OpenSearch (or a similar system) can stem from design choices related to consistency and user expectations. In aggregation queries, intermediate results from each shard can be merged to form a meaningful partial result; each shard contributes to a cumulative result even before all data is fully processed. In contrast, for document fetches, merging partial hits from different shards isn’t straightforward and can complicate the consistency of returned results. For instance, if some shards that contain highly relevant documents have not yet completed their processing, the early results might be misleading or of lower relevance. Users typically expect that a query will return the same results when run under the same conditions. Meanwhile, partial, non-final results from document searches could vary significantly between executions, depending on the shard response times, which might not be desirable or useful.