Sliced Scroll Search question, what's the minimum max slice?

[frzhang]

Hi,

My current index shards setting is 5, and I am using sliced scroll search to increase parallelism. But I found out if max slice number is less than the number of shards, the result is incomplete. Since I have another search after query, unless the max slice number >= the number of shards, the search after query has more results than the sliced scroll search.

So my questions is: the max slice number >= the shards number?

My sliced query looks like:
/1503014400000/type1,type2,type3/_search?scroll=120s
{
"_source": [ "user.id"],
"sort" : ["_doc"],
"size": 10000,
"slice": {"field": "processedTimestamp","id": 0,"max": 3},
"query": {
"bool": {
"filter": [
{"term" : {"user.locationId" : 1} },
{"range" : {"processedTimestamp" : {"gt" : 1503000000000, "lte" : 1503086400000} }}
]
}
}
}

[frzhang]

just found out there is one index without different mapping, as long as getting rid of it from the search list, the returns are consistent.

[frzhang]

unfortunately, there is still an issue:

1. if the size is <= 10K, the result is consistent (different page sizes, search after or search after)
2. if the size is > 10K, the result is different from the result with size setting <= 10K (total return is about 30K).

the max_result_window is set as 50K now.

Any ideas?