Distinct values in Azure Search Suggestions? - azure

Question

I am offloading my search feature on a relational database to Azure Search. My Products tables contains columns like serialNumber, PartNumber etc.. (there can be multiple serialNumbers with the same partNumber).
I want to create a suggestor that can autocomplete partNumbers. But in my scenario I am getting a lot of duplicates in the suggestions because the partNumber match was found in multiple entries.
How can I solve this problem ?

Answer 1

The Suggest API suggests documents, not queries. If you repeat the partNumber information for each serialNumber in your index and then suggest based on partNumber, you will get a result for each matching document. You can see this more clearly by including the key field in the $select parameter. Azure Search will eliminate duplicates within the same document, but not across documents. You will have to do that on the client side, or build a secondary index of partNumbers just for suggestions.
See this forum thread for a more in-depth discussion.
Also, feel free to vote on this UserVoice item to help us prioritize improvements to Suggestions.

Answer 2

I'm facing this problem myself. My solution does not involve a new index (this will only get messy and cost us money).
My take on this is a while-loop adding 'UserIdentity' (in your case, 'partNumber') to a filter, and re-search until my take/top-limit is met or no more suggestions exists:
public async Task<List<MachineSuggestionDTO>> SuggestMachineUser(string searchText, int take, string[] searchFields)
{
var indexClientMachine = _searchServiceClient.Indexes.GetClient(INDEX_MACHINE);
var suggestions = new List<MachineSuggestionDTO>();
var sp = new SuggestParameters
{
UseFuzzyMatching = true,
Top = 100 // Get maximum result for a chance to reduce search calls.
};
// Add searchfields if set
if (searchFields != null && searchFields.Count() != 0)
{
sp.SearchFields = searchFields;
}
// Loop until you get the desired ammount of suggestions, or if under desired ammount, the maximum.
while (suggestions.Count < take)
{
if (!await DistinctSuggestMachineUser(searchText, take, searchFields, suggestions, indexClientMachine, sp))
{
// If no more suggestions is found, we break the while-loop
break;
}
}
// Since the list might me bigger then the take, we return a narrowed list
return suggestions.Take(take).ToList();
}
private async Task<bool> DistinctSuggestMachineUser(string searchText, int take, string[] searchFields, List<MachineSuggestionDTO> suggestions, ISearchIndexClient indexClientMachine, SuggestParameters sp)
{
var response = await indexClientMachine.Documents.SuggestAsync<MachineSearchDocument>(searchText, SUGGESTION_MACHINE, sp);
if(response.Results.Count > 0){
// Fix filter if search is triggered once more
if (!string.IsNullOrEmpty(sp.Filter))
{
sp.Filter += " and ";
}
foreach (var result in response.Results.DistinctBy(r => new { r.Document.UserIdentity, r.Document.UserName, r.Document.UserCode}).Take(take))
{
var d = result.Document;
suggestions.Add(new MachineSuggestionDTO { Id = d.UserIdentity, Namn = d.UserNamn, Hkod = d.UserHkod, Intnr = d.UserIntnr });
// Add found UserIdentity to filter
sp.Filter += $"UserIdentity ne '{d.UserIdentity}' and ";
}
// Remove end of filter if it is run once more
if (sp.Filter.EndsWith(" and "))
{
sp.Filter = sp.Filter.Substring(0, sp.Filter.LastIndexOf(" and ", StringComparison.Ordinal));
}
}
// Returns false if no more suggestions is found
return response.Results.Count > 0;
}

Answer 3

public async Task<List<string>> SuggestionsAsync(bool highlights, bool fuzzy, string term)
{
SuggestParameters sp = new SuggestParameters()
{
UseFuzzyMatching = fuzzy,
Top = 100
};
if (highlights)
{
sp.HighlightPreTag = "<em>";
sp.HighlightPostTag = "</em>";
}
var suggestResult = await searchConfig.IndexClient.Documents.SuggestAsync(term, "mysuggestion", sp);
// Convert the suggest query results to a list that can be displayed in the client.
return suggestResult.Results.Select(x => x.Text).Distinct().Take(10).ToList();
}
After getting top 100 and using distinct it works for me.

Answer 4

You can use the Autocomplete API for that where does the grouping by default. However, if you need more fields together with the result, like, the partNo plus description it doesn't support it. The partNo will be distinct though.