query-parser | tutorial for building a query parser using Ruby Parslet | Parser library

I have this document indexed on Solr:

I have a field called email_txt of type text_general that holds a list of emails of type abc@xyz.com, and I'm trying to create a query that will only search the username and disregard the domain.

My query looks something like this:

I would like to use the Fuzzy Search Feature of Solr. In my dataset, I have one record that looks like this:

I got a table in this format

I referred this section

I made q as empty and added a query q.alt=NAME:tokyo with dismax parser. It worked as expected.

I added a query in q as NAME:london It returned nothing. I expected to return the docs which matches NAME:london

To find out the reason I enabled debugQuery and the query is translated as +DisjunctionMaxQuery:(((NAME:name:london) ^ 1.0) ())

I couldn't understand this translation. Could anyone clarify this please?

I have couple of questions here.

I want to search a term jumps

With Fuzzy search, I can do jump~ With wild card search, I can do jump* With stemmer I can do, jump

My understanding is that, fuzzy search gives pump. Wildcard search gives jumping as well. Stemmer gives "jumper" also.

I totally agree with the results.

1. What is the performance of thes three?

   • Wild card is not recommended if it is at the beginning of the term - my understanding as it has to match with all the tokens in the index - But in this case, it would be all the tokens which starts jump

   • Fuzzy search gives me unpredicted results - It has to do something kind of spellcheck I assume.

   • Stemmer suits only particular scenarios like it can;t match pumps.

2. How should I use these things which can give more relevant results?

I probably more confused about all these because of this section. Any suggestions please?

I have a basic question about how to get started with Fulcro and Websockets.

i) I started with the Fulcro lein template. ii) Then added the websocket client and server bits. iii) In my server, I also added a com.fulcrologic.fulcro.networking.websocket-protocols.WSListener to detect when a WS client is connecting.

Between the WSListener, and the browser's network console, I can see that the client is never making a WS connection.

• How does Fulcro make the initial WS connection?
• After that, how can I make server pushes to client?

client.cljs

I'm trying to query solr docs with empty field values and am not able to get it going:

Let's say the docs have two potentially empty fields name_de and name_en.

Querying for one of those as described in the solr docs works fine:

-name_de:[* TO *]

But as soon as I start to combine more than one query of that kind, the answer is not what I would expect:

-name_de:[* TO *] OR -name_en:[* TO *]

should deliver something like the union of both queries I would think. Yet it doesn't. I simply did not understand the answer: in my case I have 1310 docs delivered by querying for name_de, 1319 by querying for name_en - and get 950 when combining both as shown above.

As I understand the Solr docs:

Pure negative queries (all clauses prohibited) are allowed (only as a top-level clause)

these "pure negative queries" cannot be combined and the whole functionality is not supported by Lucene out of the box but an "extension" by Solr's Standard Query Parser.

But I have not been able to find relevant resources stating that more cleary and indicating the correct handling of empty values and I wonder if my approach is wholly wrong.

Does anyone have a hint for me how to handle / query these empty values in Solr correctly?

PS: Trying to incorporate the exists function didn't work out as well: calling these always delivered all the documents, regardless of their content in name_de or name_en.