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DSE Solr : Getting null response for data already in cassandra

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Started 6 months ago by shruti
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shruti
Member

Hi All ,

I am facing a situation where queries through Solr do not return any data , even when data exists in Cassandra .

My application is inserting data using Hector Api on CF indexed through Solr .
When I try to fetch data immediately using Solr Http Api , it doesnot return me any data , however if fetch after some millisecond delay , rows are returned .

Also , whenever doing insert and get through HECTOR API , I am getting the rows always .

Seems to me like there is a delay when Cassandra inserts data and if Solr tries to fetch in this time , it gets null response .

Still I am not very clear , as there was nothing which could be found on internet as well .

Does anyone have idea , how Solr Read data from Cassandra ? Does it look into CL / Memtable /SSTable ?

Or is there any configuration in solrconfig.xml / cassandra.yaml , which could help in removing this situation .

Any help / hint will be appreciated !!

Posted 6 months ago #
Piotr Kołaczkowski
Administrator

This is how normally Solr works. DSE puts data into Solr immediately, but Solr makes them available first when they are committed. Commits happen on memtable flush (so every document eventually will be committed) or you can trigger them manually by appending commit=true param to your Solr update request.

Posted 6 months ago #
shruti
Member

Thanks for clarifying . Does this mean that Solr reads data from SSTables and not from memtables ?

Now , writes in my application happens through Hector API and Solr is been used just to GET the data , so I cannot append commit=true in Solr query .

Going through Solr docs , I came across in solrconfig.xml -

<autoCommit>
<maxTime>100</maxTime>
</autoCommit>

And

<autoSoftCommit>
<maxTime>10</maxTime>
</autoSoftCommit>

However , after changing these I could not see any difference .

Is there any other way of setting auto commit in Solr in DSE (2.2) , So that whatever data is written to Cassandra is immediately available through Solr search query without any delay .

Thanks!

Posted 6 months ago #
shruti
Member

I resolved the issue by doing a solr commit in my application , every time there is an insert/delete in cassandra db through my Hector layer .

This works fine for now , but in high load scenarios this may be a performance bottleneck .

Also still my question regarding <autoCommit> in solrconfig.xml stands in DSE , as changes made to <autoCommit> did not lead to commit actually.

Posted 6 months ago #

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