Not able to retrieve data from DB

Question

Hi All, 
 
 I am running below query to get the data from a table which has 1000+ rows . But it gives me error " Expression evaluation error at function a!queryEntity: An error occurred while retrieving the data." . 
 When i query DB it doesn't take more than 20 ms . Any help on what can be done? 
 
 a!queryEntity( entity: cons!XYZ, query: a!query( logicalExpression: a!queryLogicalExpression( operator: "AND", filters: { a!queryFilter( field: "helpId", operator: "=", value: 2 ) }, ignoreFiltersWithEmptyValues: true ), pagingInfo: a!pagingInfo( startIndex: 1, batchSize: -1 ) ), fetchTotalCount: true ).data 
 
 Thanks in advance

dawitz197 · Answer

Hi Anu, 
 Check if you have datefield in the database table that has "00:00:00 000" value , sometimes it cause the retrieving data from Appian fail

Rohit Mehta · Answer

There could be various reasons for this. So you have to narrow down the possiblities. 
 1. Datastore is verified for the entity. As it might be possible something changed in the view or table which is causing the connection between the datastore and the DB. 
 2. Since you are querying all the data, there can be the possibility that the server limit of QE is reached and thus giving you the error. So try to reduce the batch size. 
 3. Try to reduce the number of columns in the QE, As I see you are fetching all the columns. 
 4. Database connection issue. 
 Let me know if it helps

ravalik · Answer

Hi Anu, 
 Batch size in appian helps in retrieving the large data sets in an efficient way whilst showing the count of whole data set. 
 Example: When batch size is set to -1, the effective batch size is unlimited. There is no preliminary count query when batch size is unlimited, (and hence the reduced latency, i.e. it's faster). 
 Thanks, 
 ravalik

Not able to retrieve data from DB

Top Replies