'Getting frequent "connection timeout" error on Databricks Job while connecting to Azure SQL Database

We have a clojure code that runs on Databricks, and fetches some large amount of data from Azure SQL Database.

Recently, we are getting frequent connection timeout errors.

I am new to Clojure, so I don't understand why this error occurs. Sometimes the code runs perfectly while sometimes it fails.

We have tried different connection parameters like "connectionretry" and "logintimeout" but it didn't work.

com.microsoft.sqlserver.jdbc.SQLServerException: Connection timed out (Read failed)
    at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:234)
    at com.microsoft.sqlserver.jdbc.SimpleInputStream.getBytes(SimpleInputStream.java:352)
    at com.microsoft.sqlserver.jdbc.DDC.convertStreamToObject(DDC.java:796)
    at com.microsoft.sqlserver.jdbc.ServerDTVImpl.getValue(dtv.java:3777)
    at com.microsoft.sqlserver.jdbc.DTV.getValue(dtv.java:247)
    at com.microsoft.sqlserver.jdbc.Column.getValue(Column.java:190)
    at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getValue(SQLServerResultSet.java:2054)
    at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getValue(SQLServerResultSet.java:2040)
    at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getObject(SQLServerResultSet.java:2372)
    at clojure.java.jdbc$dft_read_columns$fn__226.invoke(jdbc.clj:457)
    at clojure.core$mapv$fn__6953.invoke(core.clj:6627)
    at clojure.lang.LongRange.reduce(LongRange.java:233)
    at clojure.core$reduce.invokeStatic(core.clj:6544)
    at clojure.core$mapv.invokeStatic(core.clj:6618)
    at clojure.core$mapv.invoke(core.clj:6618)
    at clojure.java.jdbc$dft_read_columns.invokeStatic(jdbc.clj:457)
    at clojure.java.jdbc$dft_read_columns.invoke(jdbc.clj:453)
    at clojure.java.jdbc$result_set_seq$row_values__233.invoke(jdbc.clj:483)
    at clojure.java.jdbc$result_set_seq$thisfn__235.invoke(jdbc.clj:493)
    at clojure.java.jdbc$result_set_seq$thisfn__235$fn__236.invoke(jdbc.clj:493)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.RT.seq(RT.java:521)
    at clojure.core$seq__4357.invokeStatic(core.clj:137)
    at clojure.core$map$fn__4785.invoke(core.clj:2637)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.Cons.next(Cons.java:39)
    at clojure.lang.RT.next(RT.java:688)
    at clojure.core$next__4341.invokeStatic(core.clj:64)
    at clojure.core$dorun.invokeStatic(core.clj:3033)
    at clojure.core$doall.invokeStatic(core.clj:3039)
    at clojure.core$doall.invoke(core.clj:3039)
    at clojure.java.jdbc$query$fn__340$fn__341.invoke(jdbc.clj:1007)
    at clojure.java.jdbc$query$fn__340.invoke(jdbc.clj:1006)
sqljdbcclojureazure-sql-databasedatabricks


Solution 1:[1]

The issue isn't related to Azure SQL Database JDBC driver but the way you are establishing the connection and running queries.

Make sure you are closing the connection properly after every commit. Additionally, you have a sufficient sleep time between connections.

Also, make sure that the large data you are fetching must have required bandwidth and properly queried.

You can refer these official documentation for troubleshooting:

Troubleshooting connectivity issues and other errors with Azure SQL Database and Azure SQL Managed Instance

Resolving connectivity errors to SQL Server

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 UtkarshPal-MT

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