Solr Code indexing fails frequently without any error

Question

I have around 8-10 cores which does index periodically. Recently these cores(randomly) have stopped indexing without any error in the solr logs. All I can see is ongoing indexing even after several hours. This is so random that I could not even figure out the pattern or root cause here.

Here are the log lines from solr docker container :

For Successful Delta import, SolrLog generated as below: Time:2022-03-23 10:55:41 (SuccessLog)

2022-03-23 10:55:41.525 INFO  (qtp136157810-3850) [   x:OMSearch] o.a.s.h.d.DataImporter Loading DIH  Configuration: db-data-config.xml
2022-03-23 10:55:41.526 INFO  (qtp136157810-3850) [   x:OMSearch] o.a.s.h.d.DataImporter Data Configuration loaded successfully
2022-03-23 10:55:41.528 INFO  (qtp136157810-3850) [   x:OMSearch] o.a.s.c.S.Request [OMSearch] webapp=/solr path=/dataimport params={command=delta-import} status=0 QTime=3
2022-03-23 10:55:41.528 INFO  (Thread-5342) [   ] o.a.s.h.d.DataImporter Starting Delta Import
2022-03-23 10:55:41.531 INFO  (Thread-5342) [   ] o.a.s.h.d.SimplePropertiesWriter Read dataimport.properties
2022-03-23 10:55:41.532 INFO  (Thread-5342) [   ] o.a.s.h.d.DocBuilder Starting delta collection.
2022-03-23 10:55:41.534 INFO  (Thread-5342) [   ] o.a.s.h.d.DocBuilder Running ModifiedRowKey() for Entity: OMSearch
2022-03-23 10:55:41.534 INFO  (Thread-5342) [   ] o.a.s.h.d.JdbcDataSource Creating a connection for entity OMSearch with
 URL: jdbc:mysql://ip:port/database?useSSL=false

-- the below lines are missing in failure log

2022-03-23 10:55:41.549 INFO  (Thread-5342) [   ] o.a.s.h.d.JdbcDataSource Time taken for getConnection(): 14
2022-03-23 10:55:41.550 INFO  (Thread-5342) [   ] o.a.s.h.d.DocBuilder Completed ModifiedRowKey for Entity: OMSearch rows obtained : 0
2022-03-23 10:55:41.550 INFO  (Thread-5342) [   ] o.a.s.h.d.DocBuilder Completed DeletedRowKey for Entity: OMSearch rows obtained : 0
2022-03-23 10:55:41.550 INFO  (Thread-5342) [   ] o.a.s.h.d.DocBuilder Completed parentDeltaQuery for Entity: OMSearch
2022-03-23 10:55:41.550 INFO  (Thread-5342) [   ] o.a.s.h.d.DocBuilder Delta Import completed successfully
2022-03-23 10:55:41.550 INFO  (Thread-5342) [   ] o.a.s.h.d.DocBuilder Time taken = 0:0:0.18
2022-03-23 10:55:41.551 INFO  (Thread-5342) [   ] o.a.s.u.p.LogUpdateProcessorFactory [OMSearch]  webapp=/solr path=/dataimport params={command=delta-import} status=0 QTime=3{} 0 25

At Time:2022-03-23 10:56:01(At time of failure) solr log generated as below for OMSearch

2022-03-23 10:56:01.594 INFO  (qtp136157810-4414) [   x:OMSearch] o.a.s.h.d.DataImporter Loading DIH Configuration:db-data-config.xml
2022-03-23 10:56:01.595 INFO  (qtp136157810-4414) [   x:OMSearch] o.a.s.h.d.DataImporter Data Configuration loaded successfully
2022-03-23 10:56:01.595 INFO  (Thread-5344) [   ] o.a.s.h.d.DataImporter Starting Delta Import
2022-03-23 10:56:01.598 INFO  (qtp136157810-4414) [   x:OMSearch] o.a.s.c.S.Request [OMSearch] webapp=/solr path=/dataimport params={command=delta-import} status=0 QTime=4
2022-03-23 10:56:01.601 INFO  (Thread-5344) [   ] o.a.s.h.d.SimplePropertiesWriter Read dataimport.properties
2022-03-23 10:56:01.602 INFO  (Thread-5344) [   ] o.a.s.h.d.DocBuilder Starting delta collection.
2022-03-23 10:56:01.607 INFO  (Thread-5344) [   ] o.a.s.h.d.DocBuilder Running ModifiedRowKey() for Entity: OMSearch
2022-03-23 10:56:01.607 INFO  (Thread-5344) [   ] o.a.s.h.d.JdbcDataSource Creating a connection for entity OMSearch  with URL: jdbc:mysql://ip:port/database?useSSL=false