I am new to extended events however, I got to know about the same by reading some articles like this one
My question: Is there any event in Event Library by which we can identify Fragmented Index ?
Because I got only
I am using SQL Server 2014.
Thanks in advance
Not directly. Fragmentation exists when the physical order of an index doesn't match the logical order. And that happens when there is need to put data on a page for which there is no room, thus causing a page split. There is an event for page splits. However, I wouldn't use it to track fragmentation in the general case. The event exists more for tracking activity for one-off operations. If you want to look at fragmentation, take a look at sys.dm_db_index_physical_stats.
To add to @Ben Thuls's answer, you may track page splits using extended events and thus track fragmentation indirectly. Check this awesome article by Paul Randal to familiarize yourself with the LOP_DELETE_SPLIT log operation and then create a session which will look like that:
CREATE EVENT SESSION [Page Splits] ON SERVER
ADD EVENT sqlserver.transaction_log(SET collect_database_name = 1
WHERE (operation = $LOP_DELETE_ID$) ) --LOP_DELETE_SPLIT*
ADD TARGET package0.event_file(SET FILENAME = N'PageSplitsOutput.xel',MAX_FILE_SIZE = 200, MAX_ROLLOVER_FILES = 2, INCREMENT = 20)
WITH (MAX_MEMORY=4096 KB,EVENT_RETENTION_MODE=ALLOW_SINGLE_EVENT_LOSS,MAX_DISPATCH_LATENCY=30 SECONDS,MAX_EVENT_SIZE=0 KB,MEMORY_PARTITION_MODE=NONE,TRACK_CAUSALITY=OFF,STARTUP_STATE=OFF);
GO
And fill $LOP_DELETE_ID$ with the result from this:
SELECT *
FROM sys.dm_xe_map_values
WHERE name = 'log_op'
AND map_value = 'LOP_DELETE_SPLIT';
