This tool may be useful for you to trouble shoot your problems away.
https://www.javacodegeeks.com/2020/04/simplifying-apm-remove-the-guesswork-from-troubleshooting.html "APM tools typically use a waterfall-type view to show the blocking time of different components cascading through the control flow within an application. These types of visualizations are useful, and AppOptics has them, but they can be difficult to understand for those of us without a PhD." Especially helpful if you want to understand through visualisation and you do not have a phD. Jane thorpe janethor...@aol.com -----Original Message----- From: jane thorpe <janethor...@aol.com.INVALID> To: mich.talebzadeh <mich.talebza...@gmail.com>; liruijing09 <liruijin...@gmail.com>; user <user@spark.apache.org> CC: user <user@spark.apache.org> Sent: Sun, 12 Apr 2020 4:35 Subject: Re: Spark hangs while reading from jdbc - does nothing You seem to be implying the error is intermittent. You seem to be implying data is being ingested via JDBC. So the connection has proven itself to be working unless no data is arriving from the JDBC channel at all. If no data is arriving then one could say it could be the JDBC.If the error is intermittent then it is likely a resource involved in processing is filling to capacity. Try reducing the data ingestion volume and see if that completes, then increase the data ingested incrementally.I assume you have run the job on small amount of data so you have completed your prototype stage successfully. On Saturday, 11 April 2020 Mich Talebzadeh <mich.talebza...@gmail.com> wrote: Hi, Have you checked your JDBC connections from Spark to Oracle. What is Oracle saying? Is it doing anything or hanging? set pagesize 9999 set linesize 140 set heading off select SUBSTR(name,1,8) || ' sessions as on '||TO_CHAR(CURRENT_DATE, 'MON DD YYYY HH:MI AM') from v$database; set heading on column spid heading "OS PID" format a6 column process format a13 heading "Client ProcID" column username format a15 column sid format 999 column serial# format 99999 column STATUS format a3 HEADING 'ACT' column last format 9,999.99 column TotGets format 999,999,999,999 HEADING 'Logical I/O' column phyRds format 999,999,999 HEADING 'Physical I/O' column total_memory format 999,999,999 HEADING 'MEM/KB' -- SELECT substr(a.username,1,15) "LOGIN" , substr(a.sid,1,5) || ','||substr(a.serial#,1,5) AS "SID/serial#" , TO_CHAR(a.logon_time, 'DD/MM HH:MI') "LOGGED IN SINCE" , substr(a.machine,1,10) HOST , substr(p.username,1,8)||'/'||substr(p.spid,1,5) "OS PID" , substr(a.osuser,1,8)||'/'||substr(a.process,1,5) "Client PID" , substr(a.program,1,15) PROGRAM --,ROUND((CURRENT_DATE-a.logon_time)*24) AS "Logged/Hours" , ( select round(sum(ss.value)/1024) from v$sesstat ss, v$statname sn where ss.sid = a.sid and sn.statistic# = ss.statistic# and -- sn.name in ('session pga memory') sn.name in ('session pga memory','session uga memory') ) AS total_memory , (b.block_gets + b.consistent_gets) TotGets , b.physical_reads phyRds , decode(a.status, 'ACTIVE', 'Y','INACTIVE', 'N') STATUS , CASE WHEN a.sid in (select sid from v$mystat where rownum = 1) THEN '<-- YOU' ELSE ' ' END "INFO" FROM v$process p ,v$session a ,v$sess_io b WHERE a.paddr = p.addr AND p.background IS NULL --AND a.sid NOT IN (select sid from v$mystat where rownum = 1) AND a.sid = b.sid AND a.username is not null --AND (a.last_call_et < 3600 or a.status = 'ACTIVE') --AND CURRENT_DATE - logon_time > 0 --AND a.sid NOT IN ( select sid from v$mystat where rownum=1) -- exclude me --AND (b.block_gets + b.consistent_gets) > 0 ORDER BY a.username; exit HTH Dr Mich Talebzadeh LinkedIn https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw http://talebzadehmich.wordpress.com Disclaimer: Use it at your own risk. Any and all responsibility for any loss, damage or destructionof data or any other property which may arise from relying on this email's technical content is explicitly disclaimed.The author will in no case be liable for any monetary damages arising from suchloss, damage or destruction. On Fri, 10 Apr 2020 at 17:37, Ruijing Li <liruijin...@gmail.com> wrote: Hi all, I am on spark 2.4.4 and using scala 2.11.12, and running cluster mode on mesos. I am ingesting from an oracle database using spark.read.jdbc. I am seeing a strange issue where spark just hangs and does nothing, not starting any new tasks. Normally this job finishes in 30 stages but sometimes it stops at 29 completed stages and doesn’t start the last stage. The spark job is idling and there is no pending or active task. What could be the problem? Thanks.-- Cheers,Ruijing Li
