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On 14 Apr 2018, at 19:39, Murthy, Gautham wrote:

Hello,

We have MonetDB open files usage reaching 65k and beyond. How do we minimize the openfiles, We see most of them are mapped to memory. Reading the Monetdb papers will teach you that table columns are memory mapped files. A single database/table with more the 65k hot column/ tables seems like an application design error.

What is the storage(); function?

See documentation

What does the storage() function do when we execute it ? extract state information and makes it available as a table The usage of open files drastically reduced when the select *from storage() was executed on the database. What are the effects of running the select *from storage(); when users are accessing the database? it represents a fluent state

What is the maximum size of database MonetDB can support ? your disks Does running the storage() function when there is a large set of open files crash the database ? not reported Do we need to set any system level parameters ? shmmax, file-max etc., in principle no Do we have any standard settings as prerequisites that needs to be considered if we are hosting databases ranging 1TB to 2TB? none What should be the open files setting if we have 6-10 databases with size ranging from 100GB to 2TB ?

Do we have options to export specific schemas rather that complete database or tables? create SQL scripts Request you to please review and share the above information. Consider contacting Monetdb Solutions for pay by the hour consultancy support by the experts for your specific case. regards, martin

Open files Test Case –

DB size 630Gb Max Open files set to – 65536

[oracle@lnx1386 scripts]$ sh 10min_ofc.sh lsof -u oracle|wc -l Timestamp: 04-14-18 01:56:34 Open Files: 6559 lsof -u oracle|grep -i tcp|wc -l Timestamp: 04-14-18 01:56:34 Open Files Of TCP: 21 lsof -u oracle | grep -i /data/MYDBFARM_DIR/SV11DMP_DBFARM/TSV_PROD_DB | wc -l Timestamp: 04-14-18 01:56:35 Open Files - DB Files : 5864 lsof -u oracle | grep -i protocol: TCP | wc -l Timestamp: 04-14-18 01:56:35 Open Files Of - protocol: TCP : 2 lsof -u oracle | grep -i CLOSE_WAIT | wc –l Timestamp: 04-14-18 01:56:35 Open Files of TCP - CLOSE_WAIT: 0 lsof -u oracle | grep -i ESTABLISHED | wc -l Timestamp: 04-14-18 01:56:36 Open Files Of TCP - ESTABLISHED: 15 netstat -an |grep tcp|wc -l Timestamp: 04-14-18 01:56:36 netstat -an |grep tcp : 62 [oracle@lnx1386 scripts]$ sh /home/oracle/scripts/purge_op_fl.sh 50005 TSV_PROD_DB 1>/home/oracle/scripts/logs/purge_op_fl.stout 2>/home/oracle/scripts/logs/purge_op_fl.sterr [oracle@lnx1386 scripts]$ cat /home/oracle/scripts/purge_op_fl.sh /usr/bin/mclient -p ${1} -d ${2} < /home/oracle/scripts/purge_op_fl.sql [oracle@lnx1386 scripts]$ cat /home/oracle/scripts/purge_op_fl.sql select * from storage(); [oracle@lnx1386 scripts]$ [oracle@lnx1386 scripts]$ sh 10min_ofc.sh lsof -u oracle|wc -l Timestamp: 04-14-18 02:09:49 Open Files: 862 lsof -u oracle|grep -i tcp|wc -l Timestamp: 04-14-18 02:09:49 Open Files Of TCP: 25 lsof -u oracle | grep -i /data/MYDBFARM_DIR/SV11DMP_DBFARM/TSV_PROD_DB | wc -l Timestamp: 04-14-18 02:09:50 Open Files - DB Files : 163 lsof -u oracle | grep -i protocol: TCP | wc -l Timestamp: 04-14-18 02:09:50 Open Files Of - protocol: TCP : 2 lsof -u oracle | grep -i CLOSE_WAIT | wc –l Timestamp: 04-14-18 02:09:50 Open Files of TCP - CLOSE_WAIT: 0 lsof -u oracle | grep -i ESTABLISHED | wc -l Timestamp: 04-14-18 02:09:50 Open Files Of TCP - ESTABLISHED: 19 netstat -an |grep tcp|wc -l Timestamp: 04-14-18 02:09:50 netstat -an |grep tcp : 66 [oracle@lnx1386 scripts]$

Thank You, Gautham _______________________________________________ users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list