+++ This bug was initially created as a clone of Bug #1240577 +++ Description of problem: ======================= When a file is being continuously modified or written to, data base locks are being observed as below [2015-07-07 12:46:00.025876] E [MSGID: 101106] [gfdb_sqlite3.c:694:gf_sqlite3_find_recently_chan ged_files] 0-sqlite3: Failed preparing statment select GF_FILE_TB.GF_ID, (select group_concat( G F_PID || ',' || FNAME || ',' || FPATH || ',' || W_DEL_FLAG ||',' || LINK_UPDATE , '::') from GF_ FLINK_TB where GF_FILE_TB.GF_ID = GF_FLINK_TB.GF_ID) from GF_FILE_TB where ((GF_FILE_TB.W_SEC * 1000000 + GF_FILE_TB.W_MSEC) >= ? ) OR ((GF_FILE_TB.W_READ_SEC * 1000000 + GF_FILE_TB.W_READ_MS EC) >= ?) : database is locked Due to this a file getting continuosly written is being demoted unncessarily Version-Release number of selected component (if applicable): ========================================================== [root@nchilaka-tier01 ~]# gluster --version glusterfs 3.7.1 built on Jul 2 2015 21:01:51 Repository revision: git://git.gluster.com/glusterfs.git Copyright (c) 2006-2011 Gluster Inc. <http://www.gluster.com> GlusterFS comes with ABSOLUTELY NO WARRANTY. You may redistribute copies of GlusterFS under the terms of the GNU General Public License. [root@nchilaka-tier01 ~]# rpm -qa|grep gluster gluster-nagios-common-0.2.0-1.el6rhs.noarch vdsm-gluster-4.16.20-1.2.el6rhs.noarch glusterfs-client-xlators-3.7.1-7.el6rhs.x86_64 glusterfs-server-3.7.1-7.el6rhs.x86_64 nfs-ganesha-gluster-2.2.0-3.el6rhs.x86_64 python-gluster-3.7.1-6.el6rhs.x86_64 glusterfs-3.7.1-7.el6rhs.x86_64 glusterfs-api-3.7.1-7.el6rhs.x86_64 glusterfs-cli-3.7.1-7.el6rhs.x86_64 glusterfs-geo-replication-3.7.1-7.el6rhs.x86_64 glusterfs-rdma-3.7.1-7.el6rhs.x86_64 gluster-nagios-addons-0.2.4-2.el6rhs.x86_64 glusterfs-libs-3.7.1-7.el6rhs.x86_64 glusterfs-fuse-3.7.1-7.el6rhs.x86_64 glusterfs-ganesha-3.7.1-7.el6rhs.x86_64 Steps to Reproduce: ================== 1.create a tiered volume 2.set the tier vol options 3.now create a file and keep appending lines in a loop as below `for in in {0..1000000};do echo "hello world" >>file1 ;done` 4. Check the tier.log and it can be seen that database lock messages would be thrown sos report server rhsqe-repo.lab.eng.blr.redhat.com:/home/repo/sosreports/bug.1240569 --- Additional comment from Joseph Elwin Fernandes on 2015-07-07 05:58:29 EDT --- The reason this happens is in WAL mode opening a new db connection is an expensive operation as it will try to a lock on the WAL file(even though for a short time). The migration process opens a new connection per brick per promotion/demotion cycle. This is bad scheme. Solution: 1) Create a new connection only in tier_init per brick and have the connection alive and use it for every promotion/demotion 2) Enable pooling (Pooling=True in the connection string) when the connection is established, there isn't any locking of WAL file, because existing connections are reused internal to sqlite. http://dev.yorhel.nl/doc/sqlaccess --- Additional comment from Vijay Bellur on 2015-09-19 12:09:28 EDT --- REVIEW: http://review.gluster.org/12191 (tier/ctr: Solution for db locks for tier migrator and ctr using sqlite version less than 3.7 i.e rhel 6.7) posted (#2) for review on master by Joseph Fernandes --- Additional comment from Vijay Bellur on 2015-09-19 14:04:56 EDT --- REVIEW: http://review.gluster.org/12191 (tier/ctr: Solution for db locks for tier migrator and ctr using sqlite version less than 3.7 i.e rhel 6.7) posted (#3) for review on master by Joseph Fernandes
*** Bug 1265399 has been marked as a duplicate of this bug. ***
COMMIT: http://review.gluster.org/12325 committed in release-3.7 by Dan Lambright (dlambrig) ------ commit 489f02879afd940d201d092720dbf13b2922b134 Author: Joseph Fernandes <josferna> Date: Fri Sep 18 19:57:54 2015 +0530 tier/ctr: Solution for db locks for tier migrator and ctr using sqlite version less than 3.7 i.e rhel 6.7 Problem: On RHEL 6.7, we have sqlite version 3.6.2 which doesnt support WAL journaling mode, as this journaling mode is only available in sqlite 3.7 and above. As a result we cannot have to progreses concurrently accessing sqlite, without running into db locks! Well WAL is also need for performace on CTR side. Solution: This solution is to use CTR db connection for doing queries when WAL mode is absent. i,e tier migrator will send sync_op ipc calls to CTR, which in turn will do the query and create/update the query file suggested by tier migrator. Pending: Well this solution will stop the db locks but the performance is still an issue for CTR. We are developing an in-Memory Transaction Log (iMeTaL) which will help boost the CTR performance by doing in memory udpates on the IO path and later flush the updates to the db in a batch/segment flush. Master patch: http://review.gluster.org/#/c/12191 >> Change-Id: Ie3149643ded159234b5cc6aa6cf93b9022c2f124 >> BUG: 1240577 >> Signed-off-by: Joseph Fernandes <josferna> >> Signed-off-by: Dan Lambright <dlambrig> >> Signed-off-by: Joseph Fernandes <josferna> >> Reviewed-on: http://review.gluster.org/12191 >> Tested-by: Gluster Build System <jenkins.com> >> Reviewed-by: Luis Pabon <lpabon> Signed-off-by: Joseph Fernandes <josferna> Change-Id: Ie8c7a7e9566244c104531b579126bb57fbc6e32b BUG: 1270123 Reviewed-on: http://review.gluster.org/12325 Tested-by: NetBSD Build System <jenkins.org> Tested-by: Gluster Build System <jenkins.com> Reviewed-by: Dan Lambright <dlambrig> Tested-by: Dan Lambright <dlambrig>
This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-3.7.6, please open a new bug report. glusterfs-3.7.6 has been announced on the Gluster mailinglists [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution. [1] http://www.gluster.org/pipermail/gluster-users/2015-November/024359.html [2] http://thread.gmane.org/gmane.comp.file-systems.gluster.user