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From granthe...@apache.org
Subject [kudu] 01/02: KUDU-2677 Raise default value for --tablet_history_max_age_sec
Date Thu, 09 May 2019 18:56:51 GMT
This is an automated email from the ASF dual-hosted git repository.

granthenke pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/kudu.git

commit fa1e67f19484a94f9e5f266cf5d622c90b6069b6
Author: Will Berkeley <wdberkeley@gmail.com>
AuthorDate: Tue May 7 10:01:50 2019 -0700

    KUDU-2677 Raise default value for --tablet_history_max_age_sec
    
    This raises the default --tablet_history_max_age_sec to 1 week, to
    support incremental backup and the diff scans it relies on.
    
    Raising the default will cause clients to be able to scan further into
    the past, possibly into a region where the data has been GC'd. This
    would result in no rows returned, which might be surprising to some
    users. This condition will be temporary, and will end when the new
    default period has passed. We don't expect this to be a problem because
    we don't think many users are doing scans like this, and if they are
    they probably adjusted --tablet_history_max_age_sec and so won't be
    affected by the change in default. If they want to raise their own
    setting for the flag to accomodate incremental backups then they will
    be able to take steps to mitigate the above issue.
    
    Change-Id: I6398b57ec1abcd12c59a3588dd1a61900c0ccdeb
    Reviewed-on: http://gerrit.cloudera.org:8080/13265
    Reviewed-by: Adar Dembo <adar@cloudera.com>
    Tested-by: Kudu Jenkins
---
 src/kudu/tablet/tablet.cc | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/kudu/tablet/tablet.cc b/src/kudu/tablet/tablet.cc
index 7627ed4..7cb1053 100644
--- a/src/kudu/tablet/tablet.cc
+++ b/src/kudu/tablet/tablet.cc
@@ -134,11 +134,13 @@ DEFINE_double(tablet_throttler_burst_factor, 1.0f,
              "base rate.");
 TAG_FLAG(tablet_throttler_burst_factor, experimental);
 
-DEFINE_int32(tablet_history_max_age_sec, 15 * 60,
-             "Number of seconds to retain tablet history. Reads initiated at a "
-             "snapshot that is older than this age will be rejected. "
-             "To disable history removal, set to -1.");
+DEFINE_int32(tablet_history_max_age_sec, 60 * 60 * 24 * 7,
+             "Number of seconds to retain tablet history, including history "
+             "required to perform diff scans and incremental backups. Reads "
+             "initiated at a snapshot that is older than this age will be "
+             "rejected. To disable history removal, set to -1.");
 TAG_FLAG(tablet_history_max_age_sec, advanced);
+TAG_FLAG(tablet_history_max_age_sec, stable);
 
 DEFINE_int32(max_cell_size_bytes, 64 * 1024,
              "The maximum size of any individual cell in a table. Attempting to store "


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