From bc9ec181e2e5a273fb335d68df7beefeac48a8f6 Mon Sep 17 00:00:00 2001 From: Ronnie Sahlberg Date: Tue, 20 Mar 2012 17:07:13 +1100 Subject: STICKY document the sticky record parameters (This used to be ctdb commit e6a8306257dece02313043274789b52cef1a5647) --- ctdb/doc/ctdbd.1.xml | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/ctdb/doc/ctdbd.1.xml b/ctdb/doc/ctdbd.1.xml index 0cf365a54f..cf5b142c2b 100644 --- a/ctdb/doc/ctdbd.1.xml +++ b/ctdb/doc/ctdbd.1.xml @@ -930,6 +930,41 @@ + HopcountMakeSticky + Default: 50 + + If the database is set to 'STICKY' mode, using the 'ctdb setdbsticky' + command, any record that is seen as very hot and migrating so fast that + hopcount surpasses 50 is set to become a STICKY record for StickyDuration + seconds. This means that after each migration the record will be kept on + the node and prevented from being migrated off the node. + + + This setting allows to try to identify such records and stop them from + migrating across the cluster so fast. This will improve performance for + certain workloads, such as locking.tdb if many clients are opening/closing + the same file concurrently. + + + + StickyDuration + Default: 600 + + Once a record has been found to be fetch-lock hot and has been flagged to + become STICKY, this is for how long, in seconds, the record will be + flagged as a STICKY record. + + + + StickyPindown + Default: 200 + + Once a STICKY record has been migrated onto a node, it will be pinned down + on that node for this number of ms. Any request from other nodes to migrate + the record off the node will be deferred until the pindown timer expires. + + + MaxLACount Default: 20 -- cgit