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                              WORKLOG TASK
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
TASK...........: Unused
CREATION DATE..: Sun, 14 Feb 2010, 00:17
SUPERVISOR.....: Monty
IMPLEMENTOR....: Igor
COPIES TO......: Igor, Monty, Sergei
CATEGORY.......: Server-Sprint
TASK ID........: 86 (http://askmonty.org/worklog/?tid=86)
VERSION........: Server-5.2
STATUS.........: Assigned
PRIORITY.......: 60
WORKED HOURS...: 0
ESTIMATE.......: 80 (hours remain)
ORIG. ESTIMATE.: 80

PROGRESS NOTES:

-=-=(Igor - Tue, 16 Mar 2010, 19:30)=-=-
Title modified.
--- /tmp/wklog.86.old.22309     2010-03-16 19:30:04.000000000 +0000
+++ /tmp/wklog.86.new.22309     2010-03-16 19:30:04.000000000 +0000
@@ -1 +1 @@
-Partitioned Key Cache for MyISAM
+Unused

-=-=(Igor - Tue, 16 Mar 2010, 19:29)=-=-
High Level Description modified.
--- /tmp/wklog.86.old.22292     2010-03-16 19:29:37.000000000 +0000
+++ /tmp/wklog.86.new.22292     2010-03-16 19:29:37.000000000 +0000
@@ -1,19 +1 @@
-A partitioned key cache is a collection of structures for regular MyiSAM key
-caches called key cache partitions. Any page from a file can be placed into a
-buffer of only one partition. The number of the partition is calculated from the
-file number and the position of the page in the file, and it's always the same
-for the page. The function that maps pages into partitions takes care of even
-distribution of pages among partitions.
 
-Partition key cache mitigate one of the major problem of simple key cache:
-thread contention for key cache lock (mutex). Every call of a key cache
-interface function must acquire this lock. So threads compete for this lock even
-in the case when they have acquired shared locks for the file and pages they
-want read from are in the key cache buffers. When working with a partitioned key
-cache any key cache interface function that needs only one page has to acquire
-the key cache lock only for the partition the page is ascribed to. This makes
-the chances for threads not compete for the same key cache lock better.
-
-The idea and the original of the partitioned key cache was provided by one of
-our external contributers (see the attached file segmented_keycache_v2.diff with
-the original patch from the contributor).

-=-=(Igor - Sun, 14 Feb 2010, 00:19)=-=-
Privacy level updated.
--- /tmp/wklog.86.old.10092     2010-02-13 22:19:03.000000000 +0000
+++ /tmp/wklog.86.new.10092     2010-02-13 22:19:03.000000000 +0000
@@ -1 +1 @@
-y
+n

-=-=(Igor - Sun, 14 Feb 2010, 00:19)=-=-
Category updated.
--- /tmp/wklog.86.old.10092     2010-02-13 22:19:03.000000000 +0000
+++ /tmp/wklog.86.new.10092     2010-02-13 22:19:03.000000000 +0000
@@ -1 +1 @@
-Server-BackLog
+Server-Sprint

-=-=(Igor - Sun, 14 Feb 2010, 00:18)=-=-
Version updated.
--- /tmp/wklog.86.old.10044     2010-02-14 00:18:31.000000000 +0200
+++ /tmp/wklog.86.new.10044     2010-02-14 00:18:31.000000000 +0200
@@ -1 +1 @@
-Benchmarks-3.0
+Server-5.2



DESCRIPTION:




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