tag:blogger.com,1999:blog-5124641802818980374.post1565108134090537496..comments2023-09-06T11:58:30.752+02:00Comments on Oracle related stuff: Oracle Database Cloud (DBaaS) Performance - Part 3 - Storage - 12.2 UpdateUnknownnoreply@blogger.comBlogger2125tag:blogger.com,1999:blog-5124641802818980374.post-74197118307831786952017-02-01T00:36:33.298+01:002017-02-01T00:36:33.298+01:00Hi Mikhail,
I haven't checked this too thorou...Hi Mikhail,<br /><br />I haven't checked this too thoroughly but according to the session stats it looks like in 12.2 the same code just shows far less "db block changes", "undo change vector size", "redo size" etc., but no other stats that increase accordingly. So it's just doing less work without showing why - please note that I can't say whether this is intended behaviour or a bug.<br /><br />RandolfRandolfhttps://www.blogger.com/profile/13463198440639982695noreply@blogger.comtag:blogger.com,1999:blog-5124641802818980374.post-21929901083417609932017-01-30T08:43:29.198+01:002017-01-30T08:43:29.198+01:00Hi Randolf,
Note that the version 12.2 obviousl...Hi Randolf,<br /><br /><i><br /> Note that the version 12.2 obviously introduces an optimization that treats repeated modifications of the same kind to the same block (in this case here update a column of a row to the same value as before) not as a "db block change", therefore I had to adjust the test to update the column value to a different value each time. Running the original test case showed a totally different profile, due the minimized "db block changes".<br /></i><br /><br />Could you please elaborate on this change: Is this counting in 12.2 under a different statistic?<br /><br />RegardsMikhail Velikikhhttps://www.blogger.com/profile/12809585068205118395noreply@blogger.com