[RN 2.0.2 + Doc] Change in Metadata Overhead

From: Perry Krug <perry@couchbase.com>
Date: Tuesday, April 30, 2013 2:55 AM
To: Karen Zeller <karen.zeller@couchbase.com>
Subject: Fwd: New metadata amount?

Karen, just wanted to check whether this change was on your radar for 2.0.2 already

Always Scalable, Always On NoSQL

Perry Krug
Sr. Solutions Architect
+44.7445.029287
perry@couchbase.com

---------- Forwarded message ----------
From: Mike Wiederhold <mike@couchbase.com>
Date: Tue, Apr 23, 2013 at 5:39 PM
Subject: Re: New metadata amount?
To: Perry Krug <perry@couchbase.com>

The meta data overhead in 2.0.2 is 56 bytes whether an item is resident or non-resisdent. I removed the dirtiness from the meta data and we do not write this to disk right now, but there is a bug filed to persist this information.

• Mike

On Apr 23, 2013, at 2:52 AM, Perry Krug <perry@couchbase.com> wrote:

Hey Mike, do we have a newly revised number for the per-item metadata overhead in RAM? If I recall correctly, it was about 64 bytes as of 1.8.1...and a bunch of stuff has been removed in 2.0.2. So it it lower?

Also, the stuff that got removed...am I correct in understanding that it still gets written to disk? So is there a larger amount of overhead when an item is resident in RAM in addition to the actual key and value?

RAM used when resident = length of key + size of value + metadata (64bytes or more?)
RAM used when not resident = length of key + metadata (64 bytes or less?)

Thanks

Perry

Always Scalable, Always On NoSQL

Perry Krug
Sr. Solutions Architect
+44.7445.029287
perry@couchbase.com