andrey, svilen, many thanks again.
agreed, storing immediate children in a document is a bad idea. i think
i go for storing only an immediate parent id to get an infinite tree depth.
thanks for your inspirations guys
cheers
michael
On 22/02/13 18:49, Andrey Kuprianov wrote:
PS - storing only an immediate parent id would be the solution for an
infinite tree depth.
On Fri, Feb 22, 2013 at 1:48 PM, Andrey Kuprianov <
[email protected]> wrote:
Storing immediate children in a parent is a bad idea in a sense that you
will never be able to traverse your tree back to the root, given a child
node.
Storing all in one doc - you will run out of space before you know it.
Documents have a finite length and the larger the document, the slower it
will get to serialize and unserialize it.
Storing just an immediate parent in children might result in a costly
multiple read operations, if you want to get root of the tree given an
arbitrary child.
Therefore the only feasible solution is to store references to the parent
chain - i.e. ancestors - starting from an immediate parent and ending with
a tree root.
Here's a simple calculation for ancestors approach:
Suppose the maximum document size is 1MB. A uuid is 32 characters in
length + taking into account commas and brackets, then the depth of your
tree (I am not taking content into account) could be roughly:
((32 + 1)*n + 2 - 1) = 1024 * 1024 ==> n = 31775 levels
However, max document size is configurable from the settings (as of
CouchDB 1.2) and could easily be up to 4GB, giving you over 130mil of
levels. Should be enough... :)
On Fri, Feb 22, 2013 at 1:14 PM, Michael Heuberger <
[email protected]> wrote:
thanks andrey and svil
depth is infinite. in theory a message can have million replies forth and
back. similar like a very long email thread.
i think storing ancestors ą la andrey would be too much hassle but works
well for few levels.
svil, what did you mean with dicts and with keeping all children in one
doc? can you tell me more?
thanks,
michael
On 22/02/13 17:27, svilen wrote:
my rough guess:
if it's finite depth, then all in one doc:
- list of (item or (list of ...))
- or same with dicts
else, one doc per message keeping just link-to-parent,
or multiple links-to-grand...grand-parents and/or root.
similar to the strategies in SQL - nested etc.
keeping all chidlren of same node in one doc is also possible..
in any case either traversal or storing or both will be
difficult.
ciao
svil
On Fri, 22 Feb 2013 17:13:01 +1300
Michael Heuberger
<michael.heuberger@**binarykitchen.com<[email protected]>>
wrote:
Hello guys
I'd like to store messages in a tree like structure. Whenever you
reply to a message, then the original message becomes the parent
message.
How would you implement something like this in CouchDB? Just curious
and need a little guidance + advice here.
Thanks,
Michael
--
Binary Kitchen
Michael Heuberger
4c Dunbar Road
Mt Eden
Auckland 1024
(New Zealand)
Mobile (text only) ... +64 21 261 89 81
Email ................ [email protected]
Website .............. http://www.binarykitchen.com
--
Binary Kitchen
Michael Heuberger
4c Dunbar Road
Mt Eden
Auckland 1024
(New Zealand)
Mobile (text only) ... +64 21 261 89 81
Email ................ [email protected]
Website .............. http://www.binarykitchen.com
--
Binary Kitchen
Michael Heuberger
4c Dunbar Road
Mt Eden
Auckland 1024
(New Zealand)
Mobile (text only) ... +64 21 261 89 81
Email ................ [email protected]
Website .............. http://www.binarykitchen.com
