Since the compression is attribute level. can someone help to locate the
places where i need to add the compression(insert query) and
decompression(select query) codes?
What about writing your compression routines as user-defined data types?
http://db.apache.org/derby/docs/10.8/devguide/cdevspe
Hi,
Since the compression is attribute level. can someone help to locate the
places where i need to add the compression(insert query) and
decompression(select query) codes?
for testing: just add the compression technique to VarChar data types(in
SQLVarchar class), so when calling "insert into my
Derby already does a kind of compression on character strings as its
native in-memory representation of character data is the java 16 bit
standard, but on disk it uses a modified utf8 compression that optimizes
storage for those characters in the ASCII range. This is all handled in
the read and
What I am suggesting is you do compression at insert time and then
decompression would happen anytime you read the data during a select.
This way compress is only done once per instantiation of a row, but
decompress is done every time row is read from page to execution engine.
Note, unless specia
On Tue, Sep 6, 2011 at 11:36 PM, Mike Matrigali wrote:
> The encryption points work at
> a page level and the system counts on the number of bytes being the
> same. The reason being that we find pages by page number * number of
> bytes per page. If you decide to go at it from this level you will
The encryption points work at
a page level and the system counts on the number of bytes being the
same. The reason being that we find pages by page number * number of
bytes per page. If you decide to go at it from this level you will
need to implement an underlying filesystem to map the pages.
Hi Reka,
I would recommend looking at the Derby logic for encrypting databases.
You can probably get column compression to work by putting your
(de)compression logic alongside the (de)encryption touchpoints.
Hope this helps,
-Rick
On 9/6/11 9:21 AM, Reka Thirunavukkarasu wrote:
Hi Rick,
Tha
Hi Rick,
Thank you for your immediate reply.We are trying to achieve attribute
level compression
(in your words more compact storage of columns).Attribute level
compression is best
from the query processing point of view.Attributes fall in to three
major category Integer,
floating point and charact
Hi Reka,
Can you give us more detail about what you are trying to achieve? That
may help us figure out what the right touchpoints are. Are you trying to
achieve any of the following:
1) More aggressive garbage-collection of deleted rows...
2) More compact storage of columns...
3) More compa
