Re: [htdig-dev] Compression related performance

[Jim <li...@yg...>]

On Sat, 15 Jan 2005, Neal Richter wrote:

> Jim,
> Thanks for the numbers.  Pretty different from Joe's.
>
> Question #1)
>
>   Could you download a fresh copy of BDB 3.0.55 from
> http://www.sleepycat.com/download/index.shtml
>
> It's easy to build, I am most interested in the results when you run db_stat 
> on the uncompressed files and report back the fill-factor.  This is a measure 
> of wasted space in the BDB pages.  This won't work on the compressed index.

#> db_stat -d db.words.db
53162   Btree magic number.
7       Btree version number.
Flags:
2       Minimum keys per-page.
8192    Underlying database page size.
4       Number of levels in the tree.
9069906 Number of keys in the tree.
282     Number of tree internal pages.
703316  Number of bytes free in tree internal pages (70% ff).
52945   Number of tree leaf pages.
188M    Number of bytes free in tree leaf pages (57% ff).
0       Number of tree duplicate pages.
0       Number of bytes free in tree duplicate pages (0% ff).
0       Number of tree overflow pages.
0       Number of bytes free in tree overflow pages (0% ff).
0       Number of pages on the free list.

> Question #2)
> What page_size are you using?

8192.

> Question #3)
> Do you ever see any errors when using the compressed index?

No. I have never seen it myself with 3.2.0b6. In addition to this
database, I maintain several others that are much larger and always built
with compression enabled.

Jim