Re: Are Unix tools just slow?

Centuries ago, Nostradamus foresaw when "Daniel P. Zepeda" <[e-mail]> would write:
> On Sat, 15 Jun 2002 14:34:17 +0900
> Christopher Browne <[e-mail]> wrote:
>
>> A long time ago, in a galaxy far, far away, "Daniel P. Zepeda"
>> <[e-mail]> wrote:> I guess my real contribution to this
>> thread: I recently saw a post about> Ruby FAM. I thought it would be
>> cool to write a tool that kept the> filesystem information in an RDBMS,
>> like PostgreSQL, using FAM to keep it> updated, and also giving the
>> ability to update the actual filesystem when> the database is updated.
>> It would be really fast and easy to use with a> lot more features when
>> compared to slocate. I've started to give it a> shot, but what do you
>> all think? 
>> 
>> I think what you'd find is that the first time you did 
>>   SELECT * FROM FILES
>> it would be about as slow as running "find -print /" the first time.
>
> I agree. But I think you missed the point. It would only have to traverse
> the filesystem once, on installation, then after that FAM would keep it
> updated. 

No, I'm not missing the point.  I'm adding one that you seem to be missing.

In both cases, it would be necessary to pull a similar number of
blocks of data from disk, because in both cases, there is a database
being treated as a directory structure.

In the case of the SQL database, there might be _some_ savings in
time, from two persectives:

 a) The set of disk blocks might be somewhat more compact; 

 b) If a selection criterion was being used that would allow only
    selecting a tiny subset, then only part of the data would get
    searched.  

Of course, b) isn't the case in "SELECT * FROM FILES".

If an SQL database is being used, then perhaps the _filesystem_
doesn't have to get traversed, but that certainly doesn't eliminate
the need to traverse the _database_.

And if the database contains much the same set of data (which it
does), organized in a manner not vastly dissimilar (which would be the
case), then the differences in behaviour won't be vastly different.

Creating a DBMS doesn't magically save you time.  It comes at a cost.
Querying a database comes at a cost too.
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