Like I said, I roll my own DAO because its always going to be more
efficient, if done properly. ;-)
With respect to ease of use, I'm confused.
You only need to figure out the metadata once. It won't change, if rarely.
Then you can reuse it all the time.
All databases (relational databases) have
This is also true.
Can you 'detatch' your index? By this I mean store the index on a different
disk?
Also what type/size machine are you running your query on? How much memory?
What else is in the table? Are the rows fat?
HTH to point you down a possible decision path.
-Mikey
> -Original
> -Original Message-
> From: Arnaud Masson [mailto:amas...@gmail.com]
> Sent: Monday, May 04, 2009 8:04 AM
> To: Derby Discussion
> Subject: Re: Many background threads (rawStoreDaemon)
>
> de...@segel.com a écrit :
> >
> >> -Original Message-
> >>
> I have an application th
See my comments mixed in...
Just a caveat, you're right, I don't know your entire application, I'm just
looking at it from what little information you have shared in your posts
> -Original Message-
> From: Mikkel Kamstrup Erlandsen [mailto:m...@statsbiblioteket.dk]
> Sent: Tuesday, J
> -Original Message-
> From: knut.hat...@sun.com [mailto:knut.hat...@sun.com]
> Sent: Tuesday, January 13, 2009 4:59 AM
> To: Derby Discussion
> Subject: Re: Bad performance with UPDATE on a nested SELECT
[SNIP]
> Yes, it looks like the same query plan. I see the following problems
> with
Ok,
So the fact that even on a single table, it looks like your results are in
order of your identity index and it ignores the order by clause.
Your second index on the value doesn't appear to be used unless it's a
filter before the join and then the join uses the identity index.
> -Origin
Since you're a bit cryptic..
On Table A, you show Col_x_ID, but in your foreign key, you show Col_x. I'm
going to assume that you meant Col_x_ID.
On Table A, do you have an index on Col_x_ID? Is Col_x_ID a unique ID? If
so, is this the primary key for the table?
That would be the first
You're not returning a "part of the filesystem" but just a string that
contains the path to the file object.
_
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Friday, May 23, 2008 4:29 PM
To: Derby Discussion
Subject: Re: How to store many large files in the database?
T
on *very* badly performing query
Hi Michael,
Michael Segel wrote:
The short simple answer. You get what you pay for.
The longer answer. Query optimization is a black art. Cloudscape was
designed as a lightweight no frills embeddable DB.
Now you Cloudscape morphed in to Derby and JavaDB
> -Original Message-
> From: Bill Shannon [mailto:[EMAIL PROTECTED]
> Sent: Saturday, June 16, 2007 12:04 AM
> To: Derby Discussion
> Subject: Re: User/password encryption and deployment
>
> [EMAIL PROTECTED] wrote:
> > Maybe I am missing something but what exactly are you encrypting?
>
ROTECTED]
> Sent: Sunday, May 27, 2007 9:45 PM
> To: Derby Discussion
> Subject: Re: license question
>
> Michael Segel wrote:
> ...
> > Derby is licensed under the Apache license.
> >
> > Its pretty much open. You can do pretty much anything you want, as long
> -Original Message-
> From: Damian C [mailto:[EMAIL PROTECTED]
> Sent: Sunday, May 27, 2007 7:44 PM
> To: derby-user@db.apache.org
> Subject: Fwd: license question
>
> Jim,
> This can be tricky. I am not a lawyer - but this is my understanding
> of the situation.
[SNIP]license.
>
> Der
Well...
You could open a connection to your oracle database, then open a connection to
your derby database.
Select from oracle and then insert into derby...
(You could build on this to add commits and table locking...)
You could write your own loader to use a single thread to read from the flat
Roll over and dies?
The OP's question was could Derby handle a billion or more rows.
The answer is that it depends.
At the same time, a table with a billion rows will be less efficient than a
table with a million rows. So the first question is why a billion rows in a
single table?
To your point
t: Saturday, February 17, 2007 6:19 PM
>> To: Derby Discussion
>> Subject: Re: Multiple transactions and unexpected permanent row
>> lock in
>> SYSCOLUMNS table
>>
>>
>> On Feb 18, 2007, at 1:10 AM, Michael Segel wrote:
>>
>>&g
Making a big assumption...
If each thread has its own connection, you will be blocked on your identity
column.
But you shouldn't be blocked longer than it takes to get the identity value.
100 threads w n records per transaction? How much memory have you allocated to
your app? And is the app o
conclusion that most of
the time is lost making random i/o request for the data thats why i am trying
to keep the table sorted. since sequential hard disk access is much faster than
random i/o .
On Feb 6, 2007, at 8:09 AM, Michael Segel wrote:
What exactly are you trying to do?
Based
For example, search your documents where the wordID is the integer look up for
the word "the".
Do you see the problem?
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
derby [EMAIL PROTECTED]
(312) 952-8175 [mobile]
The trouble with stored procedures is that the performance boost depends on a
couple of factors.
It also depemds on the complexity of the business logic that you want to
incorporate in to the stored procedure.
But even still, the benefits of using stored procedures comes from having your
busin
I'm not sure where that came from, however I'm sure its somewhere on the wish
list.
Since the boolean type has been around for a while, and its implemented in
other databases, its not out of the realm of being added.
With respect to java objects, what are they?
Note: that was a rhetorical que
I'll have to check it out.
Derby, however has some additional parameters since it is also a commercial
product where Sun and IBM are providing paid for support services.
That's a dynamic that may impact the user community, along with licensing
terms, and product niche.
One may be more interest
What did you expect from Oracle?
That's right... You worked for Sun so you missed out on their routine FUD and
spin campaigns. :-P
Liesure suit Larry, can't be trusted on almost evrything he says.
Talk to most of the heritage informix types and they could tell you some
interesting fud stories
Can you provide the query?
1800 items in an IN clause?
That doesn't sound right or efficient.
Why not use a subselect?
> -Original Message-
> From: Robert Enyedi [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, November 14, 2006 9:51 AM
> To: Derby Discussion
> Subject: Large IN clause produce
Cute. Now if you said that SPAM was high in sodium, hence bad for you,
Then you'd be in hot water with hormel...
:-)
Back to being serious for a moment.
I try to set up aliases for each time I join a mailing list, or sign up for a
web page.
So when I get spam to that address, I know where the l
It sounds like a java error. Does the LONGVARCHAR overload the comparesTo()
method?
Sent via BlackBerry.
-Mike Segel
Principal
MSCC
312 952 8175
-Original Message-
From: "Sisilla Sookdeo" <[EMAIL PROTECTED]>
Date: Fri, 10 Nov 2006 14:29:03
To:
Subject: comparisons are not supported for
ut to be useful.
-- Original message --
From: "Michael Segel" <[EMAIL PROTECTED]>
> Let me clarify.
> the original poster is trying to use a yugo to pull a loaded semi up a steep
> hill.
Well,
Sort of.
I was being a tad sarcastic.
Yes you could create a poor man's mpp with derby, however it would involve
writing a preproceesor control node.
Something for a grad student to work on.
You could implement the concept of table partitioning as well.
It would be simpler to implement b
sible solution
out of hand without at least some sort of vague and reasonable explanation.
Donald
-- Original message --
From: "Michael Segel" <[EMAIL PROTECTED]>
>
> Not a good idea to use multiple files.
> Why not go all the way and make
Sorry for top post, using my crack berry.
Not a good idea to use multiple files.
Why not go all the way and make derby in to an mpp db? All you would have to do
is to preprocess the inbound query then send it off to all of the nodes, taking
the result set(s) in to a local temp file and then post
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Sent: Sunday, November 05, 2006 3:49 PM
> To: Derby Discussion
> Subject: Re: does Derby has some form of performance problem ?
>
> legolas wood wrote (2006-11-03 14:46:10):
> > Hi
> > Thank you for r
Just a hunch...
Some of your fields will get rounded up to the nearest word size.
Assume word size to be 8 bytes.
So you would have
5*8 for your big ints
3*8 for your small ints
14 rounded to nearest word size = 24
Plus 16 bytes for the pointer to the rest of the varchar.
And 16 for the time st
> -Original Message-
> From: Jean T. Anderson [mailto:[EMAIL PROTECTED]
> Sent: Sunday, October 29, 2006 1:32 PM
> To: Derby Discussion
> Subject: Re: multiple webapps many embedded vs single network
>
> Michael Segel wrote:
> ...
> > Derby wasn't d
t in that role. Note: This is in comparison to IDS, DB2, Oracle.
Derby is not one of those. It lacks the features that they have to act as a
centralized DB, however it does have a much smaller footprint.
Does that help?
>
> Michael Segel-2 wrote:
> >
> > Depends on
Depends on how tightly coupled the web apps are.
Also how tightly do you want to couple the database to the app...
Suppose at a later date you have some growth. You need to move some of your
apps to a new machine.
What do you do?
Sent via BlackBerry.
-Mike Segel
Principal
MSCC
312 952 8175
Yes.
If your PK is colA,colB,colZ then in your where clause use
WHERE colA=?
AND colB=?
AND colZ=?
Followed by the rest of your where clause. The optimizer should then choose
the pk index.
Sent via BlackBerry.
-Mike Segel
Principal
MSCC
312 952 8175
-Original Message-
From: Legolas w
> -Original Message-
> From: Dan Scott [mailto:[EMAIL PROTECTED]
> Sent: Monday, October 16, 2006 6:45 AM
> To: Derby Discussion
> Cc: [EMAIL PROTECTED]
> Subject: Re: Is it Possible to Turn off Referential Constraints for a
> DBUNIT Load?
>
[SNIP]
> And to be fair, DB2 and Oracle offer
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chris Barham
> Sent: Thursday, October 12, 2006 7:32 PM
> To: derby-user@db.apache.org
> Subject: Is it Possible to Turn off Referential Constraints for a DBUNIT
> Load?
>
> Hi,
>
> When using DBUnit to
Concurrency may have some drawbacks, if you end up holding the transaction
as you attempt to write to both databases...
If I understood the initial request, try creating an after transaction
trigger(s) on a table that you want to replicate. Have the trigger call an
SP that writes a record to a log
I believe that this is a known Derby defect.
Does anyone know if this is fixed in the
upcoming release?
From: Christine
Johnson [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 20,
2006 3:48 PM
To: Derby
Discussion
Subject: Performance of IN
operator
Hello, f
> -Original Message-
> From: Radek Terber [mailto:[EMAIL PROTECTED]
> Sent: Monday, September 18, 2006 11:21 AM
> To: Derby Discussion
> Subject: Re: Insert large using SQL
>
> Michael Segel wrote:
> >> -Original Message-
> >> From
> -Original Message-
> From: Radek Terber [mailto:[EMAIL PROTECTED]
> Sent: Monday, September 18, 2006 10:56 AM
> To: Derby Discussion
> Subject: Re: Insert large using SQL
>
> Michael Segel wrote:
> >
> >> -Original Message-
> >>
> -Original Message-
> From: Radek Terber [mailto:[EMAIL PROTECTED]
> Sent: Monday, September 18, 2006 10:25 AM
> To: Derby Discussion
> Subject: Re: Insert large using SQL
>
> Thanks for response, but i have NO acces to database over JDBC, but only
> via text stream, thus i MUST use SQL
On Friday 15 September 2006 7:15 am, Robert Enyedi wrote:
> The TO_DAYS() function returns the number of days since year 0. Did
> someone successfully port this functionality to Derby? Constructing a
> Java function for this is not as straightforward as it looks.
>
> Regards,
> Robert
Why?
When wa
(jdbc driver, database
> engine?) is running out of resources. This seems to be more frequent the
> larger the dataset gets. This dataset for example, contains about 250
> DealerTransaction rows, ~1000 DeliveryNotification rows, and ~5000
> products.
> Is this large by Derby standards?
>
> -Original Message-
> From: Geir Magnusson Jr [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, September 12, 2006 5:38 AM
> To: derby-user@db.apache.org
> Subject: 10.2 licensing issue...
>
> I read Rick's note on the 10.2 licensing issue in an archive because of
> strange move to the user li
Outch. Missed the first part of Derby's statement.
Ok.
Doesn't make sense though.
His insert is a batch insert?
Imagine if you had a table where you were inserting a record that was larger
than 64KB. (Not including blobs) Are you saying that Derby would have failed
prior to your fix?
Within th
adProduct(connection,
> > rs.getString("ProductUPC"), rs.getInt("SeedYear"));
> >
> >
> >
> > DealerTransactionDetail dealerTransactionDetail = new
> > DealerTransactionDetail(rs.getInt("ItemNumber"), rs
> >
> > .getInt
Ok,
Yeah, you're right.
I'm trying to think about what I did in my query that gave me the right
result.
In my test table, there were 65K rows and I was able to get the correct
count.
So I guess I'll have to go back to see what I did.
> -Original Message-
> From: Robert Enyedi [mailto:
Here's a simple way to do this...
Create an index on the column. It doesn't have to be unique.
Create a before insert trigger that calls a function.
The function just needs to execute a simple query:
"SELECT COUNT(*) FROM test WHERE lower(text) = ? "
In my test, I created a table test and the VARC
I'd suggest that you modify it a bit.
You probably don't want to lose case on the raw inserted data.
Case adds meaning to the content. If everything was in upper case, it would
seem like we're always SHOUTING. (Just an example.)
But the idea makes sense.
What I would suggest is that you use an
Hmmm...
I realize its been a while since I've read Derby's manual, but doesn't Derby
support Scrollable cursors?
A scrollable cursor will allow you to run a query and to fetch specific rows
from the result set. At a minimum, that is what Sergey is originally asking
and which is supported by multi
nd
> running.
>
> This is not a Derby problem, you will face the same obstacles with any
> database system.
>
>
>
> Hope this helps,
> --
> Kristian
>
> >
> > Thanks a lot
> > Flavio
> >
> >> -Messaggio originale-
>
Uhm, well, there's an ugly kludge that might work...
You could always count the number of lines in the input file before you
issue the "load" command. This will tell you the total number of rows that
"should" be loaded.
You could then periodically monitor the number of rows in the table and this
Uhm no,
Derby/Cloudscape/JavaDB (you can pick and choose your name)... is a
relational database written in Java.
With respect to column data types, you should refer to the manual... These
are also the database types supported by the JDBC class(es).
Just like any other JDBC compliant database, y
The .trim() method of a String will truncate the ending white space.
You can do a substring with a starting position of 0 and the MAX value of a
VARCHAR (which should be a constant somewhere).
This should ensure that the string is truncated and will fit.
> -Original Message-
> From: [EMAI
Not sure exactly what you are asking
If you want to find out the limits set on the VARCHAR column, the easiest
way to do this is to query the system tables. This is going to be database
dependent.
Since you also want to allow the "end user" to set the limits at install
time, again you are goi
mmediately - by replying to this message or by
> sending an email to [EMAIL PROTECTED] - and destroy all copies of
> this information, including any attachments, without reading or disclosing
> them.
>
> Thank you.
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
Ok... Is it a bug? If so where?
I mean, heck. How should the optimizer react when it has no hints from the
select statement. One would think that a table scan would make sense.
Especially when you have such a small data set.
The interesting thing is that the table scan took so long when you only
Ok,
So if your problem can be duplicated, then it's a bug.
>From the cheap seats, it looks like when you reset the base value or next
value, its losing the GENERATE BY DEFAULT and somehow the identity column is
being reset to GENERATE ALWAYS. (Not sure which is the default constraint.)
Interesti
> -Original Message-
> From: Jean T. Anderson [mailto:[EMAIL PROTECTED]
> Sent: Sunday, June 25, 2006 9:38 AM
> To: Derby Discussion
> Subject: Re: Proposal for 10.2 release schedule
>
> Daniel John Debrunner wrote:
> > [EMAIL PROTECTED] wrote:
> >>>-Original Message-
> >>>From:
rby Discussion; [EMAIL PROTECTED]
> Subject: Re: "generated by default" question
>
> On 6/16/06, Michael Segel <[EMAIL PROTECTED]> wrote:
> >
> > > I think we'll just have to agree to disagree.
> >
> > Whether you agree or disagree doesn&
On Friday 16 June 2006 1:29 am, Vic Ricker wrote:
> Michael Segel wrote:
> > Look, if you grok the math, you'll see that if you return a result from
> > the sequence that causes an error, then you've got a bug, when there's
> > another number within the result
On Friday 16 June 2006 12:10 am, Vic Ricker wrote:
> Daniel Noll wrote:
> > Ah. I was making the assumption that the indexes were implemented
> > "properly." For instance, an index should keep a certain amount in
> > memory in order to have a reasonable chance of running quickly. So the
> > max
x? ;-)
And why do you need it? ;-)
...
The point is that you don't need it.
If the insert has a value X for the identity column and X > CSV, then set CSV
= X;
It works every time.
> Michael Segel wrote:
> >> Presumably he column would be indexed if you're doing operatio
On Thursday 15 June 2006 6:38 pm, Daniel Noll wrote:
> Michael Segel wrote:
> > Uhm,
> >
> > I'm sorry, but where did I ever say 'select max()'?
> > Hint: I didn't because its not that efficient.
>
> Presumably he column would be indexed if
use
> you previously inserted a value that collided with the sequence
> generator. I think it would probably make more sense to build the
> "smarts" into your application rather than relying on Derby to do
> something that could cause performance problems.
>
> -Vic
&g
Sigh.
Don't they teach math in engineering anymore?
Lets try this one more time.
In 9.21, if N does exist, then N represents a solution set of potential
values.
In your interpretation, you are *implicitly* adding an additional boundary
that the sequence returns the MIN(N) regardless of the ov
times that its
appropriate to compare feature functionality with comparable products in an
effort to produce a better design.
> --
> Bernt Marius Johnsen, Database Technology Group,
> Staff Engineer, Technical Lead Derby/Java DB
> Sun Microsystems, Trondheim, Norway
[mjs]
But hey! What do I know?
Its not like I have a degree in Software Engineering or anything. ;-)
-Mikey
Michael Segel,
Chief Peon in Charge,
MSC Corp.
Chicago, IL, USA
On Tuesday 13 June 2006 1:19 pm, Craig L Russell wrote:
> Hi,
>
> On Jun 13, 2006, at 11:01 AM, Craig L Russell wrote:
> >>> In fact, you could argue that if the implementation skipped
> >>> returning
> >>> a sequence value just because that value had been inserted by the
> >>> user into a column,
On Tuesday 13 June 2006 1:01 pm, Craig L Russell wrote:
> Hi Mikey,
>
[SNIP]
> > [mjs] Hi Craig,
> >
> > Errr. No.
> > In short, the sequence generation is outside of the transaction,
> > therefore
> > its possible to get a jump in the sequence number due to transactions
> > rolling back or individ
you have to get creative ;-)
But hey! What do I know? ;-)
BTW, I think if you look at the index on the identity column, you may find a
way to handle the cycles and trap for the constraint so that the only time
you fail is if the table is full.
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
Right.
I don't think hilz was really suggesting piracy.
Its just as easy as to test how Informix/DB2/... handles this and to them
mimic that behavior.
You've already made a good suggestion that would be "easy" to implement.
I believe that there may be a more elegant solution if you look at the
o obligation to implement the
enhancement/feature
> -Original Message-
> From: Jean T. Anderson [mailto:[EMAIL PROTECTED]
> Sent: Friday, June 09, 2006 10:33 AM
> To: Derby Discussion
> Subject: Re: "generated by default" question
>
> Michael Seg
,2
> >>>
> >>> The system will automatically generate values for the identity column.
> >>> But now you need to manually insert some data into the identity
> column:
> >>>
> >>> INSERT INTO tauto VALUES (3,3) INSERT INTO tauto VALUES (4,4
On Tuesday 30 May 2006 1:22 pm, Mamta Satoor wrote:
> On 5/30/06, Michael Segel <[EMAIL PROTECTED]> wrote:
> > I tried to send this out earlier from a different machine...
> >
> > I read the thread of articles, and unfortunately, you're wrong, or rather
>
nsert some data into the identity
> > >> column:
> > >>
> > >> INSERT INTO tauto VALUES (3,3) INSERT INTO tauto VALUES (4,4) INSERT
> > >> INTO tauto VALUES (5,5)
> > >>
> > >> The identity column has used values 1 through 5 at t
I will have to do :
>
> alter tableRESTART WITH
>
> Is there another way to make the autoincrement smart enough to know that
> the value already exists and just generate a new value for me?
> I find it odd to have to set the "restart with" to skip the values
Uhm...
Posting in Jira and introducing it are two different things.
I notice that there is an Andrew McIntyre who works for IBM in Atlanta.
Is that you?
> -Original Message-
> From: Andrew McIntyre [mailto:[EMAIL PROTECTED]
> Sent: Friday, May 05, 2006 11:20 AM
> To: Derby Discussion; [
There are other ways of doing this, however each method has their own good
points or bad points.
One way you can do this is to create a counter table.
(This allows you to have multiple counters within a single table.)
Then you can write your own procedure that will fetch the value of the
counter
Derby is a very good, lightweight, general purpose, pure java relational
database.
Having said that, I think it's important to choose the right tool for the
right job.
Derby has its historical roots as a lightweight database. It lacks certain
features that are found in Informix or DB2 that woul
On Wednesday 05 April 2006 2:16 pm, Daniel John Debrunner wrote:
> Michael Segel wrote:
> > On Wednesday 05 April 2006 12:33 pm, Daniel John Debrunner wrote:
> >>Michael Segel wrote:
> >>>On Tuesday 04 April 2006 6:23 pm, Daniel John Debrunner wrote:
> >>>
On Wednesday 05 April 2006 12:33 pm, Daniel John Debrunner wrote:
> Michael Segel wrote:
> > On Tuesday 04 April 2006 6:23 pm, Daniel John Debrunner wrote:
> >>Daniel John Debrunner wrote:
> >>>May I suggest that if you are writing samples for others to use th
erManager.getConnection("Blah, blah, blah...");
} catch (Exception e){
e.printStackTrace();
}
}
public static void main(String argv[]){
/*
* Ok, so you know what to do
*/
}
}
-G
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
On Tuesday 04 April 2006 12:16 pm, Sunitha Kambhampati wrote:
> Michael Segel wrote:
> >On Tuesday 04 April 2006 11:48 am, Daniel John Debrunner wrote:
> >>Anil Samuel wrote:
> >>>PreparedStatement ps = con.prepareStatement("select
> >
t;
> Here's a reworked version
>
Why use a prepared statement at all? If he already knows the input values, it
would be cleaner to create a statement then excute the statement.
Statement s = con.createStatement();
s.executeUpdate(string stuff);
Less overhead.
--
--
Michael Sege
ed this, but a search on the web turned up some pointers:
>
> http://forum.java.sun.com/thread.jspa?threadID=445015&start=0
>
> Hope this helps.
>
> -Rajesh
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
xcept that when I run queries, the
> >>> server process does all the work and returns the results as a vector of
> >>> string arrays. It's never sat well with me--and as you can imagine--now
> >>> that the dataset is getting pretty big (120.000-4KB rows returned for
> >>> some queries), I'm using too much memory.
> >>>
> >>> What I'd like to do is get my jdbc connection object onto the client so
> >>> I don't have to "package" everything up when returning resultsets. The
> >>> question is how? My first idea was to just use derby's network server
> >>> and write the file protocol separately, but I'd prefer to stick with
> >>> just one socket if I can.
> >>>
> >>> Advice? Thanks for your time.
> >>> ry
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
Uhm...
Not to nitpick...
There appears to be a problem with your model.
Your cities table doesn't map to your flights table.
Note: you id airports via their 3 letter code.
But you don't map this to the cities.
While this is an example, note that some cities have multiple airports.
(NY has 3*,
> -Original Message-
> From: Kristian Waagan [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, March 08, 2006 3:52 PM
> To: Derby Discussion
> Subject: Re: Derby JDBC Embedded Driver, Prepared Statements, and Indexes
>
> Michael Segel wrote:
>
> >I have to
I have to agree with Mike that there is something missing.
First, how often are you preparing the statement?
You should only be preparing it once and within the look, set the variables
and then execute it your 1000 times.
You may see 2 seconds on the first iteration, but after that, it should be
Max,
Perhaps I wasn’t being clear.
If you write your select statement to
include a “virtual” column(s) of YEAR(), MONTH() and DAY(),
You can then group by them.
From: Max Ten
[mailto:[EMAIL PROTECTED]
Sent: Monday, March 06, 2006 10:40
PM
To: Derby Discussion
Subj
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Sent: Friday, March 03, 2006 10:28 PM
> To: Derby Discussion
> Subject: Re: SQL Exception
>
> Hi Michael,
>
> I was afraid that you might have missed some context in this thread.
> >
> >> Bernt M. Johnsen wrote (
hings, but wouldn't this eliminate problems
> of scope?
>
> I'll be looking at it with a fresher head tonight!
>
> Rhys
>
> -Original Message-
> From: Michael Segel [mailto:[EMAIL PROTECTED]
> Sent: 03 March 2006 14:46
> To: Derby Discussion
>
class called DBTools which I wrote to
> simplify DB access.
>
> I have a play with your ideas this evening and maybe post my code.
> Thanks for your thoughts.
>
> Regards,
>
> Rhys
>
> -Original Message-
> From: Michael Segel [mailto:[EMAIL PROTECTED]
On Friday 03 March 2006 3:17 am, Rhys Campbell wrote:
> Hi Rajesh,
>
>
>
> I can post some code later when I return from work. My app is written
> using Java and uses a single table Derby database. At present this only
> has three records in it. I did try to completely shutdown Derby at the
> end o
On Friday 03 March 2006 5:04 am, Thomas Vatter wrote:
> I have shutdown derby, dropped the database by removing its folder,
> started derby (no large memory consuming, stays low), recreated
> the database, imported 1300 data and showed them in my application.
> Memory stays low, but the ordering is
I am testing how derby performes in the network situation,
> because in the single user situation I have typically less data.
>
> tom
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
Ok...
Maybe I'm a tad slow... (Lack of sleep and not enough coffee...)
You said that the problem only occurs with your one result set.
When you say that you're getting the data from a spreadsheet, how are you
reading it in? Are you trying to access the raw XLS dataset? Or did you
export the data
thing like a
DRDA gateway from the CSDK.
Again, I really hadn't thought the use of Derby out yet. Was sort of thinking
about it as I worked on the Informix version
Just wondering if anyone else saw the same potential...
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
was a quasi-sales critter for the last 4 years... don't take my word for it.
Take a fifth of scotch, and think about the problem you're trying to solve.
You'll get it eventually. ;-)
--
--
Michael Segel
Principal
Michael Segel Consulting Corp.
[EMAIL PROTECTED]
(312) 952-8175 [mobile]
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