On Wed, Sep 4, 2013 at 3:51 PM, Varadan, Yamini (SCR US) (EXT) <
yamini.varadan@siemens.com> wrote:
>
> But would any one know if there is any kind of synchronization that is
> done between different processes that connect to different sqlite databases
> that might slow down one process when
Hello,
We use Qt with sqldriver Sqlite-4 in our application. (Windows XP 32 bit,
Visual studio 2005)
We are facing a performance issue in the following scenario.
There are two processes A and B. A uses sqlite DB1 and keeps populating data.
Process B uses sqlite DB2 for writing and occasionally
Trey Mack wrote:
> I have a fairly large table (10million rows) with a simple INTEGER
> PRIMARY KEY AUTOINCREMENT field.
>
> Executing 'SELECT max(rowid) FROM MyTable' is very fast, as is
> 'SELECT min(rowid) FROM MyTable'.
>
> However, 'SELECT max(rowid) - min(rowid) FROM MyTable' is slow
>
someone else might give a more technical and scientific explanation,
but my take is that "SELECT n FROM table" is just that -- a row
returned for every row in the table because there is no WHERE clause
constraining the results. "SELECT max() - 1 FROM table" on the
other hand GROUPs the result
Ah, OK, I see that doing 'SELECT 1 FROM MyTable' returns a 1 for every
row, so I can see where the effort is probably going. However, 'SELECT
max(rowid) - 1 FROM MyTable' still only produces one result row
(obviously I'm experimenting with a much smaller database now). Still
need an
I have a fairly large table (10million rows) with a simple INTEGER
PRIMARY KEY AUTOINCREMENT field.
Executing 'SELECT max(rowid) FROM MyTable' is very fast, as is 'SELECT
min(rowid) FROM MyTable'.
However, 'SELECT max(rowid) - min(rowid) FROM MyTable' is slow
(apparently accessing every
Message-
From: Dennis Cote [mailto:[EMAIL PROTECTED]
Sent: Monday, February 12, 2007 4:10 PM
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] Performance Question
Slater, Chad wrote:
> Hello,
>
> I'm having trouble with the performance of one of my queries and my
"sql
> kung fu
Slater, Chad wrote:
Hello,
I'm having trouble with the performance of one of my queries and my "sql
kung fu" is limited. Any help with this problem would be greatly
appreciated
Here's a stripped down version of the tables I'm dealing with:
CREATE TABLE A (
id INTEGER PRIMARY KEY
Hello,
I'm having trouble with the performance of one of my queries and my "sql
kung fu" is limited. Any help with this problem would be greatly
appreciated
Here's a stripped down version of the tables I'm dealing with:
CREATE TABLE A (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT
)
-Ursprüngliche Nachricht-
Von: Martin Pfeifle [mailto:[EMAIL PROTECTED]
Gesendet: Dienstag, 26. September 2006 13:35
An: sqlite-users@sqlite.org
Betreff: AW: AW: [sqlite] Performance question
>Hi Michael,
>could you please (re)post the exact create inex statements +primary k
t; <sqlite-users@sqlite.org>
Gesendet: Dienstag, den 26. September 2006, 09:34:00 Uhr
Betreff: AW: [sqlite] Performance question
-Ursprüngliche Nachricht-
Von: Dennis Cote [mailto:[EMAIL PROTECTED]
Gesendet: Freitag, 22. September 2006 17:07
An: sqlite-users@sqlite.org
Betreff: Re
-Ursprüngliche Nachricht-
Von: Dennis Cote [mailto:[EMAIL PROTECTED]
Gesendet: Freitag, 22. September 2006 17:07
An: sqlite-users@sqlite.org
Betreff: Re: [sqlite] Performance question
Michael Wohlwend wrote:
> But If I do "select data from pictures where (x betwee
Michael Wohlwend wrote:
But If I do "select data from pictures where (x between high_x and low_x)
and (y between high_y and low_y) then this takes ca. 8 seconds (!) on wince.
Michael,
If you are really writing your between clauses as above with the high
limit first, then they are not
Michael Wohlwend wrote:
I made a database of little pictures, which includes x und y coordinates and
Are x and y indexed?
Martin
-
To unsubscribe, send email to [EMAIL PROTECTED]
-Ursprüngliche Nachricht-
Von: Gerald Dachs [mailto:[EMAIL PROTECTED]
Gesendet: Freitag, 22. September 2006 11:28
An: sqlite-users@sqlite.org
Betreff: Re: [sqlite] Performance question
>My sql knowledge may be a little bit rusty and I have really no idea how
sqlite is doing "
> But If I do "select data from pictures where (x between high_x and low_x)
> and (y between high_y and low_y) then this takes ca. 8 seconds (!) on
> wince.
My sql knowledge may be a little bit rusty and I have really no idea how
sqlite is doing "between" querys. Anyway, once I have learned never
Hi,
I made a database of little pictures, which includes x und y coordinates and
a blob (between 100 and 8000 bytes in size, one blob, total db size 180MB).
If I do
"select data from pictures where x=? And y=?"
this works well, also on wince (measured myself: 1 such a select take 5
Slater, Chad wrote:
Does the ordering of columns in a table have any impact on performance?
Chad,
Not significantly if your rows have less than a couple of hundred bytes
of data. If they are larger than that they will spill into overflow
page(s). It takes longer to insert and select data
Hello,
Does the ordering of columns in a table have any impact on performance?
Chad
-
To unsubscribe, send email to [EMAIL PROTECTED]
-
On Wed, 30 Aug 2006 [EMAIL PROTECTED] wrote:
> > I have to go along with Mario, here. This is a potential show stopper,
>
> Show stopper? Really? The bug has been there for years, literally,
> and nobody has even noticed it until now - despite thousands of users
> and millions and millions of
Rob Sciuk <[EMAIL PROTECTED]> wrote:
> On Wed, 30 Aug 2006, Mario Frasca wrote:
> > On 2006-0829 13:15:02, [EMAIL PROTECTED] wrote:
> >
> > >> To my surprise (perhaps "horror") I find that SQLite has
> > >> for a very long time allowed NULL values in PRIMARY KEY
> > >> columns. [...]
> >
> > I
On Wed, 30 Aug 2006, Mario Frasca wrote:
> On 2006-0829 13:15:02, [EMAIL PROTECTED] wrote:
>
> >> To my surprise (perhaps "horror") I find that SQLite has
> >> for a very long time allowed NULL values in PRIMARY KEY
> >> columns. [...]
>
> I understand your concern about legacy programs, but most
On 2006-0829 13:15:02, [EMAIL PROTECTED] wrote:
To my surprise (perhaps "horror") I find that SQLite has
for a very long time allowed NULL values in PRIMARY KEY
columns. [...]
I understand your concern about legacy programs, but most of us expect PRIMARY
KEY to imply NOT NULL... don't
Kurt Welgehausen <[EMAIL PROTECTED]> wrote:
> [EMAIL PROTECTED] wrote:
>
> > Saying NOT NULL on a PRIMARY KEY is redundant, by the way.
> > --
> > D. Richard Hipp <[EMAIL PROTECTED]>
>
> sqlite> insert into t (k, d) values (null, 'jkl');
> sqlite> select * from t;
> k d
>
Mario Frasca wrote:
Kurt Welgehausen wrote:
[...] should I write a bug ticket
about a primary key accepting nulls?
there is already a ticket for that: 518. I reopened it three days ago.
I have right now attached a patch for it. it is quite small and I hope
it fits in the current
Kurt Welgehausen wrote:
[EMAIL PROTECTED] wrote:
Saying NOT NULL on a PRIMARY KEY is redundant, by the way.
[...]
Am I missing something, or should I write a bug ticket
about a primary key accepting nulls?
there is already a ticket for that: 518. I reopened it three days ago.
Kurt Welgehausen <[EMAIL PROTECTED]> writes:
> [EMAIL PROTECTED] wrote:
>
>> Saying NOT NULL on a PRIMARY KEY is redundant, by the way.
>> --
>> D. Richard Hipp <[EMAIL PROTECTED]>
>
> **kaw<~/tdpsa>$ sqlite3
> Loading resources from /home/kaw/.sqliterc
> SQLite version 3.3.7
> Enter ".help"
[EMAIL PROTECTED] wrote:
> Saying NOT NULL on a PRIMARY KEY is redundant, by the way.
> --
> D. Richard Hipp <[EMAIL PROTECTED]>
**kaw<~/tdpsa>$ sqlite3
Loading resources from /home/kaw/.sqliterc
SQLite version 3.3.7
Enter ".help" for instructions
sqlite> .nullvalue '<>'
sqlite> create table
"Slater, Chad" <[EMAIL PROTECTED]> wrote:
> Hello,
>
> Consider the following lookup table definition:
>
> CREATE TABLE foobar (
> id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
> table1_id INTEGER NOT NULL REFERENCES table1,
> table2_id INTEGER NOT NULL REFERENCES table2
> );
>
>
Hello,
Consider the following lookup table definition:
CREATE TABLE foobar (
id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
table1_id INTEGER NOT NULL REFERENCES table1,
table2_id INTEGER NOT NULL REFERENCES table2
);
The id primary key column is not necessary for anything in my
> On my PC the following query requires about 53 seconds:
> select * from TABG a, TABB b where (a.S='3' or a.S='12 or...) and
> b.G=a.G order by a.G asc;
>
> (On Oracle with the same scheme and data it requires only 0.4
> seconds.)
In my experience, even though SQLite has very low overhead
Hi,
> I have a question about the performance of my SQLite DB, where the
> db-file has about 20MB and which I use in a Java application via the
> Java wrapper.
First, your timing figures look indeed slower than what I would expect
(using a somewhat similar DB in type and size and a similar
32 matches
Mail list logo
