Hi again,
I've been experimenting with limiting memory usage in our SQLite-based
app. Ran into an unrelated oddity that I thought I'd ask about:
We're running a couple of massive upgrade steps on over 5 million
quite large (70+ columns) rows.
There are two unrelated steps;
1) DROP COLUMN-replac
On 4/26/17, Kim Gräsman wrote:
>
> But for some reason, the WAL-index (-shm) file also grows to about
> 40MiB in size. From the docs, I've got the impression that it would
> typically stay at around 32KiB. Does this seem normal?
The -shm file is an in-memory hash table, shared by all processes
ac
On 4/26/17, Richard Hipp wrote:
> That would imply you are changing about a
> half million pages of your database inside a single transaction.
Correction: About 5 million pages. Missed a zero. (Time for coffee, I guess)
--
D. Richard Hipp
d...@sqlite.org
Den 26 apr. 2017 3:45 em skrev "Richard Hipp" :
> On 4/26/17, Richard Hipp wrote:
> > That would imply you are changing about a
> > half million pages of your database inside a single transaction.
>
> Correction: About 5 million pages. Missed a zero. (Time for coffee, I
> guess)
>
Always tim
Also, I have question about the cache_size pragma.
If I run the query (this is regarding the count query), without first
running ANALYZE on the database, I can see that the times are affected by
the cache_size pragma as follows:
cache_size = 0
timing = 3.7 s
cache_size = -2000 (2000 kb)
timing =
On Wed, Apr 26, 2017 at 5:34 PM, Kim Gräsman wrote:
> Den 26 apr. 2017 3:45 em skrev "Richard Hipp" :
>
> > On 4/26/17, Richard Hipp wrote:
> > > That would imply you are changing about 5 million pages.
>
> Great, that means the numbers add up. This is a monster transaction
> updating 5M rows
On Wed, Apr 26, 2017 at 5:58 PM, Dominique Devienne wrote:
> On Wed, Apr 26, 2017 at 5:34 PM, Kim Gräsman wrote:
>
>> Great, that means the numbers add up. This is a monster transaction
>> updating 5M rows, and page size is 512 bytes, so I think we have roughly 1
>> row/page.
>
> Which such a sma
Whats the trick with SQLites working set to format a single statement with
parameters
where if a row exists for a given criteria, returns its Id, otherwise insert
and return the
last_insert_rowid()?
For example:
CREATE TABLE Foo (
Id INTEGER PRIMARY KEY NOT NULL,
ColA TEXTNOT NUL
On 26 Apr 2017, at 9:42pm, Joseph L. Casale wrote:
> Whats the trick with SQLites working set to format a single statement with
> parameters
> where if a row exists for a given criteria, returns its Id, otherwise insert
> and return the
> last_insert_rowid()?
It has to be two operations.
INS
With the comment that the insert or ignore method there will only work if
there's an explicit unique constraint on your given criteria.
-Original Message-
From: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] On
Behalf Of Simon Slavin
Sent: Wednesday, April 26, 2017 4
On Fri, Apr 21, 2017 at 5:18 PM, Kim Gräsman wrote:
> Hi all,
>
> On Sun, Jan 15, 2017 at 5:50 PM, Richard Hipp wrote:
>> On 1/15/17, Kim Gräsman wrote:
>>>
>>> 1) If I configure a global SQLite heap with SQLITE_CONFIG_HEAP, won't
>>> I just trade malloc heap fragmentation for SQLite private hea
On 26 Apr 2017, at 10:00pm, Kim Gräsman wrote:
> Specifically, I wonder if 4MiB for the general-purpose heap is maybe
> entirely unreasonable? Is there a way to forecast how much memory will
> be necessary for transactions and query processing, or does that
> depend entirely on the workload?
De
From: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] On
Behalf Of David Raymond
Sent: Wednesday, April 26, 2017 3:00 PM
To: SQLite mailing list
Subject: Re: [sqlite] Equivalent syntax in sqlite
> With the comment that the insert or ignore method there will only work if
> ther
If you change from an auto increment to a GUID/UUID you can simply use
'REPLACE INTO' and you don't have to worry about the select, because you'll
already know the ID.
http://www.sqlitetutorial.net/sqlite-replace-statement/
On Wed, Apr 26, 2017 at 4:05 PM, Joseph L. Casale wrote:
> From: sql
Gabriele Lanaro wrote:
> Are there any tips to make sure that the cache is used properly?
The default is 2000 pages (8 MB with the default page size), and in most
cases should be increased.
But what works best in your specific case depends on the hardware, the
OS, the software, the database schem
15 matches
Mail list logo
