e point of view of program logic it looks similar (at least for
me), but shifts security burden from you to authors of libc. And of course
this should calm static analyzers anxious about strlen(), sprintf() etc.
Valentin Davydov.
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er successfull commit. Thus you shift the
burden from SQL to filesystem which is less limited by natural data structure
and might perform better.
Valentin Davydov.
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t;M");
How to construct a query which returns coalesced sex but individual names,
such as "F: Alex, Jane. M: Alex, John."?
Sincerely,
Valentin Davydov.
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On Fri, Dec 25, 2015 at 12:51:55PM +, Simon Slavin wrote:
>
> On 25 Dec 2015, at 12:39pm, Valentin Davydov
> wrote:
>
> > It would be desirable to improve algorithm of INTEGRITY_CHECK pragma.
> > Presently it is generally useless for indexed databases which don't
Hi, All!
It would be desirable to improve algorithm of INTEGRITY_CHECK pragma.
Presently it is generally useless for indexed databases which don't fit
entirely in RAM (and which usually need checking much strongly than
smaller ones).
Valentin Davydov.
did in the past) produce some nice bugs. Attention
to developers.
> Note that there isn't a port,
I know. Despite the code being frozen for almost a full year, nobody
wants to take a trouble of maintaining FreeBSD port (perhaps me too).
Valentin Davydov.
Hi, all!
How to build native sqlite4 (preferrably statically linked shell only,
without any extensions) on a recent version of FreeBSD? It has clang
instead of gcc as a default system compiler, so makefiles bundled with
sqlite sources don't work.
Valentin Davydov.
On Wed, May 20, 2015 at 11:52:08PM +, Peter Aronson wrote:
> Now you're just getting silly. ?What if the application sets all rowids,
> everywhere to 1? ?The fact is, the chance of collision on a UUID is pretty
> astronomically low as long as a decent source of entropy is used
>
o the RAM cache. Of course,
cache itself should be populated in advance to give this benefit, and, given
current RAM prices, it seems not very feasible to steal available memory from
smart applications in favour of dumb cache.
Hope, this considerations will help you in tuning your code.
V
> number of CPU cycles.
Is there any similar benchmarks with regard to disk i/o operations rather
than CPU? Especially random read of cache misses, I mean.
Valentin Davydov.
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n abovementioned index, changing autovacuum to forced vacuum
sceduled at specific time of day etc.) or give it more resources (say,
by putting the database on an SSD drive).
Valentin Davydov.
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not been done yet.
To my opinion, the most general solution is to let to the application
programmer to decide whether to calcucale the function once (say, at
the beginning of a transaction), store the result and then access
the stored value, or to make the new call t
se.
The only definive SQLite limits are documentet in the relevant manual page.
Valentin Davydov.
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On Fri, Dec 28, 2012 at 03:35:17PM -0600, Dan Frankowski wrote:
>
> 3. Would horizontal partitioning (i.e. creating multiple tables, each for a
> different key range) help?
This would seriously impair read performance (you'd have to access two indices
instead of one).
Valenti
haps related to table size) that would change
> this write performance?
CACHE_SIZE. It makes sense to enlarge it up to the all available memory.
Valentin Davydov.
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es
of many terabytes in size, provided underlying filesystem supports them, of
course. Be prepared to wait quite a long for non-sqlite operations (copy,
delete etc.) to complete on such a big files.
Valentin Davydov.
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sqlite-
are nicely supported in the form of unsigned
integers, and prefixes/ranges - as contiguous ranges of such integers.
For example, to determine whether given IP address belongs to a particular
subnet, one can calculate "IP between NETWORK_MIN and NETWORK_MAX"
"pragma page_size=512;
create table t(c);drop table t;vacuum;"
$ wc -c test.db
512 test.db
$ sqlite3 test.db "pragma page_size;"
512
$
Valentin Davydov.
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On Sun, May 13, 2012 at 11:02:54AM +0300, Baruch Burstein wrote:
> I am using an in-memory DB to load data into it, do a few sort / find
> duplicates / SELECTs, and then dispose of the DB. It can vary in size from
> a few thousand rows to over a million.
> Would the time used for creating an index
suring validity of
input data such as right number of fields in each row etc.) and not rely
on the sqlite shell csv-parsing capabilities.
Valentin Davydov.
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e file size or
read pointer position in the input data file. Both of them grow linearly
with amount of data processed.
> I've started several loads only to find out hours later that
> nothing has been loaded.
Anyway be prepared to spend some of your t
ble RAM would help a bit.
Also, don't forget to turn off journaling and wrap all in a single
transaction when creating database for the first time.
Valentin Davydov.
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cy storage, such as SSD drive for small databases or
RAID array with plenty ow write cache memory for huge ones.
> is there an overhead with zipvfs ?
You can easily measure this overhead yourself on the in-memory database.
RAM is cheap now ;-)
Valentin Davydov.
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On Thu, Feb 09, 2012 at 02:05:53PM +, Simon Slavin wrote:
>
> On 9 Feb 2012, at 1:45pm, Valentin Davydov wrote:
>
> > CREATE TABLE T(X, Y, Z, ..., UNIQUE (X, Y, Z, ...) ON CONFLICT IGNORE);
> > CREATE INDEX IX ON T(X);
> > CREATE INDEX IY ON T(Y);
, and all time is spent
waiting for disk _reading_ (rarely interspersed with fast and happy write
bursts on each COMMIT). What is sqlite reading there? Does it try to
perfectly balance each index on each insert (million times per
transaction) or something else?
Sincerely,
Valentin Davydov
Subsystem: Shell
Title: Incorrect handling of some BLOBs.
Type: Code_Defect
Severity: Important
Priority: Unknown
Affected: All SQLite versions containing output_hex_blob() up to 3.7.9.
Environment: Tested on various FreeBSD 8.x versions, both i386 and amd64.
Probably, other operating
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