Hi,
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Look near the bottom of that web page.
Simon.
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Ignore multiprocessing for the inserting. You'll just get contention when
accessing the database. And I think you are already trying the right PRAGMAs.
I think you've done this already, but just in case ...
Insert rows in batches. Experiment with the batch size: maybe a thousand
INSERTs per
Thank you for the good suggestions. I've been applying them to a smaller
subset of my database to see how it might perform.
I had tried fiddling with the cache size but it seemed to make performance
slightly degrade in my case. In principle it should work, so perhaps my
smaller database isn't
Sounds like you're already doing the few things I would have recommended.
As an FYI in regards to the attached database limitation, you can compile your
own .dll with a higher number for SQLITE_MAX_ATTACHED, up to 125
https://www.sqlite.org/limits.html#max_attached
and then swap out the default
Have you increased the paltry default cache size? (PRAGMA CACHE_SIZE) The
bigger the better, especially since you are sorting and balancing large
B-Tree's. The more this can be done in memory without having to spill to slow
disk (or disk cache) the faster it will go ... (the best way to
No. It is not correct. Have you read the documentation?
https://sqlite.org/rescode.html#locked
Multiple threads cannot perform operations at the same time on the same
connection. This is verboten. Forbidden. Does not work. Will cause
explosions and death of children. Do not do it.
Hi everyone -
I've been using SQLite through Python (3.7) for a scientific project. The
data comes out to 10 billion rows of an 8 byte signed integer (~200-300 gb
pre-index), and while insertion takes ~6 hours, indexing takes 8 hours by
itself. Indexing also seems to slow as it is built. Does
On 28 Nov 2018, at 3:26pm, Prajeesh Prakash
wrote:
> Then is that SQLITE_LOCKED error will happen because of a conflict within the
> same database connection. Or in case of two connection two separate thread
> trying to do operation?
Your software should never make two simultaneous API calls
Hi members,
The SQLITE_LOCKED error will happen on same database connection when two thread
trying to do read/write operation at same time. SQLITE_BUSY will get when one
thread on one connection is doing read/write operation and another thread on
another connection trying to read/write the DB.
Then is that SQLITE_LOCKED error will happen because of a conflict within the
same database connection. Or in case of two connection two separate thread
trying to do operation?
>
> On November 28, 2018 at 8:16 PM Keith Medcalf wrote:
>
> The difference is that if both threads call
Thank you very much for the detailed explanation. Now i understood the concept.
> On November 28, 2018 at 8:16 PM Keith Medcalf wrote:
>
>
>
> The difference is that if both threads call the library on the same
> connection at the same time (that is, two calls are into the library are
> active
The difference is that if both threads call the library on the same connection
at the same time (that is, two calls are into the library are active at the
same time) then all hell will break loose. You application will fail. Memory
will be corrupted. You database will be corrupted. Hell
Hi Members,
Can any one please give a clear idea about SQLITE_OPEN_FULLMUTEX and
SQLITE_OPEN_NOMUTEX because i am totally confused with the concept. If we
enable FULLMUTEX what will happen if two thread trying to update the same table
(Both thread are from same DB connection) in case of
That is because some daft person is using the wrong quotes, doh!
---
The fact that there's a Highway to Hell but only a Stairway to Heaven says a
lot about anticipated traffic volume.
>-Original Message-
>From: sqlite-users [mailto:sqlite-users-
>boun...@mailinglists.sqlite.org] On
SQLITE_OPEN_FULLMUTEX ensures that EACH CONNECTION is SERIALLY ENTRANT into the
Sqlite3 library code (ie, that two threads cannot make a call into the library
on different threads AT THE SAME TIME, or put another way that only ONE THREAD
at a time on EACH CONNECTION may make a call into the
No, you are incorrect. Isolation is only BETWEEN DIFFERENT CONNECTIONS, and
has nought whatsoever to do with threads ...
---
The fact that there's a Highway to Hell but only a Stairway to Heaven says a
lot about anticipated traffic volume.
>-Original Message-
>From: sqlite-users
and the confusing behaviour is admitted to be a "quirk" in SQLite:
https://sqlite.org/quirks.html#double_quoted_string_literals_are_accepted
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Works as advertised. "Description" (with double quotes) is a field name.
'Description' with single quotes is a string constant.
-Ursprüngliche Nachricht-
Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im
Auftrag von Dale Mellor
Gesendet: Mittwoch, 28. November
Use single quotes, not double. Double quotes are used for identifiers, not
strings, so that matches rows where id and description have the same value.
On Wed, Nov 28, 2018, 1:19 AM Dale Mellor THIS VERSION
> SQLite 3.25.3 2018-11-05 20:37:38
>
Forwarded Message
From: Dale Mellor
To: sqlite-users@mailinglists.sqlite.org
Subject: Bug? Confused data entry with column name
Date: Wed, 28 Nov 2018 05:42:16 +
> > > > > > > > > > THIS SCRIPT
>
> create table test (id varchar, description varchar);
> insert into test
THIS VERSION
SQLite 3.25.3 2018-11-05 20:37:38
89e099fbe5e13c33e683bef07361231ca525b88f7907be7092058007b750alt1
zlib version 1.2.8
gcc-8.2.0
> THIS SCRIPT
create table test (id varchar, description varchar);
insert into test (id, description) values ("Description", "Duh");
Yes they are sharing the same DB connection
> On November 28, 2018 at 1:57 PM Simon Slavin wrote:
>
>
> On 28 Nov 2018, at 8:03am, Prajeesh Prakash
> wrote:
>
> > That means (with SQLITE_OPEN_FULLMUTEX) if two threads are trying to do
> > write and read to the table only one will get the
Dear,
> Le 27 nov. 2018 à 10:24, Prajeesh Prakash a
> écrit :
>
> I am using sqlite3 Asynchronous I/O on my application. So is there any way to
> get the status of the DB update (After the write operation) from the
> asyncWriterThread so that my application can do the proper error handling.
On 28 Nov 2018, at 8:03am, Prajeesh Prakash
wrote:
> That means (with SQLITE_OPEN_FULLMUTEX) if two threads are trying to do write
> and read to the table only one will get the chance to do the operation other
> thread needs to wait until the first thread finish its job . Am i correct
Are
That means (with SQLITE_OPEN_FULLMUTEX) if two threads are trying to do write
and read to the table only one will get the chance to do the operation other
thread needs to wait until the first thread finish its job . Am i correct
>
> On November 28, 2018 at 1:24 PM Hick Gunter wrote:
>
>
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