Thanks for replying Phil...
Actually I am not running separate websites - but I have to deploy to
multiple webservers which will all serve the same pages. Each
webserver
will have their own copy of the SQLite code, but they need to load the
data from a network file server to share the same data.
I guess this is why I am asking for feedback: it seems that this
case is
a marginal case for SQLite and I am just trying to assess performance
and corruption possibilities in more detail than is presented on the
SQLite web pages.
The main point that encourages me to try SQLite is that it is
recommended for 99.9% of websites. I believe my traffic is very low
and
SQLite should be recommended from that point of view.
However, although the likelihood of two users simultaneously
updating a
particular record is going to be very low I believe it is going to
happen that two users will try to update the database simultaneously.
I know that SQLite has some file locking features that have even been
improved in v 3.0. So:
- will simultaneous *database* access result in corruption?
- will simultaneous *record* access result in corruption?
- if not, when *can* corruption occur?
I don't mind making the users wait in the unlikely event of a record
collision, or even drop data once in a blue moon, but corruption is
not
acceptable.
Thanks again.
Anil.
-----Original Message-----
From: Philip Butler [mailto:[EMAIL PROTECTED]
Sent: Friday, 2 February 2007 11:39 AM
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] Appropriate uses for SQLite
I am not an expert on SQLite - but if you are running separate
websites
from your multiple servers, then why not use 4 instances of SQLite ??
That is unless the websites need to share the same database/tables.
If they do need to share the same database/tables, then PostgreSQL or
MySQL may be the more appropriate choice. They are designed to be
distributed (hence their increased overhead) while SQLite is
designed to
be lean-and-mean.
Just my 2 cents worth...
Phil
On Feb 1, 2007, at 7:03 PM, Anil Gulati -X ((agulati - Michael Page at
Cisco)) wrote:
Hi SQLite users
Thank you for your attention - I am just hoping for some
clarification
of usability of SQLite.
Referring to: http://www.sqlite.org/whentouse.html
- SQLite works well in websites
- Other RDBMS may work better for Client/Server applications
- SQLite will work over a network file system, but because of the
latency associated with most network file systems, performance will
not be great
I am trying to decide whether I can use SQLite for a website that
runs
on 4 load-balanced servers using networked file storage mounted by
all
servers for common data access. SQLite will have to load its database
from the network file space.
These servers run multiple web-sites, hence the additional servers,
but my pages are not high hit-rate. The sites I am planning
anticipate
a maximum of 200 users altogether. Current raw, uncompressed data
(mostly
text) is about 2MB growing to around 4MB. The current starter
database
of 1.6MB raw compresses to 963KB.
My concerns are:
1. Network file system
How bad is the latency introduced from using a network file system?
2. Concurrent access
I can't understand how SQLite is recommended for 99.9% of websites
but
only *high* concurrency is not recommended? I currently use a flat-
file system which uses a single file per record. If users happen to
write to the same record simultaneously one of the updates will be
lost but corruption is highly unlikely, if not impossible. It seems
that for SQLite the risk for concurrent access is always data
corruption, which would be unacceptable for me.
The issue is that there may be short periods where multiple users
will
be updating around the same time and I want to make sure that the
possibility of corruption is extremely low. I am asking for more
detailed information on the above issues to clarify my decision.
All feedback gratefully received.
Thanks.
Anil.
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