I have developed a program which uses SQLite 3.7 ... database, in it there is a rather extensive write/read module that imports , checks and updates data. This process takes 14 seconds on my PC and Im pleased as punch with the performance.
I use transactions for everything with paratetrs my PC is a Intel i7 with 18gig of ram. I have not set anything in the database. I used SQLite Expert to create the database and create the data structures including table and columns and checked that all indexes are created. In other words its all OK.
I have since deployed the program/database to 2 other machines. That 14 second process takes over 5 minutes on the other machines. Same program, identical data, identical database. The machines are upto date, one is a 3rd gen Intel i7 bought last week, the other is quite fast as well so hardware should not be an issue.
Im just not understanding what the problem could be? Is it the database itself ? I have not set anything other then encription on it. Remembering that I run the same and it takes the 14 seconds. Could it be that the database is 'optimised' to my PC ? so when I give it to others its not optimised?
I know I could turn off jurnaling to get better performance, but that would only speed up the process and still would leave the problem.
Any ideas would be welcome.
EDIT:
I have tested the program on my 7yo Dual Athelon with 3gig of ram running XP on HDD, and the procedure took 35 seconds. Well in tolerable limits considering. I just dont get what could be making 2 modern machines take 5 min ?
I have an idea that its a write issue, as using a reader they are slower but quite ecceptable.
SQLite speed is affected most by how well the disk does random reads and writes; any SSD is much more better at this than any rotating disk.
Whenever changes overflow the internal cache, they must be written to disk. You should use PRAGMA cache_size to increase the cache to more than the default 2 MB.
Changed data must be written to disk at the end of every transaction. Make sure that there are as many changes as possible in one transaction.
If much of your processing involves temporary tables or indexes, the speed is affected by the speed of the main disk. If your machines have enough RAM, you can force temporary data to RAM with PRAGMA temp_store.
You should enable Write-Ahead Logging.
Note: the default SQLite distribution does not have encryption.
Related
I am not able to find maria DB recommended RAM,disk,number of Core capacity. We are setting up initial level and very minimum data volume. So just i need maria DB recommended capacity.
Appreciate your help!!!
Seeing that over the last few years Micro-Service architecture is rapidly increasing, and each Micro-Service usually needs its own database, I think this type of question is actually becoming more appropriate.
I was looking for this answer seeing that we were exploring the possibility to create small databases on many servers, and was wondering for interest sake what the minimum requirements for a Maria/MySQL DB would be...
Anyway I got this helpful answer from here that I thought I could also share here if someone else was looking into it...
When starting up, it (the database) allocates all the RAM it needs. By default, it
will use around 400MB of RAM, which isn’t noticible with a database
server with 64GB of RAM, but it is quite significant for a small
virtual machine. If you add in the default InnoDB buffer pool setting
of 128MB, you’re well over your 512MB RAM allotment and that doesn’t
include anything from the operating system.
1 CPU core is more than enough for most MySQL/MariaDB installations.
512MB of RAM is tight, but probably adequate if only MariaDB is running. But you would need to aggressively shrink various settings in my.cnf. Even 1GB is tiny.
1GB of disk is more than enough for the code and minimal data (I think).
Please experiment and report back.
There are minor differences in requirements between Operating system, and between versions of MariaDB.
Turn off most of the Performance_schema. If all the flags are turned on, lots of RAM is consumed.
20 years ago I had MySQL running on my personal 256MB (RAM) Windows box. I suspect today's MariaDB might be too big to work on such tiny machine. Today, the OS is the biggest occupant of any basic machine's disk. If you have only a few MB of data, then disk is not an issue.
Look at it this way -- What is the smallest smartphone you can get? A few GB of RAM and a few GB of "storage". If you cut either of those numbers in half, the phone probably cannot work, even before you add apps.
MariaDB or MySQL both actually use very less memory. About 50 MB to 150 MB is the range I found in some of my servers. These servers are running a few databases, having a handful of tables each and limited user load. MySQL documentation claims in needs 2 GB. That is very confusing to me. I understand why MariaDB does not specify any minimum requirements. If they say 50 MB there are going to be a lot of folks who will want to disagree. If they say 1 GB then they are unnecessarily inflating the minimum requirements. Come to think of it, more memory means better cache and performance. However, a well designed database can do disk reads every time without any performance issues. My apache installs (on the same server) consistently use up more memory (about double) than the database.
Before starting application, I just would like to know the feasibility here.
I have data around 15GB (text and some Images) stored in SQLite database of my SD Card, I need to access it from my application. Data will get increased on daily basis and may reach till 64 GB.
Can any one tell me limitations in accessing such huge database stored in SD card from the application?
SQLite itself supports databases in that range like 16-32GB (it may start working slower, but it should still work).
However, you are likely to hit a limit of FAT32 maximum file size, which is just 4GB - and this will be tough to overcome. SQLite allows to use attached databases which allow you to split it into smaller chunks, but this is really cumbersome.
If you can format your SD card as ext4, or use internal storage as ext4, then you should not really have big problems.
I have installed PostgreSQL 9.1 server on my production server.
I have Changed all the configuration(postgresql.conf) according to system.
Everything has been working fine for a week.
After this suddenly, postgresql server becomes very slow.
Even for count(*) query on a table.It is taking too much time.
After this I have done so many activities like:
Monitor Load on system :- Normal within range of 0.5 to 1.5.
Monitor No of users logged in application :- 200 to 400. Normal
Recreated Index
Kill the ideal transactions.
Check Locks (No DeadLock Found)
Application server restarted.
Database server restarted.
After doing this all activities the performance of database server is not increased.
It is taking so much time for normal queries also.
Then I drop the database and recreated then Performance Increases
Everything working after recreating the database.
But after some days suddenly performance goes down.
This sounds like the active portion of the database is growing large enough that it doesn't fit in cache, causing actual disk access (which is orders of magnitude slower) for many of your reads. This is often caused by not vacuuming aggressively enough.
Other factors could be related to your configuration of PostgreSQL and the operating system. It's hard to give much advice without knowing:
exactly what version of PostgreSQL you're using (9.1 tells us the major release, but the minor release sometimes matters),
how you have PostgreSQL configured,
what OS you're running on,
what hardware you are using (cores, RAM, drive arrays, controllers), etc.
Part of that can be supplied by posting the results of running the query on this page:
http://wiki.postgresql.org/wiki/Server_Configuration
It might also help to select relname, relpages, and reltuples from pg_class for the tables involved and compare numbers when things are running well to when they are slow.
With the additional information, people should be able to make some pretty specific recommendations.
We are trying to Integrate SQLite in our Application and are trying to populate as a Cache. We are planning to use it as a In Memory Database. Using it for the first time. Our Application is C++ based.
Our Application interacts with the Master Database to fetch data and performs numerous operations. These Operations are generally concerned with one Table which is quite huge in size.
We replicated this Table in SQLite and following are the observations:
Number of Fields: 60
Number of Records: 1,00,000
As the data population starts, the memory of the Application, shoots up drastically to ~1.4 GB from 120MB. At this time our application is in idle state and not doing any major operations. But normally, once the Operations start, the Memory Utilization shoots up. Now with SQLite as in Memory DB and this high memory usage, we don’t think we will be able to support these many records.
Q. Is there a way to find the size of the database when it is in memory?
When I create the DB on Disk, the DB size sums to ~40MB. But still the Memory Usage of the Application remains very high.
Q. Is there a reason for this high usage. All buffers have been cleared and as said before the DB is not in memory?
Any help would be deeply appreciated.
Thanks and Regards
Sachin
A few questions come to mind...
What is the size of each record?
Do you have memory leak detection tools for your platform?
I used SQLite in a few resource constrained environments in a way similar to how you're using it and after fixing bugs it was small, stable and fast.
IIRC it was unclear when to clean up certain things used by the SQLite API and when we used tools to find the memory leaks it was fairly easy to see where the problem was.
See this:
PRAGMA shrink_memory
This pragma causes the database connection on which it is invoked to free up as much memory as it can, by calling sqlite3_db_release_memory().
There's a following statement in SQLite FAQ:
A transaction normally requires two complete rotations of the disk platter, which on a 7200RPM disk drive limits you to about 60 transactions per second.
As I know there's a cache on the harddisk and there might be also an extra cache in the disk driver that abstract the operation that is perceived by the software from the actual operation against the disk platter.
Then why and how exactly are transactions so strictly bound to disk platter rotation?
From Atomic Commit In SQLite
2.0 Hardware Assumptions
SQLite assumes that the operating
system will buffer writes and that a
write request will return before data
has actually been stored in the mass
storage device. SQLite further assumes
that write operations will be
reordered by the operating system. For
this reason, SQLite does a "flush" or
"fsync" operation at key points.
SQLite assumes that the flush or fsync
will not return until all pending
write operations for the file that is
being flushed have completed. We are
told that the flush and fsync
primitives are broken on some versions
of Windows and Linux. This is
unfortunate. It opens SQLite up to the
possibility of database corruption
following a power loss in the middle
of a commit. However, there is nothing
that SQLite can do to test for or
remedy the situation. SQLite assumes
that the operating system that it is
running on works as advertised. If
that is not quite the case, well then
hopefully you will not lose power too
often.
Because it ensures data integrity by making sure the data is actually written on to the disk rather than held in memory. Thus if the power goes off or something, the database is not corrupted.
This video http://www.youtube.com/watch?v=f428dSRkTs4 talks about reasons why (e.g. because SQLite is actually used in a lot of embedded devices where the power might well suddenly go off.)