World: r3wp
[SQLite] C library embeddable DB .
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Robert 21-Apr-2009 [1014] | I'm pretty sure a proxy process can handle 200req/s at the frontend and backend. So if 200req/s is the maximum you can get from one process, adding more processes just devides this down. But it won't scale up. |
sqlab 21-Apr-2009 [1015] | Robert, that could be a solution. Unfortunately I observed a crosstalk of events with many ip connections, means one process is awakened without data available, if I send data additionaly on the same server via ip |
Robert 21-Apr-2009 [1016] | Don't understand the problem. Is it realted to my suggestion or your current try? |
sqlab 21-Apr-2009 [1017x2] | If I have some processes serving incoming events and sending their data to a central storage process, the central process sometimes seems to get an event, but not the data with that event. When the data really arrives, I do not get the event. Maybe he got the first event meant for an other connection |
As I know, that there should be data available, I read again after timeout | |
Robert 21-Apr-2009 [1019] | Event = TCP/IP event? |
sqlab 21-Apr-2009 [1020] | yes |
Robert 21-Apr-2009 [1021] | Hm... normaly there should be event/data |
sqlab 21-Apr-2009 [1022] | normally there is, but not always. Most socket connections are static, they stay connected for hours or longer. |
Pekr 30-Apr-2009 [1023] | Reading thru SQLite changelog found this - http://sqlite.org/rtree.html ... not sure of its practical usability, but some of you might find it interesting :-) |
Maxim 30-Apr-2009 [1024] | I love the sqlite motto :-) Small. Fast. Reliable. Choose any three. |
Pekr 30-Apr-2009 [1025] | rebol.com motto - Web 3.0 starts here. Smarter, faster, better. |
Janko 30-Apr-2009 [1026] | only that fast (at sqlite) is still a little problematic to me |
Pekr 30-Apr-2009 [1027] | SQLIte is fast for simple to middle local stuff. I have few obstacles with it 1) it stores everything in one file. You can't use simplicity of file-system for simple back-up purposes. Attaching DBs (max 10 precompiled value) is not an option, as then transactions are not atomic 2) it is not secure - can't be secured easily, because encryption is not part of the package 3) serverless (both advantage = no install, but also disadvantage). It provides locking. They claim multiple instances of app can access one file, but I did not find more info on that. Dunno how granular locking you can do. You have to create server front-end yourself ... |
Janko 30-Apr-2009 [1028x3] | I use it for very simple task just so it takes case for locking of messages to bots that can come from multiple processes.. but at my small/cheap VPS that I use for bots update/insert/delete takes multiple seconds which is very bad.. all rebol writes/deletes which it does with normal files return imediately on same VPS and yesterday I tried rebDB and it was also much much faster for insert/update/delete (almost no noticable delay) for the same amount of data (300 lines) as sqlite.. funny thing is that sqlite delays the same at these operations if there is 300 or 5000 rows in table |
(I tried rebDB on same VPS - localy where comp. is fast I notice no delay at sqlite either) | |
and this is no problem with rebol binding as the delays are the same if I go to sqlite3 shell | |
Pekr 30-Apr-2009 [1031] | Have you tried put BEGIN transaction and END transaction outer commands? Because if not, then it commits each time. The difference is going to be ... well, drastic ... |
Janko 30-Apr-2009 [1032] | yes, I know for that .. that would come into play if I would be doing 10 inserts for example ,.. with begin commit it would take just 1/10 of time as without , but I am doing a simple sql scentence here. and I tried begin/commit also with this. |
Pekr 30-Apr-2009 [1033] | ah, single query? |
Janko 30-Apr-2009 [1034] | yes, and nothing big.. 5 simple rows |
Pekr 30-Apr-2009 [1035] | show me the table structure, show me the query :-) |
Janko 30-Apr-2009 [1036x2] | I talked about this in detail a while ago.. now I optimised the problem so it's not a biggie any more but I am still mad that all rebol files can do changes in moments and when I need to update the sqlite page halts for noricable time |
any query I try :) .. I talked about this to you already :) .. look a little up at 14-Apr | |
Pekr 30-Apr-2009 [1038] | Janko - I did small test for you. With no indices the speed was: 0:00:00.516 and I used LIKE expressions, which need to do searches in terms of field values .... REBOL [] print "Starting test for Janko ..." do %sqlite.r attempt [delete %janko.db] connect/direct/create %janko.db sql { CREATE TABLE [domains] ( [id] INTEGER NOT NULL PRIMARY KEY, [domain] VARCHAR NOT NULL, [user] VARCHAR NOT NULL, [processed] DATETIME NULL, [ok_count] INT NOT NULL DEFAULT 0, [fail_count] INT NOT NULL DEFAULT 0, [error] TEXT NULL ) } sql "BEGIN" for i 1 1000 1 [ sql reduce ["insert into domains values(?,?,?,?,?,?,?)" i i i i i i i] ] sql "COMMIT" start: now/time/precise sql {update domains set user = 'u3' where domain like '%1%' and user like '%1%'} print now/time/precise - start disconnect %janko.db halt |
Janko 30-Apr-2009 [1039x2] | hm... mucho interesante :) |
I will try this on my local computers and then on that VPS.. and report you back :) | |
Pekr 30-Apr-2009 [1041] | btw - what is VPS? |
Janko 30-Apr-2009 [1042x2] | virtual private server ... like you can buy here .. www.linode.com or sliceshare.com |
it's like you have your own computer that you can reinstall stuff or OS .. separated from others but it's running on virtualisation software so there are many such separate computers per one real computer , so it's *cheaper* than paying for having a full server | |
Pekr 30-Apr-2009 [1044] | ah, virtual machine, ok ... |
Janko 30-Apr-2009 [1045x2] | you can put cheyenne there or any other custom server you want |
yes | |
Janko 9-May-2009 [1047x4] | hm.. I have a question for SQL / sqlite experts : I have a query with two JOINS . There is parent table which has 2 subtables ... in each subtable I need to aggregate (SUM) some value ... select i.*, SUM(ib.price * ib.qty) as amount, SUM(ip.amount) as payed_amount from invoice_sent as i left outer join invoice_sent_b as ib on i.id = ib.id_invoice_sent left outer join invoice_sent_p as ip on i.id = ip.id_invoice_sent group by i.id order by i.title; The problem is tha because of join , the amount is correct , is the sum of values in invoice_sent_b , but payed_amount is multiplied by the number of rows invoice_sent_b has . I understand why this happens, but I don't know how to prevent it, if I want to get all data in one query. ( I know how to solve the prolem , but it's outside the DB so it's more of a hack -- I also ger COUNT of _b table rows and divide second SUM by it on client ) |
ah, my method with count won't work because count also multiplies if I have more than 1 columnt in second subtable | |
This guy has totally the same problem but no answer http://forums.devshed.com/db2-development-114/left-outer-join-3-tables-sum-field-of-2nd-3rdt-588801.html | |
found solution. I need to join with subqueries: {SELECT * FROM } table { as i LEFT OUTER JOIN ( SELECT id_} table { as ibs_paren, SUM(price * qty) as amount FROM } table {_b ib GROUP BY id_} table { ) ibs ON i.id = ibs_paren LEFT OUTER JOIN ( SELECT id_} table { as ips_paren, SUM(ip.amount) as payed_amount FROM } table {_p ip GROUP BY ip.id_} table { ) ips ON i.id = ips_paren order by title; | |
Chris 21-May-2009 [1051x3] | Has anyone done any benchmarks for running scripts from a DB instead of from the filesystem? |
Say, where there are a moderate number of moderate sized scripts - could it be quicker just to fire up an SQLite connection and access the scripts/modules from records as opposed to flat file? | |
Perhaps particularly a CGI environment where each instance is a separate process? | |
Janko 21-May-2009 [1054] | If you had persistent connection and if sqlite does some caching it could be faster, but if you need to open a connection on each request I think it would be much slower because that is more expensive (I assume).. it probably also matters how many scripts do you need to run per request |
Gregg 21-May-2009 [1055x2] | The OS caches things too, don't forget. |
It shouldn't be hard to devise a small benchmark though. | |
RobertS 22-May-2009 [1057] | . |
amacleod 26-May-2009 [1058] | I seem to get an error with sqlite after using "call" to start an external program. ** User Error: SQLite out of memory ** Near: make error! reform ["SQLite" error] Anyone experience this? |
Janko 26-May-2009 [1059] | Check if you have the right path to file.. and make it an absolute path.. and if you have the right version .. sqlite != sqlite3 |
amacleod 26-May-2009 [1060] | It works fine until I try to call another app. Paths do not change but I'm not using absolute paths. I'll need to test that... |
Janko 26-May-2009 [1061] | I got similar error but I don't know if it was for the relative path or not the right version of dll / so |
amacleod 26-May-2009 [1062] | I changed all the paths to absolute paths...it seems to have done the trick. Thanks for the hint, Janko! |
Janko 26-May-2009 [1063] | youre welcome |
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