[fdo-users] SQLite provider and transactions/batch inserts/

[Traian Stanev]

Hi Igor.

Your loop should be fast even in 3.4. The provider has since (almost) the beginning used a SQLite transaction internally to do bulk inserts in the way your code shows. 

It is strange that you are getting bad performance then -- but hard to tell why without getting more information. You can try not bulking the insert manually (so create the Insert command only once). Also take a look at SQLteConverter.cpp which has a similar workflow for converting large files -- and compare to see what it does differently. Also, what kind of geometry are you inserting?


Traian

________________________________________
From: fdo-users-bounces at lists.osgeo.org [fdo-users-bounces at lists.osgeo.org] On Behalf Of Igor Jarm [igor at sl-king.com]
Sent: Monday, April 26, 2010 7:55 AM
To: fdo-users at lists.osgeo.org
Subject: [fdo-users] SQLite provider and transactions/batch inserts/

Hello all!

I'm using SQLite FDO provider and need fast insert capabilities.

I had 4 options to test:
- individual inserts
(- transactions - not supported)
(- batch insert - not supported)
- compiled queries (*** see below)

I expected compiled queries would be comparable to SQLite transactions.
I'm, using code, that looks like this:

FdoPtr<FdoIInsert> ins = (FdoIInsert*)conn->CreateCommand(FdoCommandType_Insert);
while(!done)
{
    FdoPtr<FdoIFeatureReader> fr = ins->Execute();
    if(enoughExecutesToCommitToDatabase)  //100,1000,...
        ins = (FdoIInsert*)conn->CreateCommand(FdoCommandType_Insert);   //make a new one and release the old one
}


These are the results of timing 1000 inserts compared to unoptimized SQLite implementation:

- SQLite: 10.83s, 0.0108s per insert
- SQLite, transactions, 1000 per transaction: 0.19s, 0.0002s per insert
- FDO: 9.57s, 0.0096s per insert
- FDO: compiled queries, 1000 per commit, 9.49s, 0.0095s per insert
- FDO: compiled queries, 100 per commit, the same, etc. ...

Compiled queries are the same as executing individual inserts, .
Of course I could use SQLite directly but I have to keep everything in FDO.

Am I missing something?
Are there some plans to implement transactions or batch inserts for SQLite FDO provider?
Or is there some other way to speed up the inserts?

Thank you.

Igor Jarm



***
//Insert is special. We attempt to speed up inserts if the caller is cooperating.
//The contract is as follows -- as long as the caller reuses the SltInsert object,
//he is working with a compiled query and within a single transaction. Whenever
//the command object is freed, the transaction is committed.
class SltInsert : public SltCommand<FdoIInsert>
...