Re: [Oorexx-users] oosqlite ? step and result

[hakan <he...@us...>]

Staffan
Here is the results from my test run. 3 times for each type.
Table 1 contains unique keys and table 2 contains records to these keys (one to many relation)
Count is total items in each table.
Timer is started just before database open and ends after database close.
In the case for exec I do an iteration over the result from table 2, but do nothing. 

Using ~bindtext is faster than to create a total new query, looking the same except for the key (in table2), each time, as you can see.

I also agree that exec is more convenience to use and that even if one can cut the time reading a sqltable, it doesn't matter,
 if the result is to be presented in a ooDialog tree or whatever, that's where the time is spent (at least in my case, showing the (exec) result in a ooDialog treeview, we talk minutes!)

Anyway, I will later also try out your suggestion to use callback to construct my own directory objects when using step.
I will take it step by step :-)
/hex

---------------------------------------------------------
 - SQL exec -
Table 1 items 27982
Table 2 items 234988
Elapsed time 00:00:10.340000
 - SQL exec -
Table 1 items 27982
Table 2 items 234988
Elapsed time 00:00:10.071000
 - SQL exec -
Table 1 items 27982
Table 2 items 234988
Elapsed time 00:00:10.123000
----------------------------------------------------------
 - SQL step -
Table 1 items 27982
Table 2 items 234988
Elapsed Time  00:00:05.602000
 - SQL step -
Table 1 items 27982
Table 2 items 234988
Elapsed Time  00:00:05.971000
 - SQL step -
Table 1 items 27982
Table 2 items 234988
Elapsed Time  00:00:06.919000
---------------------------------------------------------
 - SQL Bind step -
Table 1 items 27982
Table 2 items 234988
Elapsed Time  00:00:02.450000
 - SQL Bind step -
Table 1 items 27982
Table 2 items 234988
Elapsed Time  00:00:02.460000
 - SQL Bind step -
Table 1 items 27982
Table 2 items 234988
Elapsed Time  00:00:02.460000
-------------------------------------------------------------

I used this for the timer

timer = .timer~new

    my testcode

say timer~elapsed


::class timer
::method init
   self~reset
::method reset
   expose timestamp
   timestamp = .datetime~new
::method elapsed
   expose timestamp
   return .datetime~new - timestamp


----- Ursprungligt Meddelande -----
Från: Staffan Tylen <sta...@gm...>
Till:<he...@us...> , Open Object Rexx Users <oor...@li...>
Kopia:
Datum: lördag, 20 oktober 2012 22:13
Ämne: Re: [Oorexx-users] oosqlite ? step and result


I have tried sql statements with :aname or ?1 or etc and then bind a value to that parameter with ~bindtext as I think I get a performance gain by doing so, part of the sql is already "compiled" by sqlite and it would be conveniant to get the result back as directory object for each step.
As I followed the conversation about "performance observation..." I realized that creating the directory objects with (~exec) current implementation take some resources, I have tables with ~300 000 rows and ~10 columns, and wants to have the convineance of using the directory objects as reference to the returned row together with the ~bindtext possibility, less changes to some existing code I have :-).
/hex



OK, I see what you mean. My immediate reaction is - because Rexx is an interpretive language, even if compiled, there is the possibility that there is very little to gain from using SQL bind. I believe the effort for SQLite to compile an SQL statement is almost negligible compared to Rexx compiling and executing a Rexx statement. I started to look into the possibility of using bind but found that I had nothing to gain, it just complicated my coding. As I've stated earlier, by using exec all the major processing is done in compiled code in contrast to step, where Rexx must be called for each row. I can imagine that handling 300,000 rows in Rexx will have an impact on performance.

In any case it would be very interesting if you had a chance to make a performance comparison between the two. For this you would need to establish the input and the exact format of the output, then build the step and exec routines that when executed will take you from A to B. Then use the time("E") function to time each of them.

Also remember that when you use exec you also have the callBack functionality available where you can handle individual rows just like step to build for example a directory. If I remember correctly, in the callBack routine you also have the power to terminate a query before you have processed all rows, just like step.

Staffan