Re: Blob Performance

On Wed, 29 Oct 2003 10:02:08 -0500, Bill Hunt wrote: Do you have a sniffer? The docs say that if loc_size = -1 the blob is sent as a single unit. It would be interesing to watch the traffic on the port your app opens and see if indeed the 1K 'reads' are being packaged up into 32K blocks and send that way or are still being sent as individual 1K packets. Art > Hi Art, > One last thing. I modified the blobload program that comes with esql/c > to use the LOCUSER functions like you said. My loc_read function always seems > to get called with 1024(bytes to transfer), i can't seem to get this number > larger. I tried setting loc_bufsize but it seems to be ignored. I set > loc_size = -1 and also set fetchbufsize to 32767. Anything else i can do? > > Thanks, > Bill > > "Art S. Kagel" <kagel@bloomberg.net> wrote in message > news:pan.2003.10.28.18.45.17.210129.10594@bloomberg.net... >> On Tue, 28 Oct 2003 17:50:07 -0500, Bill Hunt wrote: >> >> Sorry, I try my best to avoid having anything more to do with WinXX than I > have >> to. >> >> Art S. Kagel >> >> > Thanks Art, >> > Is there anyway to change the packet size for a VB app using oledb? >> > Also there is a variable in setnet call FET_BUFF_SIZE that i set to > 32767. >> > After setting this value i seem to get much faster transfer rates > sometimes. >> > It actually seems that every other time I log in the speed goes from > fast to >> > extremely slow. Our customer periodially saves large blobs to the > DB(20-30 >> > meg) and they are complaing about performace(several minutes to save a > file). >> > The app is in VB.NET using the oledb provider from informix. The only > thing i >> > can think to do is to create the save code in a DLL written in esqlc and > use >> > the technique you describe to save the BLOB. Would this even be > possible? >> > >> > Thanks again, >> > Bill >> > "Art S. Kagel" <kagel@bloomberg.net> wrote in message >> > news:pan.2003.10.28.16.03.04.132216.10594@bloomberg.net... >> >> On Tue, 28 Oct 2003 12:05:00 -0500, Bill Hunt wrote: >> >> >> >> There are several things you can do to improve things: >> >> >> >> 1- Increase the size of the SQL Communications Buffer. This defaults > to >> > 4k. >> >> export FETBUFSIZE=32767 (the max value) in the environment of the > task >> > or set >> >> the global variable FetBufSize = 32767; in the program after opening >> > the >> >> database and before transferring any data. >> >> 2- By default BLOBS are copied to the server by a client in 1K packets >> > (which >> >> explains the 3000 packets for the 3MB BLBO!). You can change this > in >> > the >> >> loc_t structure before inserting the BLOB by setting loc_size to -1 > and >> > using >> >> the LOCUSER method (you can find sample loc_open, loc_read, and >> > loc_close >> >> functions in my ul.ec utility in the package utils2_ak in the IIUG >> > Software >> >> Repository, these are VERY simple functions). >> >> >> >> Art S. Kagel >> >> >> >> > Hello, >> >> > I am trying to track down a problem with inserting blobs. When i >> > save a >> >> > blob to a table that is around 3 meg it consistently takes 30 seconds > or >> > so. I >> >> > am using the blobload esqlc program that comes with the client >> > SDK(2.81). I >> >> > have the same problem using a VB app with the informix oledb driver. >> > The >> >> > client is running windows XP. At first i thought it was a network > issue >> > on >> >> > the LAN, but i can ftp the file to the server in only a second or > two. >> > Then I >> >> > though it was something to do with how the DB was storing the blobs, > but >> > I was >> >> > able to unload and then load a blob(the same 3 meg file) from > dbaccess>> > on the >> >> > server in about 4 seconds. My server is Intel solaris running IDS >> > 7.23UC1. >> >> > One weird thing i noticed is that when i FTP'd the file to the server > i >> > saw >> >> > 159 packets go out across the network, when i ran blobload there were >> > over >> >> > 3000 packets sent. Any idea what this could be or how I could >> > troubleshoot >> >> > the problem. >> >> > >> >> > Let me know if you need any more info. >> >> > >> >> > Bill