Clarification Re: Writing data to blobspace

In article <jsutherl.17.000A97CD@polo.waterloo.ncr.com> jsutherl@polo.waterloo.ncr.com (John Sutherland) writes: >From: jsutherl@polo.waterloo.ncr.com (John Sutherland) >Subject: Re: Writing data to blobspace >Date: Mon, 7 Feb 1994 15:35:30 GMT >In article <2iru6q$u9@corolla.eng.sc.rolm.com> daniel@corolla.eng.sc.rolm.com (Dan Jatnieks) writes: >>From: daniel@corolla.eng.sc.rolm.com (Dan Jatnieks) >>Subject: Writing data to blobspace >>Date: 3 Feb 1994 14:35:06 -0800 >>The Informix-Online Administrator's Guide (v5.0) has the following to >>say about storing data in blobspace: >> "At any time, only one set of blobspace blob buffers can be >> used to transfer blobspace blob data. That is, only one user >> process can transfer blobspace blob data to the disk at a time." >>This seems to be saying that all access to blobspace is serial by user >>process. E.g. If I write a large, say 1Mb, piece of data into blobspace, >>then some other user must wait until all 1Mb of my data is stored to disk >>before writing their, say 2K piece of data. >>My question is why is this? It would seem to make accessing blobspace >>very slow. Can't this be designed so as to interleave by blobpage size? >>This would improve blob throughput, IMO. >>Also: >> "Blob data is transferred from the application development tool >> to the Online database server in 1-kilobyte chunks." >>The question is why doesn't it transfer the size of a blobspace page >>(at least up to some reasonable maximum size)? >>-- >> >============================================================================= >I have analyzed detailed sar output from our benchmarks doing blob reads and >writes. At least on NCR platforms, I can guarantee that the actual data >transfer is done in blobspace page size units. >========================================================================== > A clarification to my previous posting: 1) BLOB data written to disk is written exactly in blobspace page size units. For example if you have a 2KB BLOB being written to a blobspace with a 32KB page size, the data transfer to disk will be 32KB. 2) Data transfers from a workstation on the network to an Informix database server are done in roughly 1KB units to the buffers on the server. Although this may not be very efficient use of the network, it seems to be integral to the Informix architecture. We had a situation where larger transfer units would have been quite helpful and were told emphatically that it couldn't be done. ========================================================================== John Sutherland Principal Consultant Systems Performance Group 1490 Liveoak Drive Mississauga, Ontario Canada L5E 2X1 phone: (905) 891-8593 e-mail: jsutherl@tron.waterloo.ncr.com