Dynamic files are also subject to the 2GB limit. The internals of static hashed and dynamic hashed files are exactly the same, except for the location of secondary group buffers. The decision about growing and shrinking the number of primary group buffers in dynamic files is external to the file structure, but requires that the secondary group buffers are in a separate file (OVER.30) so that the primary group buffers (in DATA.30) can increase.
So dynamic files are not a solution to the 2GB problem. You may have been confusing them with distributed files. A distibuted file is primarily a logical entity that acts as an "umbrella", containing one or more (static or dynamic) hashed files called part files. The individual part files can be accessed as usual. To define a distributed file there must be some attribute of the key in the part files that can be used to make the decision about which part file that record belongs in. This may require a bit of design work, and reallocation of records to correct part files before defining the distributed file. You can have as many part files as you desire in a distributed file. However, each part file remains limited to 2GB if 32-bit addressing remains in place. The individual part files are managed (inspected, RESIZE, etc) as usual. Hashed files with 64-bit addressing can go over the 2GB limit. Yoy can convert your hashed file to 64-bit addressing with RESIZE (RESIZE filename * * * USING dirpath). The theoretical upper limit is approximately 19 million TB, but some operating systems restrict you to 1 million TB. Applying 64-bit addressing does not absolve you from the responsibility of periodic RESIZE of hashed files, and much larger files will clearly take longer. You will also find that UVFIXFILE does not support files with 64-bit addressing; you will need to get your head around the new file fixing tool. With records that size I'd also be looking at the separation figure. It's a really awkward record size for storing in hashed files. You need a large separation (perhaps 32); otherwise many - most - of your records will be treated as oversized, incurring an I/O penalty when accessing them. For Dynamic files, the best you can achieve is 4KB groups, which mitigates against this choice. ----- Original Message ----- From: [EMAIL PROTECTED] Date: Thu, 29 Jan 2004 19:28:16 +0000 To: [EMAIL PROTECTED] (u2-Users) Subject: [UV] Resize - Dynamic or 64 bit? Hi all, UV 9.6 / HPUX 11 I have a hashed file approaching the 2 gig limit. I need some help determining whether to go with the dynamic or 64 bit option. Here are some specifics. The file is our inventory history file which is, as you can imagine, used heavily. Approximately 85 percent of the records are 4k in size. I have always frowned upon using dynamic files because they seem to be slower compared to hashed. Maybe because I have never attempted to figure out how to tune them. Can anyone give me the pros/cons of using the 64 bit versus dynamic option? Thanks in advance, Scott _______________________________________________ u2-users mailing list [EMAIL PROTECTED] http://www.oliver.com/mailman/listinfo/u2-users _______________________________________________ u2-users mailing list [EMAIL PROTECTED] http://www.oliver.com/mailman/listinfo/u2-users
