From: 88175839@CPHKVX.CPHK.HK
Newsgroups: comp.os.vms
Subject: Summary: DCL CONVERT cannot reduce file size
Date: 15 Oct 92 21:37:00 GMT
Reply-To: 88175839@cphkvx.cphk.hk
Organization: The Internet

My question was:

|> I recently discovered that after we deleted pages from the VTX
|> infobase with VTX workbench function, the VTX infobase files
|> did not become smaller.
|> 
|> Thus I tried DCL CONVERT (with many different combinations of qualifiers);
|> however, out of my expectation, only the actual size of the file became
|> smaller but not the allocated size.
|> 
|> Can someone help me to reclaim those unused disk blocks ?
|> 

(The FDL file is included at the end of this summary)

Summary of the responses and the tested results with my file:

Suggestion (1): Create an FDL of the file, change the allocation in the FDL,
		then point to the FDL when converting.
	Result: size changed from 978/978 to 488/489

Suggestion (2): anal/rms/fdl x.vtd
		edit/fdl/nointeractive/analysis=x.fdl x.fdl
		convert/fdl=x.vtd/statistics/share x.vtd
	Result: size changed from 978/978 to 447/537
		(I will adopt this method in my case)
	
Suggestion (3): SET FILE/TRUNCATE
	Result: -SET-E-NOTRUNC, truncation not allowed for this file organisation

Suggestion (4): use RMS indexed files with a single key (the relative
		record number). RMS will take care of all the reclamation 
		problem, including the tricky stuff with intrelocking
		shared write access, for you.
	Result: (I do not have control of this; the file is created by a VTX.)

Suggestion (5): Convert the file from indexed to sequential, 
		sequential back to indexed
	Result: (I did not try that)

Many thanks to	DBURKE.%VAXA.decnet@npt.nusc.navy.mil
		DMC@ADMIN.DRAKE.EDU
		PARSONS@gc.maricopa.edu
		bruce@ais.com
		winalski@adserv.enet.dec.com
		hmn@sparcler.cc.ncsu.edu (with example fits well to my case)

K.C. Tam

---------------------------------------------------------------------------

The FDL file:

IDENT	"15-OCT-1992 14:00:13	VAX/VMS ANALYZE/RMS_FILE Utility"

SYSTEM
	SOURCE                  VAX/VMS

FILE
	ALLOCATION              978
	BEST_TRY_CONTIGUOUS     no
	BUCKET_SIZE             8
	CLUSTER_SIZE            3
	CONTIGUOUS              no
	EXTENSION               0
	FILE_MONITORING         no
	GLOBAL_BUFFER_COUNT     0
	NAME                    "SYSSOFT:[SME]X.VTD;1"
	ORGANIZATION            indexed
	OWNER                   [SYSTEM]
	PROTECTION              (system:RWED, owner:RWED, group:RE, world:RE)

RECORD
	BLOCK_SPAN              yes
	CARRIAGE_CONTROL        none
	FORMAT                  variable
	SIZE                    998

AREA 0
	ALLOCATION              978
	BUCKET_SIZE             8
	EXTENSION               0

KEY 0
	CHANGES                 no
	DATA_KEY_COMPRESSION    yes
	DATA_RECORD_COMPRESSION yes
	DATA_AREA               0
	DATA_FILL               100
	DUPLICATES              no
	INDEX_AREA              0
	INDEX_COMPRESSION       yes
	INDEX_FILL              100
	LEVEL1_INDEX_AREA       0
	NAME                    ""
	NULL_KEY                no
	PROLOG                  3
	SEG0_LENGTH             16
	SEG0_POSITION           0
	TYPE                    string

ANALYSIS_OF_AREA 0
	RECLAIMED_SPACE         0

ANALYSIS_OF_KEY 0
	DATA_FILL               44
	DATA_KEY_COMPRESSION    68
	DATA_RECORD_COMPRESSION 37
	DATA_RECORD_COUNT       910
	DATA_SPACE_OCCUPIED     920
	DEPTH                   1
	INDEX_COMPRESSION       53
	INDEX_FILL              23
	INDEX_SPACE_OCCUPIED    8
	LEVEL1_RECORD_COUNT     115
	MEAN_DATA_LENGTH        347
	MEAN_INDEX_LENGTH       18