Trial Compression Analysis report
The Trial utility produces the Trial Compression Analysis report, as shown in the following examples. A report is produced for every segment type processed. Compression statistics and CPU usage are included for the compression techniques selected.
Figure 1. Example 1—Trial Compression Analysis report
TRIAL COMPRESSION ANALYSIS
DATABASE HDAMSHOP SEGMENT LA7S01AA
TYPE VARIABLE SIZE 218 335 PREFIX SIZE 34 SC 01 DSG 01
KEY LENGTH 15 OFFSET 2
COMPRESSION BASIC HARDWARE EXTENDED HYBRID STATIC
TECHNIQUE CHARACTER COMPRESSION CHARACTER COMPRESSION HUFFMAN
HARDWARE
TOTAL SEGMENTS 4197 4197 4197 4197 4197
COMPRESSED SEGS 4197 4197 4197 4197 4197
UNCOMPRESSED SEGS 0 0 0 0 0
INPUT BYTES 1208736 1208736 1208736 1208736 1208736
OUTPUT BYTES 535072 416776 564922 391072 381776
PERCENT COMPRESSION 55.73 65.52 53.26 67.65 68.42
COMPRESS CPU (SEC) 0.0104 0.0212 0.0342 0.0139 0.0156
EXPAND CPU (SEC) 0.0060 0.0090 0.0225 0.0115 0.0121
SEGMENT SIZE CUM AVG CUM AVG CUM AVG CUM AVG CUM AVG
RANGE TABLE PCT PCT SIZE PCT PCT SIZE PCT PCT SIZE PCT PCT SIZE PCT PCT SIZE
1 - 37 0.0 ( 0.0) 0 0.0 ( 0.0) 0 0.0 ( 0.0) 0 0.0 ( 0.0) 0 0.0 ( 0.0) 0
38 - 57 0.0 ( 0.0) 0 0.0 ( 0.0) 0 0.0 ( 0.0) 0 0.0 ( 0.0) 0 0.0 ( 0.0) 0
58 - 77 0.0 ( 0.0) 0 0.4 ( 0.4) 76 0.0 ( 0.0) 0 2.1 ( 2.1) 74 4.1 ( 4.1) 74
78 - 97 0.2 ( 0.2) 95 49.9 (50.3) 89 0.0 ( 0.0) 0 63.1 (65.2) 87 68.0 (72.1) 86
98 - 116 35.7 (35.9) 110 38.1 (88.4) 106 6.5 ( 6.5) 114 33.6 (98.8) 105 27.6 (99.6) 106
117 - 136 35.5 (71.4) 127 11.6 (100.0) 122 54.2 (60.7) 126 1.2 (100.0) 119 0.4 (100.0) 119
137 - 156 22.9 (94.3) 147 0.0 (100.0) 0 31.5 (92.2) 147 0.0 (100.0) 0 0.0 (100.0) 0
157 - 176 5.6 (99.9) 164 0.0 (100.0) 0 7.8 (100.0) 163 0.0 (100.0) 0 0.0 (100.0) 0
177 - 196 0.0 (100.0) 178 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
197 - 216 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
217 - 236 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
237 - 256 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
257 - 275 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
276 - 295 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
296 - 315 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
LARGER THAN 316 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
AVERAGE SEGMENT SIZE 127 99 135 93 91
MINIMUM SEGMENT SIZE
(BYTES) 74 74 74 74 74
MSL SEGMENT SIZE 127 99 135 93 91
MSL COMPRESS PCT 55.73 65.52 53.26 67.64 68.41
DATA PACKER/IMS (C) COPYRIGHT 1982-2007 BMC SOFTWARE, INC. AS AN UNPUBLISHED WORK
Figure 2. Example 2—Trial Compression Analysis report
TRIAL COMPRESSION ANALYSIS
DATABASE HDAMSHOP SEGMENT LA7S01AA
TYPE VARIABLE SIZE 218 335 PREFIX SIZE 34 SC 01 DSG 01
KEY LENGTH 15 OFFSET 2
COMPRESSION CUSTOM SHARED TABLE BUILD CUST HW DICT BUILD
TECHNIQUE HUFFMAN HDSHST HDSHCD
HARDWARE
TOTAL SEGMENTS 4197 4197 4197
COMPRESSED SEGS 4197 4197 4197
UNCOMPRESSED SEGS 0 0 0
INPUT BYTES 1208736 1208736 1208736
OUTPUT BYTES 307480 307480 338298
PERCENT COMPRESSION 74.56 74.56 72.01
COMPRESS CPU (SEC) 0.0222 0.0235 0.0213
EXPAND CPU (SEC) 0.0114 0.0123 0.0051
SEGMENT SIZE CUM AVG CUM AVG CUM AVG
RANGE TABLE PCT PCT SIZE PCT PCT SIZE PCT PCT SIZE
1 - 37 0.0 ( 0.0) 0 0.0 ( 0.0) 0 0.0 ( 0.0) 0
38 - 57 2.0 ( 2.0) 56 2.0 ( 2.0) 56 0.4 ( 0.4) 54
58 - 77 63.2 (65.2) 68 63.2 (65.2) 68 48.0 (48.4) 70
78 - 97 34.3 (99.5) 83 34.3 (99.5) 83 40.5 (88.9) 86
98 - 116 0.5 (100.0) 100 0.5 (100.0) 100 9.6 (98.5) 104
117 - 136 0.0 (100.0) 0 0.0 (100.0) 0 1.5 (99.9) 121
137 - 156 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 140
157 - 176 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
177 - 196 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
197 - 216 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
217 - 236 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
237 - 256 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
257 - 275 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
276 - 295 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
296 - 315 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
LARGER THAN 316 0.0 (100.0) 0 0.0 (100.0) 0 0.0 (100.0) 0
AVERAGE SEGMENT SIZE 73 73 81
MINIMUM SEGMENT SIZE
(BYTES) 74 74 74
MSL SEGMENT SIZE 77 77 83
MSL COMPRESS PCT 73.17 73.17 71.24
DATA PACKER/IMS (C) COPYRIGHT 1982-2007 BMC SOFTWARE, INC. AS AN UNPUBLISHED WORK
The following fields are included in the Trial Compression Analysis report:
DATABASE | Name of the database | ||||||||
|---|---|---|---|---|---|---|---|---|---|
SEGMENT | Name of the segment type | ||||||||
TYPE | Type of segment, fixed or variable | ||||||||
SIZE | Size of the segment For variable-length segments, the minimum and maximum sizes of the segment are given. | ||||||||
PREFIX SIZE | Size of the segment prefix | ||||||||
SC | Segment code | ||||||||
DSG | Data set group code (this field is not present for partitions) | ||||||||
KEY LENGTH | Length of the key | ||||||||
OFFSET | Offset of the key relative to 1 | ||||||||
COMPRESSION TECHNIQUE | Each compression technique used during the Trial utility One or more of the following values can be indicated:
For SHARED TABLE TRIAL, the table name and record level are included; for SHARED TABLE BUILD, only the table name is displayed. For CUSTOM HARDWARE DICTIONARY TRIAL, the dictionary name and record level are included; for CUSTOM HARDWARE DICTIONARY BUILD, only the dictionary name is displayed. | ||||||||
TOTAL SEGMENTS | Number of segments presented for the Trial utility | ||||||||
COMPRESSED SEGS | Number of segments compressed during the Trial utility | ||||||||
UNCOMPRESSED SEGS | Number of segments presented for the Trial utility that were not compressed Segments are not compressed if compression results in making the segment larger because of compression overhead. Variable-length segments with fewer than 20 bytes after the key are not compressed. | ||||||||
INPUT BYTES | Number of bytes presented for the Trial utility, including the key | ||||||||
OUTPUT BYTES | Resulting number of bytes after compression, including the key | ||||||||
PERCENT COMPRESSION | Compression percentage attained by each compression technique The percent is calculated according to the following formula: (1 - OUTPUT BYTES/INPUT BYTES) | ||||||||
COMPRESS CPU (SEC) | Number of CPU seconds needed to compress the data sampled during the Trial utility This number allows you to compare the CPU used by the different compression techniques. | ||||||||
EXPAND CPU (SEC) | Number of CPU seconds needed to expand the data sampled during the Trial utility This number allows you to compare the CPU used by the different compression techniques. You must include the EXPAND Trial utility keyword (see EXPAND) to obtain expansion statistics. | ||||||||
SEGMENT SIZE RANGE TABLE | Table showing ranges of segment sizes For each segment size and compression technique, the following information is presented:
| ||||||||
AVERAGE SEGMENT SIZE | Average compressed segment size for each compression technique The average size is calculated by dividing the output bytes by total segments. | ||||||||
MSL | The following fields are displayed only when you specify MSL: | ||||||||
MINIMUM SEGMENT SIZE | Number of bytes specified for the MSL If you specify a percentage rather than bytes, then (PERCENTAGE(nn)) is indicated, and the length is calculated based on the percentage specified. | ||||||||
MSL SEGMENT SIZE | Average compressed segment size taking the MSL into consideration The Trial utility sets all segment occurrences that compress smaller than the MSL equal to the MSL and calculates a new average segment length. | ||||||||
MSL COMPRESS PCT | Compression percentage attained by each compression technique if the segments are compressed with the MSL specified | ||||||||
FPS | The following fields are displayed only when you specify FPS: | ||||||||
FIXED PAD SIZE | Number of bytes specified for the FPS | ||||||||
PADDED SEGMENT SIZE | Average compressed segment size taking the FPS into consideration The Trial utility sets all segment occurrences equal to the compressed segment size plus the FPS and calculates a new average segment length. | ||||||||
PADDED COMPRESS PCT | Compression percentage attained by each compression technique if the segments are compressed with the FPS specified |