HP 3000 Manuals HP 3000 Manuals
CHECK PATH
Checks paths for broken chains and incorrect pointer linkages and reports
any problems.
Syntax
{@ }
CHE[CK] PAT[H] {MasterSetName } [Quick]
{DetailSetName {( @ ) }}
{ {(SearchItemName) }}
Parameters
@ indicates that you want to check all paths in all
data sets in the database.
MasterSetName is the name of the master data set whose synonym
chains should be checked.
DetailSetName is the name of the detail data set whose paths should
be checked. The following parameters can be
specified with DetailSetName:
(@) indicates that you want to check
all the paths in a detail data
set.
(SearchItemName) is the name of the search item
defining the path to be checked.
Quick is a fast method of checking paths to validate
pointer integrity. If you specify the Quick
parameter, paths are checked using a serial read.
Using this option, the command reports if the paths
have problems, but does not indicate the location.
Description
NOTE Before using the CHECK PATH command, read chapter 8, "Maintaining
the Database."
Use this command to check paths for broken chains or incorrect pointer
linkages. For a master data set, the CHECK PATH command follows and
examines synomym chain pointers. For a detail data set, the CHECK PATH
command follows and examines detail chain pointers and the chain head
pointers in the associated master data sets.
The path checking process begins only after you issue a PERFORM COMMANDS.
Example 1
In the example below, all the paths in the ORDERS database are checked
using the CHECK PATH command without the Quick parameter. A description
of the output follows the example.
>base orders
>check path @
Check Path issued for 5 set(s).
>perform commands
PERFORM COMMANDS now or create job file [job/y/N]? y
Please wait ...
HP36386 (A.00.00) DBALTER (c) COPYRIGHT Hewlett-Packard Co. 1985
FRI, MAY 25, 1990, 11:12 AM
Database has been modified since last DBSTORE (DBA 220).
Continue [y/N] ? y
Starting data set serial reads.
.....
Tabulating statistics.
CHECK PATH
Pct
Set Name Type Max Avg Std Far Avg Packing
Search Item (PS) Chain Chain Dev Ptrs Blocks Ratio
----------------------------------------------------------------------
CUSTOMER M
SYNONYM CHAINS 1 1.00 0.00 0 1.00 N/A
PRODUCT M
SYNONYM CHAINS 2 1.07 0.25 0 1.00 N/A
SALES D
ACCOUNT ( S) 17231 2874.67 7033.14 6 1.17 6.86
STOCK# (P ) 5 2.13 1.64 6 1.13 0.89
SUP-MASTER M
SYNONYM CHAINS 1 1.00 0.00 0 1.00 N/A
INVENTORY D
STOCK# 1 1.00 0.00 0 1.00 1.00
SUPPLIER (P ) 5 5.00 0.00 0 1.00 1.00
Starting data set chained reads.
......
CHECK INFORMATION
Set Name Type
Search Item
Message(s)
------------------------------------------------------------------------
CUSTOMER M
Userlabel entry count does not match synonym chain count (CHK 570).
Record 6 is not linked into the proper synonym chain (CHK 360).
SALES D
ACCOUNT (Path 1; linked to master CUSTOMER, path 1)
Path Chain inconsistencies detected (CHK 400).
Sum of chain counts in the related master set does not
match bitmap entry count for this set (CHK 580).
Chainhead record 113 chain count mismatches entries on chain (CHK 450).
Record 3 contains bad backward pointer (CHK 440).
Record 14 contains bad backward pointer (CHK 440).
Record 15 is not linked into the proper chain (CHK 460).
Record 16 contains bad forward pointer (CHK 430).
STOCK# (Path 2; linked to master PRODUCT, path 1)
Path Chain inconsistencies detected (CHK 400).
Chainhead record 267 contains bad forward pointer (CHK 410).
Chainhead record 267 contains bad backward pointer (CHK 420).
Chainhead record 267 chain count mismatches entries on chain (CHK 450).
Record 15 is not linked into the proper chain (CHK 460).
HP36386 (A.00.00) DBCHANGE (c) COPYRIGHT Hewlett-Packard Co. 1985
>
Following is a description of the CHECK PATH output:
Data Set Name is the name of data set whose paths are being
checked.
Search Item Name is the name of the search item. Because master data
sets do not contain search items, but rather key
items, the text SYNONYM CHAINS appear in the field
instead. For detail data sets, the search item name
appears in the field.
Type is the data set type. Valid data set types are as
follows:
M is for manual master data sets.
A is for automatic master data sets.
D is for detail data sets.
Other codes that appear in this column are as
follows:
P designates primary paths.
S designates sort items.
Max Chain is the maximum number of entries in the longest
synonym or detail chain.
Avg Chain is the average number of entries per chain.
Std Dev is the standard deviation, which indicates the
accuracy of the Avg Chain statistic. The closer to
0.00 this number is, the more accurate the Avg Chain
statistic is.
Pct Far Ptrs is percent far pointers. This number is the
percentage of forward pointers that point outside the
current block.
Avg Blocks is the average number of blocks per chain.
Packing Ratio is the efficiency of the path. This is calculated by
the optimal number of blocks per chain divided by the
actual number of blocks per chain.
Example 2
In the example below, all the paths in the detail data set INVENTORY are
checked using the Quick parameter. A description of the output follows
the example.
>base orders
>check path inventory ( @ ) quick
CHECK PATH issued for 1 set(s).
>perform commands
PERFORM COMMANDS now or create job file [job/y/N]? y
Please wait ...
HP36386 (A.00.00) DBALTER (c) COPYRIGHT Hewlett-Packard Co. 1985
FRI, MAY 25, 1990, 11:14 AM
Database has been modified since last DBSTORE (DBA 220).
Continue [y/N] ?y
Starting data set serial reads.
...
Tabulating statistics.
CHECK PATH
Pct
Set Name Type Max Avg Std Far Avg Packing
Search Item (PS) Chain Chain Dev Ptrs Blocks Ratio
----------------------------------------------------------------------
INVENTORY D
STOCK# 1 1.00 0.00 0 1.00 1.00
SUPPLIER (P ) 5 5.00 0.00 0 1.00 1.00
Starting data set chained reads.
CHECK INFORMATION
Set Name Type
Search Item
Message(s)
------------------------------------------------------------------------
No problems were detected by CHECK.
HP36386 (A.00.00) DBCHANGE (c) COPYRIGHT Hewlett-Packard Co. 1985
The output for the CHECK PATH command using the Quick parameter is the
same as the standard CHECK PATH output; however, a summary version of the
standard CHECK INFORMATION output is displayed. Problems are identified,
but the specific location and records that need fixing are not isolated.