Requests display of data fields from a database page. An
individual DISPLAY command can include only one of the display
options shown. If no parameters are specified (you only specify
DISPLAY), RdbALTER displays the last object of a PAGE, a DISPLAY,
or a DEPOSIT command.
1 – Format
(B)0[mq> [4mDISPLAY[m qwqqqqqqqq>qqqqqqqwqwqqqqqqqqqqqqqqqqqqqqqqwq>
mq> page-number qj tq> * qqqqqqqqqqqqqqqqqu
tq> [4mSTORAGE_AREA[m qqqqqqu
tq> [4mCHECKSUM[m qqqqqqqqqqu
tq> [4mCOUNT[m qqqqqqqqqqqqqu
tq> display-data qqqqqqu
tq> [4mFREE_SPACE[m qqqqqqqqu
tq> [4mHEADER[m qqqqqqqqqqqqu
tq> display-entry qqqqqu
tq> display-index qqqqqu
tq> display-line qqqqqqu
tq> [4mLOCKED_SPACE[m qqqqqqu
tq> [4mNUMBER[m qqqqqqqqqqqqu
tq> [4mSPACE[m range qqqqqqqu
tq> [4mTIME_STAMP[m qqqqqqqqu
tq> [4mNEXT_AIP[m qqqqqqqqqqu
mq> [4mAIP_ENTRIES[m qqqqqqqj
(B)0[mdisplay-data =
qq> [4mDATA[m qwqwqqqqqqqqq>qqqqqqqwqwqqqqqqq>qqqqqqwqwq> offset qq>
x tq> /[4mDECIMAL[m qqqqqu tq> /[4mBYTE[m qqqqqu x
x mq> /[4mHEXADECIMAL[m qj tq> /[4mLONGWORD[m qu x
x mq> /[4mWORD[m qqqqqj x
mq> /[4mASCII[m qqwqqqqqq>qqqqqwqqqqqqqqqqqqj
mq> : qq> n qj
(B)0[mdisplay-entry =
qq> [4mENTRY[m qwqqq>qqwqwqqqqqqqqq>qqqqqqqqwqq>
tq> n qu tq> * qqqqqqqqqqqqqu
mq> * qj tq> [4mABM[m qqqqqqqqqqqu
tq> [4mLOGICAL_AREA[m qqu
tq> [4mPHYSICAL_AREA[m qu
tq> [4mALENGTH[m qqqqqqqu
tq> [4mANAME[m qqqqqqqqqu
tq> [4mTSN[m qqqqqqqqqqqu
tq> [4mRECORD_LENGTH[m qu
mq> [4mINUSE[m qqqqqqqqqj
(B)0[mdisplay-index =
qq> [4mINDEX[m qwqqq>qqwqwqqqqq>qqqqqwqq>
tq> n qu tq> * qqqqqqu
mq> * qj tq> [4mLENGTH[m qu
mq> [4mOFFSET[m qj
(B)0[mdisplay-line =
qq> [4mLINE[m qwqqq>qqwqwqqqqqqqq>qqqqqqqwqq>
tq> n qu tq> * qqqqqqqqqqqu
mq> * qj mq> [4mRECORD_TYPE[m qj
(B)0[mrange =
wq> * qqqqqqqqqqqqqqqqqqqqqqqqq>qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqwq>
mq> lower-data-page-number qwqqqqqqqqqqqqqqqq>qqqqqqqqqqqqqqqqqwj
mq> : qq> higher-data-page-number qj
2 – Arguments
2.1 – page-number
Identifies the page whose information you want to display. The
current page is the default.
2.2 – *_(asterisk)
Displays the entire page.
2.3 – STORAGE_AREA
Displays the 2-byte storage area identification.
2.4 – CHECKSUM
Displays the 4-byte page checksum field.
2.5 – COUNT
Displays the 2-byte field showing the number of line index
entries. If this number is 1, the page contains only the SYSTEM
record.
2.6 – DATA offset
Displays the number of bytes specified. If you do not specify the
HEXADECIMAL or DECIMAL qualifier, the default radix is assumed.
See the help entry for the RADIX command for information on how
to set a default radix by using the RADIX command.
The value you specify for n is the number of bytes you want to
display. The maximum value that can be specified for n is the
size of the page minus the offset. If you do not specify n, 1
byte is displayed.
The BYTE, LONGWORD, and WORD qualifiers cannot be used with the
ASCII qualifier.
2.7 – FREE_SPACE
Displays the 2-byte field indicating how much free space remains
on the page.
2.8 – HEADER
Displays the entire page header.
2.9 – ENTRY
ENTRY n
ENTRY *
Refers to an area inventory page (AIP) entry on the database
page. If you specify a value for n, it must be a number between
zero and the number of AIP entries. If you specify the asterisk
(*) parameter, the information you request with the other
DISPLAY ENTRY parameters is displayed for each AIP entry on the
database page.
2.10 – asterisk
Displays the same information that is displayed when you specify
the ABM, LOGICAL_AREA, PHYSICAL_AREA, ALENGTH, ANAME, TSN,
RECORD_LENGTH, and INUSE parameters.
2.11 – ABM
Displays the first area bit map (ABM) page for the specified area
inventory page (AIP) entry. The value is contained in a longword.
2.12 – LOGICAL_AREA
Displays the number of the logical area of an AIP entry. The
value is contained in a word.
2.13 – PHYSICAL_AREA
Displays the number of the physical area of an AIP entry. The
value is contained in a word.
2.14 – ALENGTH
Displays the length of the name of the logical area of an AIP
entry. The value is contained in 1 byte. The name of the logical
area can be from 1 to 31 bytes in length.
2.15 – ANAME
Displays the name of the logical area of an AIP entry. The value
is contained in a 31-character text field.
2.16 – TSN
Displays the value of the last transaction sequence number (TSN)
to enable snapshots for the logical area of an AIP entry.
NOTE
Beginning in Oracle Rdb V7.0, Oracle Rdb stores any
transaction sequence number that is larger than a longword
by using both the TSN field on the page and the page TSN
base. Oracle Rdb calculates the actual TSN by applying a
formula to these two values. Oracle Corporation recommends
that you do not change a TSN value that is larger than a
longword. When a TSN is larger than a longword, a nonzero
number is stored in the page TSN base (the page tail). The
following example shows the location of the page TSN and the
page TSN base:
000A 00000003 0000 page 3, physical area 10
9D091204 0006 checksum = 9D091204
009A2C0F ED786D2E 000A time stamp = 23-MAY-1996 09:08:53.36
0000 03C4 0012 964 free bytes, 0 locked
0001 0016 1 line
0005 03E4 0018 line 0: offset 03E4, 5 bytes
page TSN -----> 00000000 001C line 0: TSN 0
.
.
.
2001 03E4 line 0 (10:3:0) SYSTEM record
00 0001 03E6 1 byte in 0 sets/dynamic items
0000000000 03E9 padding '.....'
FFFFFFFF 03EE snap page pointer -1
00000000 03F2 snap pointer TSN 0
0000 03F6 MBZ '..'
00000000 03F8 page sequence number 0
page TSN base -------> 0000 03FC page TSN base 0
0000 03FE MBZ '..'
2.17 – RECORD_LENGTH
Displays the value for the length of the record size for an AIP
entry. The length is expressed in bytes. The RECORD_LENGTH value
is contained in a word.
2.18 – INUSE
Displays the AIP entry's in-use flag. The value is contained in 1
byte.
NOTE
In the next two parameters, the integers denoting INDEX
and LINE are zero based. For example, INDEX 0 refers to the
first index, and LINE 3 refers to the fourth line.
The integer n is optional. The present value of the relevant
pointer is the default.
References to INDEX and LINE are invalid if the current page
is a space area management (SPAM) page.
2.19 – INDEX n
Displays the offset field, the length field, or both from the
line index indicated by n. For example, if you enter DISPLAY
INDEX 3 OFFSET, the offset address field from the fourth line
index is displayed. If you enter DISPLAY INDEX 3 LENGTH, the
length field from the fourth line index is displayed. If you
enter either DISPLAY INDEX 3 or DISPLAY INDEX 3 *, both the
offset and the length fields from the fourth line index are
displayed.
2.20 – INDEX asterisk
INDEX *
Displays the offset field and the length field for all index
nodes on a page.
2.21 – LINE n
Displays information from an individual storage segment. You
can display the RECORD_TYPE field or the entire content of the
storage segment line indicated by n.
2.22 – LINE asterisk
LINE *
Displays information from all storage segments on a page.
2.23 – LOCKED_SPACE
Displays the 2-byte field indicating how much free space is
allocated for exclusive use by a recovery unit.
2.24 – NUMBER
Shows the 4-byte page number field.
2.25 – SPACE
SPACE range
Displays SPAM entries; it is valid only if the current page is
a SPAM page. The SPACE parameter is the only option that you can
use in DISPLAY and DEPOSIT commands that access a SPAM page. The
optional range value can be an asterisk (*), referring to all
entries, or a set of consecutive entries that you describe as
follows:
lower-data-page-number[:higher-data-page-number]
When you specify a range, you reduce the output display. The
specified range of SPAM entries is included in the display; other
SPAM entries outside your specified range can also be included in
the display.
Each entry on a SPAM page consists of 2 bits, containing a value
0 through 3 that represents a fullness threshold. For example, if
the nth SPAM entry contains a 2, it means that the nth data page
in the interval has reached a percentage of fullness greater than
the second threshold for the area, but less than or equal to the
third threshold.
2.26 – TIME_STAMP
Displays the 8-byte time stamp field.
2.27 – NEXT_AIP
Displays the page number of the next area inventory page (AIP).
2.28 – AIP_ENTRIES
Displays a value for the number of area inventory page (AIP)
entries on the current area inventory page.
3 – Examples
Example 1
The following example displays page 94 of area 1:
RdbALTER> AREA 1
RdbALTER> DISPLAY 94
0001 0000005E 0000 page 94, physical area 1
7B429FB0 0006 checksum = 7B429FB0
0093249F 9EBDB820 000A time stamp = 14-FEB-1990 10:42:35.81
0000 0004 0012 4 free bytes, 0 locked
FFFFFFFF 0016 next area bit map page -1
00000000 001A max set bit index 0
00000000 001E MBZ '....'
00001E60 0022 bitvector count 7776
00000000000000000000000000000000 0026 bitvector '................'
:::: (59 duplicate lines)
000000000000000000000000 03E6 bitvector '............'
00000000 03F2 MBZ '....'
801F 03F6 bitmap page for logical area 31
0000000000000000 03F8 MBZ '........'
Example 2
The following example displays the number of the current storage
area:
RdbALTER> DISPLAY STORAGE_AREA
0001 0000 area 1
Example 3
This example displays the number of AIP entries on area 1,
page 2 of the mf_personnel database, and the value of the highest
snapshot-enabled TSN of AIP entry 14. This example also displays
the number of the next AIP in the current storage area.
RdbALTER> AREA 1 PAGE 2
RdbALTER> DISPLAY AIP_ENTRIES
0010 0022 16 logical area entries
RdbALTER> DISPLAY ENTRY 14 TSN
entry #14
00000001 0386 snaps enabled TSN 1
RdbALTER> DISPLAY NEXT_AIP
00000003 0016 next area inventory page 3
See the Oracle Rdb Guide to Database Maintenance for more
examples of how to use the DISPLAY command.