Support For Pageinspect & Pagehack

# Unpack the toolkit with the root user
tar -xzvf Toolkits-5.0.2-Kylin-arm64.tar.gz

# Use the database instance user (e.g., omm), go to the pageinspect folder under toolkits and copy the appropriate files to the specified directory
cd pageinspect/
cp pageinspect--1.0.sql $GAUSSHOME/share/postgresql/extension
cp pageinspect.control $GAUSSHOME/share/postgresql/extension
cp pageinspect--unpackaged--1.0.sql $GAUSSHOME/share/postgresql/extension
cp pageinspect.so $GAUSSHOME/lib/postgresql

# Modify permissions
cd $GAUSSHOME/share/postgresql/extension
chmod 644 pageinspect--1.0.sql pageinspect.control pageinspect--unpackaged--1.0.sql
cd $GAUSSHOME/lib/postgresql
chmod 755 pageinspect.so

# Log into the database and create extension
gsql -r
CREATE EXTENSION pageinspect;

# View the contents of the heap data table
SELECT * FROM heap_page_items(get_raw_page('table_name','main',page_no));
# View header information on a heap page
SELECT * FROM page_header(get_raw_page('table_name','main',page_no));
# View meta page information
SELECT * FROM bt_metap('index_name');
# View the contents of the specified index page number
SELECT * FROM bt_page_items('index_name', page_no);

# Unpack the toolkit with the root user
tar -xzvf Toolkits-5.0.2-Kylin-arm64.tar.gz

# Use the database instance user (e.g., omm), go to the pagehack folder under toolkits and copy the appropriate files to the specified directory
cd pagehack/
cp pagehack $GAUSSHOME/bin
cp pagehack.so $GAUSSHOME/lib/postgresql

# Modify permissions
cd $GAUSSHOME/bin
chmod 755 pagehack
cd $GAUSSHOME/lib/postgresql
chmod 755 pagehack.so

pagehack -f [filename]

# Create the pageinspect extension, then create a row-store table and a BTree index, and insert some data into the table.
MogDB=# CREATE EXTENSION pageinspect;
CREATE EXTENSION
MogDB=# CREATE TABLE t(id int, a text);
CREATE TABLE
MogDB=# CREATE INDEX idx_id on t(id);
CREATE INDEX
MogDB=# INSERT INTO t SELECT num, repeat('ABCD', 8) || num from generate_series(1, 500) as num;
INSERT 0 500
MogDB=# SELECT * FROM t LIMIT 32;
 id |                 a
----+------------------------------------
  1 | ABCDABCDABCDABCDABCDABCDABCDABCD1
  2 | ABCDABCDABCDABCDABCDABCDABCDABCD2
  3 | ABCDABCDABCDABCDABCDABCDABCDABCD3
 ......
 32 | ABCDABCDABCDABCDABCDABCDABCDABCD32
(32 rows)

# View the contents of the heap data table
MogDB=# SELECT * FROM heap_page_items(get_raw_page('t','main',0));
 lp  | lp_off | lp_flags | lp_len | t_xmin | t_xmax | t_field3 | t_ctid  | t_infomask2 | t_infomask | t_hoff | t_bits | t_oid
-----+--------+----------+--------+--------+--------+----------+---------+-------------+------------+--------+--------+-------
   1 |   8128 |        1 |     62 |  14111 |      0 |        0 | (0,1)   |           2 |       2306 |     24 |        |
   2 |   8064 |        1 |     62 |  14111 |      0 |        0 | (0,2)   |           2 |       2306 |     24 |        |
   3 |   8000 |        1 |     62 |  14111 |      0 |        0 | (0,3)   |           2 |       2306 |     24 |        |
   4 |   7936 |        1 |     62 |  14111 |      0 |        0 | (0,4)   |           2 |       2306 |     24 |        |
   5 |   7872 |        1 |     62 |  14111 |      0 |        0 | (0,5)   |           2 |       2306 |     24 |        |

# View header information on a heap page
MogDB=# SELECT * FROM page_header(get_raw_page('t','main',0));
    lsn    | tli | flags | lower | upper | special | pagesize | version | prune_xid
-----------+-----+-------+-------+-------+---------+----------+---------+-----------
 0/C4DC510 |   0 |     0 |   516 |   576 |    8192 |     8192 |       6 |     14108
(1 row)

# View meta page information
MogDB=# SELECT * FROM bt_metap('idx_id');
 magic  | version | root | level | fastroot | fastlevel
--------+---------+------+-------+----------+-----------
 340322 |       2 |    3 |     1 |        3 |         1
(1 row)

# View the contents of the specified index page number
MogDB=# SELECT * FROM bt_page_items('idx_id', 1);
 itemoffset |  ctid   | itemlen | nulls | vars |          data
------------+---------+---------+-------+------+-------------------------
          1 | (3,9)   |      16 | f     | f    | 6e 01 00 00 00 00 00 00
          2 | (0,1)   |      16 | f     | f    | 01 00 00 00 00 00 00 00
          3 | (0,2)   |      16 | f     | f    | 02 00 00 00 00 00 00 00
          4 | (0,3)   |      16 | f     | f    | 03 00 00 00 00 00 00 00
          5 | (0,4)   |      16 | f     | f    | 04 00 00 00 00 00 00 00

# As in the previous example, the MogDB database instance has generated a row-store table/BTree index data file, and the data has been written to the file (if there is no disk you can force a checkpoint or create another table and insert data to make the transaction move forward).
# Get object OID
MogDB=# \d+
                                    List of relations
 Schema | Name | Type  | Owner  | Size  |             Storage              | Description
--------+------+-------+--------+-------+----------------------------------+-------------
 public | t    | table | omm    | 72 kB | {orientation=row,compression=no} |
(1 row)

MogDB=# \d+ t
                           Table "public.t"
 Column |  Type   | Modifiers | Storage  | Stats target | Description
--------+---------+-----------+----------+--------------+-------------
 id     | integer |           | plain    |              |
 a      | text    |           | extended |              |
Indexes:
    "idx_id" btree (id) TABLESPACE pg_default
Has OIDs: no
Options: orientation=row, compression=no

# Upon querying, table t has oid=17092 and index idx_id has oid=17098
MogDB=# select pg_relation_filepath('t');
 pg_relation_filepath
----------------------
 base/15318/17092
(1 row)

MogDB=# select pg_relation_filepath('idx_id');
 pg_relation_filepath
----------------------
 base/15318/17098
(1 row)

# Execute the following command at the command line to parse the heap data of the row-store table
[omm@mogdb-kernel-001 toolkits]$ pagehack -f /opt/mogdb/data/base/15318/17092 | head -n 32
page information of block 0/5
        pd_lsn: 0/C4DC510
        pd_checksum: 0xB4FA, verify success
        pd_flags:
        pd_lower: 516, non-empty
        pd_upper: 576, old
        pd_special: 8192, size 0
        Page size & version: 8192, 6
        pd_xid_base: 14108, pd_multi_base: 0
        pd_prune_xid: 14108

        Heap tuple information on this page

                Tuple #1 is normal: length 62, offset 8128
                        t_xmin/t_xmax/t_cid: 14111/0/0
                        ctid:(block 0/0, offset 1)
                        t_infomask: HEAP_HASVARWIDTH HEAP_XMIN_COMMITTED HEAP_XMAX_INVALID HEAP_HAS_NO_UID
                        t_infomask2: Attrs Num: 2
                        t_hoff: 24
                        t_bits:
                                NNNNNNNN


                Tuple #2 is normal: length 62, offset 8064
                        t_xmin/t_xmax/t_cid: 14111/0/0
                        ctid:(block 0/0, offset 2)
                        t_infomask: HEAP_HASVARWIDTH HEAP_XMIN_COMMITTED HEAP_XMAX_INVALID HEAP_HAS_NO_UID
                        t_infomask2: Attrs Num: 2
                        t_hoff: 24
                        t_bits:
                                NNNNNNNN

# Parsing data from BTree indexes
[omm@mogdb-kernel-001 toolkits]$ pagehack -f /opt/mogdb/data/base/15318/17098 | head -n 32
page information of block 0/4
        pd_lsn: 0/C4EBD58
        pd_checksum: 0xF9AA, verify success
        pd_flags:
        pd_lower: 48, non-empty
        pd_upper: 8168, old
        pd_special: 8168, size 24
        Page size & version: 8192, 5
        pd_xid_base: 8590274914, pd_multi_base: 4294967299
        pd_prune_xid: 8590274914

        Heap tuple information on this page

                Tuple #1 is redirected: length 2, offset 12642
                Tuple #2 is unused

                Tuple #3 is unused

                Tuple #4 is unused

                Tuple #5 is unused

                Tuple #6 is unused
        Summary (6 total): 5 unused, 0 normal, 0 dead

Normal Heap Page, special space is 0

page information of block 1/4
        pd_lsn: 0/C4EBD58
        pd_checksum: 0x95F3, verify success
        pd_flags:
        pd_lower: 1488, non-empty