标签：case current 1162 lsn sample PG id select pg
mydb=# select * from car;
id | name
----+------
1 | aa
2 | bb
3 | cc
4 | ddd
(4 rows)
Time: 0.592 ms
mydb=# select *,ctid,xmin,xmax from car;
id | name | ctid | xmin | xmax
----+------+--------+------+------
1 | aa | (0,41) | 1162 | 0
2 | bb | (0,42) | 1162 | 0
3 | cc | (0,43) | 1162 | 0
4 | ddd | (0,44) | 1162 | 1168
(4 rows)
Time: 0.198 ms
mydb=# \df+ pg_switch_wal
List of functions
Schema | Name | Result data type | Argument data types | Type | Volatility | Parallel | Owner | Security | Access privileges | Language | Source code | Description
------------+---------------+------------------+---------------------+------+------------+----------+----------+----------+---------------------+----------+---------------+------------------------
pg_catalog | pg_switch_wal | pg_lsn | | func | volatile | safe | postgres | invoker | postgres=X/postgres | internal | pg_switch_wal | switch to new wal file
(1 row)
mydb=# select pg_switch_wal();
pg_switch_wal
---------------
0/19006D98
(1 row)
Time: 56.363 ms
mydb=# select *,ctid,xmin,xmax from car;
id | name | ctid | xmin | xmax
----+------+--------+------+------
1 | aa | (0,41) | 1162 | 0
2 | bb | (0,42) | 1162 | 0
3 | cc | (0,43) | 1162 | 0
4 | ddd | (0,44) | 1162 | 1168
(4 rows)
Time: 0.294 ms
mydb=# select pg_current_xact_id();
pg_current_xact_id
--------------------
1174
(1 row)
Time: 0.480 ms
mydb=# select pg_current_wal_lsn(),pg_walfile_name(pg_current_wal_lsn()),pg_walfile_NAME_OFFSET(pg_current_wal_lsn());
pg_current_wal_lsn | pg_walfile_name | pg_walfile_name_offset
--------------------+--------------------------+--------------------------------
0/1A0000C0 | 00000002000000000000001A | (00000002000000000000001A,192)
(1 row)
Time: 0.207 ms
mydb=# begin;
BEGIN
Time: 0.067 ms
mydb=*# select pg_current_wal_lsn(),pg_walfile_name(pg_current_wal_lsn()),pg_walfile_NAME_OFFSET(pg_current_wal_lsn());
pg_current_wal_lsn | pg_walfile_name | pg_walfile_name_offset
--------------------+--------------------------+--------------------------------
0/1A0000C0 | 00000002000000000000001A | (00000002000000000000001A,192)
(1 row)
Time: 0.113 ms
mydb=*# select pg_current_xact_id();
pg_current_xact_id
--------------------
1175
(1 row)
Time: 0.104 ms
mydb=*# select pg_current_xact_id();
pg_current_xact_id
--------------------
1175
(1 row)
Time: 0.101 ms
mydb=*# select *,ctid,xmin,xmax from car;
id | name | ctid | xmin | xmax
----+------+--------+------+------
1 | aa | (0,41) | 1162 | 0
2 | bb | (0,42) | 1162 | 0
3 | cc | (0,43) | 1162 | 0
4 | ddd | (0,44) | 1162 | 1168
(4 rows)
Time: 0.391 ms
mydb=*# select *,ctid,xmin,xmax from car;
id | name | ctid | xmin | xmax
----+------+--------+------+------
1 | aa | (0,41) | 1162 | 0
2 | bb | (0,42) | 1162 | 0
3 | cc | (0,43) | 1162 | 0
4 | ddd | (0,44) | 1162 | 1168
(4 rows)
Time: 0.177 ms
mydb=*# update car set name = 'dd' where id =4 ;
UPDATE 1
Time: 0.511 ms
mydb=*# select *,ctid,xmin,xmax from car;
id | name | ctid | xmin | xmax
----+------+--------+------+------
1 | aa | (0,41) | 1162 | 0
2 | bb | (0,42) | 1162 | 0
3 | cc | (0,43) | 1162 | 0
4 | dd | (0,46) | 1175 | 0
(4 rows)
Time: 0.164 ms
mydb=*# select pg_current_xact_id();
pg_current_xact_id
--------------------
1175
(1 row)
Time: 0.100 ms
mydb=*# select pg_current_xact_id();
pg_current_xact_id
--------------------
1175
(1 row)
Time: 0.218 ms
mydb=*# commit;
COMMIT
Time: 3.861 ms
mydb=# select pg_current_xact_id();
pg_current_xact_id
--------------------
1177
(1 row)
Time: 0.532 ms
mydb=# select pg_current_xact_id();
pg_current_xact_id
--------------------
1178
(1 row)
Time: 0.233 ms
wal日志：
mydb=# select pg_relation_filenode('car');
pg_relation_filenode
----------------------
34055
(1 row)
Time: 0.586 ms
mydb=# select pg_relation_filepath('car');
pg_relation_filepath
----------------------
base/16384/34055
(1 row)
[postgres@harbor pg_wal]$ pg_waldump -f 00000002000000000000001A
rmgr: Standby len (rec/tot): 50/ 50, tx: 0, lsn: 0/1A000028, prev 0/19006D80, desc: RUNNING_XACTS nextXid 1174 latestCompletedXid 1173 oldestRunningXid 1174
rmgr: Transaction len (rec/tot): 34/ 34, tx: 1174, lsn: 0/1A000060, prev 0/1A000028, desc: COMMIT 2022-07-20 13:49:22.793491 CST
rmgr: Standby len (rec/tot): 50/ 50, tx: 0, lsn: 0/1A000088, prev 0/1A000060, desc: RUNNING_XACTS nextXid 1175 latestCompletedXid 1174 oldestRunningXid 1175
rmgr: Heap len (rec/tot): 65/ 1745, tx: 1175, lsn: 0/1A0000C0, prev 0/1A000088, desc: HOT_UPDATE off 44 xmax 1175 flags 0x00 ; new off 46 xmax 0, blkref #0: rel 1663/16384/34055 blk 0 FPW
rmgr: Standby len (rec/tot): 54/ 54, tx: 0, lsn: 0/1A000798, prev 0/1A0000C0, desc: RUNNING_XACTS nextXid 1176 latestCompletedXid 1174 oldestRunningXid 1175; 1 xacts: 1175
rmgr: Transaction len (rec/tot): 34/ 34, tx: 1176, lsn: 0/1A0007D0, prev 0/1A000798, desc: COMMIT 2022-07-20 13:50:54.674831 CST
rmgr: Standby len (rec/tot): 54/ 54, tx: 0, lsn: 0/1A0007F8, prev 0/1A0007D0, desc: RUNNING_XACTS nextXid 1177 latestCompletedXid 1176 oldestRunningXid 1175; 1 xacts: 1175
rmgr: Transaction len (rec/tot): 34/ 34, tx: 1175, lsn: 0/1A000830, prev 0/1A0007F8, desc: COMMIT 2022-07-20 13:51:43.477334 CST
rmgr: Transaction len (rec/tot): 34/ 34, tx: 1177, lsn: 0/1A000858, prev 0/1A000830, desc: COMMIT 2022-07-20 13:51:45.690891 CST
rmgr: Transaction len (rec/tot): 34/ 34, tx: 1178, lsn: 0/1A000880, prev 0/1A000858, desc: COMMIT 2022-07-20 13:51:49.435323 CST
rmgr: Standby len (rec/tot): 50/ 50, tx: 0, lsn: 0/1A0008A8, prev 0/1A000880, desc: RUNNING_XACTS nextXid 1179 latestCompletedXid 1178 oldestRunningXid 1179
rmgr: Standby len (rec/tot): 50/ 50, tx: 0, lsn: 0/1A0008E0, prev 0/1A0008A8, desc: RUNNING_XACTS nextXid 1179 latestCompletedXid 1178 oldestRunningXid 1179
rmgr: XLOG len (rec/tot): 114/ 114, tx: 0, lsn: 0/1A000918, prev 0/1A0008E0, desc: CHECKPOINT_ONLINE redo 0/1A0008E0; tli 2; prev tli 2; fpw true; xid 0:1179; oid 34444; multi 1; offset 0; oldest xid 726 in DB 13892; oldest multi 1 in DB 16384; oldest/newest commit timestamp xid: 0/0; oldest running xid 1179; online
rmgr: Standby len (rec/tot): 50/ 50, tx: 0, lsn: 0/1A000990, prev 0/1A000918, desc: RUNNING_XACTS nextXid 1179 latestCompletedXid 1178 oldestRunningXid 1179
标签：case,current,1162,lsn,sample,PG,id,select,pg 来源： https://www.cnblogs.com/chinaops/p/16497723.html
本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享； 2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关； 3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关； 4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除； 5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。