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Tracking Save Points
Jim_Knicely
- Select Field - Administrator
The SAVEPOINT SQL command creates a special mark, called a savepoint, inside a transaction. A savepoint allows all commands that are executed after it was established to be rolled back, restoring the transaction to the state it was in at the point in which the savepoint was established.
Savepoints can be nested so it can get confusing as to when a particular savepoint was issued. You can quickly list the savepoints issued for the current transaction by querying the QUERY_PROFILES system table.
Example:
dbadmin=> CREATE TABLE saves (C INT);
CREATE TABLE
dbadmin=> INSERT INTO saves SELECT 1;
OUTPUT
--------
1
(1 row)
dbadmin=> INSERT INTO saves SELECT 2;
OUTPUT
--------
1
(1 row)
dbadmin=> SAVEPOINT abc;
SAVEPOINT
dbadmin=> INSERT INTO saves SELECT 3;
OUTPUT
--------
1
(1 row)
dbadmin=> INSERT INTO saves SELECT 4;
OUTPUT
--------
1
(1 row)
dbadmin=> SAVEPOINT x1;
SAVEPOINT
dbadmin=> DELETE FROM saves WHERE c = 1;
OUTPUT
--------
1
(1 row)
dbadmin=> SAVEPOINT save_1;
SAVEPOINT
dbadmin=> SELECT query_start, query
dbadmin-> FROM query_profiles
dbadmin-> WHERE session_id = current_session()
dbadmin-> AND transaction_id = current_trans_id()
dbadmin-> AND query_type = 'TRANSACTION'
dbadmin-> ORDER BY query_start DESC;
query_start | query
-------------------------------+-------------------
2019-01-01 08:20:09.09355-05 | SAVEPOINT save_1;
2019-01-01 08:19:26.022173-05 | SAVEPOINT x1;
2019-01-01 08:10:11.703962-05 | SAVEPOINT abc;
(3 rows)
Helpful Links:
https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/SQLReferenceManual/Statements/SAVEPOINT.htm
https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/SQLReferenceManual/SystemTables/MONITOR/QUERY_PROFILES.htm
Have fun!
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