2026-03-12 20:23:15

tpt/experiments/lob_select_for_update.sql

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+-- Copyright 2018 Tanel Poder. All rights reserved. More info at http://tanelpoder.com
+-- Licensed under the Apache License, Version 2.0. See LICENSE.txt for terms & conditions.
+
+DROP TABLE tlob;
+CREATE TABLE tlob (a INT, b CLOB);
+
+INSERT INTO tlob VALUES(1, LPAD('x',2048,'x'));
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+UPDATE tlob SET b = b||b;
+
+COMMIT;
+
+SELECT DBMS_LOB.GETLENGTH(b) FROM tlob;
+
+DROP TABLE tdummy;
+CREATE table tdummy AS SELECT * FROM all_objects;
+
+DELETE tdummy; 
+
+ALTER SYSTEM CHECKPOINT;
+ALTER SYSTEM SWITCH LOGFILE;
+
+SELECT * FROM tlob WHERE a=1 FOR UPDATE;
+COMMIT;
+
+@log
+
+ALTER SYSTEM SWITCH LOGFILE;
+