Oracle 12C: Insert script takes too much time after truncate - sql

Question

We have a production environment with Oracle 12C. It has two instances and is using Oracle Data Guard to have a replica in another server.
Every time that we release a new version, we have to truncate some tables, which doesn’t have any index, and execute several scripts with inserts statements like this one:
ALTER TABLE T_I18N DISABLE ALL TRIGGERS;
TRUNCATE TABLE T_I18N;
INSERT INTO T_I18N VALUES ('sp', 'Table 1', '0', 'Tabla 1');
INSERT INTO T_I18N VALUES ('sp', 'Table 2', '0', 'Tabla 2');
INSERT INTO T_I18N VALUES ('sp', 'Table 3', '0', 'Tabla 3');
.
.
ALTER TABLE HIS_I18N ENABLE ALL TRIGGERS;
Previously, we also have disabled all the primary keys and foreign keys. To give more information, the table structure is the following one:
CREATE TABLE "T_I18N"
("T_CODE" VARCHAR2(5 BYTE),
"T_KEY" VARCHAR2(200 BYTE),
"T_C_ID" NUMBER(6,0),
"T_VALUE" VARCHAR2(500 BYTE),
CONSTRAINT "HIN_PK" PRIMARY KEY ("T_CODE", "T_KEY", "T_C_ID")
USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "TB1" ENABLE,
CONSTRAINT "HIN_CEN_FK" FOREIGN KEY ("T_C_ID")
REFERENCES "TB1"."T_CEN" ("T_C_ID") ENABLE
) SEGMENT CREATION IMMEDIATE
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
NOCOMPRESS LOGGING
STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "TB1";
The script with more Insert statements has about 20K and it takes about 12 minutes to be executed. In my opinion, it was taking too much time, so I took a different approach. I tried to drop the table, recreate it and then execute the script, and it took only 40 seconds.
I have been searching through Oracle website to understand why there are so much difference between drop/recreate and truncate, but unfortunately I couldn’t find any clue about it.
Thanks by advance. Any information or advice would be really appreciated.
Cheers!