我们遇到FORALL .. INSERT INTO .. VALUES语句的不同执行时间。我们创建了一个模拟行为的测试。运行下面的脚本显示随机分布的执行时间在0.5到7-8秒之间。
脚本在运行SQL Developer的客户端上执行，Oracle DB在同一网络上的HyperV Server VM上运行。在此VM上，分配的内存和硬盘大小看起来足够。
不同的执行时间可能是什么原因，以及我们有什么可以稳定（并最小化）执行时间的可能性？
编辑：相关性能只是FORALL .. INSERT语句需要的时间 - 在脚本中用DBMS.PUT_LINE命令清楚地表示。创建测试数据的性能与我的问题无关！
以下是测试脚本：
DECLARE
SUBTYPE t_logmsg_rec IS logmsg%ROWTYPE;
TYPE t_logmsg_list IS TABLE OF t_logmsg_rec;
l_logmsg_list t_logmsg_list := t_logmsg_list();
l_logmsg_rec t_logmsg_rec;
l_max_logmsg_key_id logmsg.KEY_ID%TYPE;
BEGIN
SELECT NVL(MAX(KEY_ID),1)
INTO l_max_logmsg_key_id
FROM logmsg;
FOR i IN 1..10000 LOOP
l_max_logmsg_key_id := l_max_logmsg_key_id + 1;
l_logmsg_rec.key_id := l_max_logmsg_key_id;
l_logmsg_rec.msg_id := 1;
l_logmsg_rec.session_id := 666;
l_logmsg_rec.log_timestamp := current_timestamp;
l_logmsg_rec.log_pck := 'perf_test';
l_logmsg_rec.log_user := 'fl';
l_logmsg_rec.log_type := 1;
l_logmsg_rec.log_msg := 'test msg ' ||i;
l_logmsg_rec.log_apl := 1;
l_logmsg_list.EXTEND;
l_logmsg_list(l_logmsg_list.COUNT) := l_logmsg_rec;
END LOOP;
dbms_output.put_line('Start: ' || current_timestamp);
FORALL l_idx IN 1 .. l_logmsg_list.COUNT
INSERT INTO logmsg VALUES l_logmsg_list (l_idx);
dbms_output.put_line('End: ' || current_timestamp);
END;
/
表创建脚本：
CREATE TABLE "SCOTT"."LOGMSG"
( "KEY_ID" NUMBER(38,0) NOT NULL ENABLE,
"MSG_ID" NUMBER(38,0) NOT NULL ENABLE,
"LOG_TYPE" NUMBER(3,0) NOT NULL ENABLE,
"LOG_TIMESTAMP" TIMESTAMP (6) NOT NULL ENABLE,
"LOG_USER" VARCHAR2(32 BYTE) NOT NULL ENABLE,
"LOG_MSG" VARCHAR2(2000 BYTE),
"LOG_APL" NUMBER(5,0),
"LOG_ATT" "SYS"."XMLTYPE" ,
"LOG_PCK" VARCHAR2(100 BYTE),
"SESSION_ID" NUMBER(38,0),
CONSTRAINT "PK_LOGMSG" PRIMARY KEY ("KEY_ID")
USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "SCOTT_I_TABLESPACE" ENABLE
) SEGMENT CREATION IMMEDIATE
PCTFREE 0 PCTUSED 40 INITRANS 1 MAXTRANS 255
NOCOMPRESS LOGGING
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "SCOTT_TABLESPACE"
XMLTYPE COLUMN "LOG_ATT" STORE AS BASICFILE CLOB (
TABLESPACE "SCOTT_TABLESPACE" DISABLE STORAGE IN ROW CHUNK 16384 RETENTION
NOCACHE LOGGING
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)) ;
CREATE INDEX "SCOTT"."IX_LOGMSG_1" ON "SCOTT"."LOGMSG" ("MSG_ID")
PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "SCOTT_I_TABLESPACE" ;
CREATE INDEX "SCOTT"."IX_LOGMSG_2" ON "SCOTT"."LOGMSG" ("SESSION_ID")
PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "SCOTT_I_TABLESPACE" ;
CREATE INDEX "SCOTT"."IX_LOGMSG_3" ON "SCOTT"."LOGMSG" ("LOG_TIMESTAMP")
PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "SCOTT_I_TABLESPACE" ;
CREATE INDEX "SCOTT"."IX_LOGMSG_C1" ON "SCOTT"."LOGMSG" ("LOG_MSG")
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 "SCOTT_I_TABLESPACE" ;
CREATE INDEX "SCOTT"."IX_LOGMSG_C2" ON "SCOTT"."LOGMSG" ("LOG_PCK")
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 "SCOTT_I_TABLESPACE" ;
答案 0 :(得分：0)
也许你可以尝试一种替代方案，你可以避免在数组中逐行填充。我试图通过单个Bulk Collect操作来说明相同的示例。希望它有所帮助。
set sqlbl on;
DECLARE
TYPE t_logmsg_tab IS TABLE OF log_msg%ROWTYPE;
lv_log_msg t_logmsg_tab;
BEGIN
--Since i can see only 10000 values are fetched so here we need not to use LIMIT clause but if
--date volume is more then we need to put LIMIT clause to prevent memory overflow
SELECT NVL(MAX(KEY_ID) OVER(ORDER BY 1),1)+LEVEL,
'1' msg_id,
'666' session_id,
current_timestamp,
'perf_test' log_pck,
'f1' log_user,
1 log_type,
'test msg '||LEVEL,
'1' log_apl
BULK COLLECT INTO
lv_log_msg
FROM l_max_logmsg_key_id
CONNECT BY LEVEL < 10001;
--Not required going for row by row processing will definitely take toll
--So avoiding and performing a bulk Collect Operation
-- SELECT NVL(MAX(KEY_ID),1)
-- INTO l_max_logmsg_key_id
-- FROM logmsg;
--
-- FOR i IN 1..10000 LOOP
-- l_max_logmsg_key_id := l_max_logmsg_key_id + 1;
-- l_logmsg_rec.key_id := l_max_logmsg_key_id;
-- l_logmsg_rec.msg_id := 1;
-- l_logmsg_rec.session_id := 666;
-- l_logmsg_rec.log_timestamp := current_timestamp;
-- l_logmsg_rec.log_pck := 'perf_test';
-- l_logmsg_rec.log_user := 'fl';
-- l_logmsg_rec.log_type := 1;
-- l_logmsg_rec.log_msg := 'test msg ' ||i;
--
-- l_logmsg_rec.log_apl := 1;
--
-- l_logmsg_list.EXTEND;
-- l_logmsg_list(l_logmsg_list.COUNT) := l_logmsg_rec;
-- END LOOP;
IF lv_log_msg.EXISTS(1) THEN
dbms_output.put_line('Start: ' || current_timestamp);
FORALL l_idx IN lv_log_msg.FIRST .. lv_log_msg.LAST
INSERT INTO logmsg VALUES lv_log_msg (l_idx);
dbms_output.put_line('End: ' || current_timestamp);
END IF;
END;
/