我正在尝试优化以下teradata查询。任何人都可以请这个。检索记录需要花费大量时间。
select top 100 I.item_sku_nbr,L.loc_nbr,MIS.MVNDR_PRTY_ID from
QA_US_MASTER_VIEWS.item I,
qa4_US_MASTER_VIEWS.location L,
qa4_US_MASTER_VIEWS.item_str IST,
qa4_US_MASTER_VIEWS.mvndr_item_str MIS
where MIS.str_LOC_ID = L.loc_id and
mis.str_loc_id = IST.str_loc_id and
IST.str_loc_id = L.loc_id and
MIS.ITEM_STAT_CD = IST.ITEM_STAT_CD and
IST.ITEM_ID = I.ITEM_ID and
MIS.ITEM_ID = IST.ITEM_ID and
I.ITEM_STAT_CD = 100 and
IST.curr_rmeth_cd = 2 and
MIS.curr_dsvc_typ_cd = 3 and
MIS.OK_TO_ORD_FLG = 'Y' and
MIS.EFF_END_DT = DATE '9999-12-31' and
IST.EFF_END_DT = DATE '9999-12-31' and
MIS.ACTV_FLG ='Y' and
IST.ACTV_FLG ='Y' and I.ACTV_FLG='Y'
解释 QA_US_MASTER.LOCATION 的计划：
1）首先，我们在视图中锁定QA_US_MASTER.LOCATION qa4_US_MASTER_VIEWS.Location用于访问。
2）接下来，我们从QA_US_MASTER.LOCATION进行全AMPs RETRIEVE步骤 在视图qa4_US_MASTER_VIEWS.Location中通过全行扫描 没有剩余条件进入假脱机1（group_amps），这是 在AMP上本地构建。假脱机1的大小估计为 高信心为10,903行（1,613,644字节）。该 该步骤的估计时间为0.01秒。
3）最后，我们向所有涉及的AMP发送END TRANSACTION步骤 处理请求。
- ＆GT;作为结果，假脱机1的内容被发送回用户 声明1.估计总时间为0.01秒。
解释 qa4_US_MASTER_VIEWS.item_str 的计划：
1）首先，我们在视图中锁定QA_US_MASTER.item_str qa4_US_MASTER_VIEWS.item_str用于访问。
2）接下来，我们从QA_US_MASTER.item_str执行全AMPs RETRIEVE步骤 在视图qa4_US_MASTER_VIEWS.item_str中通过全行扫描 没有剩余条件进入假脱机1（group_amps），这是 在AMP上本地构建。输入表将不会被缓存 内存，但它有资格进行同步扫描。结果 假脱机文件不会缓存在内存中。线轴1的大小是 低信心估计为1,229,047,917行（ 325,697,698,005字节）。此步骤的预计时间为4 分51秒。
3）最后，我们向所有涉及的AMP发送END TRANSACTION步骤 处理请求。
- ＆GT;作为结果，假脱机1的内容被发送回用户 声明1.总估计时间为4分51秒。
解释 QA_US_MASTER.ITEM 的计划：
1）首先，我们在视图qa4_US_MASTER_VIEWS.item中锁定QA_US_MASTER.ITEM 进入。
2）接下来，我们从QA_US_MASTER.ITEM进行全AMPs RETRIEVE步骤 通过没有的全行扫描查看qa4_US_MASTER_VIEWS.item Spool 1（group_amps）中的剩余条件，已构建 在AMP上本地。假脱机1的大小估计很高 信心为1,413,284行（357,560,852字节）。该 此步骤的估计时间为0.40秒。
3）最后，我们向所有涉及的AMP发送END TRANSACTION步骤 处理请求。
- ＆GT;作为结果，假脱机1的内容被发送回用户 声明1.估计总时间为0.40秒。
解释 QA_US_MASTER.MVNDR_ITEM_STR的计划：
1）首先，我们在视图中锁定QA_US_MASTER.MVNDR_ITEM_STR qa4_US_MASTER_VIEWS.mvndr_item_str用于访问。
2）接下来，我们从中进行全AMPs RETRIEVE步骤 QA_US_MASTER.MVNDR_ITEM_STR在视图中 qa4_US_MASTER_VIEWS.mvndr_item_str通过全行扫描 没有剩余条件进入假脱机1（group_amps），这是建立的 在AMP上本地。输入表不会缓存在内存中， 但它有资格进行同步扫描。结果假脱机 文件不会缓存在内存中。线轴1的大小是 高信心估计为1,316,279,746行（ 327,753,656,754字节）。此步骤的估计时间为6 分4秒。
3）最后，我们向所有涉及的AMP发送END TRANSACTION步骤 处理请求。
- ＆GT;作为结果，假脱机1的内容被发送回用户 声明1.总估计时间为6分4秒。
解释整个查询的计划：
1) First, we lock QA_US_MASTER.ITEM in view QA_US_MASTER_VIEWS.item
for access, we lock QA_US_MASTER.LOCATION in view
qa4_US_MASTER_VIEWS.location for access, we lock
QA_US_MASTER.MVNDR_ITEM_STR in view
qa4_US_MASTER_VIEWS.mvndr_item_str for access, and we lock
QA_US_MASTER.item_str in view qa4_US_MASTER_VIEWS.item_str for
access.
2) Next, we execute the following steps in parallel.
1) We do an all-AMPs RETRIEVE step from QA_US_MASTER.LOCATION in
view qa4_US_MASTER_VIEWS.location by way of an all-rows scan
with no residual conditions into Spool 3 (all_amps)
(compressed columns allowed), which is duplicated on all AMPs.
The size of Spool 3 is estimated with high confidence to be
1,013,979 rows (20,279,580 bytes). The estimated time for
this step is 0.03 seconds.
2) We do an all-AMPs RETRIEVE step from QA_US_MASTER.ITEM in
view QA_US_MASTER_VIEWS.item by way of an all-rows scan with
a condition of ("(QA_US_MASTER.ITEM in view
QA_US_MASTER_VIEWS.item.ITEM_STAT_CD = 100) AND
(QA_US_MASTER.ITEM in view QA_US_MASTER_VIEWS.item.ACTV_FLG =
'Y')") into Spool 4 (all_amps) (compressed columns allowed)
fanned out into 14 hash join partitions, which is duplicated
on all AMPs. The size of Spool 4 is estimated with low
confidence to be 30,819,363 rows (678,025,986 bytes). The
estimated time for this step is 0.81 seconds.
3) We do an all-AMPs JOIN step from Spool 3 (Last Use) by way of an
all-rows scan, which is joined to QA_US_MASTER.item_str in view
qa4_US_MASTER_VIEWS.item_str by way of an all-rows scan with a
condition of
("(QA_US_MASTER.item_str in view
qa4_US_MASTER_VIEWS.item_str.CURR_RMETH_CD = 2) AND
((QA_US_MASTER.item_str in view
qa4_US_MASTER_VIEWS.item_str.EFF_END_DT = DATE '9999-12-31') AND
(QA_US_MASTER.item_str in view
qa4_US_MASTER_VIEWS.item_str.ACTV_FLG = 'Y'))"). Spool 3 and
QA_US_MASTER.item_str are joined using a dynamic hash join, with a
join condition of ("QA_US_MASTER.item_str.STR_LOC_ID = LOC_ID").
The input table QA_US_MASTER.item_str will not be cached in memory.
The result goes into Spool 5 (all_amps) (compressed columns
allowed), which is built locally on the AMPs into 14 hash join
partitions. The size of Spool 5 is estimated with no confidence
to be 69,133,946 rows (2,419,688,110 bytes). The estimated time
for this step is 1 minute and 8 seconds.
4) We do an all-AMPs JOIN step from Spool 4 (Last Use) by way of an
all-rows scan, which is joined to Spool 5 (Last Use) by way of an
all-rows scan. Spool 4 and Spool 5 are joined using a hash join
of 14 partitions, with a join condition of ("(ITEM_ID = ITEM_ID)
AND (ACTV_FLG = ACTV_FLG)"). The result goes into Spool 6
(all_amps) (compressed columns allowed), which is redistributed by
the hash code of (QA_US_MASTER.item_str.STR_LOC_ID,
QA_US_MASTER.item_str.ITEM_STAT_CD, QA_US_MASTER.item_str.ITEM_ID,
QA_US_MASTER.ITEM.ITEM_ID, QA_US_MASTER.LOCATION.LOC_ID) to all
AMPs into 33 hash join partitions. The size of Spool 6 is
estimated with no confidence to be 36,434,893 rows (1,603,135,292
bytes). The estimated time for this step is 9.11 seconds.
5) We do an all-AMPs RETRIEVE step from QA_US_MASTER.MVNDR_ITEM_STR
in view qa4_US_MASTER_VIEWS.mvndr_item_str by way of an all-rows
scan with a condition of ("(QA_US_MASTER.MVNDR_ITEM_STR in view
qa4_US_MASTER_VIEWS.mvndr_item_str.CURR_DSVC_TYP_CD = 3) AND
((QA_US_MASTER.MVNDR_ITEM_STR in view
qa4_US_MASTER_VIEWS.mvndr_item_str.EFF_END_DT = DATE '9999-12-31')
AND ((QA_US_MASTER.MVNDR_ITEM_STR in view
qa4_US_MASTER_VIEWS.mvndr_item_str.ACTV_FLG = 'Y') AND
(QA_US_MASTER.MVNDR_ITEM_STR in view
qa4_US_MASTER_VIEWS.mvndr_item_str.OK_TO_ORD_FLG = 'Y')))") into
Spool 7 (all_amps) (compressed columns allowed) fanned out into 33
hash join partitions, which is redistributed by the hash code of (
QA_US_MASTER.MVNDR_ITEM_STR.ITEM_ID,
QA_US_MASTER.MVNDR_ITEM_STR.STR_LOC_ID,
QA_US_MASTER.MVNDR_ITEM_STR.ITEM_STAT_CD,
QA_US_MASTER.MVNDR_ITEM_STR.ITEM_ID,
QA_US_MASTER.MVNDR_ITEM_STR.STR_LOC_ID) to all AMPs. The input
table will not be cached in memory, but it is eligible for
synchronized scanning. The size of Spool 7 is estimated with no
confidence to be 173,967,551 rows (5,914,896,734 bytes). The
estimated time for this step is 2 minutes and 23 seconds.
6) We do an all-AMPs JOIN step from Spool 6 (Last Use) by way of an
all-rows scan, which is joined to Spool 7 (Last Use) by way of an
all-rows scan. Spool 6 and Spool 7 are joined using a hash join
of 33 partitions, with a join condition of ("(STR_LOC_ID =
STR_LOC_ID) AND ((ITEM_STAT_CD = ITEM_STAT_CD) AND ((ITEM_ID =
ITEM_ID) AND ((ACTV_FLG = OK_TO_ORD_FLG) AND ((ACTV_FLG = ACTV_FLG)
AND ((EFF_END_DT = EFF_END_DT) AND ((ACTV_FLG = ACTV_FLG) AND
((OK_TO_ORD_FLG = ACTV_FLG) AND ((ITEM_ID = ITEM_ID) AND
(STR_LOC_ID = LOC_ID )))))))))"). The result goes into Spool 2
(all_amps) (compressed columns allowed), which is built locally on
the AMPs. The size of Spool 2 is estimated with no confidence to
be 12,939,628 rows (336,430,328 bytes). The estimated time for
this step is 4.00 seconds.
7) We do an all-AMPs STAT FUNCTION step from Spool 2 by way of an
all-rows scan into Spool 10, which is redistributed by hash code
to all AMPs. The result rows are put into Spool 1 (group_amps),
which is built locally on the AMPs. This step is used to retrieve
the TOP 100 rows. Load distribution optimization is used.
If this step retrieves less than 100 rows, then execute step 8.
The size is estimated with no confidence to be 100 rows (3,200
bytes).
8) We do an all-AMPs STAT FUNCTION step from Spool 2 (Last Use) by
way of an all-rows scan into Spool 10 (Last Use), which is
redistributed by hash code to all AMPs. The result rows are put
into Spool 1 (group_amps), which is built locally on the AMPs.
This step is used to retrieve the TOP 100 rows. The size is
estimated with no confidence to be 100 rows (3,200 bytes).
9) Finally, we send out an END TRANSACTION step to all AMPs involved
in processing the request.
-> The contents of Spool 1 are sent back to the user as the result of
statement 1.
答案 0 :(得分：1)
您的查询中没有ORDER BY，所以您只想要100个随机行？
在Teradata中，在创建完整结果集后，TOP 完成。您应该将TOP移动到派生表中，如：
select I.item_sku_nbr,L.loc_nbr,MIS.MVNDR_PRTY_ID from
QA_US_MASTER_VIEWS.item I,
qa4_US_MASTER_VIEWS.location L,
(SELECT TOP 100 * FROM qa4_US_MASTER_VIEWS.item_str) IST,
qa4_US_MASTER_VIEWS.mvndr_item_str MIS
where MIS.str_LOC_ID = L.loc_id and
mis.str_loc_id = IST.str_loc_id and
IST.str_loc_id = L.loc_id and
MIS.ITEM_STAT_CD = IST.ITEM_STAT_CD and
IST.ITEM_ID = I.ITEM_ID and
MIS.ITEM_ID = IST.ITEM_ID and
I.ITEM_STAT_CD = 100 and
IST.curr_rmeth_cd = 2 and
MIS.curr_dsvc_typ_cd = 3 and
MIS.OK_TO_ORD_FLG = 'Y' and
MIS.EFF_END_DT = DATE '9999-12-31' and
IST.EFF_END_DT = DATE '9999-12-31' and
MIS.ACTV_FLG ='Y' and
IST.ACTV_FLG ='Y' and I.ACTV_FLG='Y'