oracle分區(qū)技術(shù)-大批量數(shù)據(jù)操作ppt課件

1、Oracle數(shù)據(jù)庫(kù)高級(jí)技術(shù)交流-大批量數(shù)據(jù)處置技術(shù)Oracle(中國(guó))顧問咨詢部羅 敏 資深技術(shù)顧問 Michael.luooracle交流內(nèi)容分區(qū)技術(shù)報(bào)表優(yōu)化技術(shù) 并行處置運(yùn)用閱歷Oracle的分區(qū)技術(shù) 分區(qū)技術(shù)內(nèi)容什么是分區(qū)?分區(qū)的益處?如何實(shí)施分區(qū)?如何評(píng)價(jià)分區(qū)的效果? Oracle的分區(qū)技術(shù)根本原理分而治之SB_ZSXX按年度進(jìn)展分區(qū)2003200420052006分區(qū)概述大數(shù)據(jù)對(duì)象 (表, 索引)被分成小物理段當(dāng)分區(qū)表建立時(shí)，記錄基于分區(qū)字段值被存儲(chǔ)到相應(yīng)分區(qū)。分區(qū)字段值可以修正。(row movement enabled)分區(qū)可以存儲(chǔ)在不同的表空間分區(qū)可以

2、有不同的物理存儲(chǔ)參數(shù)分區(qū)支持IOT表，對(duì)象表，LOB字段，varrays等分區(qū)技術(shù)的效益和目的性能Select和DML操作只訪問指定分區(qū)并行DML操作Partition-wise Join可管理性：數(shù)據(jù)刪除，數(shù)據(jù)備份歷史數(shù)據(jù)去除提高備份性能指定分區(qū)的數(shù)據(jù)維護(hù)操作可用性將缺點(diǎn)局限在分區(qū)中縮短恢復(fù)時(shí)間分區(qū)目的優(yōu)先級(jí) 高性能 數(shù)據(jù)維護(hù)才干-實(shí)施難度 高可用性缺點(diǎn)屏蔽才干分區(qū)方法分區(qū)方法:范圍 - 8Hash - 8i列表 - 9i組合 - 8iRangepartitioningHashpartitioningCompositepartitioningListpartitioning123CREATE

3、 TABLE sales (acct_no NUMBER(5), person VARCHAR2(30), sales_amount NUMBER(8), week_no NUMBER(2) PARTITION BY RANGE (week_no) (PARTITION P1 VALUES LESS THAN (4) TABLESPACE data0, PARTITION P2 VALUES LESS THAN (8) TABLESPACE data1, . PARTITION P13 VALUES LESS THAN (53)TABLESPACE data12 );分區(qū)字段：week_no.

4、VALUES LESS THAN 必需是確定值每個(gè)分區(qū)可以單獨(dú)指定物理屬性123范圍分區(qū)例最早、最經(jīng)典的分區(qū)算法Range分區(qū)經(jīng)過(guò)對(duì)分區(qū)字段值的范圍進(jìn)展分區(qū)Range分區(qū)特別適宜于按時(shí)間周期進(jìn)展數(shù)據(jù)的存儲(chǔ)。日、周、月、年等。數(shù)據(jù)管理才干強(qiáng)數(shù)據(jù)遷移數(shù)據(jù)備份數(shù)據(jù)交換范圍分區(qū)的數(shù)據(jù)能夠不均勻范圍分區(qū)與記錄值相關(guān)，實(shí)施難度和可維護(hù)性相對(duì)較差范圍分區(qū)特點(diǎn)Hash分區(qū)例create table CUSTOMERS (. column definitions .)pctfree 0 nologgingstorage ( initial 40m next 40m pctincrease 0 )partitio

5、n by hash(customer_no) partitions 8 store in (cust_data01,cust_data02)create table CUSTOMERS (. column definitions .)pctfree 0 nologgingstorage ( initial 40m next 40m pctincrease 0 )partition by hash(customer_no) (partition cust_p01 tablespace cust_data01,partition cust_p02 tablespace cust_data02,pa

6、rtition cust_p03 tablespace cust_data03,partition cust_p04 tablespace cust_data04,partition cust_p05 tablespace cust_data05,partition cust_p06 tablespace cust_data06,partition cust_p07 tablespace cust_data07,partition cust_p08 tablespace cust_data08)Hash分區(qū)特點(diǎn)基于分區(qū)字段的HASH值，自動(dòng)將記錄插入到指定分區(qū)。分區(qū)數(shù)普通是2的冪易于實(shí)施總體性

7、能最正確適宜于靜態(tài)數(shù)據(jù)HASH分區(qū)適宜于數(shù)據(jù)的均勻存儲(chǔ)HASH分區(qū)特別適宜于PDML和partition-wise joins。支持 (hash) local indexes9i 不支持 (hash) global indexes10g 支持(hash) global indexes HASH分區(qū)數(shù)據(jù)管理才干弱HASH分區(qū)對(duì)數(shù)據(jù)值無(wú)法控制列表分區(qū)例create table addresses (. column definitions .)pctfree 0 nologgingstorage ( initial 40m next 40m pctincrease 0 )partition by

8、list(city_name) (partition addr_p01 values (WELLINGTON) tablespace addr_data01,partition addr_p02 values (CHRISTCHURCH) tablespace addr_data02,partition addr_p03 values (DUNEDIN,INVERCARGILL) tablespace addr_data03,partition addr_p04 values (AUCKLAND) tablespace addr_data04,partition addr_p05 values

9、 (HAMILTON,ROTORUA,TAURANGA) tablespace addr_data05)列表分區(qū)特點(diǎn)List分區(qū)經(jīng)過(guò)對(duì)分區(qū)字段的離散值進(jìn)展分區(qū)。List分區(qū)是不排序的，而且分區(qū)之間沒有關(guān)聯(lián)關(guān)系List分區(qū)適宜于對(duì)數(shù)據(jù)離散值進(jìn)展控制。List分區(qū)只支持單個(gè)字段。List分區(qū)具有與范圍分區(qū)類似的優(yōu)缺陷數(shù)據(jù)管理才干強(qiáng)List分區(qū)的數(shù)據(jù)能夠不均勻List分區(qū)與記錄值相關(guān)，實(shí)施難度和可維護(hù)性相對(duì)較差復(fù)合分區(qū)例create table daily_trans_data (.column definitions .)partition by range(trans_datetime)subp

10、artition by hash(customer_no) subpartitions 8 store in (dtd_data01,dtd_data02) (partition dtd_20010620 values less than (to_date(21-jun-2001,dd-mon-yyyy) (subpartition dtd_20010620_s01 ,subpartition dtd_20010620_s02 ,subpartition dtd_20010620_s03 tablespace dtd_data03 ,subpartition dtd_20010620_s04

11、tablespace dtd_data04 ,subpartition dtd_20010620_s05 tablespace dtd_data05 ,subpartition dtd_20010620_s06 tablespace dtd_data06 ,subpartition dtd_20010620_s07 tablespace dtd_data07 ,subpartition dtd_20010620_s08 tablespace dtd_data08 ) ,partition dtd_20010621 values less than (to_date(22-jun-2001,dd

12、-mon-yyyy) ,partition dtd_20010622 values less than (to_date(23-jun-2001,dd-mon-yyyy) subpartitions 4 )復(fù)合分區(qū)圖示復(fù)合分區(qū)特點(diǎn)Oracle支持的Composite分區(qū)： Range-Hash,Range-List既適宜于歷史數(shù)據(jù)，又適宜于數(shù)據(jù)均勻分布與范圍分區(qū)一樣提供高可用性和管理性更好的PDML和partition-wise joins性能實(shí)現(xiàn)粒度更細(xì)的操作支持復(fù)合 local indexes不支持復(fù)合compositeglobal indexes？分區(qū)索引不分區(qū)分區(qū)不分區(qū) 分區(qū)表索引Gl

13、obalNonpartitioned indexLocal partitioned indexGlobal Partitioned Index不同的分區(qū)索引紹興杭州溫州03年04年08年分區(qū)索引分區(qū)表索引的分類：Local Prefixed indexLocal Non-prefiexed indexGlobal Prefixed indexNon Partition IndexGlobal索引的分區(qū)不同與表分區(qū)Local索引的分區(qū)與表分區(qū)一樣An index is prefixed if it is partitioned on a left prefix of the index colu

14、mns.分區(qū)表上的非分區(qū)索引等同于Global索引分區(qū)索引Global索引必需是范圍分區(qū) - 9i之前Global索引可以是HASH分區(qū) - 10g新特性Global索引不支持Bitmap索引Unique索引必需是prefixed，或者包含分區(qū)字段Local索引non-prefixed, non-unique可以不包含分區(qū)字段create index cust_idx1 on customers(customer_name)global partition by range (customer_name)(partition cust_p01 values less than (H) tabl

15、espace cust_index01,partition cust_p02 values less than (N) tablespace cust_index02,partition cust_p03 values less than (T) tablespace cust_index03,partition cust_p04 values less than (MAXVALUE) tablespace cust_index04)create index cust_idx2 on customers(customer_no) local(partition cust_idx_p01 tab

16、lespace cust_index01,partition cust_idx_p02 tablespace cust_index02,partition cust_idx_p03 tablespace cust_index03,partition cust_idx_p04 tablespace cust_index04,partition cust_idx_p05 tablespace cust_index05,partition cust_idx_p06 tablespace cust_index06,partition cust_idx_p07 tablespace cust_index

17、07,partition cust_idx_p08 tablespace cust_index08)create index cust_idx3 on customers(customer_type) local;分區(qū)索引舉例分區(qū)表索引的運(yùn)用OLTP系統(tǒng)中的建議Global和unique local index性能優(yōu)于nonunique local indexLocal index提供了更好的可用性數(shù)據(jù)倉(cāng)庫(kù)系統(tǒng)中的建議Local index更適宜于數(shù)據(jù)裝載和分區(qū)維護(hù)在大量數(shù)據(jù)統(tǒng)計(jì)時(shí)，能充分利用Local index并行查詢才干在性能、高可用性和可管理性之間進(jìn)展平衡分區(qū)索引選擇戰(zhàn)略分區(qū)裁剪功能P

18、artition pruning: Only the relevant partitions are accessed.99-May99-Apr99-Feb99-Jan99-Mar99-JunsalesSQL SELECT SUM(sales_amount) 2 FROM sales 3 WHERE sales_date BETWEEN 4 TO_DATE(01-MAR-1999, 5 DD-MON-YYYY) AND 6 TO_DATE(31-MAY-1999, 7 DD-MON-YYYY);分區(qū)裁剪舉例1 select * from daily_trans_summ 2* where tr

19、ans_datetime between to_date(25-jun-2001 08,DD-mon-yyyy hh24) and to_date(28-jun-2001 18,DD-mon-yyyy hh24) Partition Partition Operation Options Object Name Start Stop - - - - - SELECT STATEMENT PARTITION RANGE ITERATOR 231 234 TABLE ACCESS FULL DAILY_TRANS_SUMM 231 234 1 select * from daily_trans_s

20、umm 2* where trans_datetime in (25-jun-2001,28-jun-2001) Partition Partition Operation Options Object Name Start Stop - - - - - SELECT STATEMENT PARTITION RANGE INLIST KEY(INLIST) KEY(INLIST) TABLE ACCESS FULL DAILY_TRANS_SUMM KEY(INLIST) KEY(INLIST) Nonpartition-wise joinFull partition-wise joinPar

21、tial partition-wise joinQuery slavePartitionPartitioned table123Partition-Wise JoinPartition-wise JoinsTables and indexes that are partitioned identically are equi-partitioned. A full partition-wise join occurs when joining two equi-partitioned tables that are partitioned on the join key. Oracle spl

22、its the join into joins of pairs of partitions.A partial partition-wise join occurs when only one of the tables is partitioned on the join key.Partition-wise joins occur when joining a hash partition table to a composite partition table if the hash partitioning and sub-partitioning is on the join ke

23、y.Oracle assigns parallel query slaves to process the partition joins.Partition-wise Joins舉例1 select /*+ full(c) */ c.customer_no, count(*)2 from customers c, daily_trans_data d3 where c.customer_no = d.customer_no4 and d.trans_datetime between to_date(25-jun-2001,dd-mon-yyyy)5 and to_date(28-jun-20

24、01,dd-mon-yyyy)6* group by c.customer_no Partition Partition Operation Options Object Name Start Stop - - - - - SELECT STATEMENT PARTITION HASH ALL 1 8 SORT GROUP BY HASH JOIN PARTITION RANGE ITERATOR 50 53 TABLE ACCESS FULL DAILY_TRANS_DATA 393 424 TABLE ACCESS FULL CUSTOMERS 1 8 分區(qū)表設(shè)計(jì)原那么表的大?。寒?dāng)表的大小

25、超越1.5GB2GB，或?qū)τ贠LTP系統(tǒng)，表的記錄超越1000萬(wàn)，都應(yīng)思索對(duì)表進(jìn)展分區(qū)。 數(shù)據(jù)訪問特性：基于表的大部分查詢運(yùn)用，只訪問表中少量的數(shù)據(jù)。對(duì)于這樣表進(jìn)展分區(qū)，可充分利用分區(qū)排除無(wú)關(guān)數(shù)據(jù)查詢的特性。 數(shù)據(jù)維護(hù)：按時(shí)間段刪除成批的數(shù)據(jù)，例如按月刪除歷史數(shù)據(jù)。對(duì)于這樣的表需求思索進(jìn)展分區(qū)，以滿足維護(hù)的需求。數(shù)據(jù)備份和恢復(fù)： 按時(shí)間周期進(jìn)展表空間的備份時(shí)，將分區(qū)與表空間建立對(duì)應(yīng)關(guān)系。只讀數(shù)據(jù)：假設(shè)一個(gè)表中大部分?jǐn)?shù)據(jù)都是只讀數(shù)據(jù)，經(jīng)過(guò)對(duì)表進(jìn)展分區(qū)，可將只讀數(shù)據(jù)存儲(chǔ)在只讀表空間中，對(duì)于數(shù)據(jù)庫(kù)的備份是非常有益的。 并行數(shù)據(jù)操作：對(duì)于經(jīng)常執(zhí)行并行操作如Parallel Insert,Paralle

26、l Update等的表應(yīng)思索進(jìn)展分區(qū)。 表的可用性：當(dāng)對(duì)表的部分?jǐn)?shù)據(jù)可用性要求很高時(shí)，應(yīng)思索進(jìn)展表分區(qū)。 分區(qū)表的管理功能分區(qū)的添加ADD分區(qū)的刪除DROP分區(qū)的合并MERGE分區(qū)的清空TRUNCATE分區(qū)的交換EXCHANGE分區(qū)的緊縮COALESE分區(qū)的挪動(dòng)MOVE分區(qū)的分別SPLIT修正分區(qū)的Default Attribute分區(qū)的更名RENAME分區(qū)索引的管理功能分區(qū)索引的刪除DROP分區(qū)索引的修正MODIFY分區(qū)索引Default Attribute的修正分區(qū)索引的重建REBUILD分區(qū)索引的更名RENAME分區(qū)索引的分別SPLIT分區(qū)索引的Unusable分區(qū)表和Local索引OC

27、T2002SEP2002AUG2002NOV 2001OCT2001新月份數(shù)據(jù)的加載和索引的維護(hù)NOV2002NOV2002NOV2002NOV2002NOV2002NOV2002NOV2002NOV2002NOV2002NOV2002.“滾動(dòng)窗口操作 - 大量數(shù)據(jù)高速裝載OCT2002SEP2002NOV2002NOV 2001NOV 2001OCT2001OCT2002SEP2002NOV2002DEC 2001NOV 2001OCT2001OCT2002SEP2002NOV2002DEC 2001NOV 2001OCT2001OCT2002SEP2002NOV2002DEC 2001NO

28、V 2001OCT2001OCT2002SEP2002NOV2002DEC 2001NOV 2001OCT2001OCT2002SEP2002NOV2002DEC 2001NOV 2001OCT2001OCT2002SEP2002NOV2002DEC 2001NOV 2001OCT2001OCT2002SEP2002NOV2002DEC 2001NOV 2001OCT2001NOV2002刪除或歸檔最老月份的數(shù)據(jù)OCT2001OCT2001新月份數(shù)據(jù)的加載和索引的維護(hù).分區(qū)表和Local索引“滾動(dòng)窗口操作 - 大量數(shù)據(jù)高速裝載分區(qū)交換功能經(jīng)過(guò)交換數(shù)據(jù)段，實(shí)現(xiàn)分區(qū)和非分區(qū)表的數(shù)據(jù)交換。以及子分區(qū)

29、和分區(qū)表的數(shù)據(jù)交換非常快捷的數(shù)據(jù)挪動(dòng)方式。特別是沒有validation和索引維護(hù)操作時(shí)Local 索引自動(dòng)維護(hù)Global索引必需重建分區(qū)交換的運(yùn)用- 全文檢索12：00分區(qū) BF_DXX_stage中間表11：00數(shù)據(jù)的加載 2建立context 索引 3partition的exchangeBF_DXX表* 初始化任務(wù)* 整理任務(wù) 2：00分區(qū)1：00分區(qū) 分區(qū)交換的運(yùn)用- 全文檢索第一步：1：00數(shù)據(jù)的加載insert into BF_DXX_stage(SJ,TEXT3) values(to_date(2004.03.02,YYYY.MM.DD),大撒反對(duì)撒);第二步：建立contex

30、t 索引CREATE INDEX IDX_ BF_DXX _STAGE ON BF_DXX_stage(text3) INDEXTYPE IS CTXSYS.CONTEXT PARAMETERS(LEXER MYLEXER STORAGE MYSTORE FILTER CTXSYS.NULL_FILTER MEMORY 100M) parallel 4;第三步：partition的交換alter table BF_DXX exchange partition p2 with table BF_DXX_stage including indexes;遷移表空間(Transportable Tab

31、lespace)技術(shù)簡(jiǎn)介 第一步：exp transport_tablespace=yes第二步：FTP 數(shù)據(jù)文件和dmp文件第三步：imp transport_tablespace=yes地市系統(tǒng)imp卸載文件省級(jí)系統(tǒng)FTP數(shù)據(jù)文件卸載文件數(shù)據(jù)文件exp遷移表空間技術(shù)的作用業(yè)務(wù)系統(tǒng)數(shù)據(jù)向數(shù)據(jù)倉(cāng)庫(kù)系統(tǒng)的遷移 對(duì)業(yè)務(wù)系統(tǒng)和數(shù)據(jù)倉(cāng)庫(kù)系統(tǒng)的數(shù)據(jù)進(jìn)展定期歸檔 數(shù)據(jù)倉(cāng)庫(kù)向數(shù)據(jù)集市的數(shù)據(jù)遷移 數(shù)據(jù)對(duì)外發(fā)布 按表空間進(jìn)展時(shí)間點(diǎn)的數(shù)據(jù)恢復(fù)(TSPITR) 遷移表空間技術(shù)的優(yōu)點(diǎn)性能大大高于export/import或PL/SQL編寫的程序 由于Dmp文件只包含表空間的構(gòu)造信息，因此該技術(shù)的真正開銷在于數(shù)據(jù)文件的

32、傳輸。 對(duì)源系統(tǒng)的影響非常小 只需求將被遷移的表空間設(shè)置為只讀方式 可同時(shí)傳輸索引數(shù)據(jù)，防止在目的數(shù)據(jù)庫(kù)中重建索引 分區(qū)交換的運(yùn)用- ETL在源系統(tǒng)中，將需求抽取的數(shù)據(jù)以如下語(yǔ)句方式，抽取到建立在單獨(dú)表空間上的中間表中： CREATE TABLE . AS SELECT INSERT /*+ APPEND */ AS SELECT 以TTS方式將中間表的表空間傳輸?shù)綌?shù)據(jù)倉(cāng)庫(kù)之中。 exp transportable_tablespace=Yes FTP 中間表表空間的數(shù)據(jù)文件imp transportable_tablespace=Yes 在數(shù)據(jù)倉(cāng)庫(kù)中對(duì)中間表進(jìn)展各種數(shù)據(jù)歸并等清洗任務(wù)，并建立

33、需求的各種索引。 經(jīng)過(guò)exchange技術(shù)，將中間表數(shù)據(jù)及索引直接交換到分區(qū)表中。 Alter table exchange partition with table including indexes; 分區(qū)交換的運(yùn)用-反復(fù)記錄刪除問題描畫： 在運(yùn)用SQL*Loader進(jìn)展數(shù)據(jù)加載sor_acct_dcc_saamt_c表時(shí)，由于操作失誤，反復(fù)加載，導(dǎo)致分區(qū)ETL_LOAD_DATE_0606出現(xiàn)反復(fù)記錄，也使得兩個(gè)獨(dú)一索引：IDX_SAACNAMT_C_1，IDX_SAACNAMT_C_2的ETL_LOAD_DATE_0606分區(qū)不可用UNUSABLE。用戶在試圖重新創(chuàng)建該分區(qū)索引時(shí)，出現(xiàn)

34、如下錯(cuò)誤：SQL alter index IDX_SAACNAMT_C_2 rebuild partition ETL_LOAD_DATE_0606;alter index IDX_SAACNAMT_C_2 rebuild partition ETL_LOAD_DATE_0606*ORA-01452: cannot CREATE UNIQUE INDEX; duplicate keys found 分區(qū)交換的運(yùn)用-反復(fù)記錄刪除在試圖刪除該分區(qū)的反復(fù)記錄時(shí)，又出現(xiàn)如下錯(cuò)誤：SQL delete from sor_acct_dcc_saamt_c partition(ETL_LOAD_DATE_0

35、606)where rowid not in (select min(rowid) from sor_acct_dcc_saamt_c partition(ETL_LOAD_DATE_0606) group by ETL_LOAD_DATE, CUST_ACCT_NO, SA_CURR_COD, SA_CURR_IDEN);*ORA-01502: index GYFX.IDX_SAACNAMT_C_1 or partition of such index is in unusable state分區(qū)交換的運(yùn)用-反復(fù)記錄刪除簡(jiǎn)一方法是徹底刪除這兩個(gè)獨(dú)一索引，重新創(chuàng)建。 數(shù)據(jù)量大，時(shí)間太長(zhǎng)。影響系

36、統(tǒng)的可用性。 更完備的處理方式創(chuàng)建一個(gè)與sor_acct_dcc_saamt_c構(gòu)造一樣的暫時(shí)表test。 SQL create table test as select * from sor_acct_dcc_saamt_c where 1=2; 將sor_acct_dcc_saamt_c表分區(qū)ETL_LOAD_DATE_0606數(shù)據(jù)交換到暫時(shí)表test。 SQL alter table sor_acct_dcc_saamt_c exchange partition ETL_LOAD_DATE_0606 with table test; 分區(qū)交換的運(yùn)用-反復(fù)記錄刪除更完備的處理方式刪除tes

37、t中的反復(fù)記錄 delete from test where rowid not in (select min(rowid) from test group by ETL_LOAD_DATE, CUST_ACCT_NO, SA_CURR_COD, SA_CURR_IDEN); 由于test表沒有任何索引，可防止上述ORA-01502錯(cuò)誤。 將暫時(shí)表test數(shù)據(jù)交換回sor_acct_dcc_saamt_c表分區(qū)ETL_LOAD_DATE_0606 。 alter table sor_acct_dcc_saamt_c exchange partition ETL_LOAD_DATE_0606 w

38、ith table test; 分區(qū)交換的運(yùn)用-反復(fù)記錄刪除更完備的處理方式重新創(chuàng)建創(chuàng)建該分區(qū)索引IDX_SAACNAMT_C_1，IDX_SAACNAMT_C_2 alter index IDX_SAACNAMT_C_1 rebuild partition ETL_LOAD_DATE_0606 tablespace ETL0_R_LOAD_IDX_200606; alter index IDX_SAACNAMT_C_2 rebuild partition ETL_LOAD_DATE_0606 tablespace ETL0_R_LOAD_IDX_200606; 此時(shí)反復(fù)記錄曾經(jīng)刪除，可防止上

39、述ORA-01452錯(cuò)誤 現(xiàn)有系統(tǒng)實(shí)施分區(qū)的閱歷分區(qū)對(duì)象確實(shí)定：存儲(chǔ)空間最大的前20個(gè)表Select * from (Select * from dba_segments order by bytes desc) where rownum = 20;分析大表的操作行為Select * from (Select sql_text,executions from v$sqlarea where upper(sql_text) like %SB_ZSXX% order by executions desc) where rownum CREATE MATERIALIZED VIEW sales_summary 2 TABLESPACE users 3 PARALLEL (DEGREE 4) 4 BUILD IMMEDIATE 5 ENABLE QUERY REWRITE 6 AS 7 SELECT d_name, 8 SUM (s.quantity_sold), 8 SUM (s.amount_sold) 9 FROM sales s, products p 10 WHERE d_id = d_id 11 GROUP BY d_name; 物化視圖創(chuàng)建和查詢重寫例SQL SELECT d_name,SUM (s.quantity_sold), 2 SUM (s.amou