Oracle Consistent在兩臺服務器和性能之間有所不同

因此，我們有一些複雜的SQL查詢。我們系統的性能在大約1.1秒內返回結果。在客戶環境中，查詢返回大約2.4-2.5秒。在兩臺服務器上運行統計數據，我們注意到一致性get的巨大差異。我們比較了一些參數，看看是否存在緩存差異，但我不完全確定要看什麼。我們確實注意到他們的系統上的DB_FILE_MULTIBLOCK_READ_COUNT是8，而我們的128.基本上，看下面的內容，有沒有什麼方向可以讓我們去讓這些統計數據更緊密地匹配。Oracle Consistent在兩臺服務器和性能之間有所不同

或者，一致性得到如此不同並不重要？

**Our Statistics** 
0 recursive calls 
0 db block gets 
28344 consistent gets 
0 physical reads 
188 redo size 
1664150 bytes sent via SQL*Net to client 
36494 bytes received via SQL*Net from client 
3272 SQL*Net roundtrips to/from client 
1 sorts (memory) 
0 sorts (disk) 
49053 rows processed 

**Client Statistics** 
      0 recursive calls 
      1 db block gets 
    306456 consistent gets 
     288 physical reads 
     188 redo size 
    1879562 bytes sent via SQL*Net to client 
     36494 bytes received via SQL*Net from client 
     3272 SQL*Net roundtrips to/from client 
      0 sorts (memory) 
      0 sorts (disk) 
     49053 rows processed

我們的計劃：選擇

49053行。

Execution Plan 
----------------------------------------------------------      
Plan hash value: 60030630              

-------------------------------------------------------------------------------- 
-------------------------------------------------        

| Id | Operation        | Name       
| Rows | Bytes |TempSpc| Cost (%CPU)| Time  |        

-------------------------------------------------------------------------------- 
-------------------------------------------------        

| 0 | SELECT STATEMENT      |         
| 454M| 160G|  | 262K (7)| 00:52:27 |        

|* 1 | HASH JOIN RIGHT OUTER     |         
| 454M| 160G|  | 262K (7)| 00:52:27 |        

| 2 | VIEW         |         
|  9 | 1935 |  |  6 (17)| 00:00:01 |        

| 3 | MERGE JOIN       |         
|  9 | 198 |  |  6 (17)| 00:00:01 |        

| 4 |  TABLE ACCESS BY INDEX ROWID  | TBLWORKFLOWSTAGES    
|  9 | 144 |  |  2 (0)| 00:00:01 |        

| 5 |  INDEX FULL SCAN     | PK_TBLWORKFLOWSTAGES   
|  9 |  |  |  1 (0)| 00:00:01 |        

|* 6 |  SORT JOIN       |         
|  9 | 54 |  |  4 (25)| 00:00:01 |        

| 7 |  TABLE ACCESS FULL     | TBLWORKFLOWSTAGETREE   
|  9 | 54 |  |  3 (0)| 00:00:01 |        

|* 8 | HASH JOIN RIGHT OUTER    |         
| 454M| 69G|  | 258K (6)| 00:51:48 |        

| 9 | TABLE ACCESS FULL     | TBLTASKDEFINITIONS    
|  4 | 148 |  |  3 (0)| 00:00:01 |        

|* 10 | HASH JOIN       |         
| 454M| 53G| 22M| 255K (4)| 00:51:10 |        

|* 11 |  INDEX FAST FULL SCAN    | IDX_IAM_AS_ID_IN_ID_ACCESS  
| 983K| 11M|  | 1842 (2)| 00:00:23 |        

|* 12 |  FILTER        |         
|  |  |  |   |   |        

|* 13 |  HASH JOIN RIGHT OUTER    |         
| 39M| 4385M|  | 9180 (71)| 00:01:51 |        

| 14 |  TABLE ACCESS FULL    | TBLASSETSTATUSES    
|  4 | 24 |  |  3 (0)| 00:00:01 |        

|* 15 |  HASH JOIN      |         
| 79M| 8313M|  | 8614 (69)| 00:01:44 |        

|* 16 |  HASH JOIN RIGHT SEMI   |         
| 8316 | 446K|  | 2167 (2)| 00:00:27 |        

| 17 |   INDEX FULL SCAN    | PK_TBLWORKFLOWSTAGETREEPARENTS 
|  7 | 21 |  |  1 (0)| 00:00:01 |        

| 18 |   VIEW       |         
| 49895 | 2533K|  | 2165 (2)| 00:00:26 |        

| 19 |   UNION-ALL      |         
|  |  |  |   |   |        

| 20 |   NESTED LOOPS ANTI   |         
|  1 | 144 |  |  1 (0)| 00:00:01 |        

| 21 |   NESTED LOOPS    |         
|  1 | 106 |  |  1 (0)| 00:00:01 |        

| 22 |    INDEX FULL SCAN   | PK_TBLWORKMGMTGP    
|  1 | 13 |  |  0 (0)| 00:00:01 |        

|* 23 |    TABLE ACCESS BY INDEX ROWID| TBLASSETTASKS     
|  1 | 93 |  |  1 (0)| 00:00:01 |        

|* 24 |    INDEX UNIQUE SCAN   | PK_TBLASSETTASKS    
|  1 |  |  |  1 (0)| 00:00:01 |        

|* 25 |   INDEX FULL SCAN    | PK_TBLASSETTASKCOPIES   
|  1 | 38 |  |  0 (0)| 00:00:01 |        

| 26 |   NESTED LOOPS ANTI   |         
| 49894 | 6626K|  | 2164 (2)| 00:00:26 |        

| 27 |   NESTED LOOPS    |         
| 49894 | 4775K|  | 2163 (2)| 00:00:26 |        

|* 28 |    TABLE ACCESS FULL   | TBLASSETTASKS     
| 122K| 10M|  | 2147 (1)| 00:00:26 |        

|* 29 |    INDEX UNIQUE SCAN   | PK_TBLWORKMGMTINST    
|  1 |  5 |  |  0 (0)| 00:00:01 |        

|* 30 |   INDEX FULL SCAN    | PK_TBLASSETTASKCOPIES   
|  1 | 38 |  |  0 (0)| 00:00:01 |        

|* 31 |  TABLE ACCESS FULL    | TBLASSETS      
| 827M| 41G|  | 622 (1)| 00:00:08 |        

-------------------------------------------------------------------------------- 
-------------------------------------------------        


Predicate Information (identified by operation id):        
---------------------------------------------------        

    1 - access("QUERYTABLE"."AST_CURRENT_WFST_ID"="DISPLAYTABLE1"."WFST_ID"(+)) 
    6 - access("WFST"."WFS_ID"="WFS"."WFS_ID")         
     filter("WFST"."WFS_ID"="WFS"."WFS_ID")         
    8 - access("DISPLAYTABLE2"."TD_ID"(+)="QUERYTABLE"."TD_ID")     
    10 - access("TBLASSETS"."AS_ID"="TBLINSPECTORASSETMAP"."AS_ID")    
    11 - filter("TBLINSPECTORASSETMAP"."IN_ID"=1 AND ("TBLINSPECTORASSETMAP"."IAM_ 
ASSET_ACCESS_LEVEL"=0 OR               

       "TBLINSPECTORASSETMAP"."IAM_ASSET_ACCESS_LEVEL"=1))    
    12 - filter("TBLASSETSTATUSES"."ASSET_STATUS_HIDE_REPORTS" IS NULL OR "TBLASSE 
TSTATUSES"."ASSET_STATUS_HIDE_REPORTS"=0)          

    13 - access("TBLASSETSTATUSES"."ASSET_STATUS_ID"(+)="TBLASSETS"."ASSET_STATUS_ 
ID")                    

    15 - access("QUERYTABLE"."AS_ID"="TBLASSETS"."AS_ID")       
    16 - access("QUERYTABLE"."AST_CURRENT_WFST_ID"="PARENT_WFST_ID")    
    23 - filter("TBLASSETTASKS"."AST_TYPE"=3 AND "AST_DELETED"=0)     
    24 - access("TBLASSETTASKS"."AST_ID"="TBLWORKMGMTGP"."AST_ID")     
    25 - access("TBLASSETTASKS"."AST_GUID"="COPY_AST_GUID")      
     filter("TBLASSETTASKS"."AST_GUID"="COPY_AST_GUID")      
    28 - filter("TBLASSETTASKS"."AST_TYPE"=4 AND "AST_DELETED"=0)     
    29 - access("TBLASSETTASKS"."AST_ID"="TBLWORKMGMTINST"."AST_ID")    
    30 - access("TBLASSETTASKS"."AST_GUID"="COPY_AST_GUID")      
     filter("TBLASSETTASKS"."AST_GUID"="COPY_AST_GUID")      
    31 - filter("AS_DELETED"=0 AND ("TBLASSETS"."AS_ASSET_DEF"=0 OR "TBLASSETS"."A 
S_ASSET_DEF"=1))                 


Note                    
-----                   
    - SQL profile "SYS_SQLPROF_014054654a1d0000" used for this statement   


Statistics 
----------------------------------------------------------      
      0 recursive calls              
      0 db block gets              
     28343 consistent gets              
      0 physical reads              
      0 redo size               
    1664150 bytes sent via SQL*Net to client         
     36494 bytes received via SQL*Net from client        
     3272 SQL*Net roundtrips to/from client         
      1 sorts (memory)              
      0 sorts (disk)              
     49053 rows processed

他們的計劃：

Execution Plan 
----------------------------------------------------------      
Plan hash value: 854387336              

-------------------------------------------------------------------------------- 
------------------------------------------          

| Id | Operation        | Name       
| Rows | Bytes | Cost (%CPU)| Time  |          

-------------------------------------------------------------------------------- 
------------------------------------------          

| 0 | SELECT STATEMENT      |        
|  1 | 353 | 1321 (1)| 00:00:16 |          

| 1 | NESTED LOOPS OUTER      |        
|  1 | 353 | 1321 (1)| 00:00:16 |          

| 2 | NESTED LOOPS OUTER     |        
|  1 | 149 | 1319 (1)| 00:00:16 |          

|* 3 | FILTER        |        
|  |  |   |   |          

| 4 |  NESTED LOOPS OUTER     |        
|  1 | 114 | 1318 (1)| 00:00:16 |          

| 5 |  NESTED LOOPS      |        
|  1 | 110 | 1317 (1)| 00:00:16 |          

| 6 |  NESTED LOOPS      |        
|  1 | 103 | 1317 (1)| 00:00:16 |          

| 7 |  NESTED LOOPS SEMI    |        
|  1 | 54 | 1316 (1)| 00:00:16 |          

| 8 |   VIEW       |        
| 49426 | 2509K| 1315 (1)| 00:00:16 |          

| 9 |   NESTED LOOPS ANTI    |        
| 49426 | 6178K| 1315 (1)| 00:00:16 |          

| 10 |   VIEW       | VW_JF_SET$10554C5A    
| 49427 | 4344K| 1314 (1)| 00:00:16 |          

| 11 |   UNION-ALL     |        
|  |  |   |   |          

| 12 |    NESTED LOOPS    |        
|  |  |   |   |          

| 13 |    NESTED LOOPS    |        
|  1 | 106 |  1 (0)| 00:00:01 |          

| 14 |    INDEX FULL SCAN   | PK_TBLWORKMGMTGP    
|  1 | 13 |  0 (0)| 00:00:01 |          

|* 15 |    INDEX UNIQUE SCAN   | PK_TBLASSETTASKS    
|  1 |  |  0 (0)| 00:00:01 |          

|* 16 |    TABLE ACCESS BY INDEX ROWID| TBLASSETTASKS     
|  1 | 93 |  1 (0)| 00:00:01 |          

| 17 |    NESTED LOOPS    |        
| 49426 | 4730K| 1313 (1)| 00:00:16 |          

|* 18 |    TABLE ACCESS BY INDEX ROWID| TBLASSETTASKS     
| 49426 | 4488K| 1310 (1)| 00:00:16 |          

|* 19 |    INDEX RANGE SCAN   | TBLINSPECTIONREPORT_IR_TYPE 
| 49456 |  | 106 (1)| 00:00:02 |          

|* 20 |    INDEX UNIQUE SCAN   | PK_TBLWORKMGMTINST    
|  1 |  5 |  0 (0)| 00:00:01 |          

|* 21 |   INDEX FULL SCAN    | PK_TBLASSETTASKCOPIES   
|  1 | 38 |  0 (0)| 00:00:01 |          

|* 22 |   INDEX RANGE SCAN    | PK_TBLWORKFLOWSTAGETREEPARENTS 
|  1 |  2 |  0 (0)| 00:00:01 |          

|* 23 |  TABLE ACCESS BY INDEX ROWID  | TBLASSETS      
|  1 | 49 |  1 (0)| 00:00:01 |          

|* 24 |   INDEX RANGE SCAN    | IDX_ASSET_STATUS_ASID_DELETED 
|  1 |  |  0 (0)| 00:00:01 |          

| 25 |  INLIST ITERATOR     |        
|  |  |   |   |          

|* 26 |  INDEX RANGE SCAN     | IDX_IAM_AS_ID_IN_ID_ACCESS  
|  2 | 14 |  0 (0)| 00:00:01 |          

| 27 |  TABLE ACCESS BY INDEX ROWID  | TBLASSETSTATUSES    
|  1 |  4 |  1 (0)| 00:00:01 |          

|* 28 |  INDEX UNIQUE SCAN     | PK_TBLASSETSTATUS    
|  1 |  |  0 (0)| 00:00:01 |          

| 29 | TABLE ACCESS BY INDEX ROWID   | TBLTASKDEFINITIONS    
|  1 | 35 |  1 (0)| 00:00:01 |          

|* 30 |  INDEX UNIQUE SCAN     | PK_TBLTASKDEFINITIONS   
|  1 |  |  0 (0)| 00:00:01 |          

| 31 | VIEW PUSHED PREDICATE     |        
|  1 | 204 |  2 (0)| 00:00:01 |          

| 32 | NESTED LOOPS       |        
|  1 | 18 |  2 (0)| 00:00:01 |          

| 33 |  TABLE ACCESS BY INDEX ROWID   | TBLWORKFLOWSTAGETREE   
|  1 |  4 |  1 (0)| 00:00:01 |          

|* 34 |  INDEX UNIQUE SCAN     | PK_TBLWORKFLOWSTAGEFLOW  
|  1 |  |  0 (0)| 00:00:01 |          

| 35 |  TABLE ACCESS BY INDEX ROWID   | TBLWORKFLOWSTAGES    
|  9 | 126 |  1 (0)| 00:00:01 |          

|* 36 |  INDEX UNIQUE SCAN     | PK_TBLWORKFLOWSTAGES   
|  1 |  |  0 (0)| 00:00:01 |          

-------------------------------------------------------------------------------- 
------------------------------------------          


Predicate Information (identified by operation id):        
---------------------------------------------------        

    3 - filter("TBLASSETSTATUSES"."ASSET_STATUS_HIDE_REPORTS" IS NULL OR   
       "TBLASSETSTATUSES"."ASSET_STATUS_HIDE_REPORTS"=0)     
    15 - access("TBLASSETTASKS"."AST_ID"="TBLWORKMGMTGP"."AST_ID")     
    16 - filter("TBLASSETTASKS"."AST_TYPE"=3 AND "AST_DELETED"=0)     
    18 - filter("AST_DELETED"=0)             
    19 - access("TBLASSETTASKS"."AST_TYPE"=4)          
    20 - access("TBLASSETTASKS"."AST_ID"="TBLWORKMGMTINST"."AST_ID")    
    21 - access("ITEM_1"="COPY_AST_GUID")           
     filter("ITEM_1"="COPY_AST_GUID")           
    22 - access("AST_CURRENT_WFST_ID"="PARENT_WFST_ID")       
    23 - filter("TBLASSETS"."AS_ASSET_DEF"=0 OR "TBLASSETS"."AS_ASSET_DEF"=1)  
    24 - access("AS_ID"="TBLASSETS"."AS_ID" AND "AS_DELETED"=0)     
    26 - access("TBLASSETS"."AS_ID"="TBLINSPECTORASSETMAP"."AS_ID" AND "TBLINSPECT 
ORASSETMAP"."IN_ID"=1 AND              

       ("TBLINSPECTORASSETMAP"."IAM_ASSET_ACCESS_LEVEL"=0 OR "TBLINSPECTO 
RASSETMAP"."IAM_ASSET_ACCESS_LEVEL"=1))           

    28 - access("TBLASSETSTATUSES"."ASSET_STATUS_ID"(+)="TBLASSETS"."ASSET_STATUS_ 
ID")                    

    30 - access("DISPLAYTABLE2"."TD_ID"(+)="TD_ID")        
    34 - access("WFST"."WFST_ID"="AST_CURRENT_WFST_ID")       
    36 - access("WFST"."WFS_ID"="WFS"."WFS_ID")         


Statistics 
----------------------------------------------------------      
      0 recursive calls              
      0 db block gets              
    337565 consistent gets              
      0 physical reads              
      0 redo size               
    1728165 bytes sent via SQL*Net to client         
     23140 bytes received via SQL*Net from client        
     3272 SQL*Net roundtrips to/from client         
      0 sorts (memory)              
      0 sorts (disk)              
     49051 rows processed

來源

2013-08-21 hammer

第一件事是第一件事。這兩個系統上的查詢計劃是否相同？這兩個系統是否有完全相同的數據（即，您是從系統導出到您的環境中，還是在客戶使用實時數據運行時使用一些測試數據運行）？數據集有多不同？例如，如果您擁有100萬行測試數據，但客戶擁有2000萬行實時數據，則即使兩個查詢最終返回相同數量的行，比較統計數據也不會有意義。 –

應該提到這一點。數據完全一樣。我們幾天前進行了他們的數據導入。查詢計劃只有不同，因爲在客戶數據庫上進行了連接優化，而我們沒有使用該優化。除了連接優化之外，查詢計劃不會有所不同。相同的索引等。 – hammer

在這種情況下，「連接優化」是什麼意思？如果查詢計劃不同且客戶的網站性能下降，您確定客戶網站上的查詢計劃比您本地查詢計劃更有效嗎？如果你迫使兩個計劃相同，會發生什麼？ –

在DB_FILE_MULTIBLOCK_READ_COUNT的差異使得全表掃描可能是更有效的在系統上比他們的。在更新的版本中，你應該避免明確地設置它，因爲它將默認在該環境中儘可能最大化。 8聽起來不合理地低。

導入數據不會與數據佈局完全匹配 - 您仍然可以在數據存儲中有意義的差異，並且唯一的方法就是確保數據和索引的佈局完全相同一個表空間的運輸。

PGA的較低設置可以想象會阻止較大的散列連接，因爲多通道排序的成本增加可能會提高估計成本。

因此無論如何，它看起來像你的解釋計劃時間估計是瘋狂的。您是否查看過收集系統統計信息，以便優化程序對單塊和多塊讀取以及cpu操作所需的時間進行公平估計？

來源

2013-08-21 19:59:11

我不熟悉收集系統統計信息。我認爲這與收集表格統計數據不同？我們也可以推薦一個DB_FILE_MULTIBLOCK_READ_COUNT的臨時調整。謝謝你的幫助。 – hammer

是的，它配置系統性能：http://docs.oracle.com/cd/E25054_01/server.1111/e16638/stats.htm#i41496 –

最顯著不同的是，您的系統使用SQL配置文件（如賈斯汀洞猜測）：

Note                    
-----                   
    - SQL profile "SYS_SQLPROF_014054654a1d0000" used for this statement

退房the manual對SQL配置，比如如何對它們進行修改和服務器之間移動它們的信息。

另外，this article by Kerry Osborne可以幫助您查看配置文件正在執行的操作。

如果您想快速強制計劃保持一致，請使用選項format => 'outline'運行dbms_xplan。這將創建一大批將完全控制計劃的提示。你可能做而不是想要永久使用這些提示。但是，如果您可以在臨時查詢中快速複製計劃，則至少可以排除其他環境差異。

來源

2013-08-28 18:44:36

Oracle Consistent在兩臺服務器和性能之間有所不同

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