ついに最初の質問をします (私は長年のストーカーですが)。
先日、仕事中に SQL クエリが私の注意を引きました。問題は、演算子WHEREを使用してインデックスを可能な値と比較するときの句のパフォーマンスです。IN
SELECT SUM (parts.quantity) AS quantity,
concessions.concessionCode,
concessions.description AS concessionDesc,
parts.type,
activities.activityCode,
REPLACE (activities.activityCode, activities.lvl2 || '-', '') AS activityCodeDisplay,
strings.activityDesc,
strings.activityDesc2,
strings.activityDesc3
FROM tb_parts parts,
tb_activities activities,
tb_strings strings,
tb_concessions concessions
WHERE parts.activityCode = activities.activityCode
AND parts.concessionCode = activities.concessionCode
AND activities.concessionCode = concesions.concessionCode
AND activities.concessionCode = strings.concessionCode
AND activities.activityCode = strings.activityCode
AND strings.language = 'ENG'
--AND parts.concesionCode IN ('ZD', 'G9', 'TR', 'JS0')
AND parts.concesionCode IN ('ZD', 'G9')
AND parts.date >= TO_DATE ('01/01/2013 00:00:00', 'DD/MM/YYYY HH24:MI:SS')
AND parts.date <= TO_DATE ('30/04/2013 23:59:59', 'DD/MM/YYYY HH24:MI:SS')
AND parts.type IN ('U', 'M')
AND parts.value = 'E'
GROUP BY concesions.concessionCode,
concesions.description,
parts.type,
activities.activityCode,
REPLACE (activities.activityCode, activities.lvl2|| '-', ''),
strings.activityDesc,
strings.activityDesc2,
strings.activityDesc3
ORDER BY concesions.concessionCode;
私が抱えている問題はこれです-クエリがそのまま実行される場合（ の2つの値を使用IN）、30秒かかります。(コメント行にあるように) 4 つの値で実行すると、クエリは 5 秒かかります。インデックスを複数の値と比較すると時間がかかると思いますが、そうではないようです。私は日中に「テスト」を数回繰り返しましたが、それらは常に多かれ少なかれ同じです（30 +-1、5 +-1）。
なぜこれがそのような方法で動作しているのかについての洞察は大歓迎です!
PSテーブル/列の名前を翻訳したので、矛盾がある場合は申し訳ありません。
PPS私はこのコードを結合で書き直しましたが、はるかに高速ですが、この異常の背後にある理由はまだ私を悩ませています:)
編集：ついに仕事に！いくつかの試行錯誤の後、これら 2 つのバージョンの実行計画を作成できました。また、クエリの 3 番目のバージョンの実行計画を作成することもできました( where. また、表のデータについていくつか質問がありましたので、以下にいくつかの情報を示します。
All the stats are analyzed the day that queries were executed
Table parts
total rows - 3.2 M
matches for 2 values - 1.08 M (~34%)
matches for 4 values - 1.30 M (~41%)
Table activities
total rows - 3866
matches for 2 values - 321 (~ 8%)
matches for 4 values - 644 (~16%)
Table strings
total rows - 7436
matches for 2 values - 642 (~ 8%)
matches for 4 values - 1288 (~17%)
Index in_parts
codConcession
username
date
そのため、動的サンプリングを使用した場合（正しく実行した場合、つまりキーワード/*+ dynamic_sampling(tb_parts 10) */の後にある場合）は、（+2/3sを除いて）大きな違いはないと思いますSELECT
2 つの値の場合:
-----------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-----------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 186 | 864 (1)| 00:00:11 |
| 1 | SORT ORDER BY | | 1 | 186 | 864 (1)| 00:00:11 |
| 2 | HASH GROUP BY | | 1 | 186 | 864 (1)| 00:00:11 |
|* 3 | TABLE ACCESS BY INDEX ROWID | tb_parts | 1 | 37 | 818 (1)| 00:00:10 |
| 4 | NESTED LOOPS | | 1 | 186 | 862 (1)| 00:00:11 |
| 5 | NESTED LOOPS | | 1 | 149 | 44 (0)| 00:00:01 |
| 6 | NESTED LOOPS | | 34 | 2108 | 10 (0)| 00:00:01 |
| 7 | INLIST ITERATOR | | | | | |
| 8 | TABLE ACCESS BY INDEX ROWID| tb_concesions | 2 | 54 | 2 (0)| 00:00:01 |
|* 9 | INDEX UNIQUE SCAN | pk_concession | 2 | | 1 (0)| 00:00:01 |
| 10 | TABLE ACCESS BY INDEX ROWID | tb_activities | 17 | 595 | 4 (0)| 00:00:01 |
|* 11 | INDEX RANGE SCAN | pk_activity | 17 | | 2 (0)| 00:00:01 |
| 12 | TABLE ACCESS BY INDEX ROWID | tb_strings | 1 | 87 | 1 (0)| 00:00:01 |
|* 13 | INDEX UNIQUE SCAN | pk_string | 1 | | 0 (0)| 00:00:01 |
|* 14 | INDEX RANGE SCAN | in_parts | 454 | | 648 (1)| 00:00:08 |
-----------------------------------------------------------------------------------------------------
PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
3 - filter("parts"."value"='E'
AND ("parts"."type"='M' OR "parts"."type"='U')
AND "parts"."activityCode"="activities"."activityCode")
9 - access("concessions"."concessionCode"='G9'
OR "concessions"."concessionCode"='ZD')
11 - access("activities"."concessionCode"="concessions"."concessionCode")
filter("activities"."concessionCode"='G9'
OR "activities"."concessionCode"='ZD')
13 - access("activities"."concessionCode"="strings"."concessionCode"
AND "activities"."activityCode"="strings"."activityCode"
AND "strings"."language"='ENG')
filter("strings"."concessionCode"='G9'
OR "strings"."concessionCode"='ZD')
14 - access("parts"."concessionCode"="activities"."concessionCode"
AND "parts"."date">=TO_DATE('2013-01-01 00:00:00',
'syyyy-mm-dd hh24:mi:ss')
AND "parts"."date"<=TO_DATE(' 2013-04-30 23:59:59',
'syyyy-mm-dd hh24:mi:ss'))
filter("parts"."date">=TO_DATE('2013-01-01 00:00:00',
'syyyy-mm-dd hh24:mi:ss')
AND ("parts"."concessionCode"='G9'
OR "parts"."concessionCode"='ZD')
AND "parts"."date"<=TO_DATE(' 2013-04-30 23:59:59',
'syyyy-mm-dd hh24:mi:ss'))
4 つの値の場合:
----------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 186 | 7412 (2)| 00:01:29 |
| 1 | SORT ORDER BY | | 1 | 186 | 7412 (2)| 00:01:29 |
| 2 | HASH GROUP BY | | 1 | 186 | 7412 (2)| 00:01:29 |
| 3 | NESTED LOOPS | | 1 | 186 | 7410 (2)| 00:01:29 |
|* 4 | HASH JOIN | | 17 | 1683 | 7393 (2)| 00:01:29 |
|* 5 | HASH JOIN | | 136 | 8432 | 21 (5)| 00:00:01 |
| 7 | TABLE ACCESS BY INDEX ROWID| tb_concesions | 4 | 108 | 2 (0)| 00:00:01 |
|* 8 | INDEX UNIQUE SCAN | pk_concession | 4 | | 1 (0)| 00:00:01 |
|* 9 | TABLE ACCESS FULL | tb_activities | 644 | 22540 | 18 (0)| 00:00:01 |
|* 10 | TABLE ACCESS FULL | tb_parts | 4310 | 155K| 7372 (2)| 00:01:29 |
| 11 | TABLE ACCESS BY INDEX ROWID | tb_strings | 1 | 87 | 1 (0)| 00:00:01 |
|* 12 | INDEX UNIQUE SCAN | pk_string | 1 | | 0 (0)| 00:00:01 |
----------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
PLAN_TABLE_OUTPUT
----------------------------------------------------------------------------------------------------
---------------------------------------------------
4 - access("parts"."activityCode"="activities"."activityCode"
AND "parts"."concessionCode"="activities"."concessionCode")
5 - access("activities"."concessionCode"="concessions"."concessionCode")
8 - access("concessions"."concessionCode"='G9'
OR "concessions"."concessionCode"='JS0'
OR "concessions"."concessionCode"='TR'
OR "concessions"."concessionCode"='ZD')
9 - filter("activities"."concessionCode"='G9'
OR "activities"."concessionCode"='JS0'
OR "activities"."concessionCode"='TR'
OR "activities"."concessionCode"='ZD')
10 - filter("parts"."date">=TO_DATE(' 2013-01-01 00:00:00',
'syyyy-mm-dd hh24:mi:ss')
AND "parts"."value"='E'
AND ("parts"."type"='M' OR "parts"."type"='U')
AND ("parts"."concessionCode"='G9'
OR "parts"."concessionCode"='JS0'
OR "parts"."concessionCode"='TR'
OR "parts"."concessionCode"='ZD')
AND "parts"."date"<=TO_DATE(' 2013-04-30 23:59:59',
'syyyy-mm-dd hh24:mi:ss'))
12 - access("activities"."concessionCode"="strings"."concessionCode"
AND "activities"."activityCode"="strings"."activityCode"
AND "strings"."language"='ENG')
filter("strings"."concessionCode"='G9'
OR "strings"."concessionCode"='JS0'
OR "strings"."concessionCode"='TR'
OR "strings"."concessionCode"='ZD')
最後に6 つの値:
----------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 186 | 4525 (1)| 00:00:55 |
| 1 | SORT ORDER BY | | 1 | 186 | 4525 (1)| 00:00:55 |
| 2 | HASH GROUP BY | | 1 | 186 | 4525 (1)| 00:00:55 |
| 3 | NESTED LOOPS | | 1 | 186 | 4523 (1)| 00:00:55 |
|* 4 | HASH JOIN | | 9 | 891 | 4514 (1)| 00:00:55 |
|* 5 | HASH JOIN | | 136 | 8432 | 21 (5)| 00:00:01 |
| 6 | INLIST ITERATOR | | | | | |
| 7 | TABLE ACCESS BY INDEX ROWID| tb_concesions | 4 | 108 | 2 (0)| 00:00:01 |
|* 8 | INDEX UNIQUE SCAN | pk_concession | 4 | | 1 (0)| 00:00:01 |
|* 9 | TABLE ACCESS FULL | tb_activities | 644 | 22540 | 18 (0)| 00:00:01 |
| 10 | INLIST ITERATOR | | | | | |
|* 11 | TABLE ACCESS BY INDEX ROWID | tb_parts | 2155 | 79735 | 4493 (1)| 00:00:54 |
|* 12 | INDEX RANGE SCAN | in_parts | 8620 | | 1277 (1)| 00:00:16 |
| 13 | TABLE ACCESS BY INDEX ROWID | tb_strings | 1 | 87 | 1 (0)| 00:00:01 |
|* 14 | INDEX UNIQUE SCAN | pk_string | 1 | | 0 (0)| 00:00:01 |
----------------------------------------------------------------------------------------------------
PLAN_TABLE_OUTPUT
----------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
4 - access("parts"."activityCode"="activities"."activityCode"
AND "parts"."concessionCode"="activities"."concessionCode")
5 - access("activities"."concessionCode"="concessions"."concessionCode")
8 - access("concessions"."concessionCode"='G9'
OR "concessions"."concessionCode"='JS0'
OR "concessions"."concessionCode"='TR'
OR "concessions"."concessionCode"='ZD')
9 - filter("activities"."concessionCode"='G9'
OR "activities"."concessionCode"='JS0'
OR "activities"."concessionCode"='TR'
OR "activities"."concessionCode"='ZD')
11 - filter("parts"."value"='E'
AND ("parts"."type"='M' OR "parts"."type"='U'))
12 - access(("parts"."concessionCode"='G9'
OR "parts"."concessionCode"='ZD')
AND "parts"."date">=TO_DATE(' 2013-01-01 00:00:00',
'syyyy-mm-dd hh24:mi:ss')
AND "parts"."date"<=TO_DATE(' 2013-04-30 23:59:59',
'syyyy-mm-dd hh24:mi:ss'))
filter("parts"."date">=TO_DATE(' 2013-01-01 00:00:00',
'syyyy-mm-dd hh24:mi:ss')
AND "parts"."date"<=TO_DATE(' 2013-04-30 23:59:59',
'syyyy-mm-dd hh24:mi:ss'))
14 - access("activities"."concessionCode"="strings"."concessionCode"
AND "activities"."activityCode"="strings"."activityCode"
AND "strings"."language"='ENG')
filter("strings"."concessionCode"='G9'
OR "strings"."concessionCode"='JS0'
OR "strings"."concessionCode"='TR'
OR "strings"."concessionCode"='ZD')
実行計画との打ち合わせはこれが初めてなので、遅延の原因は何なのか推測するしかありません。値が 4 ～ 6 の場合、FULL ACCESS から ACCESS BY INDEX への変更であると推測できます。また、テーブルにアクセスすると、4 つの値 (id 10) のフィルターには 4 つの譲歩値がすべて含まれます。一方、6 つの値の場合、2 つの割引値はアクセス部分にあり、フィルターには日付、型、および値のみが含まれます。