鐩綍
---
涓�锛庣浉鍏崇殑姒傚康
Rowid
鐨勬蹇?/p>
Recursive Sql
姒傚康
Predicate(
璋撹瘝
)
DRiving Table(
椹卞姩琛?/p>
)
Probed Table(
琚帰鏌ヨ〃
)
缁勫悎绱㈠紩
(concatenated index)
鍙�夋嫨鎬?/p>
(selectivity)
浜岋紟
oracle
璁块棶鏁版嵁鐨勫瓨鍙栨柟娉?/p>
1
锛?/p>
鍏ㄨ〃鎵弿锛?/p>
Full Table Scans
锛?/p>
FTS
锛?/p>
2
锛?/p>
閫氳繃
ROWID
鐨勮〃瀛樺彇锛?/p>
Table Access by ROWID
鎴?/p>
rowid lookup
锛?/p>
3
锛夌储寮曟壂鎻忥紙
Index Scan
鎴?/p>
index lookup
锛夋湁
4
绉嶇被鍨嬬殑绱㈠紩鎵弿锛?/p>
锛?/p>
1
锛?/p>
绱㈠紩鍞竴鎵弿锛?/p>
index unique scan
锛?/p>
锛?/p>
2
锛?/p>
绱㈠紩鑼冨洿鎵弿锛?/p>
index range scan
锛?/p>
鍦ㄩ潪鍞竴绱㈠紩涓婇兘浣跨敤绱㈠紩鑼冨洿鎵弿銆?/p>
浣跨敤
index
rang
scan
鐨?/p>
3
绉嶆儏鍐碉細
锛?/p>
a
锛?/p>
鍦ㄥ敮涓�绱㈠紩鍒椾笂浣跨敤浜?/p>
range
鎿嶄綔绗?/p>
锛?/p>
><<>>=
<=
between
锛?/p>
锛?/p>
b
锛?/p>
鍦ㄧ粍鍚堢储寮曚笂锛屽彧浣跨敤閮ㄥ垎鍒楄繘琛屾煡璇紝瀵艰嚧鏌ヨ鍑哄琛?/p>
锛?/p>
c
锛?/p>
瀵归潪鍞竴绱㈠紩鍒椾笂杩涜鐨勪换浣曟煡璇€�?/p>
锛?/p>
3
锛?/p>
绱㈠紩鍏ㄦ壂鎻忥紙
index full scan
锛?/p>
锛?/p>
4
锛?/p>
绱㈠紩蹇�熸壂鎻忥紙
index fast full scan
锛?/p>
涓夈�佽〃涔嬮棿鐨勮繛鎺?/p>
1
锛屾帓搴?/p>
- -
鍚堝苟杩炴帴锛?/p>
Sort Merge Join
锛?/p>
SMJ
锛?/p>
2
锛屽祵濂楀惊鐜紙
Nested Loops
锛?/p>
NL
锛?/p>
3
锛屽搱甯岃繛鎺ワ紙
Hash Join
锛?/p>
HJ
锛?/p>
鍙﹀锛岀瑳鍗″効涔樼Н锛?/p>
Cartesian Product
锛?/p>
鎬荤粨
Oracle
杩炴帴鏂规硶
Oracle
鎵ц璁″垝鎬荤粨姒傝堪
+++
涓�锛庣浉鍏崇殑姒傚康
Rowid
鐨勬蹇?/p>
锛?/p>
rowid
鏄竴涓吉鍒楋紝鏃㈢劧鏄吉鍒楋紝閭ｄ箞杩欎釜鍒楀氨涓嶆槸鐢ㄦ埛瀹氫箟锛岃�屾槸绯荤粺鑷?/p>
宸辩粰鍔犱笂鐨勩�?/p>
瀵规瘡涓〃閮芥湁涓�涓?/p>
rowid
鐨勪吉鍒楋紝浣嗘槸琛ㄤ腑骞朵笉鐗╃悊瀛樺偍
ROWID
鍒楃殑鍊笺�備笉杩囦綘
鍙互鍍忎娇鐢ㄥ叾瀹冨垪閭ｆ牱浣跨敤瀹冿紝浣嗘槸涓嶈兘鍒犻櫎鏀瑰垪锛屼篃涓嶈兘瀵硅鍒楃殑鍊艰繘琛?/p>
淇敼銆佹彃鍏ャ�備竴鏃?