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Locking Technique

Locking protocol

Bharghavi
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Locking Technique

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  1. DBMS Presentation:

  2. LOCKING PROTOCOLS: BHARGHAVI ALYANA 22911A1270 IT-B

  3. What is locking? I? ? tra?i? ligh? signa? tha?  indicate? STOP  & G?, Whe? 1 signa? i? allowe? t? pas? a? ? tim? & othe? signal? ar? locke?. Tra?i? Signa?

  4. What is locking? I? ? databas? Transactio?, onl? 1 transactio? i? performe? a? ? tim? mea? whil? othe? transaction? ar? locke? . Lockin?

  5. Loc? Base? Protocol?: S X -->Loc? wil? acquir? b? th?         transactio? the? i? perform? assigne? operation? b? accessin? th? dat?-item?. -->Afte? completio? of transactio? i?'l? releas? loc?. YES NO S NO X NO

  6. TYPES OF LOCKS SHARED -S EXCLUSIVE -X READ READ WRITE

  7. PROBLEMS IN S/X LOCKING : T1 T2 X(A) R(A) W(A) U(A) 1. Ma? no? su?icien? t? produc? onl? serializabl? schedul?. S(A) R(A) U(A) X(B) R(B) W(B) U(B)

  8. PROBLEMS IN S/X LOCKING : T1 T2 X(A) R(A) W(A) U(A) | | | | | ---- Collapse 2. Ma? no? fre? fro? irrecoverabilit?. S(A) R(A) ------ ------ ------ ------ Commit Recoverabl? Irrecoverabl?

  9. PROBLEMS IN S/X LOCKING : Infinit? Tim? T1 T2 G X(A) 3. Ma? no? fre? fro? deadloc?. X(B) G W X(B) X(A) W

  10. PROBLEMS IN S/X LOCKING :  T1        T2           T3 T4 S(A) | | | U(A) 1 W X(A) | | | 7 4. Ma? no? fre? fro? starvatio?. 2 S(A) | | | U(A) G S(A) | | | U(A) 3 4 5 6

  11. THANK YOU

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