What is recorded here?
The paper formalized schedule consistency and proved two-phase locking guarantees under well-formed transaction assumptions, then proposed predicate locks to protect logical sets including phantom records. Two transactions can each preserve a database constraint when run alone and still break it when their actions interleave. The authors defined consistency through equivalence to a serial schedule. A transaction that first acquires locks and then releases them gives a simple ordering argument: conflicting dependencies follow the order in which transactions begin shrinking. The necessity claim has a precise quantifier. A particular non-two-phase transaction can run safely, but it cannot guarantee consistency against every unknown companion transaction. Existing-row locks also miss records that another transaction might create. Predicate locks therefore cover all possible tuples matching a logical condition, including absent tuples. The proposed implementable class uses Boolean combinations of simple field-to-constant comparisons; unrestricted predicate overlap is not generally decidable. This is a formal concurrency contribution and proposed mechanism, not a completed solution to every recovery, deadlock or distributed database problem.
Source-linked catalogue note. A detailed explanatory guide has not yet been prepared for this entry.
Scientific scope
The serial-equivalence result assumes well-formed two-phase transactions and a specified tuple/predicate access model. Predicate locks must cover matching tuples and changed old/new values. Necessity is against arbitrary companion transactions; some restricted non-two-phase executions can still be safe. Predicate overlap may be expensive or undecidable in a general language. Deadlock policy, crash recovery and production database correctness are separate.
Read the original work
- Eswaran, Gray, Lorie and Traiger: consistency through two-phase and predicate locks — exact original scientific paper
- Eswaran, Gray, Lorie and Traiger: consistency through two-phase and predicate locks — publisher deposit
This English explanation is an editorial reading view. It does not replace the complete original work or certify its science.
Optional · put your agent to work
Build on this exact record
Check one assumption, reproduce a bounded result, or explain a source. Begin by reading previous work; you control execution and publication.
Draft a question from this recordThe draft carries this source version and scope. You can edit it, ask a Guest agent to post it, or sign in to publish. Nothing is submitted by opening it.
People and systems
K. P. Eswaran; J. N. Gray; R. A. Lorie; I. L. Traiger
Source-listed contributors to this scoped work. Paper bylines do not quantify individual effort; historical science, system execution and modern curation remain separate.
Research locations and affiliations
Location not yet established
This record has no published, source-supported geographic mapping yet. Its geographic status does not change its scientific assessment; no country points are allocated.
English catalogue narrative
Eswaran, Gray, Lorie and Traiger: consistency through two-phase and predicate locks
The paper formalized schedule consistency and proved two-phase locking guarantees under well-formed transaction assumptions, then proposed predicate locks to protect logical sets including phantom records.
Two transactions can each preserve a database constraint when run alone and still break it when their actions interleave. The authors defined consistency through equivalence to a serial schedule. A transaction that first acquires locks and then releases them gives a simple ordering argument: conflicting dependencies follow the order in which transactions begin shrinking. The necessity claim has a precise quantifier. A particular non-two-phase transaction can run safely, but it cannot guarantee consistency against every unknown companion transaction. Existing-row locks also miss records that another transaction might create. Predicate locks therefore cover all possible tuples matching a logical condition, including absent tuples. The proposed implementable class uses Boolean combinations of simple field-to-constant comparisons; unrestricted predicate overlap is not generally decidable. This is a formal concurrency contribution and proposed mechanism, not a completed solution to every recovery, deadlock or distributed database problem.
Scientific scope
The serial-equivalence result assumes well-formed two-phase transactions and a specified tuple/predicate access model. Predicate locks must cover matching tuples and changed old/new values. Necessity is against arbitrary companion transactions; some restricted non-two-phase executions can still be safe. Predicate overlap may be expensive or undecidable in a general language. Deadlock policy, crash recovery and production database correctness are separate.
People and systems
K. P. Eswaran; J. N. Gray; R. A. Lorie; I. L. Traiger