Database Concurrency Control
{"Image DocumentName": "Database Concurrency Control", "Image ImageDescription": "Multiversion Two-Phase Locking Using Certify Locks. Steps. X is the committed version of a data item. T creates a second version X\u2019 after obtaining a write lock on X. Other transactions continue to read X. T is ready to commit so it obtains a certify lock on X\u2019. The committed version X becomes X\u2019. T releases its certify lock on X\u2019, which is X now. Compatibility tables for. read/write locking scheme read/write/certify locking scheme.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}