ICDE 2007: Quality Contracts

"Preference-Aware Query and Update Scheduling in Web-Databases" -Huiming Qu, Alexandros Labrinidis

QC: Quality Contracts -> combines response time (QoS) and staleness (QoD)
QUTS (Query Update Time Sharing): adaptive algorithm to maximize the total profit from submitted QCs

QUTS make use of two level scheduling scheme that dynamically allocates CPU resources to updates and queries according to user preferences.

There are 3 policies:
1. FIFO: queue containing both updates and queries; are executed according to their arrival time
2. FIFI-UH: two queues -one for the updates and one for the queries. Updates have priority
3. FIFI-QH: two queues -one for the updates and one for the queries. Queries have priority

Average Staleness = # of unapplied updates

QUTS: is able to take the "best" profit dimension of the other policies: high QoS from QH and high QoD from UH using static QC design
QUTS: perform very close to ideal case when we vary qos_max and qod_max over time

Reference:
"Preference-Aware Query and Update Scheduling in Web-Databases"
or
"Preference-Aware Query and Update Scheduling in Web-Databases"