ENHANCING DATABASE PERFORMANCE IN A DSS ENVIRONMENT VIA QUERY CACHING

A key element in all decision support systems is availability of sufficiently good and timely data to support the decision making process. Much research was, and is, devoted to data and information quality: attributes, assurance that quality data is used in the decision process, etc. In this paper we concentrate on a particular dimension of data availability and usage -the retrieval of data in a timely and decision enhancing manner. We propose to augment the decision support databases by an adaptive and efficient query cache. The cache contains snapshots of the decision support database, each being the answer to a recently invoked query. A snapshot can be reused by the originating user, or a different user, at a later time --provided the use of cached data leads to savings over the use of a new query, and these savings exceed the cost of using stale date. The proposed scheme is conceptually different from conventional data replication schemes. In data replication schemes the data items to be replicated and the protocols for concurrency control are defined at the system level. In our scheme the cache is populated dynamically and the snapshots it contains are refreshed only if the cost of using stale information is higher than cost of refreshing the snapshots. At the same time, users can still decide to refresh the stored snapshot, based on their own decision environment. Our scheme thus enhances the data retrievalprocess, while supporting a more efficient data retrieval at both the user level and the data warehouse leve

A differential refresh scheme for remote end-user\u27s views

The growth of end-user computing and recent developments in information technology, such as client/server architecture and data warehouse, promote the use of remote materialized views (RMVs) to support end-users. This article presents a differential scheme to refresh remote end-user\u27s views. The scheme stores the effects of updates relevant to the RMV in a difference table which is transmitted to the remote site upon receiving the refresh request to update the RMV. The scheme provides a fast response to a user\u27s refresh request. We discuss the data structures and algorithms of the scheme. Performance measures are developed and compared with the regeneration scheme

USE OF STALE ANSWERS IN DATABASE APPLICATIONS

In a typical database application, it is commonly assumed that user information requirements can only be satisfied by the most current data. The desirable attributes of infolmation often include being up-to-date, timeliness, and accuracy, with the implicit assumption that without these attributes a response to a query has little or no value. This assumption is challenged in this work. We consider the tradeoff between the cost of incomplete information, due to the use of stale data, and the incremental cost of providing a current answer. We propose that the database system be extended to include a data cache, in which copies of frequently needed data will be kept. Objects in the cache are not updated as the database changes, but rather are refreshed whenever the cost of using stale data exceeds some prespecified level. We also discuss alternative refresh policies and cache search schemes

TRIUMF brown reports TRI-79-2

TRIUMFNon UBCUnreviewedResearche

Efficacy and safety of two neutralising monoclonal antibody therapies, sotrovimab and BRII-196 plus BRII-198, for adults hospitalised with COVID-19 (TICO): a randomised controlled trial

We aimed to assess the efficacy and safety of two neutralising monoclonal antibody therapies (sotrovimab [Vir Biotechnology and GlaxoSmithKline] and BRII-196 plus BRII-198 [Brii Biosciences]) for adults admitted to hospital for COVID-19 (hereafter referred to as hospitalised) with COVID-19. In this multinational, double-blind, randomised, placebo-controlled, clinical trial (Therapeutics for Inpatients with COVID-19 [TICO]), adults (aged ≥18 years) hospitalised with COVID-19 at 43 hospitals in the USA, Denmark, Switzerland, and Poland were recruited. Patients were eligible if they had laboratory-confirmed SARS-CoV-2 infection and COVID-19 symptoms for up to 12 days. Using a web-based application, participants were randomly assigned (2:1:2:1), stratified by trial site pharmacy, to sotrovimab 500 mg, matching placebo for sotrovimab, BRII-196 1000 mg plus BRII-198 1000 mg, or matching placebo for BRII-196 plus BRII-198, in addition to standard of care. Each study product was administered as a single dose given intravenously over 60 min. The concurrent placebo groups were pooled for analyses. The primary outcome was time to sustained clinical recovery, defined as discharge from the hospital to home and remaining at home for 14 consecutive days, up to day 90 after randomisation. Interim futility analyses were based on two seven-category ordinal outcome scales on day 5 that measured pulmonary status and extrapulmonary complications of COVID-19. The safety outcome was a composite of death, serious adverse events, incident organ failure, and serious coinfection up to day 90 after randomisation. Efficacy and safety outcomes were assessed in the modified intention-to-treat population, defined as all patients randomly assigned to treatment who started the study infusion. This study is registered with ClinicalTrials.gov, NCT04501978. Between Dec 16, 2020, and March 1, 2021, 546 patients were enrolled and randomly assigned to sotrovimab (n=184), BRII-196 plus BRII-198 (n=183), or placebo (n=179), of whom 536 received part or all of their assigned study drug (sotrovimab n=182, BRII-196 plus BRII-198 n=176, or placebo n=178; median age of 60 years [IQR 50–72], 228 [43%] patients were female and 308 [57%] were male). At this point, enrolment was halted on the basis of the interim futility analysis. At day 5, neither the sotrovimab group nor the BRII-196 plus BRII-198 group had significantly higher odds of more favourable outcomes than the placebo group on either the pulmonary scale (adjusted odds ratio sotrovimab 1·07 [95% CI 0·74–1·56]; BRII-196 plus BRII-198 0·98 [95% CI 0·67–1·43]) or the pulmonary-plus complications scale (sotrovimab 1·08 [0·74–1·58]; BRII-196 plus BRII-198 1·00 [0·68–1·46]). By day 90, sustained clinical recovery was seen in 151 (85%) patients in the placebo group compared with 160 (88%) in the sotrovimab group (adjusted rate ratio 1·12 [95% CI 0·91–1·37]) and 155 (88%) in the BRII-196 plus BRII-198 group (1·08 [0·88–1·32]). The composite safety outcome up to day 90 was met by 48 (27%) patients in the placebo group, 42 (23%) in the sotrovimab group, and 45 (26%) in the BRII-196 plus BRII-198 group. 13 (7%) patients in the placebo group, 14 (8%) in the sotrovimab group, and 15 (9%) in the BRII-196 plus BRII-198 group died up to day 90. Neither sotrovimab nor BRII-196 plus BRII-198 showed efficacy for improving clinical outcomes among adults hospitalised with COVID-19. US National Institutes of Health and Operation Warp Spee