Sap Se

Industry-university Cooperation Foundation Hanyang University

Won Jun Chang

Jaehyok Chong

Youngbin Bok

Sungguk Lim

Heesik Shin

Won Il Park

Won Ii Park

Kijoong Kim

Computer-readable media, methods, and systems are disclosed for proactively compiling in-memory database management system (DBMS) query plans upon startup of the in-memory DBMS. During normal operation of the in-memory DBMS, alternative query plans having associated execution statistics are collected and captured. Thereafter, the alternative query plans are selectively persisted and in response to detecting performance regressions, the regressed query plan is compared with prior query plans. In response to determining that a prior query plan performs better, the regressed query plan is replaced with the prior query plan. Upon a restart of the in-memory DBMS, a selected portion of the plurality of alternative query execution plans is loaded, and the plurality of alternative query execution plans are compiled. New queries are received and executed based on the proactively compiled query plans.

Proactive query plan compilation

A computer implemented method can receive an incoming query statement, identify a database object specified in the incoming query statement, and search a query hint registry for a first hint record which includes the database object and a first hint paired with the database object. Responsive to finding the first hint record in the query hint registry, the method can generate a modified query statement by appending the first hint to the incoming query statement and obtain a query execution plan based on the modified query statement.

Statement hint with database objects

An electrode structure for a secondary battery includes a potential sheath capable of suppressing a side reaction between an electrode and an electrolyte through electric potential control. The electrode structure for the secondary battery uses the electric potential control so that an unstable SEI layer, which causes decrease in cycle characteristic and capacity of an anode material, occurs only on the surface of a potential sheath without occurring on the surface of the anode active material, thereby being capable of completely solving the problems of the existing nanostructured electrode. A method for manufacturing an electrode for a secondary battery includes the steps of: (a) preparing a template form; (b) coating a graphene on the template foam; (c) removing the template foam to form a graphene foam, wherein the template foam partially remains on an internal surface of the graphene foam; and (d) growing a nanowire by using the template foam remaining on the internal surface of the graphene foam as a seed.

Electrode structure comprising potential sheath for secondary battery and fabrication method therefor

A computer implemented method can receive a request for a fallback query execution plan of a query in a database system. The query involves an object of the database system. The object is associated with a captured object. The method can evaluate whether the object and the captured object have the same logical structure. Responsive to an indication that the object and the captured object have the same logical structure, the method can reuse the fallback query execution plan to execute the query. The evaluating includes identifying a logical structure of the captured object stored in an object definition table, obtaining a current logical structure of the object, and comparing the logical structure of the captured object with the current logical structure of the object.

Database object validation for reusing captured query plans

Methods and apparatus are disclosed for staged query compilation. One or more intermediate plans between a query and its execution plan are stored according to a common specification for plan data structures. Data sources, a plan flow, and annotations can be stored in respective fields of the plan data structure, which can be extended with a field for a serialized execution plan. Plan data structures provide a stable interface for integration of local and external software modules, and decouple plan representation from plan optimization. Use cases are disclosed for integrating offline optimization with inline software modules, for integrating local query handling with external services, for caching intermediate plans, and for archiving plans across version changes of optimizers. A hub architecture flexibly supports numerous compilation workflows. Disclosed technologies are suitable for cloud deployments and for migration of databases into the cloud.

Staged query compilation with common data structure

Methods, systems, and computer-readable storage media for receiving a query plan and a set of query parameters of the query plan, the query plan corresponding to a query submitted to a database system, and determining that the set of query parameters matches a filter in a set of filters, each parameter in a set of parameters of the filter matching a query parameter in the set of query parameters, and in response: providing the query plan to an abstract query plan generator that generates an abstract query plan based on the query plan, and storing the abstract query plan in an abstract query plan store.

Customizable filtering for query plan stability in database systems using abstract query plans

The present invention relates to an electrode structure for a secondary battery comprising a potential sheath capable of suppressing a side reaction between an electrode and an electrolyte through electric potential control, and a method for manufacturing the same. The electrode structure for the secondary battery according to the present invention uses the electric potential control so that an unstable SEI layer, which causes decrease in cycle characteristic and capacity of an anode material, occurs only on the surface of a potential sheath without occurring on the surface of the anode active material, thereby being capable of completely solving the problems of the existing nanostructured electrode. The electrode structure of the present invention exhibits very excellent cycle performance that is difficult to predict from the conventional nanowire electrode structure by virtue of a synergistic effect of the potential sheath and the nanowire anode active material, and has an effect that is stable upon charging and discharging with high rate and can exert stable performance even if small cracks occur on the potential sheath.

Methods, systems, and computer-readable storage media for receiving, by a current database system, a query plan file representative of a captured query plan from a source database system, receiving, by the current database system, a set of definitions including one or more definitions, each definition in the set of definitions corresponding to an object that is implicated by the query plan, the object being included in a set of objects, and determining, by the current database system, that each definition in the set of definitions is identical to a respective definition of a corresponding object within the current database system, and in response: executing the captured query plan in the current database system to provide a query result.

Growing community of inventors

Seoul, South Korea

Won Jun Chang