Abstract: Methods and computer systems for storing a query plan in a cache are provided. The method can include: determining a use frequency of the query plan; determining a target storage layer for storing the query plan based on the determined use frequency, wherein the cache includes at least two storage layers and each of the storage layers is associated with a compression level of query plans; processing the query plan according to the compression level of the target storage layer; and storing the processed query plan in the target storage layer.

Abstract: A switched-mode power supply (SMPS) chip and system are disclosed, which are used for determining a maximum power output of a solar photovoltaic panel connected to the SMPS chip. The SMPS chip includes a sampled current comparator module, a logic control module connected to the sampled current comparator module, and a charge/discharge control module connected to the logic control module. According to the present invention, an output current from the SMPS system to an external load is detected and serves as a basis for incrementally adjusting a minimum input voltage of the SMPS chip and hence an output voltage of the solar photovoltaic panel. In this way, an output voltage level of solar photovoltaic panel corresponding to the maximum power output thereof under a given condition can be determined. Through keeping the solar photovoltaic panel operating at that output voltage level, it is ensured that the solar photovoltaic panel provides the maximum power output under the given condition.

Abstract: A method, system and computer program product for processing queries in a hybrid database system. A database management system of the hybrid database system obtains an estimated execution time of a query by an online transaction processing engine. The database management system further obtains an estimated execution time of the query by a database accelerator. Furthermore, the database management system determines a wait time (which could be zero) for the database accelerator to process the query. The database management system then determines whether the online transaction processing engine or the database accelerator will process the query using the estimated execution time of the query by the online transaction processing engine, the estimated execution time of the query by the database accelerator and the wait time (which could be zero) for the database accelerator to process the query. In this manner, the processing of queries in hybrid database systems is optimized.

Abstract: A counting circuit and a chip are disclosed. The counting circuit includes a charge counter module including a pulse processing module and a first capacitor. The pulse processing module is configured to covert a received pulse signal into a counting current and to transfer the converted counting current to the first capacitor. The first capacitor is configured to receive the counting current and store charge carried in the counting current. The counting circuit takes a voltage of the first capacitor as a basis for counting.

Abstract: A blockchain may store transactions for various purposes which may be later accessed by interested parties for ledger verification. One example method of operation may comprise one or more of receiving a blockchain transaction, identifying a proof-of-work is generated for the blockchain transaction via a network entity, transmitting the proof-of-work and a select portion of ledger data to a registered third party via an encrypted message based on a third party key, validating the proof-of-work via the third party, and providing a reward to the network entity.

Abstract: A short-circuit protection circuit, chip and system for a switched-mode power supply are disclosed. The short-circuit protection circuit includes: a sampling module for sampling an input voltage and producing a first voltage from the input voltage; a generation module for generating a second voltage from a reference voltage; a comparison module for comparing the first voltage and the second voltage; and an output module for producing, from a result of the comparison performed by the comparison module, and outputting a control signal for controlling an external power transistor in the event of a short circuit in the switched-mode power supply. According to the present invention, when an output short circuit is detected, a hiccup-mode duty cycle is adjusted according to the input voltage, thus avoiding great energy loss when the input voltage is high and enabling loaded startup or automatic output recovery after the short circuit condition is removed when the input voltage is low.

Abstract: A decoding circuit and a chip are disclosed. The decoding circuit includes, connected in a sequence, a charge/discharge unit, a capacitor and a conversion unit. The charge/discharge unit is able to charge and discharge the capacitor, and a ratio of a total time required to transfer any amount of charge into the capacitor to a total time required to transfer the same amount of charge from the capacitor is a predetermined value. The conversion unit is configured to output a third level when a voltage on the capacitor exceeds a predetermined voltage and to otherwise output a fourth level.

Abstract: A method for dynamic filter pushdown for massive parallel processing databases on the cloud, including acquiring one or more filters corresponding to a query, acquiring statistics information of one or more database tables, determining a selectivity of the one or more database tables based on the statistics information, determining whether the selectivity satisfies a threshold condition, and pushing down the one or more filters to the one or more database tables based on the determination of whether the selectivity satisfies a threshold condition.

Abstract: A decoding circuit and a chip are disclosed. The decoding circuit includes, connected in a sequence, a charge/discharge unit, a capacitor and a conversion unit. The charge/discharge unit is able to charge and discharge the capacitor, and a ratio of a total time required to transfer any amount of charge into the capacitor to a total time required to transfer the same amount of charge from the capacitor is a predetermined value. The conversion unit is configured to output a third level when a voltage on the capacitor exceeds a predetermined voltage and to otherwise output a fourth level.

Abstract: Embodiments of the present disclosure provide methods and devices for formatting a database. The method can include clustering, into each block, a set of sequence of elements from each column of a database; generating a file storing one or more blocks having the clustered set of sequences of elements; providing a first table storing file schema information that associates the elements with the file; and providing a second table for storing block schema information that associates the columns with the one or more blocks.

Abstract: A current limit control circuit and a switched-mode power supply chip incorporating the current limit control circuit are disclosed. The current limit control circuit includes an output current sampling module, a first voltage comparator module, a hysteresis comparator module, a logic control module, a capacitor charging/discharging module and a current limit control module. The capacitor charging/discharging module is configured to charge/discharge a capacitor and thus change its output voltage, and the hysteresis comparator module is configured to produce a current limit control signal which allows the switched-mode power supply to output a high current for a specified period of time. Upon elapse of the period, the power transistor is controlled to cause a low current to be output. This ensures that the demand of a load for a transient current is satisfied while ensuring safe and stable operation of the chip for a long time.

Abstract: The present disclosure provides systems and methods for prefetching data in databases. One method for prefetching data in a database comprises receiving a database query on the database, determining one or more sets of adjacent columns access by the database query, and for each set of adjacent columns of the one or more determined sets, prefetching data in the adjacent columns.

Abstract: A counting circuit and a chip are disclosed. The counting circuit includes a charge counter module including a pulse processing module and a first capacitor. The pulse processing module is configured to covert a received pulse signal into a counting current and to transfer the converted counting current to the first capacitor. The first capacitor is configured to receive the counting current and store charge carried in the counting current. The counting circuit takes a voltage of the first capacitor as a basis for counting.

Abstract: The present disclosure provides a method for generating a classification model in a database system. The method comprises generating a plurality of database tables by performing data clustering on a database, acquiring a plurality of queries associated with information from the database, generating training data by executing each of the plurality of queries on the plurality of database tables, and training a classification model using the training data, wherein the classification model is used to select a database table for a query based on corresponding performance information associated with the query on the database during executing of the query. The present disclosure also provides a method for executing a query on a database using a classification model. The method comprises obtaining the classification model, obtaining a database query, generating a target table by inputting the database query into the classification model, and executing the database query on the target table.

Abstract: Efficient large column values storage in columnar databases is disclosed, including: providing a database comprising a write storage, a read storage, and an auxiliary storage, and wherein the auxiliary storage is used to store a large column value of a row that is associated with either the write storage or the read storage, wherein the large column value comprises a column value that meets a set of large column value criteria; and operating the database using the write storage, the read storage, and the auxiliary storage.

Abstract: The methods and computer systems for storing a query plan in a cache. The method can include: determining a use frequency of the query plan; determining a target storage layer for storing the query plan based on the determined use frequency, wherein the cache includes at least two storage layers and each of the storage layers is associated with a compression level of query plans; processing the query plan according to the compression level of the target storage layer; and storing the processed query plan in the target storage layer.

Abstract: Embodiments of the present disclosure provide methods and devices for inserting data in a database. The method can include caching one or more rows of data in a delta table in response to a request to insert the one or more rows in a destination table, wherein the destination table is one of a group of destination tables of a first database, and wherein the delta table contains requested changes of rows of the destination table, the changes being caused by a data operation; determining a priority of the destination table based on runtime information of the destination table relative to the group of destination tables; and scheduling the merging of the inserted rows from the delta table to the destination table based on the determined priority of the destination table. The destination table is in a format of a file storing one or more blocks, each block having a set of sequence of elements clustered from each column of the destination table.

Abstract: Intelligent merging for efficient updates in columnar databases are disclosed, including: determining a current age associated with a row in a database, wherein the database comprises a write storage and a read storage, wherein the row is located in the write storage; determining a set of one or more merge criteria based at least in part on a modification age distribution, wherein the modification age distribution is dynamically determined based at least in part on previous transactions at the database; determining whether the current age meets the set of merge criteria; and in response to a determination that the current age meets the set of merge criteria, merging the row from the write storage into the read storage.

Abstract: A method, system and computer program product for providing consolidated access to data of a plurality of source databases. Tables of each of the source databases are replicated to a shared accelerator. The source DBMSs are configured to dispatch queries to the accelerator for accelerating query execution. The accelerator is configured such that the replicated tables can only be accessed by the source DBMS having provided said tables for executing a dispatched query. A user can select one of the source DBMSs to act as a consolidated DBMS—C-DBMS. The C-DBMS provides the consolidated access. The user is enabled to select tables managed by another one of the DBMSs. In response to receiving the selection of the tables, the accelerator is re-configuring such that the C-DBMS is granted access also to the copies of the selected tables in the accelerator.

Abstract: A method, system and computer program product for providing consolidated access to data of a plurality of source databases. Tables of each of the source databases are replicated to a shared accelerator. The source DBMSs are configured to dispatch queries to the accelerator for accelerating query execution. The accelerator is configured such that the replicated tables can only be accessed by the source DBMS having provided said tables for executing a dispatched query. A user can select one of the source DBMSs to act as a consolidated DBMS—C-DBMS. The C-DBMS provides the consolidated access. The user is enabled to select tables managed by another one of the DBMSs. In response to receiving the selection of the tables, the accelerator is re-configuring such that the C-DBMS is granted access also to the copies of the selected tables in the accelerator.