Abstract: Systems and methods for managing a highly available distributed database comprising: a memory storing instructions; and one or more processors configured to execute the instructions to: determine that a source node, in a distributed database comprising the source node and one or more replica nodes, is not available; select a most-updated replica node from the one or more replica nodes; switch a role of the most-updated replica node to source; update a data store to label the source node as unavailable and the selected replica node as being a promoted source node; send a notification to a user device to update a database topology based on the updated data store; determine whether the user device has updated the database topology; and upon determining the user device has not updated the database topology, continue to send the notification to the user device until the user device has updated the database topology.

Abstract: A display apparatus and a display system are provided, and relate to the field of display device technologies, to enhance visual experience generated when a picture is displayed by using an existing reflective display window such as a windshield and a bathroom mirror, so that a sense of presence and immersion is improved. The display apparatus includes an image generation unit and an optical imaging unit. The image generation unit is configured to generate a real image whose display surface is a curved surface. The optical imaging unit is configured to perform imaging on the real image, to generate an enlarged virtual image corresponding to the real image, where a display surface of the virtual image is a curved surface adaptive to the display surface of the real image.

Abstract: A display apparatus and method are provided. The display apparatus includes a multi-focus image generation unit and a time sequence control unit. The multi-focus image generation unit is connected to the time sequence control unit. The time sequence control unit is configured to: generate a plurality of time sequence instructions that belong to a first switching period, and send the plurality of time sequence instructions that belong to the first switching period. The multi-focus image generation unit is configured to: receive the plurality of time sequence instructions that belong to the first switching period from the time sequence control unit, and generate a plurality of corresponding 3D image blocks at different distances based on the plurality of time sequence instructions. The plurality of 3D image blocks respectively corresponds to a 3D image and include different depth information for display in the first switching period.

Abstract: This application provides example multi-focal-plane image generation apparatuses, example head-up display apparatuses, example methods, and example devices. One example apparatus includes a pattern generation device and a focal length adjuster. The pattern generation device is configured to generate a light beam that carries image information, and irradiate the light beam to a surface of the focal length adjuster. The focal length adjuster is configured to perform focal length adjustment on the light beam that is irradiated to the surface of the focal length adjuster to generate a plurality of focal planes of the multi-focal-plane image generation apparatus.

Abstract: A mop bucket for cleaning and squeezing a flat mop, comprises a bucket body and a squeezing device disposed inside the bucket body; wherein, the bucket body has a squeezing water section and a cleaning section, which are respectively at two different positions when used; when the mop head of the flat mop is removably inserted into the squeezing device, the squeezing device presses against the wiper on the mop head and scrapes the wiper on the mop head. The present invention also discloses a cleaning tool set. The mop bucket of the present invention can clean and squeeze a wiper on the flat mop by integrating both functions of cleaning and squeezing together, provide better cleaning and squeezing effects, and realize a convenient and labor-saving squeezing operation and pleasurable user experience.

Abstract: A system for database backup including a controller, a metadata database coupled to the controller, a backup tool coupled to the controller, and a plurality of nodes coupled to the backup tool and accessed through a file system. The controller is configured to determine a first data change in node; in response to determining the first data change, freeze the file system; and generate an incremental snapshot of the at least one of the plurality of nodes (where the incremental snapshot including a portion of the at least one of the plurality of nodes). The controller is also configured to upload an encrypted copy of the incremental snapshot to a cloud storage; update the metadata database by storing an entry associating the incremental snapshot with the at least one of the plurality of nodes and unfreezing the file system.

Abstract: Systems and methods for managing a highly available distributed database comprising: a memory storing instructions; and one or more processors configured to execute the instructions to: determine that a source node, in a distributed database comprising the source node and one or more replica nodes, is not available; select a most-updated replica node from the one or more replica nodes; switch a role of the most-updated replica node to source; update a data store to label the source node as unavailable and the selected replica node as being a promoted source node; send a notification to a user device to update a database topology based on the updated data store; determine whether the user device has updated the database topology; and upon determining the user device has not updated the database topology, continue to send the notification to the user device until the user device has updated the database topology.

Abstract: Systems and methods for managing a highly available distributed hybrid database comprising: a memory storing instructions; and one or more processors configured to execute the instructions to: receive a query from a user device to retrieve data from a distributed database comprising a source node, a first plurality of replica nodes, and a second plurality of replica nodes, wherein the source node and the first plurality of replica nodes form a transactional cluster, and wherein the second plurality of replica nodes forms an analytical cluster; determine whether to process the query using the transactional cluster or the analytical cluster based on one or more rules; translate the query into a first protocol that the determined cluster comprehends; select a replica node corresponding to the determined cluster; process the query using the selected replica node; and send data associated with results from processing the query to the user device.

Abstract: A squeeze flat mop cleaning tool having an adjustable squeeze opening is provided. The squeeze flat mop cleaning tool comprises a mop bucket and a flat mop; the flat mop comprises a mop stick and a flat mop head, and a wiper is provided on the flat mop head; the mop bucket has an independent squeezing area and an independent cleaning area, and a squeeze device is mounted on the mop bucket; the squeeze device comprises a scraper plate and a support member, and a squeeze opening is formed between the scraper plate and the support member. The scraper plate is rotatably provided on the mop bucket, and the size of the squeeze opening can be changed by the rotation of the scraper plate.

Abstract: Methods and systems for database query efficiency improvement are disclosed. In one embodiment, a method includes mirroring a primary database to a secondary database; creating a testing database comprising the schema; receiving a query; running the query on the testing database; and evaluating the query by: identifying predicates in the query; determining most common values for each column name by querying the secondary database; creating, for each column name, a list comprising at least one of the most common values; creating a test predicate comprising one of the column names and an entry for the list corresponding to the column name; creating a test query comprising one or more test predicates; determining a resource utilization of the query by running each of the test queries on the secondary database; and providing, to a user interface for display, an efficiency improvement recommendation when the resource utilization exceeds a threshold.

Abstract: Systems and methods for managing a highly available distributed database comprising: a memory storing instructions; and one or more processors configured to execute the instructions to: determine that a source node, in a distributed database comprising the source node and one or more replica nodes, is not available; select a most-updated replica node from the one or more replica nodes; switch a role of the most-updated replica node to source; update a data store to label the source node as unavailable and the selected replica node as being a promoted source node; send a notification to a user device to update a database topology based on the updated data store; determine whether the user device has updated the database topology; and upon determining the user device has not updated the database topology, continue to send the notification to the user device until the user device has updated the database topology.

Abstract: Systems and methods for managing a highly available distributed hybrid database comprising: a memory storing instructions; and one or more processors configured to execute the instructions to: receive a query from a user device to retrieve data from a distributed database comprising a source node, a first plurality of replica nodes, and a second plurality of replica nodes, wherein the source node and the first plurality of replica nodes form a transactional cluster, and wherein the second plurality of replica nodes forms an analytical cluster; determine whether to process the query using the transactional cluster or the analytical cluster based on one or more rules; translate the query into a first protocol that the determined cluster comprehends; select a replica node corresponding to the determined cluster; process the query using the selected replica node; and send data associated with results from processing the query to the user device.

Abstract: A fully-automated handheld pressure calibrator, comprising a housing, and gas circuit and electrical circuit components installed in the housing. The gas circuit components comprise a pressure source capable of supplying a pressurized gas. The gas circuit and electrical circuit components are integrated and installed in the housing in a modular manner, and the shape of the housing is suitable to be held in a hand. The pressure calibrator of the present invention enables all kinds of functions including pressure generation, pressure control, pressure instrument connection, and recording, result calculation, and report output of a pressure calibration process, and is suitable for on-site an on-line calibration of a pressure instrument.

Abstract: Methods and systems for database query efficiency improvement are disclosed. In one embodiment, a method includes mirroring a primary database to a secondary database; creating a testing database comprising the schema; receiving a query; running the query on the testing database; and evaluating the query by: identifying predicates in the query; determining most common values for each column name by querying the secondary database; creating, for each column name, a list comprising at least one of the most common values; creating a test predicate comprising one of the column names and an entry for the list corresponding to the column name; creating a test query comprising one or more test predicates; determining a resource utilization of the query by running each of the test queries on the secondary database; and providing, to a user interface for display, an efficiency improvement recommendation when the resource utilization exceeds a threshold.

Abstract: A mop bucket for cleaning and squeezing a flat mop, comprises a bucket body and a squeezing device disposed inside the bucket body; wherein, the bucket body has a squeezing water section and a cleaning section, which are respectively at two different positions when used; when the mop head of the flat mop is removably inserted into the squeezing device, the squeezing device presses against the wiper on the mop head and scrapes the wiper on the mop head. The present invention also discloses a cleaning tool set. The mop bucket of the present invention can clean and squeeze a wiper on the flat mop by integrating both functions of cleaning and squeezing together, provide better cleaning and squeezing effects, and realize a convenient and labor-saving squeezing operation and pleasurable user experience.

Abstract: A mop bucket for cleaning and squeezing a flat mop, comprises a bucket body and a squeezing device disposed inside the bucket body; wherein, the bucket body has a squeezing water section and a cleaning section, which are respectively at two different positions when used; when the mop head of the flat mop is removably inserted into the squeezing device, the squeezing device presses against the wiper on the mop head and scrapes the wiper on the mop head. The present invention also discloses a cleaning tool set. The mop bucket of the present invention can clean and squeeze a wiper on the flat mop by integrating both functions of cleaning and squeezing together, provide better cleaning and squeezing effects, and realize a convenient and labor-saving squeezing operation and pleasurable user experience.