Sap Se

Zhen Tian

Yinghua Ouyang

Paul Willems

Boyang Zhang

Xun Zhang

Yanchen Cao

Jian Jun Wang

Xun Cheng

Taehyung Lee

Hong-Hai Do

Nitesh Maheshwari

Taeyoung Jeong

Sen Zhang

Dongmei Xv

Yuncong Qiao

Faming Qu

Hongyong Lu

Yanxin Luo

The present disclosure involves systems, software, and computer implemented methods for managing database query plans with dynamic conditions. One example method includes receiving a request to process a query based on a dynamic condition. In response to determining that a plan cache does not include a cached query plan for the query, query plan compilation is triggered to generate a query plan. In response to determining that a cached query plan exists, for each query view, a condition provider procedure is invoked to generate a first filter string. First filter strings are compared to corresponding second filter strings in the cached plan. In response to determining that a first filter string does not match the corresponding second filter string, query plan compilation is triggered. In response to determining that each filter string matches each corresponding second filter string, the database query is executed using the cached query plan.

Caching database query plans that include dynamic conditions

The present disclosure involves systems, software, and computer implemented methods for managing database query plans with dynamic conditions. One example method includes receiving a request to process a query based on at least one dynamic condition. A serialized abstract query plan is identified, deserialized, and converted into a query optimizer tree. A condition provider procedure is invoked to generate a first filter string for each view in the query optimizer tree. Comparisons are made to determine matches between first filter strings and corresponding second filter string stored in the query optimizer tree. In response to determining that a first filter string does not match the corresponding second filter string, query plan compilation is triggered. In response to determining that each filter string matches each corresponding second filter string, a query plan is generated based on the converted query optimizer tree and the query is executed using the query plan.

Persisting database query plans that include dynamic conditions

A method, a system, and a computer program product for generating an executable query plan. A query requiring access to data stored in a database system is received. Based on the received query, a query execution plan having a plurality of query execution pipelines is generated. Each query execution pipeline in the plurality of query execution pipelines is configured to execute a plurality of operations in a predetermined order associated with each query execution pipeline. The generated query execution plan is fragmented into a plurality of fragments. Each fragment has one or more query execution pipelines in the plurality of query execution pipelines. Each fragment of the generated query execution plan is transmitted to one or more execution locations in a plurality of execution locations for execution. Each fragment of the generated query execution plan is executed at one or more execution locations. One or more results of executions are combined to generate a response to the received query.

Distributed query plan generation

1. Implementations of the present disclosure include receiving, by a database system, a query from an entity, providing a parse tree based on the query, the parse tree including nodes representative of operations to be executed and data objects stored within the database system, generating a module tree based on the parse tree, the module tree including a set of modules provided in sequential order from a root module to a leaf module, and executing an authorization check using the module tree by, for each module, determining a set of data objects and, for each data object in the set of data objects, determining whether the entity is one or more of authorized access the data object and perform an operation on the data object.

Authorization checks and auditing for queries in database systems

The present disclosure involves systems, software, and computer implemented methods for processing correlated calculated fields in correlated subqueries. One example method includes receiving a request to process a database query that includes at least one subquery and processing each subquery. A determination is made as to whether each subquery includes a correlated calculated field that is a calculated field that is not included in a first datasource queried by the subquery but is included in a second datasource queried by an outer query that includes the subquery. If the subquery does not include a correlated calculated field, the subquery is processed without modification. If the subquery includes a correlated calculated field, metadata is retrieved for the outer query of the subquery that queries the second datasource and includes the correlated calculated field. The subquery is rewritten using the metadata and the rewritten subquery is processed.

Processing correlated calculated fields in correlated subqueries

The present disclosure involves systems, software, and computer implemented methods for efficient memory leak detection in database systems. One example method includes receiving a query at a database system. Memory allocations and deallocations are traced during processing of the query. Each memory allocation entry in a tracing file can be processed, including determining, for each allocation, whether a memory deallocation entry exists in the tracing file. A determination can be made as to whether a memory leak has occurred in response to determining whether a memory deallocation entry corresponding to a memory allocation entry exists in the tracing file. For example, a determination can be made that a memory leak has occurred in response to determining that no memory deallocation entry corresponding to an allocated memory address exists in the tracing file. One or more actions can be performed in response to determining that a memory leak has occurred.

Efficient memory leak detection in database systems

A method for workload balancing is implemented in a computer system including a primary database system and a secondary database system, the secondary database system being configured as a backup system for the primary database system. The method includes compiling a query received from a client application. The query indicates one or more source tables have corresponding replicate tables. The compiling comprises replace the one or more source tables with the corresponding replicate tables. The method can generate a query execution plan based on the compiled query, determine a per-table result lag based on minimum commit times of the corresponding replicate tables, and compare the per-table result lag with a predefined threshold. Responsive to a determination that the per-table result lag exceeds the predefined threshold, the method can recompile the query by falling back to the one or more source tables from the corresponding replicate tables.

Efficient workload balancing in replicated databases based on result lag computation

A computer system comprises one or more processors, a primary database system, and a secondary database system. The secondary database system is configured as a hot-standby system for the primary database system. The secondary database system is capable of providing at least a minimum amount of essential functionality of the primary database system during a disruption to the primary database system. The primary database system is configured by programming instructions, executable on the computer system, to cause the one or more processors to determine from a query request from a client application directed to the primary database system that workload from a query may be shifted to the secondary database system and selectively instruct the client application to direct the secondary database system to execute the query based on a per-table calculated result lag. Related apparatus, systems, techniques and articles are also described.

A method, a system, and a computer program product for generating a query executable plan. A query requiring access to data stored in a database system is received. Based on the received query, a query execution plan having a plurality of query execution pipelines is generated. Each query execution pipeline in the plurality of query execution pipelines is configured to execute a plurality of operations in a predetermined order associated with each query execution pipeline. The generated query execution plan is fragmented into a plurality of fragments. Each fragment has one or more query execution pipelines in the plurality of query execution pipelines. The received query is executed by executing each fragment in the plurality of fragments.

Scaled-out query execution engine

A secondary database system is configured to act as a backup system for a primary database system. The primary database system receives a query request from a client application in advance of receiving a query. Thereafter, the primary database system determines that a routing hint in the query request indicates that workload from the query may be shifted to the secondary database system. It can then be determined that execution of the query does not involve writing data. The primary database system then determines to instruct the client application to route the query to the secondary database system based on the routing hint. The primary database system then instructs the client application to route the query to the secondary database system. The query is then compiled and executed on the secondary database system such that a replica table does not replace the source table.

Efficient query compilation in replicated databases

A computer system is configured to provide a database system. The computer system comprises one or more processors, a primary database system implemented by the one or more processors, and a secondary database system implemented by the one or more processors. The secondary database system is configured as a hot-standby system for the primary database system. The secondary database system is capable of providing at least a minimum amount of essential functionality of the primary database system during a disruption to the primary database system. The primary database system is configured by programming instructions, executable on the computer system, to cause the one or more processors to determine from a query request from a client application directed to the primary database system that workload from a query may be shifted to the secondary database system and selectively instruct the client application to direct the secondary database system to execute the query based on a per-table calculated result lag. Related apparatus, systems, techniques and articles are also described.

Methods, systems, and computer-readable storage media for providing a table in a database system, the table including a column having a column data type set to an abstract data type, receiving a first data record to be added to the table, the first data record including a first data value to be included in the column, determining a first data type corresponding to a data type of the first data value, changing the column data type from the abstract data type to the first data type, receiving a second data record to be added to the table, the second data record including a second data value to be including in the column, determining a second data type corresponding to the data type of the second data value, and selectively changing the column data type to the second data type.

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Xi'an, China

Zhen Tian