Sybase, Inc.

Leon Xiong

Xu-Dong Qian

Peter J Schneider

Santosh Pendap

Ming-li Rui

Methods, systems, and computer program products for decompressing data are described. An ordinal column number of columnar data to be accessed is obtained, the ordinal column number identifying a location of the columnar data in a corresponding uncompressed row, the columnar data being stored in a first data structure. A breakpoint value in a breakpoint field of the at least partially compressed row is determined, the breakpoint value indicating a location of an end of a common prefix in the corresponding uncompressed row, the common prefix being stored in a second data structure. The ordinal column number of the columnar data to be accessed and a column number indicated by the breakpoint value are compared, the comparison identifying one or more locations of the columnar data to be accessed.

Row, table, and index decompression

High performance index creation using parallel query plans with repartitioning scan and vector-based repartitioning scan is described. An example method includes extracting index key columns from data rows of the database table to build a set of index rows, wherein the index on the database table is defined by a plurality of index key columns including a first index key column and a second index key column. Partition boundary values are generated to divide up the index rows into range-partitioned sets, and the index rows are sorted based on values of the index key columns. A repartitioning scan, including a SARG-based or a vector-based partitioning scan is performed on the index rows, using a plurality of worker threads executing in parallel to build sub-indexes. Subsequently, each range-partitioned set of index rows are assigned to a worker thread in the plurality of worker threads. Accordingly, the sub-indexes generated from the plurality of work threads are merged to build the index for the database table.

High performance index creation

Methods, systems, and computer program products for compressing a row are described. A common prefix may be obtained and data in the row matching the common prefix may be identified. A column number of a column corresponding to a breakpoint of the common prefix may be determined and data matching the common prefix may be deleted from the row. An identifier of the common prefix may be inserted into the row and a breakpoint field in the row may be set to the determined column number.

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Shanghai, China

Leon Xiong