Efficient join on dynamically compressed inner for improved fit into cache hierarchy
First Claim
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1. A method comprising:
- joining, using a hash join process, data between at least two column data sets from hash table columns from at least two hash tables, wherein values of one or more join keys of each of the data sets is represented in a compressed form, indicated by an encoding scheme; and
dynamically compressing the one or more join keys with a compression scheme during an outer scan operation of the hash join process, the compression scheme being dynamically selected based on join key data type, wherein different compression schemes are selected for the hash table columns including;
numerical typed key columns, decimal typed key columns and character string typed key columns.
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Abstract
A method includes joining data between at least two data sets. Values of one or more join attributes of each of the data sets is represented in a compressed form, indicated by an encoding scheme. A compression scheme for the one or more join attributes is dynamically selected.
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Citations
18 Claims
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1. A method comprising:
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joining, using a hash join process, data between at least two column data sets from hash table columns from at least two hash tables, wherein values of one or more join keys of each of the data sets is represented in a compressed form, indicated by an encoding scheme; and dynamically compressing the one or more join keys with a compression scheme during an outer scan operation of the hash join process, the compression scheme being dynamically selected based on join key data type, wherein different compression schemes are selected for the hash table columns including;
numerical typed key columns, decimal typed key columns and character string typed key columns. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer program product for performing a hash join process, the computer program product comprising a computer readable storage medium having program code embodied therewith, the program code executable by a processor to:
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joining, using the hash join process, data between at least two column data sets from hash table columns from at least two hash tables, wherein values of one or more join keys of each of the column data sets is represented in a compressed form, indicated by an encoding scheme; and dynamically compressing the one or more join keys with a compression scheme during an outer scan operation of the hash join process, the compression scheme being dynamically selected based on join keys data type, wherein different compression schemes are selected for the hash table columns including;
numerical typed key columns, decimal typed key columns and character string typed key columns. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method comprising:
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hashing join keys onto a particular one of at least two hash tables and partitioning the particular one hash table; performing a hash join process on column data sets from hash table columns from the at least two hash tables, wherein one or more join keys of each of the data sets are represented in a compressed form, indicated by an encoding scheme; and dynamically compressing the one or more join keys with an encoding scheme during an outer scan operation of the hash join process, the encoding scheme being dynamically selected based on join attribute data type, wherein different encoding schemes for the one or more join keys are selected for the hash table columns including;
numerical typed key columns, decimal typed key columns and character string typed key columns. - View Dependent Claims (18)
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Specification