Details
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Task
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Status: Open (View Workflow)
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Major
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Resolution: Unresolved
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None
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None
Description
Today, we only have the option to checksum a table:
CHECKSUM TABLE tbl_name [, tbl_name] ... [ QUICK | EXTENDED ]
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However, it would be useful to be able to specify a subset of data, especially a single partition.
Additionally, it would be best if it would be possible to get a checksum of data in an un-partitioned table, then copy this data into a partitioned table, aggregate the checksum values of each partition, and get the same value as un-partitioned table.
( Relates to: MDEV-16249 )
Attachments
Issue Links
- relates to
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MDEV-16249 CHECKSUM TABLE for a spider table is not parallel and saves all data in memory in the spider head by default
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- Closed
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MDEV-16520 Out-Of-Memory running big aggregate query on Spider Engine
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- Closed
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I can imagine a new syntax something like extending the MD5 aggregate functions to take multiple columns might be useful.
I can imagine adding syntax like
CHECKSUM TABLE tbl_name [PARTITION BY partition_options] [, tbl_name ]
might be useful for non-partitioned tables, as it would allow for parallel checksum calculation, even in the non-partitioned case.
Already there exists some partition CHECKSUM data in information_schema. https://mariadb.com/kb/en/library/information-schema-partitions-table/