When a UNION operation involving DECIMAL datatypes with scale and digits
before the decimal exceeds the currently supported maximum precision
of 38, we throw an error to the user:
"MCS-2060: Union operation exceeds maximum DECIMAL precision of 38".
This is until MCOL-5417 is implemented where ColumnStore will have
full parity with MariaDB server in terms of maximum supported DECIMAL
precision and scale of 65 and 38 digits respectively.
exact functionality that does not use MDB hash function.
This patch also takes a bit from Robin Hood hash map implementation forgotten
that reduces hash function collision rate.
* Introduce multigeneration aggregation
* Do not save unused part of RGDatas to disk
* Add IO error explanation (strerror)
* Reduce memory usage while aggregating
* introduce in-memory generations to better memory utilization
* Try to limit the qty of buckets at a low limit
* Refactor disk aggregation a bit
* pass calculated hash into RowAggregation
* try to keep some RGData with free space in memory
* do not dump more than half of rowgroups to disk if generations are
allowed, instead start a new generation
* for each thread shift the first processed bucket at each iteration,
so the generations start more evenly
* Unify temp data location
* Explicitly create temp subdirectories
whether disk aggregation/join are enabled or not
Original SH implementation sends the result set back to the client
thus it can't be used in INSERT..SELECT, SELECT INTO OUTFILE,CREATE
TABLE AS SELECT etc.
CLX-77 feature has been backported into MDB to enable SH to run
query part of the mentioned queries.
This patch fixes:
MCOL-3557 - Row Based Replication events to ColumnStore tables will no
longer cause MariaDB to crash, it will error instead.
MCOL-3556 - Remove the Columnstore.xml variable to turn on ColumnStore
tables applying replication events and instead make it a system variable
that can be set in my.cnf called "columnstore_replication_slave". This
allows it to be set per-UM.
