In this part we will discuss how NDB batch handling works. Query
execution of
complex SQL queries means that more rows can be delivered than
the receiver is
capable of receiving. This means that we need to create a data
flow from the
producer where the data resides and the query executor in the
MySQL Server.
The MySQL Server uses a record where the storage engine have to
copy the result
row into the record. This means that the storage of batches of
rows is taken
care of by the storage engine.
When NDB performs a range scan it will decide on the possible
parallelism before
the scan is started. The NDB API have to allocate enough memory
to ensure that
we have memory prepared to receive the rows as they arrive in a
flow of result
rows from the data nodes. It is possible to set batch size of
hundreds and even
thousands of rows for a query.
The …
Showing entries 1 to 1
Dec
09
2019
Showing entries 1 to 1