"
Some queries are very unlikely to hit cache. Usually this includes
range queries on large tables, but other patterns are possible.
While the database should adapt to the query pattern, sometimes the
user has information the database does not have. By passing this
information along, the user helps the database manage its resources
more optimally.
To do this, this patch introduces a BYPASS CACHE clause to the
SELECT statement. A query thus marked will not attempt to read
from the cache, and instead will read from sstables and memtables
only. This reduces CPU time spent to query and populate the cache,
and will prevent the cache from being flooded with data that is
not likely to be read again soon. The existing cache disabled path
is engaged when the option is selected.
Tests: unit (release), manual metrics verification with ccm with and without the
BYPASS CACHE clause.
Ref #3770.
"
* tag 'cache-bypass/v2' of https://github.com/avikivity/scylla:
doc: document SELECT ... BYPASS CACHE
tests: add test for SELECT ... BYPASS CACHE
cql: add SELECT ... BYPASS CACHE clause
db: add query option to bypass cache
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