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2a371c2689
"
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
Scylla
Quick-start
$ git submodule update --init --recursive
$ sudo ./install-dependencies.sh
$ ./configure.py --mode=release
$ ninja-build -j4 # Assuming 4 system threads.
$ ./build/release/scylla
$ # Rejoice!
Please see HACKING.md for detailed information on building and developing Scylla.
Running Scylla
- Run Scylla
./build/release/scylla
- run Scylla with one CPU and ./tmp as data directory
./build/release/scylla --datadir tmp --commitlog-directory tmp --smp 1
- For more run options:
./build/release/scylla --help
Building Fedora RPM
As a pre-requisite, you need to install Mock on your machine:
# Install mock:
sudo yum install mock
# Add user to the "mock" group:
usermod -a -G mock $USER && newgrp mock
Then, to build an RPM, run:
./dist/redhat/build_rpm.sh
The built RPM is stored in /var/lib/mock/<configuration>/result directory.
For example, on Fedora 21 mock reports the following:
INFO: Done(scylla-server-0.00-1.fc21.src.rpm) Config(default) 20 minutes 7 seconds
INFO: Results and/or logs in: /var/lib/mock/fedora-21-x86_64/result
Building Fedora-based Docker image
Build a Docker image with:
cd dist/docker
docker build -t <image-name> .
Run the image with:
docker run -p $(hostname -i):9042:9042 -i -t <image name>