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4537ec7426
The multishard mutation query used the semaphore obtained from `database::user_read_concurrency_sem()` to pause-resume shard readers. This presented a problem when `multishard_mutation_query()` was reading from system tables. In this case the readers themselves would obtain their permits from the system read concurrency semaphore. Since the pausing of shard readers used the user read semaphore, pausing failed to fulfill its objective of alleviating pressure on the semaphore the reads obtained their permits from. In some cases this lead to a deadlock during system reads. To ensure the correct semaphore is used for pausing-resuming readers, obtain the semaphore from the `table` object. To avoid looking up the table on every pause or resume call, cache the semaphores when readers are created. Fixes: #4096 Signed-off-by: Botond Dénes <bdenes@scylladb.com> Message-Id: <c784a3cd525ce29642d7216fbe92638fa7884e88.1547729119.git.bdenes@scylladb.com>
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. Note: GCC >= 8.1.1 is require to compile 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>