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README.md

CoroBase: Coroutine-Oriented Main-Memory Database Engine

CoroBase is a research database engine that models transactions as C++20 stackless coroutine to hide CPU cache misses. See details in our VLDB 2021 paper:

[1] Yongjun He, Jiacheng Lu and Tianzheng Wang. CoroBase: Coroutine-Oriented Main-Memory Database Engine. VLDB 2021.

CoroBase inherits the shared-everything architecture, synchronization and concurrency control protocol from ERMIA. See our SIGMOD'16 paper [2] for a description of ERMIA, our VLDBJ paper [3] for details in concurrency control, and our VLDB paper [4] for replication.

[2] Kangnyeon Kim, Tianzheng Wang, Ryan Johnson and Ippokratis Pandis. ERMIA: Fast Memory-Optimized Database System for Heterogeneous Workloads. SIGMOD 2016.

[3] Tianzheng Wang, Ryan Johnson, Alan Fekete and Ippokratis Pandis. Efficiently making (almost) any concurrency control mechanism serializable. The VLDB Journal, Volume 26, Issue 4. 2017.

[4] Tianzheng Wang, Ryan Johnson and Ippokratis Pandis. Query Fresh: Log Shipping on Steroids. VLDB 2018.

Software dependencies

Ubuntu

apt-get install -y cmake clang-8 libc++-8-dev libc++abi-8-dev
apt-get install -y libnuma-dev libibverbs-dev libgflags-dev libgoogle-glog-dev

Environment configurations

Make sure you have enough huge pages.

  • CoroBase uses mmap with MAP_HUGETLB (available after Linux 2.6.32) to allocate huge pages. Almost all memory allocations come from the space carved out here. Assuming the default huge page size is 2MB, the command below will allocate 2x MB of memory:
sudo sh -c 'echo [x pages] > /proc/sys/vm/nr_hugepages'

This limits the maximum for --node-memory-gb to 10 for a 4-socket machine (see below).

  • mlock limits. Add the following to /etc/security/limits.conf (replace "[user]" with your login):
[user] soft memlock unlimited
[user] hard memlock unlimited

Re-login to apply.


Build it

We do not allow building in the source directory. Suppose we build in a separate directory:

$ mkdir build
$ cd build
$ cmake ../ -DCMAKE_BUILD_TYPE=[Debug/Release/RelWithDebInfo]
$ make -jN

Currently the code can compile under Clang 8.0+. E.g., to use Clang 8.0, issue the following cmake command instead:

$ CC=clang-8.0 CXX=clang++-8.0 cmake ../ -DCMAKE_BUILD_TYPE=[Debug/Release/RelWithDebInfo]

After make there will be two executables under build:

ermia_SI that runs CoroBase (optimized 2-level coroutine-to-transaction design) and ERMIA with snapshot isolation (not serializable);

ermia_adv_coro_SI that runs CoroBase (fully-nested coroutine-to-transaction design) with snapshot isolation (not serializable);

Run it

$run.sh \
       [executable] \
       [benchmark] \
       [scale-factor] \
       [num-threads] \
       [duration (seconds)] \
       "[other system-wide runtime options]" \
       "[other benchmark-specific runtime options]"`

Run example

Sequential (baseline):
$./run.sh ./ermia_SI ycsb 10 48 20 \
         "-physical_workers_only=1 -index_probe_only=1 -node_memory_gb=75 -null_log_device=1" \
         "-w C -r 10 -s 1000000000 -t sequential"

CoroBase (optimized 2-level coroutine-to-transaction design)
$./run.sh ./ermia_SI ycsb 10 48 20 \
         "-physical_workers_only=1 -index_probe_only=1 -node_memory_gb=75 -null_log_device=1 -coro_tx=1 -coro_batch_size=8" \
         "-w C -r 10 -s 1000000000 -t simple-coro"

CoroBase (fully-nested coroutine-to-transaction design)
$./run.sh ./ermia_adv_coro_SI ycsb 10 48 20 \
         "-physical_workers_only=1 -index_probe_only=1 -node_memory_gb=75 -null_log_device=1 -coro-tx=1 -coro_batch_size=8" \
         "-w C -r 10 -s 1000000000 -t adv-coro"

Coroutine-based multiget (flattened coroutines)
$./run.sh ./ermia_SI ycsb 10 48 20 \
         "-physical_workers_only=1 -index_probe_only=1 -node_memory_gb=75 -null_log_device=1" \
         "-w C -r 10 -s 1000000000 -t multiget-simple-coro"

Coroutine-based multiget (fully-nested coroutines)
$./run.sh ./ermia_adv_coro_SI ycsb 10 48 20 \
         "-physical_workers_only=1 -index_probe_only=1 -node_memory_gb=75 -null_log_device=1 -coro_tx=1" \
         "-w C -r 10 -s 1000000000 -t multiget-adv-coro"

AMAC-based multiget
$./run.sh ./ermia_SI ycsb 10 48 20 \
         "-physical_workers_only=1 -index_probe_only=1 -node_memory_gb=75 -null_log_device=1" \
         "-w C -r 10 -s 1000000000 -t multiget-amac"

System-wide runtime options

-node_memory_gb: how many GBs of memory to allocate per socket.

-null_log_device: flush log buffer to /dev/null. With more than 30 threads, log flush (even to tmpfs) can easily become a bottleneck because of a mutex in the kernel held during the flush. This option does not disable logging, but it voids the ability to recover.

-tmpfs_dir: location of the log buffer's mmap file. Default: /tmpfs/.

-enable_gc: turn on garbage collection. Currently there is only one GC thread.

-enable_chkpt: enable checkpointing.

-phantom_prot: enable phantom protection.

-warm-up: strategy to load versions upon recovery. Candidates are:

  • eager: load all latest versions during recovery, so the database is fully in-memory when it starts to process new transactions;
  • lazy: start a thread to load versions in the background after recovery, so the database is partially in-memory when it starts to process new transactions.
  • none: load versions on-demand upon access.

Benchmark-specific runtime options

-w C: YCSB-C read-only workload.

-s 1000000000: number of records in the database table.

-r 10: 10 querys per transaction.

-t sequential: 'sequential' for ERMIA implementation, 'simple-coro' for the optimized 2-level coroutine-to-transaction implementation, and 'adv-coro' for the fully-nested coroutines implementation.