Persistent memory friendly hashing index that, to appear at VLDB 2020:
Dash: Scalable Hashing on Persistent Memory.
Baotong Lu, Xiangpeng Hao, Tianzheng Wang and Eric Lo.
VLDB 2020.
Paper preprint at https://arxiv.org/pdf/2003.07302.pdf.
- Dash EH - Proposed Dash extendible hashing
- Dash LH - Proposed Dash linear Hashing
- CCEH - PMDK patched CCEH variant used in our benchmark
- Level Hashing - PMDK patched level hashing variant used in our benchmark
- Mini benchmark framework
- All benchmark results
Fully open-sourced under MIT license.
We tested our build with Linux Kernel 5.5.3 and gcc 9.2.0.
mkdir build && cd build
cmake -DCMAKE_BUILD_TYPE=Release -DUSE_PMEM=ON ..
make -j./build/test_pmem --helpshort
Usage:
./build/test_pmem [OPTION...]
-index the index to evaluate:dash-ex/dash-lh/cceh/level (default: "dash-ex")
-op the type of operation to execute:insert/pos/neg/delete/mixed (default: "full")
-n the number of warm-up workload (default: 0)
-p the number of operations(insert/search/delete) to execute (default: 20000000)
-t the number of concurrent threads (default: 1)
-r search ratio for mixed workload: 0.0~1.0 (default: 1.0)
-s insert ratio for mixed workload: 0.0~1.0 (default: 0.0)
-d delete ratio for mixed workload: 0.0~1.0 (default: 0.0)
-e whether to register epoch in application level: 0/1 (default: 0)
-k the type of stored keys: fixed/variable (default: "fixed")
-vl the length of the variable length key (default: 16)We noticed a possible mmap bug on our testing environment: MAP_SHARED_VALIDATE is incompatible with MAP_FIXED_NOREPLACE.
To ensure safe memory mapping, we modified the original PMDK to use MAP_SHARED rather than MAP_SHARED_VALIDATE, which has the same functionality as the former one except for extra flag validation.
For a more detailed explanation and minimal reproducible code, please check out our blog post about this issue.
For any questions, please contact us at btlu@cse.cuhk.edu.hk and tzwang@sfu.ca.