Example how to use Flatbuffer with RocksDB. The program write/read key values. Keys are strings and values are Flatbuffer byte array of 92 bytes.

Install

• Install rocksdb, flatbuffer.
• flatc --cpp game.fbs to get the game_generated.h.

Build & Run

mkdir build
cd build
cmake ..
make
./rocksdb-main

Test Setup

• ASUS Series ROG Zephyrus S Model GX531GX-XS74
• Intel Core i7-8750H 2.20 GHz
• 16 GB DDR4 (8 GB x 2)
• 512 GB PCIe NVMe SSD
• GeForce RTX 2080 Max-Q 8 GB GDDR6
• Ubuntu 16.04 LTS 64-bit

Resource sampling is at 0.5 seconds, so anything faster than 0.5s shows up as 0% CPU.

K-V Objects	Time (ms)	CPU (%)	Real (MB)	Virtual (MB)	Disk Size
1	0.000	0.000	0.777	4.398	152K
10	0.889	0.000	0.660	4.398	156K
100	2.438	0.000	0.762	4.398	168K
1000	25.359	0.000	0.762	4.398	280K
10000	278.974	0.000	22.598	361.199	1.5M
100000	2892.830	101.100	33.578	432.402	13M
1000000	29171.700	98.700	98.348	552.551	115M

Note:

• Filesystem only test uncompressed is 99Mb.
• 2nd run, for the 1M test, db size increases from 115M to 178M.
• 3rd run increases to 291M.
• 4th run shrinks to 229M.
• 5th run shrinks to 178M.
• 6th run increases to 291M.
• 7th run shrinks 229M.
• All runs share similar execution times (ms), around 28-29s.

References

• psrecord --include-children --log $prog_name.log --interval 0.5 --plot plot-$prog_name.png $argv
• https://unix.stackexchange.com/questions/554/how-to-monitor-cpu-memory-usage-of-a-single-process