Note: PostgreSQL version 14 introduced their own bit_count. You may find their implementation here (or here) for comparison. It is therefore recommended to only use this repository for postgres versions <14. More information in this blog post.
Provides popcount, popcount32, popcount64, popcountAsm, popcountAsm64 and popcount256 functions to PostgreSQL. The extension was elected to provide all algorithms to enable a conscious choice on runtime. Statistical benchmark data suggests that popcountAsm64 should be chosen in most cases.
The extension is available on PGXN.
pgxn install popcountIf you want to compile it yourself, pg_config is required.
make install
make installcheck
The test bench was running an Intel(R) Xeon(R) Platinum 8168 CPU @ 2.70GHz on Ubuntu 18.04 and PostgreSQL 10.3.
More information in this blog post.
The test bench was running an Intel(R) Xeon(R) Platinum 8358 CPU @ 2.60GHz on Ubuntu 22.04 and PostgreSQL 14.7. It can be reproduced the following way.
./helper/generate_db_postgres.sh -d 500000 -a "2048 4096 8192"
./benchmark/postgres.sh -s popcountAsm64 -t 50 -d 500000 -a "2048 4096 8192"| option | values | comment |
|---|---|---|
| -s | popcount, popcount32, popcount64, popcountAsm, popcountAsm64, popcount256 |
8bit lookup table, 32bit hamming weight, 64bit hamming weight, 32 bit intrinsic function, 64 bit intrinsic function, unrolled assembly instruction. |
| -t | integer | Number of trials. |
| -d | integer | Number of rows in domain. |
| -a | integer | Bit alignments to test. |
| --units | - | Whether time units should be printed or not. |
Setup instructions on Ubuntu 22.04 LTS for convenience.
# install dependencies
sudo apt update
sudo apt install build-essential postgresql postgresql-contrib libpq-dev postgresql-server-dev-14 make
sudo systemctl start postgresql.service
# install extension...
sudo -i -u postgres
git clone https://github.com/eschmar/postgresql-popcount.git
cd postgresql-popcount
make install
make installcheck
# .. and enable it
psql
CREATE EXTENSION popcount;
\q