pg_eviltransform (Rust/pgrx)

中文文档 (Chinese README)

pg_eviltransform extends PostGIS ST_Transform with BD09/GCJ02 support.

It exposes one public function name, following the same overload interface as ST_Transform:

• ST_EvilTransform(geometry, to_srid integer)
• ST_EvilTransform(geometry, to_proj text)
• ST_EvilTransform(geometry, from_proj text, to_srid integer)
• ST_EvilTransform(geometry, from_proj text, to_proj text)

Behavior:

• If neither side uses custom coordinates, it delegates directly to ST_Transform.
• If BD09/GCJ02 is involved, it transforms via WGS84 (4326) when needed.

Custom SRIDs:

• 990001: GCJ02
• 990002: BD09

Regex SQL Variant

regex_eviltransform.sql defines Regex_EvilTransform(...) with the same overload interface as ST_EvilTransform(...).

Regex_EvilTransform is a SQL/PLpgSQL + regex implementation used for comparison and benchmarking against pg_eviltransform.

Citation

Patent reference for the regex-based SQL approach:

• CN112000902B

If you use the regex-based SQL approach, cite:

@patent{CN112000902B,
  title     = {用于地图区域绘制的方法、电子设备和存储介质},
  author    = {梁展钊},
  number    = {CN112000902B},
  year      = {2021},
  type      = {Chinese Patent},
  assignee  = {Shanghai Maice Data Technology Co., Ltd.; Maice (Shanghai) Intelligent Technology Co., Ltd.},
  url       = {https://patents.google.com/patent/CN112000902B}
}

Thanks

• googollee/eviltransform for the open-source coordinate transform implementation and reference formulas.

Requirements

• Rust stable
• cargo-pgrx (cargo install --locked cargo-pgrx --version 0.17.0)
• PostgreSQL + PostGIS (PG 14-18 supported)
• librttopo-dev (for the native GSERIALIZED fast path)

Packaging note:

• DEB packages have no hard runtime package dependency to keep installation lightweight.
• PostgreSQL/PostGIS are kept as suggested packages to avoid pulling a large dependency tree during apt install.
• Runtime still requires PostGIS (CREATE EXTENSION postgis) before CREATE EXTENSION pg_eviltransform.

Build

cargo pgrx init \
  --pg14=/usr/lib/postgresql/14/bin/pg_config \
  --pg15=/usr/lib/postgresql/15/bin/pg_config \
  --pg16=/usr/lib/postgresql/16/bin/pg_config \
  --pg17=/usr/lib/postgresql/17/bin/pg_config \
  --pg18=/usr/lib/postgresql/18/bin/pg_config

cargo pgrx package --release --features pg18 --no-default-features --pg-config /usr/lib/postgresql/18/bin/pg_config

Test (native Rust)

cargo test
cargo pgrx test pg18 --features pg18

Usage

-- Preferred: explicit literals (no need to remember custom SRID numbers)
SELECT ST_EvilTransform(ST_SetSRID('POINT(120 30)'::geometry, 4326), 'GCJ02');
SELECT ST_EvilTransform(ST_SetSRID('POINT(120 30)'::geometry, 4326), 'BD09');

-- Equivalent numeric custom SRID form
SELECT ST_EvilTransform(ST_SetSRID('POINT(120 30)'::geometry, 4326), 990001);

-- BD09 (990002) -> Web Mercator (3857)
SELECT ST_EvilTransform(ST_SetSRID('POINT(120.011070620552 30.0038830555128)'::geometry, 990002), 3857);

-- from_proj / to_proj overload with literals
SELECT ST_EvilTransform('POINT(120 30)'::geometry, 'EPSG:4326', 'GCJ02');

Benchmark (PG18)

Use the benchmark script to compare ST_EvilTransform and Regex_EvilTransform:

# optional env: PGHOST, PGPORT, PGUSER, PGDATABASE, ROWS
scripts/benchmark_pg18.sh

It will:

• Ensure postgis and pg_eviltransform extensions exist.
• Load regex_eviltransform.sql (creating Regex_EvilTransform).
• Generate benchmark data in public.bench_points.
• Run EXPLAIN (ANALYZE, BUFFERS) for ST_EvilTransform and Regex_EvilTransform.
• Write report to benchmark_pg18_report.txt (or custom output path).

Example:

ROWS=500000 PGDATABASE=testdb scripts/benchmark_pg18.sh /tmp/bench_pg18.txt

Latest run (PG18, ROWS=200000, report: benchmark_pg18_report.txt):

Scenario	ST_EvilTransform	Regex_EvilTransform	Speedup (Regex / ST)
4326 -> 990001	92.402 ms	2832.821 ms	30.7x
990002 -> 3857 (via 4326)	183.856 ms	8393.272 ms	45.7x

Release Debian (Trixie, PG14-18)

scripts/release_debian_trixie.sh

This builds .deb artifacts under dist/:

• postgresql-14-pg-eviltransform_<version>_trixie_<arch>.deb
• postgresql-15-pg-eviltransform_<version>_trixie_<arch>.deb
• postgresql-16-pg-eviltransform_<version>_trixie_<arch>.deb
• postgresql-17-pg-eviltransform_<version>_trixie_<arch>.deb
• postgresql-18-pg-eviltransform_<version>_trixie_<arch>.deb

GitHub Release CI publishes both amd64 and arm64 package artifacts (.deb + .rpm).

License

MIT. See LICENSE.