data.table 1.18.0 causes Postgresql server crash (segmentation fault) with pl/R on Debian servers

Since version 1.18.0, loading data.table in a pl/R function on a PostgreSQL server on Debian (12 and 13 at least) causes a segmentation fault which crashes the PostgreSQL instance (17 and 18 tested).

Steps to reproduce on a fresh Debian (12 or 13) VM:

Install PostgreSQL

sudo apt update
sudo apt install -y postgresql-common
sudo /usr/share/postgresql-common/pgdg/apt.postgresql.org.sh
sudo apt install postgresql-17

Install R

sudo apt install r-base r-base-dev

Install R packages

To be usable by PostgreSQL, packages are installed as sudo.

sudo R
install.packages(c("dplyr", "data.table"))
exit

data.table v 1.18.0 is installed by default, since it's the last available version.

Install pl/R

sudo apt install postgresql-17-plr

Create and test a pl/R function loading data.table

sudo -iu postgres psql
create extension plr;

SELECT * FROM plr_environ();
SELECT load_r_typenames();
SELECT * FROM r_typenames();
SELECT plr_array_accum('{23,35}', 42);

CREATE OR REPLACE FUNCTION public.r_test(int) RETURNS int AS $code$
    library(data.table)
    return(arg1)
$code$ LANGUAGE 'plr' STRICT;

select * from public.r_test(1);

The PostgreSQL server crashes with a segmentation fault caused by the r_test function call. If you comment the data.table loading, the function works fine.

In R, data.table loading works fine, the problem is only related to pl/R in PostgreSQL.
If you replace data.table v 1.18.0 by v 1.17.8 (or earlier), everything works fine.

On an Ubuntu Server 24.04, the problem does not occur.

Confirmed. We're seeing a name collision, similar to #4369:

Thread 1 "postgres" received signal SIGSEGV, Segmentation fault.
__strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:76
(gdb) bt
#0  __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:76
#1  0x0000563701d3a577 in hash_create (tabname=tabname@entry=0x13 <error: Cannot access memory at address 0x13>, nelem=140507227299856, info=0x10, flags=67)
    at ./build/../src/backend/utils/hash/dynahash.c:390 # ← PostgreSQL
#2  0x00007fca4849663d in chmatchMain (x=<optimized out>, table=<optimized out>, nomatch=0, chin=<optimized out>, chmatchdup=false)
    at chmatch.c:60 # ← data.table
#3  0x00007fca65aff6fa in R_doDotCall (fun=fun@entry=0x7fca48496860 <chin_R>, nargs=nargs@entry=2, cargs=cargs@entry=0x7ffe680b0270, call=call@entry=0x563705f95470)
    at ./src/main/dotcode.c:871 # ← R

Version 1.18.0 introduced a function named hash_create. It's too bad that the PostgreSQL server already has a function named like that, with the dynamic linker resolving the wrong symbol.

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data.table 1.18.0 causes Postgresql server crash (segmentation fault) with pl/R on Debian servers #7605

Install PostgreSQL

Install R

Install R packages

Install pl/R

Create and test a pl/R function loading data.table

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data.table 1.18.0 causes Postgresql server crash (segmentation fault) with pl/R on Debian servers #7605

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Install PostgreSQL

Install R

Install R packages

Install pl/R

Create and test a pl/R function loading data.table

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aitap commented on Jan 19, 2026

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