Server closed the connection on executing prepared statement

[saygoodbyye]

What happens?

Server crashes on executing prepared statement

➜  pg_duckdb git:(main) ✗ psql                                                                     
psql (17.8)
Type "help" for help.

test=# create extension pg_duckdb ;
CREATE EXTENSION
test=# prepare test_sql as select r['upper'], r['LOWER'] from read_parquet('/home/test/work/pg_duckdb/test/regression/data/uppercase.parquet') r;
PREPARE
test=# execute test_sql ;
server closed the connection unexpectedly
	This probably means the server terminated abnormally
	before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
The connection to the server was lost. Attempting reset: Failed.
!?>

To Reproduce

configure:

CFLAGS='-Og' ./configure --enable-tap-tests --enable-debug --enable-cassert --with-openssl --with-icu --with-lz4 --with-libxml --quiet --prefix=$PGPREFIX

postgresql.conf:

shared_preload_libraries='pg_duckdb'

test.sql:

create extension pg_duckdb;
prepare test_sql as select r['upper'], r['LOWER'] from read_parquet('/home/test/work/pg_duckdb/test/regression/data/uppercase.parquet') r;
execute test_sql;

backtrace:

#0  __pthread_kill_implementation (threadid=<optimized out>, signo=6, no_tid=0) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (threadid=<optimized out>, signo=6) at ./nptl/pthread_kill.c:89
#2  __GI___pthread_kill (threadid=<optimized out>, signo=signo@entry=6) at ./nptl/pthread_kill.c:100
#3  0x00007f64bda45e2e in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#4  0x00007f64bda28888 in __GI_abort () at ./stdlib/abort.c:77
#5  0x00005f5c12bd01ad in ExceptionalCondition (conditionName=conditionName@entry=0x5f5c12cd1ddf "false", fileName=fileName@entry=0x5f5c12cd39ab "execTuples.c", lineNumber=lineNumber@entry=1090) at assert.c:66
#6  0x00005f5c12898e06 in slot_deform_heap_tuple (slot=0x5f5c235d0ff8, tuple=<optimized out>, offp=0x5f5c235d1060, natts=2) at execTuples.c:1090
#7  tts_minimal_getsomeattrs (slot=0x5f5c235d0ff8, natts=<optimized out>) at execTuples.c:549
#8  0x00005f5c1289ab22 in slot_getsomeattrs_int (slot=0x5f5c235d0ff8, attnum=2) at execTuples.c:1999
#9  0x00005f5c1267655a in slot_getsomeattrs (slot=0x5f5c235d0ff8, attnum=<optimized out>) at ../../../../src/include/executor/tuptable.h:358
#10 slot_getallattrs (slot=slot@entry=0x5f5c235d0ff8) at ../../../../src/include/executor/tuptable.h:370
#11 0x00005f5c12676762 in printtup (slot=0x5f5c235d0ff8, self=0x5f5c233679a8) at printtup.c:318
#12 0x00005f5c12a806b5 in RunFromStore (portal=portal@entry=0x5f5c23422030, direction=direction@entry=ForwardScanDirection, count=count@entry=0, dest=0x5f5c233679a8) at pquery.c:1097
#13 0x00005f5c12a8079b in PortalRunSelect (portal=portal@entry=0x5f5c23422030, forward=forward@entry=true, count=0, count@entry=9223372036854775807, dest=dest@entry=0x5f5c233679a8) at pquery.c:918
#14 0x00005f5c12a8206d in PortalRun (portal=portal@entry=0x5f5c23422030, count=count@entry=9223372036854775807, isTopLevel=isTopLevel@entry=true, run_once=run_once@entry=true, dest=dest@entry=0x5f5c233679a8, altdest=altdest@entry=0x5f5c233679a8, 
    qc=0x7ffe07048800) at pquery.c:766
#15 0x00005f5c12a7e0f8 in exec_simple_query (query_string=query_string@entry=0x5f5c23366b50 "execute test_sql;") at postgres.c:1278
#16 0x00005f5c12a80171 in PostgresMain (dbname=<optimized out>, username=<optimized out>) at postgres.c:4767
#17 0x00005f5c12a793f6 in BackendMain (startup_data=<optimized out>, startup_data_len=<optimized out>) at backend_startup.c:105
#18 0x00005f5c129d01ff in postmaster_child_launch (child_type=child_type@entry=B_BACKEND, startup_data=startup_data@entry=0x7ffe07048a24 "", startup_data_len=startup_data_len@entry=4, client_sock=client_sock@entry=0x7ffe07048a60) at launch_backend.c:277
#19 0x00005f5c129d4994 in BackendStartup (client_sock=client_sock@entry=0x7ffe07048a60) at postmaster.c:3596
#20 0x00005f5c129d4c0a in ServerLoop () at postmaster.c:1678
#21 0x00005f5c129d6393 in PostmasterMain (argc=argc@entry=3, argv=argv@entry=0x5f5c2330e850) at postmaster.c:1376
#22 0x00005f5c128eda12 in main (argc=3, argv=0x5f5c2330e850) at main.c:199

OS:

Ubuntu 25.10

pg_duckdb Version (if built from source use commit hash):

dafe12d

Postgres Version (if built from source use commit hash):

dfd85098030475dbc38abe623f852d3aa1e1a40b

Hardware:

No response

Full Name:

Egor Chindyaskin

Affiliation:

Postgres Professional

What is the latest build you tested with? If possible, we recommend testing with the latest nightly build.

I have tested with a source build

Did you include all relevant data sets for reproducing the issue?

Yes

Did you include all code required to reproduce the issue?

• Yes, I have

Did you include all relevant configuration (e.g., CPU architecture, Linux distribution) to reproduce the issue?

• Yes, I have