Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Subject: BUG #19496: Assert("ItemPointerIsValid(pointer)") when using
 pageinspect
To: pgsql-bugs@lists.postgresql.org
From: PG Bug reporting form <noreply@postgresql.org>
Cc: s.lyubimov@postgrespro.ru
Reply-To: s.lyubimov@postgrespro.ru, pgsql-bugs@lists.postgresql.org
Date: Wed, 27 May 2026 05:24:37 +0000
Message-ID: <19496-3472e9cce4a93d76@postgresql.org>
Auto-Submitted: auto-generated
Archived-At: 
 <https://www.postgresql.org/message-id/19496-3472e9cce4a93d76%40postgresql.org>
Precedence: bulk

The following bug has been logged on the website:

Bug reference:      19496
Logged by:          Sergey Lyubimov
Email address:      s.lyubimov@postgrespro.ru
PostgreSQL version: 18.4
Operating system:   Ubuntu 24.04
Description:       =20

Hi,
I found an assertion failure in pageinspect.

SQL:
CREATE EXTENSION IF NOT EXISTS pageinspect;
WITH page AS (
    SELECT set_byte(
             set_byte(
               set_byte(
                 set_byte(
                   set_byte(
                     set_byte(
                       set_byte(
                         set_byte(decode(repeat('00', 8192), 'hex'),
                                  12, 40),
                         14, 248),
                       15, 31),
                     16, 248),
                   17, 31),
                 18, 4),
               19, 32),
             8190, 131) AS p
  )
  SELECT * FROM gin_leafpage_items((SELECT p FROM page));

Backtrace:
#0  __pthread_kill_implementation (no_tid=3D0, signo=3D6, threadid=3D<optim=
ized
out>) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=3D6, threadid=3D<optimized out>) at
./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=3D<optimized out>, signo=3Dsigno@entry=3D=
6) at
./nptl/pthread_kill.c:89
#3  0x000076adb2a4527e in __GI_raise (sig=3Dsig@entry=3D6) at
../sysdeps/posix/raise.c:26
#4  0x000076adb2a288ff in __GI_abort () at ./stdlib/abort.c:79
#5  0x00005e7e26d0ccac in ExceptionalCondition
(conditionName=3DconditionName@entry=3D0x5e7e26d76143
"ItemPointerIsValid(pointer)", fileName=3DfileName@entry=3D0x5e7e26db1c58
"../../../../src/include/storage/itemptr.h",
lineNumber=3DlineNumber@entry=3D126) at assert.c:65
#6  0x00005e7e267a0dd8 in ItemPointerGetOffsetNumber
(pointer=3D0x5e7e377646b8) at ../../../../src/include/storage/itemptr.h:126
#7  ItemPointerGetOffsetNumber (pointer=3D0x5e7e377646b8) at
../../../../src/include/storage/itemptr.h:124
#8  ginPostingListDecodeAllSegments (segment=3D<optimized out>,
segment@entry=3D0x5e7e377646b8, len=3D<optimized out>,
ndecoded_out=3Dndecoded_out@entry=3D0x7ffd3fe41100) at ginpostinglist.c:324
#9  0x00005e7e267a100b in ginPostingListDecode
(plist=3Dplist@entry=3D0x5e7e377646b8,
ndecoded_out=3Dndecoded_out@entry=3D0x7ffd3fe41100) at ginpostinglist.c:286
#10 0x000076adb35630ed in gin_leafpage_items (fcinfo=3D0x5e7e3775e6c0) at
ginfuncs.c:264
#11 0x00005e7e2699309d in ExecMakeTableFunctionResult
(setexpr=3D0x5e7e3772e7f0, econtext=3D0x5e7e3772e690, argContext=3D<optimiz=
ed
out>, expectedDesc=3D0x5e7e3772f240, randomAccess=3Dfalse) at execSRF.c:235
#12 0x00005e7e269a7d7d in FunctionNext (node=3D0x5e7e3772e480) at
nodeFunctionscan.c:95
#13 0x00005e7e26987a2b in ExecProcNode (node=3D0x5e7e3772e480) at
../../../src/include/executor/executor.h:327
#14 ExecutePlan (queryDesc=3D0x5e7e3762f480, operation=3DCMD_SELECT,
sendTuples=3Dtrue, numberTuples=3D0, direction=3D<optimized out>,
dest=3D0x5e7e3775b778) at execMain.c:1736
#15 standard_ExecutorRun (queryDesc=3D0x5e7e3762f480, direction=3D<optimized
out>, count=3D0) at execMain.c:377
#16 0x00005e7e26ba1c58 in PortalRunSelect
(portal=3Dportal@entry=3D0x5e7e376a55f0, forward=3Dforward@entry=3Dtrue, co=
unt=3D0,
count@entry=3D9223372036854775807, dest=3Ddest@entry=3D0x5e7e3775b778) at
pquery.c:917
#17 0x00005e7e26ba3316 in PortalRun (portal=3Dportal@entry=3D0x5e7e376a55f0,
count=3Dcount@entry=3D9223372036854775807, isTopLevel=3DisTopLevel@entry=3D=
true,
dest=3Ddest@entry=3D0x5e7e3775b778, altdest=3Daltdest@entry=3D0x5e7e3775b77=
8,
qc=3Dqc@entry=3D0x7ffd3fe41500) at pquery.c:761
#18 0x00005e7e26b9eeaa in exec_simple_query (
    query_string=3D0x5e7e37602450 "WITH page AS (\n    SELECT set_byte(\n",=
 '
' <repeats 13 times>, "set_byte(\n", ' ' <repeats 15 times>, "set_byte(\n",
' ' <repeats 17 times>, "set_byte(\n", ' ' <repeats 19 times>,
"set_byte(\n", ' ' <repeats 21 times>, "set_byte(\n", ' ' <repeats 23
times>, "set_by"...) at postgres.c:1290
#19 0x00005e7e26ba0aa4 in PostgresMain (dbname=3D<optimized out>,
username=3D<optimized out>) at postgres.c:4856
#20 0x00005e7e26b9aa53 in BackendMain (startup_data=3D<optimized out>,
startup_data_len=3D<optimized out>) at backend_startup.c:124
#21 0x00005e7e26ad6371 in postmaster_child_launch (child_type=3D<optimized
out>, child_slot=3D1, startup_data=3Dstartup_data@entry=3D0x7ffd3fe419b0,
startup_data_len=3Dstartup_data_len@entry=3D24,
client_sock=3Dclient_sock@entry=3D0x7ffd3fe419d0) at launch_backend.c:268
#22 0x00005e7e26ada052 in BackendStartup (client_sock=3D0x7ffd3fe419d0) at
postmaster.c:3627
#23 ServerLoop () at postmaster.c:1728
#24 0x00005e7e26adbbc2 in PostmasterMain (argc=3Dargc@entry=3D3,
argv=3Dargv@entry=3D0x5e7e375fc0b0) at postmaster.c:1415
#25 0x00005e7e2677232e in main (argc=3D3, argv=3D0x5e7e375fc0b0) at main.c:=
231

logfile:
TRAP: failed Assert("ItemPointerIsValid(pointer)"), File:
"../../../../src/include/storage/itemptr.h", Line: 126, PID: 1668693
postgres: packer postgres [local]
SELECT(ExceptionalCondition+0x6d)[0x5d3ea15c813d]
postgres: packer postgres [local]
SELECT(ginPostingListDecodeAllSegments+0x1d8)[0x5d3ea10ac398]

Branch: REL_18_STABLE (commit: 196b4b5)
GCC version: 14.2.0

CONFIGURE =3D  '--enable-debug' '--enable-cassert'

postgres=3D# SELECT version();
                                                  version
---------------------------------------------------------------------------=
---------------------------------
 PostgreSQL 18.4 on x86_64-pc-linux-gnu, compiled by gcc-14 (Ubuntu
14.2.0-4ubuntu2~24.04.1) 14.2.0, 64-bit