Re: BUG #19700: PostgreSQL: an SP-GiST index on `inet` makes IPv6 rows invisible

On Mon, 21 Sept 2026 at 11:05, Kirill Reshke <reshkekirill(at)gmail(dot)com> wrote:

> With this (obvious?) diff issue disappears:
>
> reshke(at)reshke:~/postgres$ git diff src/backend/utils/adt/network_spgist.c
> diff --git a/src/backend/utils/adt/network_spgist.c
> b/src/backend/utils/adt/network_spgist.c
> index 52e3c666d4f..1cd065f57c4 100644
> --- a/src/backend/utils/adt/network_spgist.c
> +++ b/src/backend/utils/adt/network_spgist.c
> @@ -191,9 +191,8 @@ inet_spg_picksplit(PG_FUNCTION_ARGS)
>
> if (ip_bits(tmp) < commonbits)
> commonbits = ip_bits(tmp);
> - commonbits = bitncommon(ip_addr(prefix), ip_addr(tmp),
> commonbits);
> - if (commonbits == 0)
> - break;
> + if (commonbits != 0)
> + commonbits = bitncommon(ip_addr(prefix),
> ip_addr(tmp), commonbits);
> }
>
> /* Don't need labels; allocate output arrays */
>
> --
> Best regards,
> Kirill Reshke

This hits assert
/* allTheSame isn't possible for such a tuple */
Assert(!in->allTheSame);

```
Program received signal SIGABRT, Aborted.
0x00007f54fe69eb2c in pthread_kill () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0 0x00007f54fe69eb2c in pthread_kill () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007f54fe64527e in raise () from /lib/x86_64-linux-gnu/libc.so.6
#2 0x00007f54fe6288ff in abort () from /lib/x86_64-linux-gnu/libc.so.6
#3 0x0000563787e6093f in ExceptionalCondition
(conditionName=conditionName(at)entry=0x563787ef0ff8 "!in->allTheSame",
fileName=fileName(at)entry=0x563787ef0fe7 "network_spgist.c",
lineNumber=lineNumber(at)entry=85) at assert.c:65
#4 0x0000563787db5fb2 in inet_spg_choose (fcinfo=<optimized out>) at
network_spgist.c:85
#5 0x0000563787e6b46e in FunctionCall2Coll
(flinfo=flinfo(at)entry=0x5637c16b8bb0, collation=<optimized out>,
arg1=arg1(at)entry=140721627228416, arg2=arg2(at)entry=140721627228464) at
fmgr.c:1163
#6 0x000056378797be95 in spgdoinsert
(index=index(at)entry=0x7f54fe996898, state=state(at)entry=0x7ffc4e9a6af0,
heapPtr=heapPtr(at)entry=0x5637c16b7908,
datums=datums(at)entry=0x7ffc4e9a6c80,
isnulls=isnulls(at)entry=0x7ffc4e9a6c60) at spgdoinsert.c:2188
#7 0x000056378797e087 in spginsert (index=0x7f54fe996898,
values=0x7ffc4e9a6c80, isnull=0x7ffc4e9a6c60, ht_ctid=0x5637c16b7908,
heapRel=<optimized out>, checkUnique=<optimized out>,
indexUnchanged=false, indexInfo=0x5637c16b8470) at spginsert.c:206
#8 0x0000563787ae42cd in ExecInsertIndexTuples
(resultRelInfo=resultRelInfo(at)entry=0x5637c16b6c30,
estate=estate(at)entry=0x5637c16b66e0, flags=flags(at)entry=0,
slot=slot(at)entry=0x5637c16b78d0,
arbiterIndexes=arbiterIndexes(at)entry=0x0,
specConflict=specConflict(at)entry=0x0) at execIndexing.c:449
#9 0x0000563787b1aafd in ExecInsert
(context=context(at)entry=0x7ffc4e9a6f00,
resultRelInfo=resultRelInfo(at)entry=0x5637c16b6c30,
slot=slot(at)entry=0x5637c16b78d0, canSetTag=<optimized out>,
inserted_tuple=inserted_tuple(at)entry=0x0,
insert_destrel=insert_destrel(at)entry=0x0) at nodeModifyTable.c:1272
#10 0x0000563787b1c457 in ExecModifyTable (pstate=0x5637c16b6a20) at
nodeModifyTable.c:4712
#11 0x0000563787ae503b in ExecProcNode (node=0x5637c16b6a20) at
../../../src/include/executor/executor.h:327
#12 ExecutePlan (dest=0x5637c176e3f0, direction=<optimized out>,
numberTuples=0, sendTuples=false, operation=CMD_INSERT,
queryDesc=0x5637c16b5af0) at execMain.c:1766
#13 standard_ExecutorRun (queryDesc=0x5637c16b5af0,
direction=<optimized out>, count=0) at execMain.c:377
#14 0x0000563787cf9f7b in ProcessQuery (plan=<optimized out>,
sourceText=0x5637c168c960 "INSERT INTO inet19700 VALUES ('8000::1');",
params=0x0, queryEnv=0x0, dest=0x5637c176e3f0, qc=0x7ffc4e9a7240)
at pquery.c:162
#15 0x0000563787cfabae in PortalRunMulti
(portal=portal(at)entry=0x5637c17121f0, isTopLevel=isTopLevel(at)entry=true,
setHoldSnapshot=setHoldSnapshot(at)entry=false,
dest=dest(at)entry=0x5637c176e3f0,
altdest=altdest(at)entry=0x5637c176e3f0, qc=qc(at)entry=0x7ffc4e9a7240)
at pquery.c:1269
#16 0x0000563787cfafd2 in PortalRun
(portal=portal(at)entry=0x5637c17121f0,
count=count(at)entry=9223372036854775807,
isTopLevel=isTopLevel(at)entry=true, dest=dest(at)entry=0x5637c176e3f0,
altdest=altdest(at)entry=0x5637c176e3f0, qc=qc(at)entry=0x7ffc4e9a7240)
at pquery.c:784
#17 0x0000563787cf6b1d in exec_simple_query
(query_string=0x5637c168c960 "INSERT INTO inet19700 VALUES
('8000::1');") at postgres.c:1297
#18 0x0000563787cf87c6 in PostgresMain (dbname=<optimized out>,
username=<optimized out>) at postgres.c:4946
#19 0x0000563787cf2673 in BackendMain (startup_data=<optimized out>,
startup_data_len=<optimized out>) at backend_startup.c:124
#20 0x0000563787c30021 in postmaster_child_launch
(child_type=<optimized out>, child_slot=2,
startup_data=startup_data(at)entry=0x7ffc4e9a7710,
startup_data_len=startup_data_len(at)entry=24,
client_sock=client_sock(at)entry=0x7ffc4e9a7730) at launch_backend.c:268
#21 0x0000563787c33cb2 in BackendStartup (client_sock=0x7ffc4e9a7730)
at postmaster.c:3640
#22 ServerLoop () at postmaster.c:1727
#23 0x0000563787c358ad in PostmasterMain (argc=argc(at)entry=3,
argv=argv(at)entry=0x5637c16861b0) at postmaster.c:1414
#24 0x00005637878d850e in main (argc=3, argv=0x5637c16861b0) at main.c:227
(gdb)

```

repro is alike [0]

CREATE TABLE inet19700 (c inet);
CREATE INDEX inet19700_idx ON inet19700 USING spgist (c inet_ops);

INSERT INTO inet19700 SELECT '10.0.0.1' FROM generate_series(1, 290);

-- TRAP: FailedAssertion("!in->allTheSame")
INSERT INTO inet19700 VALUES ('8000::1');

So, I updated inet_spg_choose to support the 'allTheSame' case. While
inserting, simply redirect to the first node.
inet_spg_inner_consistent needs the same fix (otherwise index scans
would hit the same assertion.)

[0] https://www.postgresql.org/message-id/flat/537BE1A9(dot)1050006(at)sigaev(dot)ru

--
Best regards,
Kirill Reshke