Re: Small query using LATERAL that segfaults Postgres

po 13. 7. 2020 v 20:06 odesílatel Tom Ellis <
tom-lists-postgresql(dot)org(at)jaguarpaw(dot)co(dot)uk> napsal:

> This small query seems to segfault Postgres. I've tried on the
> version of Postgres 11 that comes with Debian Stable and all versions
> on https://www.db-fiddle.com/ including 13 (Beta). DB Fiddle actually
> says "An unexpected error occurred." but I suspect that's the
> segfault.
>
> Tom
>
>
> SELECT
> 0
> FROM (SELECT
> TRUE as "r",
> SUM(0)
> ) as "T1",
> LATERAL
> (SELECT TRUE as "b"
> UNION ALL
> SELECT
> "r" as "b"
> FROM (SELECT 0 ORDER BY COALESCE(0)) as "T1"
> ) as "T2"
> WHERE "b"
>
>
here is stacktrace

Program received signal SIGABRT, Aborted.
0x00007f269e6e9a25 in raise () from /lib64/libc.so.6
Missing separate debuginfos, use: dnf debuginfo-install
libgcc-10.1.1-1.fc32.x86_64
(gdb) bt
#0 0x00007f269e6e9a25 in raise () from /lib64/libc.so.6
#1 0x00007f269e6d2895 in abort () from /lib64/libc.so.6
#2 0x000000000090340b in ExceptionalCondition
(conditionName=conditionName(at)entry=0xa55fef "var->varno == rti",
errorType=errorType(at)entry=0x959029 "FailedAssertion",
fileName=fileName(at)entry=0xa55f10 "allpaths.c",
lineNumber=lineNumber(at)entry=3532) at assert.c:67
#3 0x00000000006e3041 in qual_is_pushdown_safe (subquery=0x2b7cc40,
safetyInfo=0x7ffcc3355530, qual=0x2b7a998, rti=6)
at allpaths.c:3532
#4 set_subquery_pathlist (rte=0x2b77258, rti=<optimized out>,
rel=0x2b7a5e0, root=0x2b6fdb0) at allpaths.c:2262
#5 set_rel_size (root=root(at)entry=0x2b6fdb0, rel=rel(at)entry=0x2b7a5e0,
rti=rti(at)entry=6, rte=rte(at)entry=0x2b77258) at allpaths.c:422
#6 0x00000000006e2101 in set_append_rel_size (rte=0x2b77258, rti=2,
rel=0x2b6e850, root=0x2b798a0) at allpaths.c:1111
#7 set_rel_size (root=root(at)entry=0x2b6fdb0, rel=rel(at)entry=0x2b6e850,
rti=rti(at)entry=2, rte=rte(at)entry=0x2b68098) at allpaths.c:383
#8 0x00000000006e4ea0 in set_base_rel_sizes (root=<optimized out>) at
allpaths.c:323
#9 make_one_rel (root=root(at)entry=0x2b6fdb0, joinlist=joinlist(at)entry=0x2b79f08)
at allpaths.c:185
#10 0x0000000000709b69 in query_planner (root=root(at)entry=0x2b6fdb0,
qp_callback=qp_callback(at)entry=0x70a240 <standard_qp_callback>,
qp_extra=qp_extra(at)entry=0x7ffcc33557a0) at planmain.c:269
#11 0x000000000070edfb in grouping_planner (root=<optimized out>,
inheritance_update=false, tuple_fraction=<optimized out>)
at planner.c:2058
#12 0x0000000000711907 in subquery_planner (glob=glob(at)entry=0x2b67ac8,
parse=parse(at)entry=0x2b67be0,
parent_root=parent_root(at)entry=0x0, hasRecursion=hasRecursion(at)entry=false,
tuple_fraction=tuple_fraction(at)entry=0)
at planner.c:1015
#13 0x0000000000712cbb in standard_planner (parse=0x2b67be0,
query_string=<optimized out>, cursorOptions=256,
boundParams=<optimized out>) at planner.c:405
#14 0x00000000007dd4a8 in pg_plan_query (querytree=0x2b67be0,
query_string=query_string(at)entry=0x2aa23f0 "SELECT\n0\nFROM (SELECT\n
TRUE as \"r\",\n SUM(0)\n ) as \"T1\",\nLATERAL\n(SELECT TRUE
as \"b\"\n UNION ALL\n SELECT\n \"r\" as \"b\"\n
FROM (SELECT 0 ORDER BY COALESCE(0)) as \""...,
cursorOptions=cursorOptions(at)entry=256, boundParams=boundParams(at)entry=0x0)
at postgres.c:875
#15 0x00000000007dd5a1 in pg_plan_queries (querytrees=0x2b6fd58,
query_string=query_string(at)entry=0x2aa23f0 "SELECT\n0\nFROM (SELECT\n
TRUE as \"r\",\n SUM(0)\n ) as \"T1\",\nLATERAL\n(SELECT TRUE
as \"b\"\n UNION ALL\n SELECT\n \"r\" as \"b\"\n
FROM (SELECT 0 ORDER BY COALESCE(0)) as \""...,
cursorOptions=cursorOptions(at)entry=256, boundParams=boundParams(at)entry=0x0)
at postgres.c:966
#16 0x00000000007dd8f8 in exec_simple_query (
query_string=0x2aa23f0 "SELECT\n0\nFROM (SELECT\n TRUE as \"r\",\n
SUM(0)\n ) as \"T1\",\nLATERAL\n(SELECT TRUE as \"b\"\n
UNION ALL\n SELECT\n \"r\" as \"b\"\n FROM (SELECT 0
ORDER BY COALESCE(0)) as \""...)
at postgres.c:1158
#17 0x00000000007df755 in PostgresMain (argc=<optimized out>,
argv=argv(at)entry=0x2ad06e8, dbname=<optimized out>,
username=<optimized out>) at postgres.c:4315
#18 0x00000000007579e9 in BackendRun (port=0x2ac6fe0) at postmaster.c:4523

Regards

Pavel