BUG #18866: Running pg_freespace() on views triggers an Abort

The following bug has been logged on the website:

Bug reference: 18866
Logged by: Robins Tharakan
Email address: tharakan(at)gmail(dot)com
PostgreSQL version: Unsupported/Unknown
Operating system: Ubuntu
Description:

Hi,

Passing a view to pg_freespace() triggers an Abort on HEAD. This has been so
since the beginning (049ef3398d05c9dc8f48aa9a6d68440661cfeb87). Given that
this is just an assert, feel free to skip - but thought I'd bring it up, in
case this needs a review.

SQL / Backtrace / Error Log excerpt given below:

SQL
===
$ cat crashing.sql
CREATE EXTENSION pg_freespacemap;
SELECT pg_freespace('pg_roles', 0);

SQL Output
==========
$ psql -f crashing.sql
CREATE EXTENSION
psql:crashing.sql:2: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
psql:crashing.sql:2: error: connection to server was lost

Backtrace
=========
#5 0x00005b073976f7e0 in ExceptionalCondition (conditionName=0x5b07399bb930
"RelFileNumberIsValid(rlocator.relNumber)", fileName=0x5b07399bb90c
"smgr.c", lineNumber=228)
at assert.c:66
No locals.
#6 0x00005b0739556b62 in smgropen (rlocator=..., backend=-1) at
smgr.c:228
brlocator = {locator = {spcOid = 1101590320, dbOid = 23303,
relNumber = 1615569600}, backend = 31264}
reln = 0x5b0741ab40a8
found = 65
#7 0x00005b07395163cb in RelationGetSmgr (rel=0x7a2060b99bf8) at
../../../../src/include/utils/rel.h:579
No locals.
#8 0x00005b0739516dc2 in fsm_readbuf (rel=0x7a2060b99bf8, addr=...,
extend=false) at freespace.c:558
blkno = 2
buf = -998073056
reln = 0x0
#9 0x00005b0739516705 in GetRecordedFreeSpace (rel=0x7a2060b99bf8,
heapBlk=0) at freespace.c:254
addr = {level = 0, logpageno = 0}
slot = 0
buf = 23303
cat = 22 '\026'
#10 0x00007a2061ab630c in pg_freespace (fcinfo=0x5b0741b07928) at
pg_freespacemap.c:38
relid = 12000
blkno = 0
freespace = -17281
rel = 0x7a2060b99bf8
__func__ = "pg_freespace"
#11 0x00005b0739259dc4 in ExecInterpExpr (state=0x5b0741b077d0,
econtext=0x5b0741b074b8, isnull=0x0) at execExprInterp.c:1001
d = 100086724982736
fcinfo = 0x5b0741b07928
args = 0x5b0741b07948
op = 0x5b0741b07b50
resultslot = 0x5b0741b07708
innerslot = 0x0
outerslot = 0x0
scanslot = 0x0
oldslot = 0x0
newslot = 0x0

Surfacing Commit
================
Checking (62f36d6924c~0) - 62f36d6924 - fail
Checking (62f36d6924c~10) - 023fb51275 - fail
Checking (62f36d6924c~30) - e215166c9c - fail
.
.
.
Checking (62f36d6924c~3560) - b31ba5310b - fail
Checking (62f36d6924c~3565) - e5b8c4f68f - pass
Checking (62f36d6924c~3562) - 049ef3398d - fail
Checking (62f36d6924c~3563) - cd7f19da34 - pass
Surfacing commit is 049ef3398d05c9dc8f48aa9a6d68440661cfeb87

Postgres Error Logs
===================
TRAP: failed Assert("RelFileNumberIsValid(rlocator.relNumber)"), File:
"smgr.c", Line: 228, PID: 2372149
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(ExceptionalCondition+0xbb)[0x5b073976f7ad]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(smgropen+0x5e)[0x5b0739556b62]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x6b83cb)[0x5b07395163cb]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x6b8dc2)[0x5b0739516dc2]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(GetRecordedFreeSpace+0x50)[0x5b0739516705]
/home/smith/proj/blamepg/lib/postgresql/pg_freespacemap.so(pg_freespace+0xc4)[0x7a2061ab730c]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x3fbdc4)[0x5b0739259dc4]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(ExecInterpExprStillValid+0x5b)[0x5b073925c94a]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x461f27)[0x5b07392bff27]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x461fe5)[0x5b07392bffe5]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x462046)[0x5b07392c0046]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x462269)[0x5b07392c0269]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x418aba)[0x5b0739276aba]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x40aeaf)[0x5b0739268eaf]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x40df9e)[0x5b073926bf9e]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(standard_ExecutorRun+0x1cc)[0x5b07392696eb]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(ExecutorRun+0x54)[0x5b073926951c]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x707af2)[0x5b0739565af2]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(PortalRun+0x274)[0x5b0739565720]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x6ffc69)[0x5b073955dc69]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(PostgresMain+0xb8d)[0x5b0739563461]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x6fafe7)[0x5b0739558fe7]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(postmaster_child_launch+0x174)[0x5b073945cac4]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x605664)[0x5b0739463664]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(+0x602a7e)[0x5b0739460a7e]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(PostmasterMain+0x1546)[0x5b0739460374]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(main+0x38c)[0x5b07392ff7db]
/lib/x86_64-linux-gnu/libc.so.6(+0x2a1ca)[0x7a206042a1ca]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x8b)[0x7a206042a28b]
postgres: smith: smith postgres 127.0.0.1(51026)
SELECT(_start+0x25)[0x5b0738f43eb5]
2025-03-25 21:32:25.437 ACDT [2372118] LOG: client backend (PID 2372149)
was terminated by signal 6: Aborted
2025-03-25 21:32:25.437 ACDT [2372118] DETAIL: Failed process was running:
SELECT public.pg_freespace('pg_roles', 0);
2025-03-25 21:32:25.437 ACDT [2372118] LOG: terminating any other active
server processes

Thanks to SQLSmith / SQLReduce.
-
Robins