Thread: pg15 inherited stats expressions: cache lookup failed for statistics object

postgres=# \set QUIET 
CREATE TABLE stxdinp (i int, j int) PARTITION BY RANGE(i);
CREATE TABLE stxdinp1 PARTITION OF stxdinp FOR VALUES FROM (1)TO(10);
INSERT INTO stxdinp SELECT generate_series(1,9)a;
CREATE STATISTICS stxdp ON i,j FROM stxdinp;
ANALYZE stxdinp;
explain SELECT i, j, COUNT(1) FROM ONLY stxdinp GROUP BY 1,2;
ERROR:  cache lookup failed for statistics object 4060843

It's evidently an issue with 269b532ae (Add stxdinherit flag to
pg_statistic_ext_data)

(gdb) bt
#0  pg_re_throw () at elog.c:1795
#1  0x000000000096578a in errfinish (filename=<optimized out>, filename@entry=0xaf0442 "extended_stats.c",
lineno=lineno@entry=2467,funcname=funcname@entry=0xaf0720 <__func__.28166> "statext_expressions_load") at elog.c:588
 
#2  0x00000000007efd07 in statext_expressions_load (stxoid=3914359, inh=<optimized out>, idx=idx@entry=0) at
extended_stats.c:2467
#3  0x0000000000913947 in examine_variable (root=root@entry=0x2b5b530, node=node@entry=0x2b88820,
varRelid=varRelid@entry=7,vardata=vardata@entry=0x7ffe5baa2f00) at selfuncs.c:5264
 
#4  0x00000000009141ae in get_restriction_variable (root=root@entry=0x2b5b530, args=args@entry=0x2b88a30,
varRelid=varRelid@entry=7,vardata=vardata@entry=0x7ffe5baa2f90, other=other@entry=0x7ffe5baa2f88, 
 
    varonleft=varonleft@entry=0x7ffe5baa2f87) at selfuncs.c:4848
#5  0x0000000000915535 in eqsel_internal (fcinfo=<optimized out>, negate=negate@entry=false) at selfuncs.c:263
#6  0x00000000009155f6 in eqsel (fcinfo=<optimized out>) at selfuncs.c:226
#7  0x000000000096a373 in FunctionCall4Coll (flinfo=flinfo@entry=0x7ffe5baa3090, collation=collation@entry=0,
arg1=arg1@entry=45462832,arg2=arg2@entry=1320, arg3=arg3@entry=45648432, arg4=arg4@entry=7) at fmgr.c:1198
 
#8  0x000000000096a92a in OidFunctionCall4Coll (functionId=<optimized out>, collation=collation@entry=0,
arg1=arg1@entry=45462832,arg2=arg2@entry=1320, arg3=arg3@entry=45648432, arg4=arg4@entry=7) at fmgr.c:1434
 
#9  0x000000000077e759 in restriction_selectivity (root=root@entry=0x2b5b530, operatorid=operatorid@entry=1320,
args=0x2b88a30,inputcollid=0, varRelid=varRelid@entry=7) at plancat.c:1880
 
#10 0x0000000000728dc9 in clause_selectivity_ext (root=root@entry=0x2b5b530, clause=0x2b889d8, clause@entry=0x2b86e88,
varRelid=varRelid@entry=7,jointype=jointype@entry=JOIN_INNER, sjinfo=sjinfo@entry=0x0, 
 
    use_extended_stats=use_extended_stats@entry=true) at clausesel.c:875
#11 0x00000000007291b6 in clauselist_selectivity_ext (root=root@entry=0x2b5b530, clauses=0x2b88fc0, varRelid=7,
jointype=jointype@entry=JOIN_INNER,sjinfo=sjinfo@entry=0x0, use_extended_stats=use_extended_stats@entry=true)
 
    at clausesel.c:185
#12 0x000000000072962e in clauselist_selectivity (root=root@entry=0x2b5b530, clauses=<optimized out>,
varRelid=<optimizedout>, jointype=jointype@entry=JOIN_INNER, sjinfo=sjinfo@entry=0x0) at clausesel.c:108
 
#13 0x000000000072fb1d in get_parameterized_baserel_size (root=root@entry=0x2b5b530, rel=rel@entry=0x2b73900,
param_clauses=param_clauses@entry=0x2b88f68)at costsize.c:5015
 
#14 0x00000000007836f6 in get_baserel_parampathinfo (root=root@entry=0x2b5b530, baserel=baserel@entry=0x2b73900,
required_outer=required_outer@entry=0x2b86478)at relnode.c:1346
 
#15 0x0000000000776819 in create_seqscan_path (root=root@entry=0x2b5b530, rel=rel@entry=0x2b73900,
required_outer=required_outer@entry=0x2b86478,parallel_workers=parallel_workers@entry=0) at pathnode.c:937
 
#16 0x000000000077a32c in reparameterize_path (root=root@entry=0x2b5b530, path=path@entry=0x2b847b0,
required_outer=required_outer@entry=0x2b86478,loop_count=loop_count@entry=1) at pathnode.c:3872
 
#17 0x00000000007249bc in get_cheapest_parameterized_child_path (root=root@entry=0x2b5b530, rel=<optimized out>,
required_outer=required_outer@entry=0x2b86478)at allpaths.c:1996
 
#18 0x0000000000727619 in add_paths_to_append_rel (root=root@entry=0x2b5b530, rel=rel@entry=0x2b6a6a8,
live_childrels=live_childrels@entry=0x2b858e8)at allpaths.c:1597
 
#19 0x0000000000728084 in set_append_rel_pathlist (root=root@entry=0x2b5b530, rel=rel@entry=0x2b6a6a8, rti=rti@entry=6,
rte=rte@entry=0x2b5e1c0)at allpaths.c:1270
 
#20 0x0000000000727e17 in set_rel_pathlist (root=root@entry=0x2b5b530, rel=0x2b6a6a8, rti=rti@entry=6, rte=0x2b5e1c0)
atallpaths.c:483
 
#21 0x0000000000727f8a in set_base_rel_pathlists (root=root@entry=0x2b5b530) at allpaths.c:355
#22 0x00000000007286fd in make_one_rel (root=root@entry=0x2b5b530, joinlist=joinlist@entry=0x2b6fd98) at
allpaths.c:225
#23 0x00000000007512d5 in query_planner (root=root@entry=0x2b5b530, qp_callback=qp_callback@entry=0x75300a
<standard_qp_callback>,qp_extra=qp_extra@entry=0x7ffe5baa3670) at planmain.c:276
 
#24 0x00000000007589ec in grouping_planner (root=root@entry=0x2b5b530, tuple_fraction=<optimized out>,
tuple_fraction@entry=0)at planner.c:1467
 
#25 0x000000000075a5f2 in subquery_planner (glob=<optimized out>, parse=parse@entry=0x2b23c08,
parent_root=parent_root@entry=0x2736768,hasRecursion=hasRecursion@entry=false, tuple_fraction=<optimized out>) at
planner.c:1044
#26 0x0000000000726567 in set_subquery_pathlist (root=root@entry=0x2736768, rel=rel@entry=0x2755f30, rti=rti@entry=6,
rte=rte@entry=0x28c9980)at allpaths.c:2589
 
#27 0x000000000072681c in set_rel_size (root=root@entry=0x2736768, rel=rel@entry=0x2755f30, rti=rti@entry=6,
rte=rte@entry=0x28c9980)at allpaths.c:425
 
#28 0x0000000000726996 in set_base_rel_sizes (root=root@entry=0x2736768) at allpaths.c:326
#29 0x0000000000728663 in make_one_rel (root=root@entry=0x2736768, joinlist=joinlist@entry=0x274d038) at
allpaths.c:188
#30 0x00000000007512d5 in query_planner (root=root@entry=0x2736768, qp_callback=qp_callback@entry=0x75300a
<standard_qp_callback>,qp_extra=qp_extra@entry=0x7ffe5baa39d0) at planmain.c:276
 
#31 0x00000000007589ec in grouping_planner (root=root@entry=0x2736768, tuple_fraction=<optimized out>,
tuple_fraction@entry=0)at planner.c:1467
 
#32 0x000000000075a5f2 in subquery_planner (glob=glob@entry=0x2483430, parse=parse@entry=0x289c7c8,
parent_root=parent_root@entry=0x0,hasRecursion=hasRecursion@entry=false, tuple_fraction=tuple_fraction@entry=0)
 
    at planner.c:1044

I think this is what's needed.

diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 14e0885f19f..4450f0d682f 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -5240,6 +5240,8 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
             /* skip stats without per-expression stats */
             if (info->kind != STATS_EXT_EXPRESSIONS)
                 continue;
+            if (info->inherit != rte->inh)
+                continue;
 
             pos = 0;
             foreach(expr_item, info->exprs)

On Mon, Oct 31, 2022 at 01:12:09PM +0800, Richard Guo wrote:
> BTW, I noticed a micro-optimization opportunity in examine_variable that
> we can fetch the RangeTblEntry for 'onerel' outside the foreach loop
> when iterating the extended stats so that we can do it only once rather
> than for each stat.

Isn't that the kind of thing where we'd better have some regression
coverage?
--
Michael

On Tue, Nov 01, 2022 at 05:33:24PM +0800, Richard Guo wrote:
> On Mon, Oct 31, 2022 at 1:33 PM Michael Paquier <michael@paquier.xyz> wrote:
> 
> > On Mon, Oct 31, 2022 at 01:12:09PM +0800, Richard Guo wrote:
> > > BTW, I noticed a micro-optimization opportunity in examine_variable that
> > > we can fetch the RangeTblEntry for 'onerel' outside the foreach loop
> > > when iterating the extended stats so that we can do it only once rather
> > > than for each stat.
> >
> > Isn't that the kind of thing where we'd better have some regression
> > coverage?
> 
> Yeah, we need to have some regression tests for that.  I come up with a
> case in stats_ext like below

Well done

> This case should be able to cover both expression stats and ndistinct
> stats.  Hence, attach v2 patch.

Thanks for finishing it up.

I added a CF entry and marked RFC.
This should be included in v15.1.

-- 
Justin

Justin Pryzby <pryzby@telsasoft.com> writes:
> I added a CF entry and marked RFC.
> This should be included in v15.1.

Right, done.

            regards, tom lane

On Tue, Nov 01, 2022 at 02:35:43PM -0400, Tom Lane wrote:
> Justin Pryzby <pryzby@telsasoft.com> writes:
> > I added a CF entry and marked RFC.
> > This should be included in v15.1.
> 
> Right, done.

Thanks.  Yesterday, I realized that the bug was exposed here after we
accidentally recreated a table as relkind=r rather than relkind=p...

-- 
Justin