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Reject incorrect range_bounds_histograms in stats import functions

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pg_restore_attribute_stats() and pg_restore_extended_stats()
(expressions) can handle a STATISTIC_KIND_BOUNDS_HISTOGRAM value, but
did not check its shape when importing, especially regarding:
- Empty ranges.
- Unsorted elements.

These properties are respected by ANALYZE in compute_range_stats(), when
computing a histogram for a [multi]range, and by the planner when
reading the data from the stats catalogs.  The effects of importing data
with these properties depend on the compilation options:
- A assertion would be hit, if enabled.
- A non-sensical value that would make the load of the stats fail.
- A failure is hit if an empty range is loaded.

While the owner of the table or the one with MAINTAIN rights is
responsible for the stats data inserted, buggy data makes little sense
if their load is going to fail.  This commit adds a validation step to
match what compute_range_stats() expects.

This issue would be unlikely hit in practice, so no backpatch is done.

Author: Ewan Young <kdbase.hack@gmail.com>
Discussion: https://postgr.es/m/CAON2xHNM809WLR_g0ymKgU-tWxtbyH1Xvh4fqzRqy9YP2A59pg@mail.gmail.com
This commit is contained in:
Michael Paquier 2026-07-09 14:23:42 +09:00
parent c1702cb513
commit df293aed46
6 changed files with 172 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
src/backend/statistics/attribute_stats.c
View file

@ -488,7 +488,8 @@ attribute_statistics_update(FunctionCallInfo fcinfo)
atttypid, atttypmod,
&converted);
if (converted)
if (converted &&
statatt_check_bounds_histogram(stavalues))
{
statatt_set_slot(values, nulls, replaces,
STATISTIC_KIND_BOUNDS_HISTOGRAM,

2
src/backend/statistics/extended_stats_funcs.c
View file

@ -1491,7 +1491,7 @@ import_pg_statistic(Relation pgsd, JsonbContainer *cont,
extexprargname[RANGE_BOUNDS_HISTOGRAM_ELEM],
&val_ok);
if (val_ok)
if (val_ok && statatt_check_bounds_histogram(stavalues))
statatt_set_slot(values, nulls, replaces,
STATISTIC_KIND_BOUNDS_HISTOGRAM,
InvalidOid, InvalidOid,

77
src/backend/statistics/stat_utils.c
View file

@ -33,6 +33,7 @@
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/rangetypes.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/typcache.h"
@ -742,3 +743,79 @@ statatt_init_empty_tuple(Oid reloid, int16 attnum, bool inherited,
nulls[Anum_pg_statistic_stacoll1 + slotnum - 1] = false;
}
}
/*
* Check that an imported bounds histogram (STATISTIC_KIND_BOUNDS_HISTOGRAM)
* is shaped the same way ANALYZE builds it in compute_range_stats().
*
* For both range-typed and multirange-typed columns the histogram is an array
* of ranges, so we take the range type from the array's element type.
*/
bool
statatt_check_bounds_histogram(Datum arrayval)
{
ArrayType *arr = DatumGetArrayTypeP(arrayval);
Oid rngtypid = ARR_ELEMTYPE(arr);
TypeCacheEntry *typcache;
int16 elmlen;
bool elmbyval;
char elmalign;
Datum *elems;
bool *nulls;
int nelems;
RangeBound prev_lower = {0};
RangeBound prev_upper = {0};
typcache = lookup_type_cache(rngtypid, TYPECACHE_RANGE_INFO);
/*
* The element type should always be a range type here. This is
* defensive. If it isn't, the bounds histogram is never consulted by the
* range estimator, and there is nothing to verify.
*/
if (typcache->rngelemtype == NULL)
return true;
get_typlenbyvalalign(rngtypid, &elmlen, &elmbyval, &elmalign);
deconstruct_array(arr, rngtypid, elmlen, elmbyval, elmalign,
&elems, &nulls, &nelems);
for (int i = 0; i < nelems; i++)
{
RangeBound lower,
upper;
bool empty;
/*
* NULL elements are already rejected by statatt_build_stavalues() and
* array_in_safe().
*/
range_deserialize(typcache, DatumGetRangeTypeP(elems[i]),
&lower, &upper, &empty);
if (empty)
{
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("\"%s\" must not contain empty ranges",
"range_bounds_histogram")));
return false;
}
if (i > 0 &&
(range_cmp_bounds(typcache, &lower, &prev_lower) < 0 ||
range_cmp_bounds(typcache, &upper, &prev_upper) < 0))
{
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("\"%s\" must have its lower and upper bounds sorted in ascending order",
"range_bounds_histogram")));
return false;
}
prev_lower = lower;
prev_upper = upper;
}
return true;
}

2
src/include/statistics/stat_utils.h
View file

@ -58,4 +58,6 @@ extern Datum statatt_build_stavalues(const char *staname, FmgrInfo *array_in, Da
extern bool statatt_get_elem_type(Oid atttypid, char atttyptype,
Oid *elemtypid, Oid *elem_eq_opr);
extern bool statatt_check_bounds_histogram(Datum arrayval);
#endif /* STATS_UTILS_H */

56
src/test/regress/expected/stats_import.out
View file

@ -1187,6 +1187,34 @@ AND attname = 'arange';
stats_import | test | arange | f | 0.29 | 0 | 0 | | | | | | | | {399,499,Infinity} | 0.5 | {"[-1,1)","[0,4)","[1,4)","[1,100)"}
(1 row)
-- warn: range bounds histogram with unsorted elements
SELECT pg_catalog.pg_restore_attribute_stats(
'schemaname', 'stats_import',
'relname', 'test',
'attname', 'arange',
'inherited', false::boolean,
'range_bounds_histogram', '{"[50,60)","[1,2)","[90,100)","[5,6)"}'::text
);
WARNING: "range_bounds_histogram" must have its lower and upper bounds sorted in ascending order
pg_restore_attribute_stats
----------------------------
f
(1 row)
-- warn: range bounds histogram with empty range
SELECT pg_catalog.pg_restore_attribute_stats(
'schemaname', 'stats_import',
'relname', 'test',
'attname', 'arange',
'inherited', false::boolean,
'range_bounds_histogram', '{empty,"[1,2)","[3,4)"}'::text
);
WARNING: "range_bounds_histogram" must not contain empty ranges
pg_restore_attribute_stats
----------------------------
f
(1 row)
-- warn: cannot set most_common_elems for range type, rest ok
SELECT pg_catalog.pg_restore_attribute_stats(
'schemaname', 'stats_import',
@ -2358,6 +2386,34 @@ HINT: "range_length_histogram", "range_empty_frac", and "range_bounds_histogram
f
(1 row)
-- warn: range bounds histogram with unsorted elements
SELECT pg_catalog.pg_restore_extended_stats(
'schemaname', 'stats_import',
'relname', 'test_mr',
'statistics_schemaname', 'stats_import',
'statistics_name', 'test_mr_stat',
'inherited', false,
'exprs', '[{"range_length_histogram": "{10179,10189,10199}", "range_empty_frac": "0", "range_bounds_histogram": "{\"[50,60)\",\"[1,2)\",\"[90,100)\"}"}]'::jsonb);
WARNING: "range_bounds_histogram" must have its lower and upper bounds sorted in ascending order
pg_restore_extended_stats
---------------------------
f
(1 row)
-- warn: range bounds histogram with empty range
SELECT pg_catalog.pg_restore_extended_stats(
'schemaname', 'stats_import',
'relname', 'test_mr',
'statistics_schemaname', 'stats_import',
'statistics_name', 'test_mr_stat',
'inherited', false,
'exprs', '[{"range_length_histogram": "{10179,10189,10199}", "range_empty_frac": "0", "range_bounds_histogram": "{empty,\"[1,2)\",\"[3,4)\"}"}]'::jsonb);
WARNING: "range_bounds_histogram" must not contain empty ranges
pg_restore_extended_stats
---------------------------
f
(1 row)
-- ok: multirange stats
SELECT pg_catalog.pg_restore_extended_stats(
'schemaname', 'stats_import',

34
src/test/regress/sql/stats_import.sql
View file

@ -885,6 +885,24 @@ AND tablename = 'test'
AND inherited = false
AND attname = 'arange';
-- warn: range bounds histogram with unsorted elements
SELECT pg_catalog.pg_restore_attribute_stats(
'schemaname', 'stats_import',
'relname', 'test',
'attname', 'arange',
'inherited', false::boolean,
'range_bounds_histogram', '{"[50,60)","[1,2)","[90,100)","[5,6)"}'::text
);
-- warn: range bounds histogram with empty range
SELECT pg_catalog.pg_restore_attribute_stats(
'schemaname', 'stats_import',
'relname', 'test',
'attname', 'arange',
'inherited', false::boolean,
'range_bounds_histogram', '{empty,"[1,2)","[3,4)"}'::text
);
-- warn: cannot set most_common_elems for range type, rest ok
SELECT pg_catalog.pg_restore_attribute_stats(
'schemaname', 'stats_import',
@ -1696,6 +1714,22 @@ SELECT pg_catalog.pg_restore_extended_stats(
'statistics_name', 'test_mr_stat',
'inherited', false,
'exprs', '[{"range_bounds_histogram": "{\"[1,10200)\"}", "range_length_histogram": "{10179}"}]'::jsonb);
-- warn: range bounds histogram with unsorted elements
SELECT pg_catalog.pg_restore_extended_stats(
'schemaname', 'stats_import',
'relname', 'test_mr',
'statistics_schemaname', 'stats_import',
'statistics_name', 'test_mr_stat',
'inherited', false,
'exprs', '[{"range_length_histogram": "{10179,10189,10199}", "range_empty_frac": "0", "range_bounds_histogram": "{\"[50,60)\",\"[1,2)\",\"[90,100)\"}"}]'::jsonb);
-- warn: range bounds histogram with empty range
SELECT pg_catalog.pg_restore_extended_stats(
'schemaname', 'stats_import',
'relname', 'test_mr',
'statistics_schemaname', 'stats_import',
'statistics_name', 'test_mr_stat',
'inherited', false,
'exprs', '[{"range_length_histogram": "{10179,10189,10199}", "range_empty_frac": "0", "range_bounds_histogram": "{empty,\"[1,2)\",\"[3,4)\"}"}]'::jsonb);
-- ok: multirange stats
SELECT pg_catalog.pg_restore_extended_stats(