postgres.git / summary / log / commit / refs
commit d42ffda685f5dbd123df59c2f8050e8fb09164c7
Author: Tomas Vondra <tomas.vondra@postgresql.org>
Date: Thu May 18 11:00:31 2023 +0000
First released in: 16.0, 11.21, 12.16, 13.12, 14.9, 15.4
Fix handling of NULLs when merging BRIN summaries
When merging BRIN summaries, union_tuples() did not correctly update the
target hasnulls/allnulls flags. When merging all-NULL summary into a
summary without any NULL values, the result had both flags set to false
(instead of having hasnulls=true).
This happened because the code only considered the hasnulls flags,
ignoring the possibility the source summary has allnulls=true.
Discovered while investigating issues with handling empty BRIN ranges
and handling of NULL values, but it's a separate problem (has nothing to
do with empty ranges).
Fixed by considering both flags on the source summary, and updating the
hasnulls flag on the target summary.
Backpatch to 11. The bug exists since 9.5 (where BRIN indexes were
introduced), but those releases are EOL already.
Discussion: https://postgr.es/m/9d993d0d-e431-2196-9ccc-0554d0e60154%40enterprisedb.com
src/backend/access/brin/brin_inclusion.c | 10 +++++++++-
src/backend/access/brin/brin_minmax.c | 10 +++++++++-
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/src/backend/access/brin/brin_inclusion.c b/src/backend/access/brin/brin_inclusion.c
index 9d7cb36a47a..75195ce23bd 100644
--- a/src/backend/access/brin/brin_inclusion.c
+++ b/src/backend/access/brin/brin_inclusion.c
@@ -515,10 +515,13 @@ brin_inclusion_union(PG_FUNCTION_ARGS)
FmgrInfo *finfo;
Datum result;
+ /* Does the "b" summary represent any NULL values? */
+ bool b_has_nulls = (col_b->bv_hasnulls || col_b->bv_allnulls);
+
Assert(col_a->bv_attno == col_b->bv_attno);
/* Adjust "hasnulls". */
- if (!col_a->bv_hasnulls && col_b->bv_hasnulls)
+ if (!col_a->bv_allnulls && b_has_nulls)
col_a->bv_hasnulls = true;
/* If there are no values in B, there's nothing left to do. */
@@ -533,10 +536,15 @@ brin_inclusion_union(PG_FUNCTION_ARGS)
* B into A, and we're done. We cannot run the operators in this case,
* because values in A might contain garbage. Note we already established
* that B contains values.
+ *
+ * Also adjust "hasnulls" in order not to forget the summary represents NULL
+ * values. This is not redundant with the earlier update, because that only
+ * happens when allnulls=false.
*/
if (col_a->bv_allnulls)
{
col_a->bv_allnulls = false;
+ col_a->bv_hasnulls = true;
col_a->bv_values[INCLUSION_UNION] =
datumCopy(col_b->bv_values[INCLUSION_UNION],
attr->attbyval, attr->attlen);
diff --git a/src/backend/access/brin/brin_minmax.c b/src/backend/access/brin/brin_minmax.c
index ad0d18ed39f..57c9294f269 100644
--- a/src/backend/access/brin/brin_minmax.c
+++ b/src/backend/access/brin/brin_minmax.c
@@ -249,10 +249,13 @@ brin_minmax_union(PG_FUNCTION_ARGS)
FmgrInfo *finfo;
bool needsadj;
+ /* Does the "b" summary represent any NULL values? */
+ bool b_has_nulls = (col_b->bv_hasnulls || col_b->bv_allnulls);
+
Assert(col_a->bv_attno == col_b->bv_attno);
/* Adjust "hasnulls" */
- if (!col_a->bv_hasnulls && col_b->bv_hasnulls)
+ if (!col_a->bv_allnulls && b_has_nulls)
col_a->bv_hasnulls = true;
/* If there are no values in B, there's nothing left to do */
@@ -267,10 +270,15 @@ brin_minmax_union(PG_FUNCTION_ARGS)
* B into A, and we're done. We cannot run the operators in this case,
* because values in A might contain garbage. Note we already established
* that B contains values.
+ *
+ * Also adjust "hasnulls" in order not to forget the summary represents NULL
+ * values. This is not redundant with the earlier update, because that only
+ * happens when allnulls=false.
*/
if (col_a->bv_allnulls)
{
col_a->bv_allnulls = false;
+ col_a->bv_hasnulls = true;
col_a->bv_values[0] = datumCopy(col_b->bv_values[0],
attr->attbyval, attr->attlen);
col_a->bv_values[1] = datumCopy(col_b->bv_values[1],
[parent: 0966291a4ade]