Release 2.20.3 (#8248)

## 2.20.3 (2025-06-11)

This release contains bug fixes since the 2.20.2 release. We recommend
that you upgrade at the next available opportunity.

**Bugfixes**
* [#8107](#8107) Adjust
SkipScan cost for quals needing full scan of indexed data.
* [#8211](#8211) Fixed dump
and restore when chunk skipping is enabled.
* [#8216](#8216) Fix for
dropped quals bug in SkipScan.
* [#8230](#8230) Fix for
inserting into compressed data when a vectorized check is not available.
* [#8236](#8236) Fixed the
snapshot handling in background workers.

**Thanks**
* @ikaakkola for reporting that SkipScan is slow when non-index quals do
not match any tuples.

Author: philkra

.unreleased/fix_8107

@@ -4,6 +4,20 @@
 `psql` with the `-X` flag to prevent any `.psqlrc` commands from
 accidentally triggering the load of a previous DB version.**
 
+## 2.20.3 (2025-06-11)
+
+This release contains bug fixes since the 2.20.2 release. We recommend that you upgrade at the next available opportunity.
+
+**Bugfixes**
+* [#8107](https://github.com/timescale/timescaledb/pull/8107) Adjust SkipScan cost for quals needing full scan of indexed data.
+* [#8211](https://github.com/timescale/timescaledb/pull/8211) Fixed dump and restore when chunk skipping is enabled.
+* [#8216](https://github.com/timescale/timescaledb/pull/8216) Fix for dropped quals bug in SkipScan.
+* [#8230](https://github.com/timescale/timescaledb/pull/8230) Fix for inserting into compressed data when vectorised check is not available.
+* [#8236](https://github.com/timescale/timescaledb/pull/8236) Fixed the snapshot handling in background workers.
+
+**Thanks**
+* @ikaakkola for reporting that SkipScan is slow when non-index quals do not match any tuples.
+
 ## 2.20.2 (2025-06-02)
 
 This release contains bug fixes since the 2.20.1 release. We recommend that you upgrade at the next available opportunity.

.unreleased/pr_8211

@@ -45,11 +45,12 @@ set(MOD_FILES
     updates/2.19.2--2.19.3.sql
     updates/2.19.3--2.20.0.sql
     updates/2.20.0--2.20.1.sql
-    updates/2.20.1--2.20.2.sql)
+    updates/2.20.1--2.20.2.sql
+    updates/2.20.2--2.20.3.sql)
 
 # The downgrade file to generate a downgrade script for the current version, as
 # specified in version.config
-set(CURRENT_REV_FILE 2.20.2--2.20.1.sql)
+set(CURRENT_REV_FILE 2.20.3--2.20.2.sql)
 # Files for generating old downgrade scripts. This should only include files for
 # downgrade from one version to its previous version since we do not support
 # skipping versions when downgrading.
@@ -90,7 +91,8 @@ set(OLD_REV_FILES
     2.19.3--2.19.2.sql
     2.20.0--2.19.3.sql
     2.20.1--2.20.0.sql
-    2.20.2--2.20.1.sql)
+    2.20.2--2.20.1.sql
+    2.20.3--2.20.2.sql)
 
 set(MODULE_PATHNAME "$libdir/timescaledb-${PROJECT_VERSION_MOD}")
 set(LOADER_PATHNAME "$libdir/timescaledb")

.unreleased/pr_8216

@@ -0,0 +1,5 @@
+-- Make chunk_id use NULL to mark special entries instead of 0
+-- (Invalid chunk) since that doesn't work with the FK constraint on
+-- chunk_id.
+ALTER TABLE _timescaledb_catalog.chunk_column_stats ALTER COLUMN chunk_id DROP NOT NULL;
+UPDATE _timescaledb_catalog.chunk_column_stats SET chunk_id = NULL WHERE chunk_id = 0;

.unreleased/pr_8230

@@ -0,0 +1,25 @@
+-- Add back the chunk_column_stats NOT NULL constraint. But first
+-- delete all entries with with NULL since they will no longer be
+-- allowed. Note that reverting chunk_id back to 0 because it will
+-- violate the FK constraint. Even if we would revert, the downgrade
+-- tests for "restore" would fail due to violating entries. Removing
+-- the entries effectively means that collecting column stats for
+-- those columns will be disabled. It can be enabled again after
+-- downgrade. We emit a warning if anything was disabled.
+DO $$
+DECLARE
+    num_null_chunk_ids int;
+BEGIN
+
+    SELECT count(*) INTO num_null_chunk_ids
+    FROM _timescaledb_catalog.chunk_column_stats WHERE chunk_id IS NULL;
+
+    IF num_null_chunk_ids > 0 THEN
+       RAISE WARNING 'chunk skipping has been disabled for all hypertables'
+              USING HINT = 'Use enable_chunk_skipping() to re-enable chunk skipping';
+    END IF;
+END
+$$;
+
+DELETE FROM _timescaledb_catalog.chunk_column_stats WHERE chunk_id IS NULL;
+ALTER TABLE _timescaledb_catalog.chunk_column_stats ALTER COLUMN chunk_id SET NOT NULL;

.unreleased/pr_8236

@@ -1,5 +0,0 @@
--- Make chunk_id use NULL to mark special entries instead of 0
--- (Invalid chunk) since that doesn't work with the FK constraint on
--- chunk_id.
-ALTER TABLE _timescaledb_catalog.chunk_column_stats ALTER COLUMN chunk_id DROP NOT NULL;
-UPDATE _timescaledb_catalog.chunk_column_stats SET chunk_id = NULL WHERE chunk_id = 0;