diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 33bba98d5c5..9c0b011f0d3 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -68,7 +68,7 @@ USER citus
 
 # build postgres versions separately for effective parrallelism and caching of already built versions when changing only certain versions
 FROM base AS pg14
-RUN MAKEFLAGS="-j $(nproc)" pgenv build 14.12
+RUN MAKEFLAGS="-j $(nproc)" pgenv build 14.15
 RUN rm .pgenv/src/*.tar*
 RUN make -C .pgenv/src/postgresql-*/ clean
 RUN make -C .pgenv/src/postgresql-*/src/include install
@@ -80,7 +80,7 @@ RUN cp -r .pgenv/src .pgenv/pgsql-* .pgenv/config .pgenv-staging/
 RUN rm .pgenv-staging/config/default.conf
 
 FROM base AS pg15
-RUN MAKEFLAGS="-j $(nproc)" pgenv build 15.7
+RUN MAKEFLAGS="-j $(nproc)" pgenv build 15.10
 RUN rm .pgenv/src/*.tar*
 RUN make -C .pgenv/src/postgresql-*/ clean
 RUN make -C .pgenv/src/postgresql-*/src/include install
@@ -92,7 +92,7 @@ RUN cp -r .pgenv/src .pgenv/pgsql-* .pgenv/config .pgenv-staging/
 RUN rm .pgenv-staging/config/default.conf
 
 FROM base AS pg16
-RUN MAKEFLAGS="-j $(nproc)" pgenv build 16.3
+RUN MAKEFLAGS="-j $(nproc)" pgenv build 16.6
 RUN rm .pgenv/src/*.tar*
 RUN make -C .pgenv/src/postgresql-*/ clean
 RUN make -C .pgenv/src/postgresql-*/src/include install
@@ -211,7 +211,7 @@ COPY --chown=citus:citus .psqlrc .
 RUN sudo chown --from=root:root citus:citus -R ~
 
 # sets default pg version
-RUN pgenv switch 16.3
+RUN pgenv switch 16.6
 
 # make connecting to the coordinator easy
 ENV PGPORT=9700
diff --git a/.github/actions/save_logs_and_results/action.yml b/.github/actions/save_logs_and_results/action.yml
index 0f238835d19..b344c68f2ef 100644
--- a/.github/actions/save_logs_and_results/action.yml
+++ b/.github/actions/save_logs_and_results/action.yml
@@ -6,7 +6,7 @@ inputs:
 runs:
   using: composite
   steps:
-  - uses: actions/upload-artifact@v3.1.1
+  - uses: actions/upload-artifact@v4.6.0
     name: Upload logs
     with:
       name: ${{ inputs.folder }}
diff --git a/.github/actions/setup_extension/action.yml b/.github/actions/setup_extension/action.yml
index 96b408e7e43..33129f17de6 100644
--- a/.github/actions/setup_extension/action.yml
+++ b/.github/actions/setup_extension/action.yml
@@ -17,7 +17,7 @@ runs:
           echo "PG_MAJOR=${{ inputs.pg_major }}" >> $GITHUB_ENV
         fi
     shell: bash
-  - uses: actions/download-artifact@v3.0.1
+  - uses: actions/download-artifact@v4.1.8
     with:
       name: build-${{ env.PG_MAJOR }}
   - name: Install Extension
diff --git a/.github/actions/upload_coverage/action.yml b/.github/actions/upload_coverage/action.yml
index 0b5f581a6a4..ba80ba63afa 100644
--- a/.github/actions/upload_coverage/action.yml
+++ b/.github/actions/upload_coverage/action.yml
@@ -21,7 +21,7 @@ runs:
       mkdir -p /tmp/codeclimate
       cc-test-reporter format-coverage -t lcov -o /tmp/codeclimate/${{ inputs.flags }}.json lcov.info
     shell: bash
-  - uses: actions/upload-artifact@v3.1.1
+  - uses: actions/upload-artifact@v4.6.0
     with:
       path: "/tmp/codeclimate/*.json"
-      name: codeclimate
+      name: codeclimate-${{ inputs.flags }}
diff --git a/.github/workflows/build_and_test.yml b/.github/workflows/build_and_test.yml
index 70bc0bcb9a6..32c761766d5 100644
--- a/.github/workflows/build_and_test.yml
+++ b/.github/workflows/build_and_test.yml
@@ -31,14 +31,14 @@ jobs:
       pgupgrade_image_name: "ghcr.io/citusdata/pgupgradetester"
       style_checker_image_name: "ghcr.io/citusdata/stylechecker"
       style_checker_tools_version: "0.8.18"
-      sql_snapshot_pg_version: "16.3"
-      image_suffix: "-v13fd57c"
-      pg14_version: '{ "major": "14", "full": "14.12" }'
-      pg15_version: '{ "major": "15", "full": "15.7" }'
-      pg16_version: '{ "major": "16", "full": "16.3" }'
-      upgrade_pg_versions: "14.12-15.7-16.3"
+      sql_snapshot_pg_version: "16.6"
+      image_suffix: "-v5779674"
+      pg14_version: '{ "major": "14", "full": "14.15" }'
+      pg15_version: '{ "major": "15", "full": "15.10" }'
+      pg16_version: '{ "major": "16", "full": "16.6" }'
+      upgrade_pg_versions: "14.15-15.10-16.6"
     steps:
-      # Since GHA jobs needs at least one step we use a noop step here.
+      # Since GHA jobs need at least one step we use a noop step here.
       - name: Set up parameters
         run: echo 'noop'
   check-sql-snapshots:
@@ -48,7 +48,7 @@ jobs:
       image: ${{ needs.params.outputs.build_image_name }}:${{ needs.params.outputs.sql_snapshot_pg_version }}${{ needs.params.outputs.image_suffix }}
       options: --user root
     steps:
-    - uses: actions/checkout@v3.5.0
+    - uses: actions/checkout@v4
     - name: Check Snapshots
       run: |
         git config --global --add safe.directory ${GITHUB_WORKSPACE}
@@ -125,7 +125,7 @@ jobs:
     - name: Build
       run: "./ci/build-citus.sh"
       shell: bash
-    - uses: actions/upload-artifact@v3.1.1
+    - uses: actions/upload-artifact@v4.6.0
       with:
         name: build-${{ env.PG_MAJOR }}
         path: |-
@@ -284,10 +284,12 @@ jobs:
             check-arbitrary-configs parallel=4 CONFIGS=$TESTS
     - uses: "./.github/actions/save_logs_and_results"
       if: always()
+      with:
+        folder: ${{ env.PG_MAJOR }}_arbitrary_configs_${{ matrix.parallel }}
     - uses: "./.github/actions/upload_coverage"
       if: always()
       with:
-        flags: ${{ env.pg_major }}_upgrade
+        flags: ${{ env.PG_MAJOR }}_arbitrary_configs_${{ matrix.parallel }}
         codecov_token: ${{ secrets.CODECOV_TOKEN }}
   test-pg-upgrade:
     name: PG${{ matrix.old_pg_major }}-PG${{ matrix.new_pg_major }} - check-pg-upgrade
@@ -335,6 +337,8 @@ jobs:
       if: failure()
     - uses: "./.github/actions/save_logs_and_results"
       if: always()
+      with:
+        folder: ${{ env.old_pg_major }}_${{ env.new_pg_major }}_upgrade
     - uses: "./.github/actions/upload_coverage"
       if: always()
       with:
@@ -380,10 +384,12 @@ jobs:
         done;
     - uses: "./.github/actions/save_logs_and_results"
       if: always()
+      with:
+        folder: ${{ env.PG_MAJOR }}_citus_upgrade
     - uses: "./.github/actions/upload_coverage"
       if: always()
       with:
-        flags: ${{ env.pg_major }}_upgrade
+        flags: ${{ env.PG_MAJOR }}_citus_upgrade
         codecov_token: ${{ secrets.CODECOV_TOKEN }}
   upload-coverage:
     if: always()
@@ -399,10 +405,11 @@ jobs:
       - test-citus-upgrade
       - test-pg-upgrade
     steps:
-      - uses: actions/download-artifact@v3.0.1
+      - uses: actions/download-artifact@v4.1.8
         with:
-          name: "codeclimate"
-          path: "codeclimate"
+          pattern: codeclimate*
+          path: codeclimate
+          merge-multiple: true
       - name: Upload coverage results to Code Climate
         run: |-
           cc-test-reporter sum-coverage codeclimate/*.json -o total.json
@@ -516,6 +523,7 @@ jobs:
       matrix: ${{ fromJson(needs.prepare_parallelization_matrix_32.outputs.json) }}
     steps:
     - uses: actions/checkout@v4
+    - uses: actions/download-artifact@v4.1.8
     - uses: "./.github/actions/setup_extension"
     - name: Run minimal tests
       run: |-
diff --git a/.github/workflows/flaky_test_debugging.yml b/.github/workflows/flaky_test_debugging.yml
index 7135f99fa02..812fbe2418a 100644
--- a/.github/workflows/flaky_test_debugging.yml
+++ b/.github/workflows/flaky_test_debugging.yml
@@ -34,7 +34,7 @@ jobs:
         echo "PG_MAJOR=${PG_MAJOR}" >> $GITHUB_ENV
         ./ci/build-citus.sh
       shell: bash
-    - uses: actions/upload-artifact@v3.1.1
+    - uses: actions/upload-artifact@v4.6.0
       with:
         name: build-${{ env.PG_MAJOR }}
         path: |-
diff --git a/.github/workflows/packaging-test-pipelines.yml b/.github/workflows/packaging-test-pipelines.yml
index 26b5cfc9593..db0fd08efd0 100644
--- a/.github/workflows/packaging-test-pipelines.yml
+++ b/.github/workflows/packaging-test-pipelines.yml
@@ -116,7 +116,6 @@ jobs:
         # for each deb based image and we use POSTGRES_VERSION to set
         # PG_CONFIG variable in each of those runs.
         packaging_docker_image:
-          - debian-buster-all
           - debian-bookworm-all
           - debian-bullseye-all
           - ubuntu-focal-all
@@ -130,7 +129,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set pg_config path and python parameters for deb based distros
         run: |
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 78d1d2a7c24..ee3f2d0a203 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,51 @@
+### citus v13.0.1 (February 4th, 2025) ###
+
+* Drops support for PostgreSQL 14 (#7753)
+
+### citus v13.0.0 (January 17, 2025) ###
+
+* Adds support for PostgreSQL 17 (#7699, #7661)
+
+* Adds `JSON_TABLE()` support in distributed queries (#7816)
+
+* Propagates `MERGE ... WHEN NOT MATCHED BY SOURCE` (#7807)
+
+* Propagates `MEMORY` and `SERIALIZE` options of `EXPLAIN` (#7802)
+
+* Adds support for identity columns in distributed partitioned tables (#7785)
+
+* Allows specifying an access method for distributed partitioned tables (#7818)
+
+* Allows exclusion constraints on distributed partitioned tables (#7733)
+
+* Allows configuring sslnegotiation using `citus.node_conn_info` (#7821)
+
+* Avoids wal receiver timeouts during large shard splits (#7229)
+
+* Fixes a bug causing incorrect writing of data to target `MERGE` repartition
+  command (#7659)
+
+* Fixes a crash that happens because of unsafe catalog access when re-assigning
+  the global pid after `application_name` changes (#7791)
+
+* Fixes incorrect `VALID UNTIL` setting assumption made for roles when syncing
+  them to new nodes (#7534)
+
+* Fixes segfault when calling distributed procedure with a parameterized
+  distribution argument (#7242)
+
+* Fixes server crash when trying to execute `activate_node_snapshot()` on a
+  single-node cluster (#7552)
+
+* Improves `citus_move_shard_placement()` to fail early if there is a new node
+  without reference tables yet (#7467)
+
+### citus v12.1.6 (Nov 14, 2024) ###
+
+* Propagates `SECURITY LABEL .. ON ROLE` statements (#7304)
+
+* Fixes crash caused by running queries with window partition (#7718)
+
 ### citus v12.1.5 (July 17, 2024) ###
 
 * Adds support for MERGE commands with single shard distributed target tables
diff --git a/README.md b/README.md
index 2cf17098ffc..44fd65f50a2 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-| **<br/>The Citus database is 100% open source.<br/><img width=1000/><br/>Learn what's new in the [Citus 12.1 release blog](https://www.citusdata.com/blog/2023/09/22/adding-postgres-16-support-to-citus-12-1/) and the [Citus Updates page](https://www.citusdata.com/updates/).<br/><br/>**|
+| **<br/>The Citus database is 100% open source.<br/><img width=1000/><br/>Learn what's new in the [Citus 13.0 release blog](https://www.citusdata.com/blog/2025/02/06/distribute-postgresql-17-with-citus-13/) and the [Citus Updates page](https://www.citusdata.com/updates/).<br/><br/>**|
 |---|
 <br/>
 
@@ -95,14 +95,14 @@ Install packages on Ubuntu / Debian:
 ```bash
 curl https://install.citusdata.com/community/deb.sh > add-citus-repo.sh
 sudo bash add-citus-repo.sh
-sudo apt-get -y install postgresql-16-citus-12.1
+sudo apt-get -y install postgresql-17-citus-13.0
 ```
 
-Install packages on CentOS / Red Hat:
+Install packages on Red Hat:
 ```bash
 curl https://install.citusdata.com/community/rpm.sh > add-citus-repo.sh
 sudo bash add-citus-repo.sh
-sudo yum install -y citus121_16
+sudo yum install -y citus130_17
 ```
 
 To add Citus to your local PostgreSQL database, add the following to `postgresql.conf`:
diff --git a/citus-tools b/citus-tools
deleted file mode 160000
index 3376bd6845f..00000000000
--- a/citus-tools
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 3376bd6845f0614908ed304f5033bd644c82d3bf
diff --git a/src/backend/columnar/columnar_tableam.c b/src/backend/columnar/columnar_tableam.c
index ca3a5f4c4aa..fd3d171c6f5 100644
--- a/src/backend/columnar/columnar_tableam.c
+++ b/src/backend/columnar/columnar_tableam.c
@@ -3021,6 +3021,8 @@ AvailableExtensionVersionColumnar(void)
 
 	ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("citus extension is not found")));
+
+	return NULL; /* keep compiler happy */
 }
 
 
diff --git a/src/backend/distributed/metadata/metadata_cache.c b/src/backend/distributed/metadata/metadata_cache.c
index 402dedb8a91..4f1b942a085 100644
--- a/src/backend/distributed/metadata/metadata_cache.c
+++ b/src/backend/distributed/metadata/metadata_cache.c
@@ -2522,6 +2522,8 @@ AvailableExtensionVersion(void)
 
 	ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					errmsg("citus extension is not found")));
+
+	return NULL; /* keep compiler happy */
 }
 
 
diff --git a/src/backend/distributed/planner/insert_select_planner.c b/src/backend/distributed/planner/insert_select_planner.c
index 60d6ce466ca..15588025396 100644
--- a/src/backend/distributed/planner/insert_select_planner.c
+++ b/src/backend/distributed/planner/insert_select_planner.c
@@ -1810,6 +1810,8 @@ CastExpr(Expr *expr, Oid sourceType, Oid targetType, Oid targetCollation,
 		ereport(ERROR, (errmsg("could not find a conversion path from type %d to %d",
 							   sourceType, targetType)));
 	}
+
+	return NULL; /* keep compiler happy */
 }
 
 
diff --git a/src/backend/distributed/planner/multi_explain.c b/src/backend/distributed/planner/multi_explain.c
index 4584e774024..db30f4b6045 100644
--- a/src/backend/distributed/planner/multi_explain.c
+++ b/src/backend/distributed/planner/multi_explain.c
@@ -190,6 +190,14 @@ PG_FUNCTION_INFO_V1(worker_save_query_explain_analyze);
 void
 CitusExplainScan(CustomScanState *node, List *ancestors, struct ExplainState *es)
 {
+#if PG_VERSION_NUM >= PG_VERSION_16
+	if (es->generic)
+	{
+		ereport(ERROR, (errmsg(
+							"EXPLAIN GENERIC_PLAN is currently not supported for Citus tables")));
+	}
+#endif
+
 	CitusScanState *scanState = (CitusScanState *) node;
 	DistributedPlan *distributedPlan = scanState->distributedPlan;
 	EState *executorState = ScanStateGetExecutorState(scanState);
@@ -992,18 +1000,12 @@ BuildRemoteExplainQuery(char *queryString, ExplainState *es)
 	appendStringInfo(explainQuery,
 					 "EXPLAIN (ANALYZE %s, VERBOSE %s, "
 					 "COSTS %s, BUFFERS %s, WAL %s, "
-#if PG_VERSION_NUM >= PG_VERSION_16
-					 "GENERIC_PLAN %s, "
-#endif
 					 "TIMING %s, SUMMARY %s, FORMAT %s) %s",
 					 es->analyze ? "TRUE" : "FALSE",
 					 es->verbose ? "TRUE" : "FALSE",
 					 es->costs ? "TRUE" : "FALSE",
 					 es->buffers ? "TRUE" : "FALSE",
 					 es->wal ? "TRUE" : "FALSE",
-#if PG_VERSION_NUM >= PG_VERSION_16
-					 es->generic ? "TRUE" : "FALSE",
-#endif
 					 es->timing ? "TRUE" : "FALSE",
 					 es->summary ? "TRUE" : "FALSE",
 					 formatStr,
diff --git a/src/backend/distributed/planner/multi_logical_optimizer.c b/src/backend/distributed/planner/multi_logical_optimizer.c
index 371ba54e650..28680deb036 100644
--- a/src/backend/distributed/planner/multi_logical_optimizer.c
+++ b/src/backend/distributed/planner/multi_logical_optimizer.c
@@ -1557,9 +1557,10 @@ MasterAggregateMutator(Node *originalNode, MasterAggregateWalkerContext *walkerC
 	}
 	else if (IsA(originalNode, Var))
 	{
-		Var *newColumn = copyObject((Var *) originalNode);
-		newColumn->varno = masterTableId;
-		newColumn->varattno = walkerContext->columnId;
+		Var *origColumn = (Var *) originalNode;
+		Var *newColumn = makeVar(masterTableId, walkerContext->columnId,
+								 origColumn->vartype, origColumn->vartypmod,
+								 origColumn->varcollid, origColumn->varlevelsup);
 		walkerContext->columnId++;
 
 		newNode = (Node *) newColumn;
diff --git a/src/backend/distributed/shared_library_init.c b/src/backend/distributed/shared_library_init.c
index bd65fa60c01..6d26b802f64 100644
--- a/src/backend/distributed/shared_library_init.c
+++ b/src/backend/distributed/shared_library_init.c
@@ -2890,14 +2890,27 @@ ApplicationNameAssignHook(const char *newval, void *extra)
 	DetermineCitusBackendType(newval);
 
 	/*
-	 * AssignGlobalPID might read from catalog tables to get the the local
-	 * nodeid. But ApplicationNameAssignHook might be called before catalog
-	 * access is available to the backend (such as in early stages of
-	 * authentication). We use StartupCitusBackend to initialize the global pid
-	 * after catalogs are available. After that happens this hook becomes
-	 * responsible to update the global pid on later application_name changes.
-	 * So we set the FinishedStartupCitusBackend flag in StartupCitusBackend to
-	 * indicate when this responsibility handoff has happened.
+	 * We use StartupCitusBackend to initialize the global pid after catalogs
+	 * are available. After that happens this hook becomes responsible to update
+	 * the global pid on later application_name changes. So we set the
+	 * FinishedStartupCitusBackend flag in StartupCitusBackend to indicate when
+	 * this responsibility handoff has happened.
+	 *
+	 * Also note that when application_name changes, we don't actually need to
+	 * try re-assigning the global pid for external client backends and
+	 * background workers because application_name doesn't affect the global
+	 * pid for such backends - note that !IsExternalClientBackend() check covers
+	 * both types of backends. Plus,
+	 * trying to re-assign the global pid for such backends would unnecessarily
+	 * cause performing a catalog access when the cached local node id is
+	 * invalidated. However, accessing to the catalog tables is dangerous in
+	 * certain situations like when we're not in a transaction block. And for
+	 * the other types of backends, i.e., the Citus internal backends, we need
+	 * to re-assign the global pid when the application_name changes because for
+	 * such backends we simply extract the global pid inherited from the
+	 * originating backend from the application_name -that's specified by
+	 * originating backend when openning that connection- and this doesn't require
+	 * catalog access.
 	 *
 	 * Another solution to the catalog table acccess problem would be to update
 	 * global pid lazily, like we do for HideShards. But that's not possible
@@ -2907,7 +2920,7 @@ ApplicationNameAssignHook(const char *newval, void *extra)
 	 * as reasonably possible, which is also why we extract global pids in the
 	 * AuthHook already (extracting doesn't require catalog access).
 	 */
-	if (FinishedStartupCitusBackend)
+	if (FinishedStartupCitusBackend && !IsExternalClientBackend())
 	{
 		AssignGlobalPID(newval);
 	}
diff --git a/src/backend/distributed/test/run_from_same_connection.c b/src/backend/distributed/test/run_from_same_connection.c
index 52b2e0b181b..d22ee442834 100644
--- a/src/backend/distributed/test/run_from_same_connection.c
+++ b/src/backend/distributed/test/run_from_same_connection.c
@@ -190,6 +190,9 @@ run_commands_on_session_level_connection_to_node(PG_FUNCTION_ARGS)
 
 /*
  * override_backend_data_gpid is a wrapper around SetBackendDataGpid().
+ * Also sets distributedCommandOriginator to true since the only caller of
+ * this method calls this function actually wants this backend to
+ * be treated as a distributed command originator with the given global pid.
  */
 Datum
 override_backend_data_gpid(PG_FUNCTION_ARGS)
@@ -199,6 +202,7 @@ override_backend_data_gpid(PG_FUNCTION_ARGS)
 	uint64 gpid = PG_GETARG_INT64(0);
 
 	SetBackendDataGlobalPID(gpid);
+	SetBackendDataDistributedCommandOriginator(true);
 
 	PG_RETURN_VOID();
 }
diff --git a/src/backend/distributed/transaction/backend_data.c b/src/backend/distributed/transaction/backend_data.c
index 67acadd2940..9b6e7d122ba 100644
--- a/src/backend/distributed/transaction/backend_data.c
+++ b/src/backend/distributed/transaction/backend_data.c
@@ -855,6 +855,16 @@ GetCurrentDistributedTransactionId(void)
 void
 AssignDistributedTransactionId(void)
 {
+	/*
+	 * MyBackendData should always be available. However, we observed some
+	 * crashes where certain hooks were not executed.
+	 * Bug 3697586: Server crashes when assigning distributed transaction
+	 */
+	if (!MyBackendData)
+	{
+		ereport(ERROR, (errmsg("backend is not ready for distributed transactions")));
+	}
+
 	pg_atomic_uint64 *transactionNumberSequence =
 		&backendManagementShmemData->nextTransactionNumber;
 
@@ -964,6 +974,23 @@ SetBackendDataGlobalPID(uint64 gpid)
 }
 
 
+/*
+ * SetBackendDataDistributedCommandOriginator sets the distributedCommandOriginator
+ * field on MyBackendData.
+ */
+void
+SetBackendDataDistributedCommandOriginator(bool distributedCommandOriginator)
+{
+	if (!MyBackendData)
+	{
+		return;
+	}
+	SpinLockAcquire(&MyBackendData->mutex);
+	MyBackendData->distributedCommandOriginator = distributedCommandOriginator;
+	SpinLockRelease(&MyBackendData->mutex);
+}
+
+
 /*
  * GetGlobalPID returns the global process id of the current backend.
  */
diff --git a/src/include/distributed/backend_data.h b/src/include/distributed/backend_data.h
index 8014fe5a6a9..5b3fcf2ac22 100644
--- a/src/include/distributed/backend_data.h
+++ b/src/include/distributed/backend_data.h
@@ -61,6 +61,7 @@ extern void AssignGlobalPID(const char *applicationName);
 extern uint64 GetGlobalPID(void);
 extern void SetBackendDataDatabaseId(void);
 extern void SetBackendDataGlobalPID(uint64 gpid);
+extern void SetBackendDataDistributedCommandOriginator(bool distributedCommandOriginator);
 extern uint64 ExtractGlobalPID(const char *applicationName);
 extern int ExtractNodeIdFromGlobalPID(uint64 globalPID, bool missingOk);
 extern int ExtractProcessIdFromGlobalPID(uint64 globalPID);
diff --git a/src/test/regress/citus_tests/upgrade/citus_upgrade_test.py b/src/test/regress/citus_tests/upgrade/citus_upgrade_test.py
index 1ab44803117..c25a3448238 100755
--- a/src/test/regress/citus_tests/upgrade/citus_upgrade_test.py
+++ b/src/test/regress/citus_tests/upgrade/citus_upgrade_test.py
@@ -62,10 +62,16 @@ def run_citus_upgrade_tests(config, before_upgrade_schedule, after_upgrade_sched
 
     install_citus(config.post_tar_path)
 
+    # disable 2pc recovery for all nodes to work around https://github.com/citusdata/citus/issues/7875
+    disable_2pc_recovery_for_all_nodes(config.bindir, config)
+
     restart_databases(config.bindir, config.datadir, config.mixed_mode, config)
     run_alter_citus(config.bindir, config.mixed_mode, config)
     verify_upgrade(config, config.mixed_mode, config.node_name_to_ports.values())
 
+    # re-enable 2pc recovery for all nodes
+    enable_2pc_recovery_for_all_nodes(config.bindir, config)
+
     run_test_on_coordinator(config, after_upgrade_schedule)
     remove_citus(config.post_tar_path)
 
@@ -146,6 +152,18 @@ def restart_database(pg_path, abs_data_path, node_name, node_ports, logfile_pref
     subprocess.run(command, check=True)
 
 
+def disable_2pc_recovery_for_all_nodes(pg_path, config):
+    for port in config.node_name_to_ports.values():
+        utils.psql(pg_path, port, "ALTER SYSTEM SET citus.recover_2pc_interval TO -1;")
+        utils.psql(pg_path, port, "SELECT pg_reload_conf();")
+
+
+def enable_2pc_recovery_for_all_nodes(pg_path, config):
+    for port in config.node_name_to_ports.values():
+        utils.psql(pg_path, port, "ALTER SYSTEM RESET citus.recover_2pc_interval;")
+        utils.psql(pg_path, port, "SELECT pg_reload_conf();")
+
+
 def run_alter_citus(pg_path, mixed_mode, config):
     for port in config.node_name_to_ports.values():
         if mixed_mode and port in (
diff --git a/src/test/regress/expected/issue_7705.out b/src/test/regress/expected/issue_7705.out
new file mode 100644
index 00000000000..20b078226ad
--- /dev/null
+++ b/src/test/regress/expected/issue_7705.out
@@ -0,0 +1,248 @@
+--- Test for verifying that column references (var nodes) in targets that cannot be pushed down
+--- do not cause issues for the postgres planner, in particular postgres versions 16+, where the
+--- varnullingrels field of a VAR node may contain relids of join relations that can make the var
+--- NULL; in a rewritten distributed query without a join such relids do not have a meaning.
+--- Issue #7705: [SEGFAULT] Querying distributed tables with window partition causes segmentation fault
+--- https://github.com/citusdata/citus/issues/7705
+CREATE SCHEMA issue_7705;
+SET search_path to 'issue_7705';
+SET citus.next_shard_id TO 30070000;
+SET citus.shard_replication_factor TO 1;
+SET citus.enable_local_execution TO ON;
+CREATE TABLE t1 (id INT PRIMARY KEY);
+INSERT INTO t1 VALUES (1), (2);
+CREATE TABLE t2 (id INT, account_id INT, a2 INT, PRIMARY KEY(id, account_id));
+INSERT INTO t2 VALUES (3, 1, 10), (4, 2, 20), (5, 1, NULL);
+SELECT create_distributed_table('t1', 'id');
+NOTICE:  Copying data from local table...
+NOTICE:  copying the data has completed
+DETAIL:  The local data in the table is no longer visible, but is still on disk.
+HINT:  To remove the local data, run: SELECT truncate_local_data_after_distributing_table($$issue_7705.t1$$)
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+SELECT create_distributed_table('t2', 'account_id');
+NOTICE:  Copying data from local table...
+NOTICE:  copying the data has completed
+DETAIL:  The local data in the table is no longer visible, but is still on disk.
+HINT:  To remove the local data, run: SELECT truncate_local_data_after_distributing_table($$issue_7705.t2$$)
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+-- Test the issue seen in #7705; a target expression with
+-- a window function that cannot be pushed down because the
+-- partion by is not on the distribution column also includes
+-- a column from the inner side of a left outer join, which
+-- produces a non-empty varnullingrels set in PG 16 (and higher)
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+ id | max
+---------------------------------------------------------------------
+  1 |  10
+  2 |  20
+  1 |
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+                                                                                                                                                             QUERY PLAN
+---------------------------------------------------------------------
+ WindowAgg
+   Output: remote_scan.id, max(remote_scan.max) OVER (?), remote_scan.worker_column_3
+   ->  Sort
+         Output: remote_scan.worker_column_3, remote_scan.id, remote_scan.max
+         Sort Key: remote_scan.worker_column_3
+         ->  Custom Scan (Citus Adaptive)
+               Output: remote_scan.worker_column_3, remote_scan.id, remote_scan.max
+               Task Count: 4
+               Tasks Shown: One of 4
+               ->  Task
+                     Query: SELECT worker_column_1 AS id, worker_column_2 AS max, worker_column_3 FROM (SELECT t1.id AS worker_column_1, t2.a2 AS worker_column_2, t2.id AS worker_column_3 FROM (issue_7705.t1_30070000 t1 LEFT JOIN issue_7705.t2_30070004 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.account_id)))) worker_subquery
+                     Node: host=localhost port=xxxxx dbname=regression
+                     ->  Hash Right Join
+                           Output: t1.id, t2.a2, t2.id
+                           Inner Unique: true
+                           Hash Cond: (t2.account_id = t1.id)
+                           ->  Seq Scan on issue_7705.t2_30070004 t2
+                                 Output: t2.id, t2.account_id, t2.a2
+                           ->  Hash
+                                 Output: t1.id
+                                 ->  Seq Scan on issue_7705.t1_30070000 t1
+                                       Output: t1.id
+(22 rows)
+
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t2 RIGHT OUTER JOIN t1 ON t1.id = t2.account_id;
+ id | max
+---------------------------------------------------------------------
+  1 |  10
+  2 |  20
+  1 |
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t2 RIGHT OUTER JOIN t1 ON t1.id = t2.account_id;
+                                                                                                                                                             QUERY PLAN
+---------------------------------------------------------------------
+ WindowAgg
+   Output: remote_scan.id, max(remote_scan.max) OVER (?), remote_scan.worker_column_3
+   ->  Sort
+         Output: remote_scan.worker_column_3, remote_scan.id, remote_scan.max
+         Sort Key: remote_scan.worker_column_3
+         ->  Custom Scan (Citus Adaptive)
+               Output: remote_scan.worker_column_3, remote_scan.id, remote_scan.max
+               Task Count: 4
+               Tasks Shown: One of 4
+               ->  Task
+                     Query: SELECT worker_column_1 AS id, worker_column_2 AS max, worker_column_3 FROM (SELECT t1.id AS worker_column_1, t2.a2 AS worker_column_2, t2.id AS worker_column_3 FROM (issue_7705.t2_30070004 t2 RIGHT JOIN issue_7705.t1_30070000 t1 ON ((t1.id OPERATOR(pg_catalog.=) t2.account_id)))) worker_subquery
+                     Node: host=localhost port=xxxxx dbname=regression
+                     ->  Hash Right Join
+                           Output: t1.id, t2.a2, t2.id
+                           Inner Unique: true
+                           Hash Cond: (t2.account_id = t1.id)
+                           ->  Seq Scan on issue_7705.t2_30070004 t2
+                                 Output: t2.id, t2.account_id, t2.a2
+                           ->  Hash
+                                 Output: t1.id
+                                 ->  Seq Scan on issue_7705.t1_30070000 t1
+                                       Output: t1.id
+(22 rows)
+
+SELECT  DISTINCT t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+ id | max
+---------------------------------------------------------------------
+  1 |
+  1 |  10
+  2 |  20
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT DISTINCT t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+                                                                                                                                                                QUERY PLAN
+---------------------------------------------------------------------
+ HashAggregate
+   Output: remote_scan.id, (max(remote_scan.max) OVER (?)), remote_scan.worker_column_3
+   Group Key: remote_scan.id, max(remote_scan.max) OVER (?)
+   ->  WindowAgg
+         Output: remote_scan.id, max(remote_scan.max) OVER (?), remote_scan.worker_column_3
+         ->  Sort
+               Output: remote_scan.worker_column_3, remote_scan.id, remote_scan.max
+               Sort Key: remote_scan.worker_column_3
+               ->  Custom Scan (Citus Adaptive)
+                     Output: remote_scan.worker_column_3, remote_scan.id, remote_scan.max
+                     Task Count: 4
+                     Tasks Shown: One of 4
+                     ->  Task
+                           Query: SELECT worker_column_1 AS id, worker_column_2 AS max, worker_column_3 FROM (SELECT t1.id AS worker_column_1, t2.a2 AS worker_column_2, t2.id AS worker_column_3 FROM (issue_7705.t1_30070000 t1 LEFT JOIN issue_7705.t2_30070004 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.account_id)))) worker_subquery
+                           Node: host=localhost port=xxxxx dbname=regression
+                           ->  Hash Right Join
+                                 Output: t1.id, t2.a2, t2.id
+                                 Inner Unique: true
+                                 Hash Cond: (t2.account_id = t1.id)
+                                 ->  Seq Scan on issue_7705.t2_30070004 t2
+                                       Output: t2.id, t2.account_id, t2.a2
+                                 ->  Hash
+                                       Output: t1.id
+                                       ->  Seq Scan on issue_7705.t1_30070000 t1
+                                             Output: t1.id
+(25 rows)
+
+CREATE SEQUENCE test_seq START 101;
+CREATE OR REPLACE FUNCTION TEST_F(int) returns INT language sql stable as $$ select $1 + 42; $$ ;
+-- Issue #7705 also occurs if a target expression includes a column
+-- of a distributed table that is on the inner side of a left outer
+-- join and a call to nextval(), because nextval() cannot be pushed
+-- down, and must be run on the coordinator
+SELECT t1.id, TEST_F(t2.a2 + nextval('test_seq') :: int)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+ id | test_f
+---------------------------------------------------------------------
+  1 |    153
+  1 |
+  2 |    165
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT t1.id, TEST_F(t2.a2 + nextval('test_seq') :: int)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+                                                                                                                                         QUERY PLAN
+---------------------------------------------------------------------
+ Result
+   Output: remote_scan.id, ((remote_scan.test_f + (nextval('test_seq'::regclass))::integer) + 42)
+   ->  Sort
+         Output: remote_scan.id, remote_scan.test_f
+         Sort Key: remote_scan.id
+         ->  Custom Scan (Citus Adaptive)
+               Output: remote_scan.id, remote_scan.test_f
+               Task Count: 4
+               Tasks Shown: One of 4
+               ->  Task
+                     Query: SELECT worker_column_1 AS id, worker_column_2 AS test_f FROM (SELECT t1.id AS worker_column_1, t2.a2 AS worker_column_2 FROM (issue_7705.t1_30070000 t1 LEFT JOIN issue_7705.t2_30070004 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.account_id)))) worker_subquery
+                     Node: host=localhost port=xxxxx dbname=regression
+                     ->  Hash Right Join
+                           Output: t1.id, t2.a2
+                           Inner Unique: true
+                           Hash Cond: (t2.account_id = t1.id)
+                           ->  Seq Scan on issue_7705.t2_30070004 t2
+                                 Output: t2.id, t2.account_id, t2.a2
+                           ->  Hash
+                                 Output: t1.id
+                                 ->  Seq Scan on issue_7705.t1_30070000 t1
+                                       Output: t1.id
+(22 rows)
+
+SELECT t1.id, CASE nextval('test_seq') % 2 = 0 WHEN true THEN t2.a2 ELSE 1 END
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+ id | case
+---------------------------------------------------------------------
+  1 |   10
+  1 |    1
+  2 |   20
+(3 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT t1.id, CASE nextval('test_seq') %2 = 0 WHEN true THEN t2.a2 ELSE 1 END
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+                                                                                                                                         QUERY PLAN
+---------------------------------------------------------------------
+ Result
+   Output: remote_scan.id, CASE ((nextval('test_seq'::regclass) % '2'::bigint) = 0) WHEN CASE_TEST_EXPR THEN remote_scan."case" ELSE 1 END
+   ->  Sort
+         Output: remote_scan.id, remote_scan."case"
+         Sort Key: remote_scan.id
+         ->  Custom Scan (Citus Adaptive)
+               Output: remote_scan.id, remote_scan."case"
+               Task Count: 4
+               Tasks Shown: One of 4
+               ->  Task
+                     Query: SELECT worker_column_1 AS id, worker_column_2 AS "case" FROM (SELECT t1.id AS worker_column_1, t2.a2 AS worker_column_2 FROM (issue_7705.t1_30070000 t1 LEFT JOIN issue_7705.t2_30070004 t2 ON ((t1.id OPERATOR(pg_catalog.=) t2.account_id)))) worker_subquery
+                     Node: host=localhost port=xxxxx dbname=regression
+                     ->  Hash Right Join
+                           Output: t1.id, t2.a2
+                           Inner Unique: true
+                           Hash Cond: (t2.account_id = t1.id)
+                           ->  Seq Scan on issue_7705.t2_30070004 t2
+                                 Output: t2.id, t2.account_id, t2.a2
+                           ->  Hash
+                                 Output: t1.id
+                                 ->  Seq Scan on issue_7705.t1_30070000 t1
+                                       Output: t1.id
+(22 rows)
+
+--- cleanup
+\set VERBOSITY TERSE
+DROP SCHEMA issue_7705 CASCADE;
+NOTICE:  drop cascades to 4 other objects
+RESET all;
diff --git a/src/test/regress/expected/pg16.out b/src/test/regress/expected/pg16.out
index a035fcfc4a2..546c0a832de 100644
--- a/src/test/regress/expected/pg16.out
+++ b/src/test/regress/expected/pg16.out
@@ -81,29 +81,9 @@ SELECT create_distributed_table('tenk1', 'unique1');
 (1 row)
 
 SET citus.log_remote_commands TO on;
-EXPLAIN (GENERIC_PLAN) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
-NOTICE:  issuing BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;SELECT assign_distributed_transaction_id(xx, xx, 'xxxxxxx');
-DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
-NOTICE:  issuing SAVEPOINT citus_explain_savepoint
-DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
-NOTICE:  issuing EXPLAIN (ANALYZE FALSE, VERBOSE FALSE, COSTS TRUE, BUFFERS FALSE, WAL FALSE, GENERIC_PLAN TRUE, TIMING FALSE, SUMMARY FALSE, FORMAT TEXT) SELECT unique1 FROM pg16.tenk1_950001 tenk1 WHERE (thousand OPERATOR(pg_catalog.=) 1000)
-DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
-NOTICE:  issuing ROLLBACK TO SAVEPOINT citus_explain_savepoint
-DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
-NOTICE:  issuing COMMIT
-DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
-                                   QUERY PLAN
----------------------------------------------------------------------
- Custom Scan (Citus Adaptive)  (cost=0.00..0.00 rows=0 width=0)
-   Task Count: 1
-   Tasks Shown: All
-   ->  Task
-         Node: host=localhost port=xxxxx dbname=regression
-         ->  Seq Scan on tenk1_950001 tenk1  (cost=0.00..35.50 rows=10 width=4)
-               Filter: (thousand = 1000)
-(7 rows)
-
-EXPLAIN (GENERIC_PLAN, ANALYZE) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
+EXPLAIN (GENERIC_PLAN) SELECT unique1 FROM tenk1 WHERE thousand = $1;
+ERROR:  EXPLAIN GENERIC_PLAN is currently not supported for Citus tables
+EXPLAIN (GENERIC_PLAN, ANALYZE) SELECT unique1 FROM tenk1 WHERE thousand = $1;
 ERROR:  EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together
 SET citus.log_remote_commands TO off;
 -- Proper error when creating statistics without a name on a Citus table
diff --git a/src/test/regress/expected/remove_coordinator.out b/src/test/regress/expected/remove_coordinator.out
index 0226a7cd073..e2fd5df027b 100644
--- a/src/test/regress/expected/remove_coordinator.out
+++ b/src/test/regress/expected/remove_coordinator.out
@@ -5,6 +5,37 @@ SELECT master_remove_node('localhost', :master_port);
 
 (1 row)
 
+-- to silence -potentially flaky- "could not establish connection after" warnings in below test
+SET client_min_messages TO ERROR;
+-- to fail fast when the hostname is not resolvable, as it will be the case below
+SET citus.node_connection_timeout to '1s';
+BEGIN;
+  SET application_name TO 'new_app_name';
+  -- that should fail because of bad hostname & port
+  SELECT citus_add_node('200.200.200.200', 1, 200);
+ERROR:  connection to the remote node postgres@200.200.200.200:1 failed
+  -- Since above command failed, now Postgres will need to revert the
+  -- application_name change made in this transaction and this will
+  -- happen within abort-transaction callback, so we won't be in a
+  -- transaction block while Postgres does that.
+  --
+  -- And when the application_name changes, Citus tries to re-assign
+  -- the global pid but it does so only for Citus internal backends,
+  -- and doing so for Citus internal backends doesn't require being
+  -- in a transaction block and is safe.
+  --
+  -- However, for the client external backends (like us here), Citus
+  -- doesn't re-assign the global pid because it's not needed and it's
+  -- not safe to do so outside of a transaction block. This is because,
+  -- it would require performing a catalog access to retrive the local
+  -- node id when the cached local node is invalidated like what just
+  -- happened here because of the failed citus_add_node() call made
+  -- above.
+  --
+  -- So by failing here (rather than crashing), we ensure this behavior.
+ROLLBACK;
+RESET client_min_messages;
+RESET citus.node_connection_timeout;
 -- restore coordinator for the rest of the tests
 SELECT citus_set_coordinator_host('localhost', :master_port);
  citus_set_coordinator_host
diff --git a/src/test/regress/expected/upgrade_pg_dist_cleanup_after_0.out b/src/test/regress/expected/upgrade_pg_dist_cleanup_after_0.out
index d71fad887c9..168c64ccaa3 100644
--- a/src/test/regress/expected/upgrade_pg_dist_cleanup_after_0.out
+++ b/src/test/regress/expected/upgrade_pg_dist_cleanup_after_0.out
@@ -28,3 +28,12 @@ SELECT * FROM pg_dist_cleanup;
 CALL citus_cleanup_orphaned_resources();
 NOTICE:  cleaned up 1 orphaned resources
 DROP TABLE table_with_orphaned_shards;
+-- Re-enable automatic shard cleanup by maintenance daemon as
+-- we have disabled it in upgrade_pg_dist_cleanup_before.sql
+ALTER SYSTEM RESET citus.defer_shard_delete_interval;
+SELECT pg_reload_conf();
+ pg_reload_conf
+---------------------------------------------------------------------
+ t
+(1 row)
+
diff --git a/src/test/regress/expected/upgrade_pg_dist_cleanup_before_0.out b/src/test/regress/expected/upgrade_pg_dist_cleanup_before_0.out
index a0cf9ceb1ea..dd6c8868e32 100644
--- a/src/test/regress/expected/upgrade_pg_dist_cleanup_before_0.out
+++ b/src/test/regress/expected/upgrade_pg_dist_cleanup_before_0.out
@@ -30,6 +30,23 @@ SELECT COUNT(*) FROM pg_dist_placement WHERE shardstate = 1 AND shardid IN (SELE
 (1 row)
 
 -- create an orphaned placement based on an existing one
+--
+-- But before doing that, first disable automatic shard cleanup
+-- by maintenance daemon so that we can reliably test the cleanup
+-- in upgrade_pg_dist_cleanup_after.sql.
+ALTER SYSTEM SET citus.defer_shard_delete_interval TO -1;
+SELECT pg_reload_conf();
+ pg_reload_conf
+---------------------------------------------------------------------
+ t
+(1 row)
+
+SELECT pg_sleep(0.1);
+ pg_sleep
+---------------------------------------------------------------------
+
+(1 row)
+
 INSERT INTO pg_dist_placement(placementid, shardid, shardstate, shardlength, groupid)
     SELECT nextval('pg_dist_placement_placementid_seq'::regclass), shardid, 4, shardlength, 3-groupid
     FROM pg_dist_placement
diff --git a/src/test/regress/multi_schedule b/src/test/regress/multi_schedule
index 220ce1964f1..bbb4047a950 100644
--- a/src/test/regress/multi_schedule
+++ b/src/test/regress/multi_schedule
@@ -103,7 +103,7 @@ test: multi_dropped_column_aliases foreign_key_restriction_enforcement
 test: binary_protocol
 test: alter_table_set_access_method
 test: alter_distributed_table
-test: issue_5248 issue_5099 issue_5763 issue_6543 issue_6758 issue_7477
+test: issue_5248 issue_5099 issue_5763 issue_6543 issue_6758 issue_7477 issue_7705
 test: object_propagation_debug
 test: undistribute_table
 test: run_command_on_all_nodes
diff --git a/src/test/regress/sql/issue_7705.sql b/src/test/regress/sql/issue_7705.sql
new file mode 100644
index 00000000000..950933017ad
--- /dev/null
+++ b/src/test/regress/sql/issue_7705.sql
@@ -0,0 +1,72 @@
+--- Test for verifying that column references (var nodes) in targets that cannot be pushed down
+--- do not cause issues for the postgres planner, in particular postgres versions 16+, where the
+--- varnullingrels field of a VAR node may contain relids of join relations that can make the var
+--- NULL; in a rewritten distributed query without a join such relids do not have a meaning.
+--- Issue #7705: [SEGFAULT] Querying distributed tables with window partition causes segmentation fault
+--- https://github.com/citusdata/citus/issues/7705
+
+CREATE SCHEMA issue_7705;
+SET search_path to 'issue_7705';
+SET citus.next_shard_id TO 30070000;
+SET citus.shard_replication_factor TO 1;
+SET citus.enable_local_execution TO ON;
+
+CREATE TABLE t1 (id INT PRIMARY KEY);
+INSERT INTO t1 VALUES (1), (2);
+
+CREATE TABLE t2 (id INT, account_id INT, a2 INT, PRIMARY KEY(id, account_id));
+INSERT INTO t2 VALUES (3, 1, 10), (4, 2, 20), (5, 1, NULL);
+
+SELECT create_distributed_table('t1', 'id');
+SELECT create_distributed_table('t2', 'account_id');
+
+-- Test the issue seen in #7705; a target expression with
+-- a window function that cannot be pushed down because the
+-- partion by is not on the distribution column also includes
+-- a column from the inner side of a left outer join, which
+-- produces a non-empty varnullingrels set in PG 16 (and higher)
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t2 RIGHT OUTER JOIN t1 ON t1.id = t2.account_id;
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT  t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t2 RIGHT OUTER JOIN t1 ON t1.id = t2.account_id;
+
+SELECT  DISTINCT t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT DISTINCT t1.id, MAX(t2.a2) OVER (PARTITION BY t2.id)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id;
+
+CREATE SEQUENCE test_seq START 101;
+CREATE OR REPLACE FUNCTION TEST_F(int) returns INT language sql stable as $$ select $1 + 42; $$ ;
+
+-- Issue #7705 also occurs if a target expression includes a column
+-- of a distributed table that is on the inner side of a left outer
+-- join and a call to nextval(), because nextval() cannot be pushed
+-- down, and must be run on the coordinator
+SELECT t1.id, TEST_F(t2.a2 + nextval('test_seq') :: int)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT t1.id, TEST_F(t2.a2 + nextval('test_seq') :: int)
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+
+SELECT t1.id, CASE nextval('test_seq') % 2 = 0 WHEN true THEN t2.a2 ELSE 1 END
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+EXPLAIN (VERBOSE, COSTS OFF, TIMING OFF)
+SELECT t1.id, CASE nextval('test_seq') %2 = 0 WHEN true THEN t2.a2 ELSE 1 END
+FROM t1 LEFT OUTER JOIN t2 ON t1.id = t2.account_id
+ORDER BY t1.id;
+
+--- cleanup
+\set VERBOSITY TERSE
+DROP SCHEMA issue_7705 CASCADE;
+RESET all;
diff --git a/src/test/regress/sql/pg16.sql b/src/test/regress/sql/pg16.sql
index 99024edcba8..0312fcdff93 100644
--- a/src/test/regress/sql/pg16.sql
+++ b/src/test/regress/sql/pg16.sql
@@ -58,8 +58,8 @@ CREATE TABLE tenk1 (
 SELECT create_distributed_table('tenk1', 'unique1');
 
 SET citus.log_remote_commands TO on;
-EXPLAIN (GENERIC_PLAN) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
-EXPLAIN (GENERIC_PLAN, ANALYZE) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
+EXPLAIN (GENERIC_PLAN) SELECT unique1 FROM tenk1 WHERE thousand = $1;
+EXPLAIN (GENERIC_PLAN, ANALYZE) SELECT unique1 FROM tenk1 WHERE thousand = $1;
 SET citus.log_remote_commands TO off;
 
 -- Proper error when creating statistics without a name on a Citus table
diff --git a/src/test/regress/sql/remove_coordinator.sql b/src/test/regress/sql/remove_coordinator.sql
index b0df327d15f..35a8a57189b 100644
--- a/src/test/regress/sql/remove_coordinator.sql
+++ b/src/test/regress/sql/remove_coordinator.sql
@@ -1,5 +1,41 @@
 -- removing coordinator from pg_dist_node should update pg_dist_colocation
 SELECT master_remove_node('localhost', :master_port);
 
+-- to silence -potentially flaky- "could not establish connection after" warnings in below test
+SET client_min_messages TO ERROR;
+
+-- to fail fast when the hostname is not resolvable, as it will be the case below
+SET citus.node_connection_timeout to '1s';
+
+BEGIN;
+  SET application_name TO 'new_app_name';
+
+  -- that should fail because of bad hostname & port
+  SELECT citus_add_node('200.200.200.200', 1, 200);
+
+  -- Since above command failed, now Postgres will need to revert the
+  -- application_name change made in this transaction and this will
+  -- happen within abort-transaction callback, so we won't be in a
+  -- transaction block while Postgres does that.
+  --
+  -- And when the application_name changes, Citus tries to re-assign
+  -- the global pid but it does so only for Citus internal backends,
+  -- and doing so for Citus internal backends doesn't require being
+  -- in a transaction block and is safe.
+  --
+  -- However, for the client external backends (like us here), Citus
+  -- doesn't re-assign the global pid because it's not needed and it's
+  -- not safe to do so outside of a transaction block. This is because,
+  -- it would require performing a catalog access to retrive the local
+  -- node id when the cached local node is invalidated like what just
+  -- happened here because of the failed citus_add_node() call made
+  -- above.
+  --
+  -- So by failing here (rather than crashing), we ensure this behavior.
+ROLLBACK;
+
+RESET client_min_messages;
+RESET citus.node_connection_timeout;
+
 -- restore coordinator for the rest of the tests
 SELECT citus_set_coordinator_host('localhost', :master_port);
diff --git a/src/test/regress/sql/upgrade_pg_dist_cleanup_after.sql b/src/test/regress/sql/upgrade_pg_dist_cleanup_after.sql
index e84c35b608c..333ac60ca93 100644
--- a/src/test/regress/sql/upgrade_pg_dist_cleanup_after.sql
+++ b/src/test/regress/sql/upgrade_pg_dist_cleanup_after.sql
@@ -13,3 +13,8 @@ SELECT COUNT(*) FROM pg_dist_placement WHERE shardid IN (SELECT shardid FROM pg_
 SELECT * FROM pg_dist_cleanup;
 CALL citus_cleanup_orphaned_resources();
 DROP TABLE table_with_orphaned_shards;
+
+-- Re-enable automatic shard cleanup by maintenance daemon as
+-- we have disabled it in upgrade_pg_dist_cleanup_before.sql
+ALTER SYSTEM RESET citus.defer_shard_delete_interval;
+SELECT pg_reload_conf();
diff --git a/src/test/regress/sql/upgrade_pg_dist_cleanup_before.sql b/src/test/regress/sql/upgrade_pg_dist_cleanup_before.sql
index 62ec8a1fb46..ec0eef353dc 100644
--- a/src/test/regress/sql/upgrade_pg_dist_cleanup_before.sql
+++ b/src/test/regress/sql/upgrade_pg_dist_cleanup_before.sql
@@ -16,6 +16,16 @@ SELECT create_distributed_table('table_with_orphaned_shards', 'a');
 -- show all 32 placements are active
 SELECT COUNT(*) FROM pg_dist_placement WHERE shardstate = 1 AND shardid IN (SELECT shardid FROM pg_dist_shard WHERE logicalrelid='table_with_orphaned_shards'::regclass);
 -- create an orphaned placement based on an existing one
+--
+-- But before doing that, first disable automatic shard cleanup
+-- by maintenance daemon so that we can reliably test the cleanup
+-- in upgrade_pg_dist_cleanup_after.sql.
+
+ALTER SYSTEM SET citus.defer_shard_delete_interval TO -1;
+SELECT pg_reload_conf();
+
+SELECT pg_sleep(0.1);
+
 INSERT INTO pg_dist_placement(placementid, shardid, shardstate, shardlength, groupid)
     SELECT nextval('pg_dist_placement_placementid_seq'::regclass), shardid, 4, shardlength, 3-groupid
     FROM pg_dist_placement