SIGSEGV in getCdbComponentInfo() when standby coordinator is on dedicated host (apache#1702)

* Fix null dereference on dedicated hot standby coordinator

getCdbComponentInfo() populates hostPrimaryCountHash with primary hosts only.
When IS_HOT_STANDBY_QD() is true, mirror and standby hosts are also looked up
in the hash but return NULL on dedicated standby nodes that host no primary
segments. Replace Assert(found) with a null-safe check to prevent SIGSEGV.

Author: jangjang0401

src/backend/cdb/cdbutil.c

@@ -593,8 +593,13 @@ getCdbComponentInfo(void)
 			continue;
 
 		hsEntry = (HostPrimaryCountEntry *) hash_search(hostPrimaryCountHash, cdbInfo->config->hostname, HASH_FIND, &found);
-		Assert(found);
-		cdbInfo->hostPrimaryCount = hsEntry->segmentCount;
+		Assert(found || IS_HOT_STANDBY_QD());
+		/*
+		 * Standby and mirror entries can legitimately live on hosts that do not
+		 * own any primary segments. In that case the lookup is absent and the
+		 * count should be treated as zero instead of dereferencing a NULL entry.
+		 */
+		cdbInfo->hostPrimaryCount = found ? hsEntry->segmentCount : 0;
 	}
 
 	for (i = 0; i < component_databases->total_entry_dbs; i++)
@@ -605,8 +610,13 @@ getCdbComponentInfo(void)
 			continue;
 
 		hsEntry = (HostPrimaryCountEntry *) hash_search(hostPrimaryCountHash, cdbInfo->config->hostname, HASH_FIND, &found);
-		Assert(found);
-		cdbInfo->hostPrimaryCount = hsEntry->segmentCount;
+		Assert(found || IS_HOT_STANDBY_QD());
+		/*
+		 * Standby and mirror entries can legitimately live on hosts that do not
+		 * own any primary segments. In that case the lookup is absent and the
+		 * count should be treated as zero instead of dereferencing a NULL entry.
+		 */
+		cdbInfo->hostPrimaryCount = found ? hsEntry->segmentCount : 0;
 	}
 
 	hash_destroy(hostPrimaryCountHash);

src/test/regress/expected/vacuum_gp.out

@@ -446,6 +446,8 @@ create table relcache_leak_in_motion(v1 int);
 NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'v1' as the Apache Cloudberry data distribution key for this table.
 HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
 insert into relcache_leak_in_motion values(generate_series(0, 10000));
+BEGIN;
+SET LOCAL synchronous_commit = local;
 SELECT gp_inject_fault('interconnect_stop_recv_chunk', 'interrupt', dbid)
   FROM gp_segment_configuration WHERE content = -1 and role='p';
  gp_inject_fault 
@@ -457,11 +459,8 @@ analyze relcache_leak_in_motion;
 ERROR:  canceling statement due to user request
 SELECT gp_inject_fault('interconnect_stop_recv_chunk', 'reset', dbid)
   FROM gp_segment_configuration WHERE content = -1 and role='p';
- gp_inject_fault 
------------------
- Success:
-(1 row)
-
+ERROR:  current transaction is aborted, commands ignored until end of transaction block
+COMMIT;
 -- start_ignore
 drop table if exists relcache_leak_in_motion;
 -- end_ignore

src/test/regress/sql/vacuum_gp.sql

@@ -298,11 +298,14 @@ drop table if exists relcache_leak_in_motion;
 -- end_ignore
 create table relcache_leak_in_motion(v1 int);
 insert into relcache_leak_in_motion values(generate_series(0, 10000));
+BEGIN;
+SET LOCAL synchronous_commit = local;
 SELECT gp_inject_fault('interconnect_stop_recv_chunk', 'interrupt', dbid)
   FROM gp_segment_configuration WHERE content = -1 and role='p';
 analyze relcache_leak_in_motion;
 SELECT gp_inject_fault('interconnect_stop_recv_chunk', 'reset', dbid)
   FROM gp_segment_configuration WHERE content = -1 and role='p';
+COMMIT;
 -- start_ignore
 drop table if exists relcache_leak_in_motion;
 -- end_ignore