Hi, all
 I got a crash when copy partition tables with mass data in Cloudberry DB[0](based on Postgres14.4, Greenplum 7).
 I have a test on Postgres and it has the similar issue(different places but same function).
 However it’s a little hard to reproduce because it happened when inserting next tuple after a previous copy multi insert buffer is flushed.
 To reproduce easily, change the Macros to:
#define MAX_BUFFERED_TUPLES 1#define MAX_PARTITION_BUFFERS 0 Config and make install, when initdb, a core dump will be as:  
 #0 0x000055de617211b9 in CopyMultiInsertInfoNextFreeSlot (miinfo=0x7ffce496d360, rri=0x55de6368ba88)
  at copyfrom.c:592
 #1 0x000055de61721ff1 in CopyFrom (cstate=0x55de63592ce8) at copyfrom.c:985
 #2 0x000055de6171dd86 in DoCopy (pstate=0x55de63589e00, stmt=0x55de635347d8, stmt_location=0, stmt_len=195,
  processed=0x7ffce496d590) at copy.c:306
 #3 0x000055de61ad7ce8 in standard_ProcessUtility (pstmt=0x55de635348a8,
  queryString=0x55de63533960 "COPY information_schema.sql_features (feature_id, feature_name, sub_feature_id, sub
 _feature_name, is_supported, comments) FROM E'/home/gpadmin/install/pg17/share/postgresql/sql_features.txt';\n",
  readOnlyTree=false, context=PROCESS_UTILITY_TOPLEVEL, params=0x0, queryEnv=0x0, dest=0x55de620b0ce0 <debugtupDR>,
  qc=0x7ffce496d910) at utility.c:735
 #4 0x000055de61ad7614 in ProcessUtility (pstmt=0x55de635348a8,
  queryString=0x55de63533960 "COPY information_schema.sql_features (feature_id, feature_name, sub_feature_id, sub
 _feature_name, is_supported, comments) FROM E'/home/gpadmin/install/pg17/share/postgresql/sql_features.txt';\n",
  readOnlyTree=false, context=PROCESS_UTILITY_TOPLEVEL, params=0x0, queryEnv=0x0, dest=0x55de620b0ce0 <debugtupDR>,
  qc=0x7ffce496d910) at utility.c:523
 #5 0x000055de61ad5e8f in PortalRunUtility (portal=0x55de633dd7a0, pstmt=0x55de635348a8, isTopLevel=true,
  setHoldSnapshot=false, dest=0x55de620b0ce0 <debugtupDR>, qc=0x7ffce496d910) at pquery.c:1158
 #6 0x000055de61ad6106 in PortalRunMulti (portal=0x55de633dd7a0, isTopLevel=true, setHoldSnapshot=false,
  dest=0x55de620b0ce0 <debugtupDR>, altdest=0x55de620b0ce0 <debugtupDR>, qc=0x7ffce496d910) at pquery.c:1315
 #7 0x000055de61ad5550 in PortalRun (portal=0x55de633dd7a0, count=9223372036854775807, isTopLevel=true,
  run_once=true, dest=0x55de620b0ce0 <debugtupDR>, altdest=0x55de620b0ce0 <debugtupDR>, qc=0x7ffce496d910)
  at pquery.c:791```
 The root cause is:  we may call CopyMultiInsertInfoFlush() to flush buffer during COPY tuples, ex: insert from next tuple, 
 CopyMultiInsertInfoNextFreeSlot() will get a crash due to null pointer of buffer.
 To fix it: instead of call CopyMultiInsertInfoSetupBuffer() outside, I put it into CopyMultiInsertInfoNextFreeSlot() to avoid such issues.
 [0] 
https://github.com/cloudberrydb/cloudberrydb