3 files changed, 29 insertions, 10 deletions

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 26f3ddbf853..1cea03d73a6 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -20,8 +20,6 @@
 #include "miscadmin.h"
 #include "utils/memutils.h"
 
-const XLogRecPtr XLogRecPtrForTemp = {1, 1};
-
 /* Working state for gistbuild and its callback */
 typedef struct
 {
@@ -130,7 +128,7 @@ gistbuild(PG_FUNCTION_ARGS)
 		PageSetTLI(page, ThisTimeLineID);
 	}
 	else
-		PageSetLSN(page, XLogRecPtrForTemp);
+		PageSetLSN(page, GetXLogRecPtrForTemp());
 
 	UnlockReleaseBuffer(buffer);
 
@@ -421,7 +419,7 @@ gistplacetopage(GISTInsertState *state, GISTSTATE *giststate)
 		{
 			for (ptr = dist; ptr; ptr = ptr->next)
 			{
-				PageSetLSN(ptr->page, XLogRecPtrForTemp);
+				PageSetLSN(ptr->page, GetXLogRecPtrForTemp());
 			}
 		}
 
@@ -489,7 +487,7 @@ gistplacetopage(GISTInsertState *state, GISTSTATE *giststate)
 			PageSetTLI(state->stack->page, ThisTimeLineID);
 		}
 		else
-			PageSetLSN(state->stack->page, XLogRecPtrForTemp);
+			PageSetLSN(state->stack->page, GetXLogRecPtrForTemp());
 
 		if (state->stack->blkno == GIST_ROOT_BLKNO)
 			state->needInsertComplete = false;
@@ -1025,7 +1023,7 @@ gistnewroot(Relation r, Buffer buffer, IndexTuple *itup, int len, ItemPointer ke
 		PageSetTLI(page, ThisTimeLineID);
 	}
 	else
-		PageSetLSN(page, XLogRecPtrForTemp);
+		PageSetLSN(page, GetXLogRecPtrForTemp());
 
 	END_CRIT_SECTION();
 }
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 7d51070788c..d88f5ea0f81 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -677,3 +677,24 @@ gistoptions(PG_FUNCTION_ARGS)
 		PG_RETURN_BYTEA_P(result);
 	PG_RETURN_NULL();
 }
+
+/*
+ * Temporary GiST indexes are not WAL-logged, but we need LSNs to detect
+ * concurrent page splits anyway. GetXLogRecPtrForTemp() provides a fake
+ * sequence of LSNs for that purpose. Each call generates an LSN that is
+ * greater than any previous value returned by this function in the same
+ * session.
+ */
+XLogRecPtr
+GetXLogRecPtrForTemp(void)
+{
+	static XLogRecPtr counter = {0, 1};
+
+	counter.xrecoff++;
+	if (counter.xrecoff == 0)
+	{
+		counter.xlogid++;
+		counter.xrecoff++;
+	}
+	return counter;
+}
diff --git a/src/backend/access/gist/gistvacuum.c b/src/backend/access/gist/gistvacuum.c
index 3691e17e441..af5fef1ea24 100644
--- a/src/backend/access/gist/gistvacuum.c
+++ b/src/backend/access/gist/gistvacuum.c
@@ -134,7 +134,7 @@ gistDeleteSubtree(GistVacuum *gv, BlockNumber blkno)
 		PageSetTLI(page, ThisTimeLineID);
 	}
 	else
-		PageSetLSN(page, XLogRecPtrForTemp);
+		PageSetLSN(page, GetXLogRecPtrForTemp());
 
 	END_CRIT_SECTION();
 
@@ -253,7 +253,7 @@ vacuumSplitPage(GistVacuum *gv, Page tempPage, Buffer buffer, IndexTuple *addon,
 	else
 	{
 		for (ptr = dist; ptr; ptr = ptr->next)
-			PageSetLSN(BufferGetPage(ptr->buffer), XLogRecPtrForTemp);
+			PageSetLSN(BufferGetPage(ptr->buffer), GetXLogRecPtrForTemp());
 	}
 
 	for (ptr = dist; ptr; ptr = ptr->next)
@@ -467,7 +467,7 @@ gistVacuumUpdate(GistVacuum *gv, BlockNumber blkno, bool needunion)
 				pfree(rdata);
 			}
 			else
-				PageSetLSN(page, XLogRecPtrForTemp);
+				PageSetLSN(page, GetXLogRecPtrForTemp());
 		}
 
 		END_CRIT_SECTION();
@@ -791,7 +791,7 @@ gistbulkdelete(PG_FUNCTION_ARGS)
 					pfree(rdata);
 				}
 				else
-					PageSetLSN(page, XLogRecPtrForTemp);
+					PageSetLSN(page, GetXLogRecPtrForTemp());
 
 				END_CRIT_SECTION();
 			}