Fix _bt_allequalimage() call within critical section.

_bt_allequalimage() does complicated things, so it's not OK to call it
in a critical section. Per buildfarm failure on 'prion', which uses
-DRELCACHE_FORCE_RELEASE -DCATCACHE_FORCE_RELEASE options.

Discussion: https://www.postgresql.org/message-id/6e5bbc08-cdfc-b2b3-9e23-1a914b9850a9@iki.fi
Backpatch-through: 16, like commit ccadf73163 that introduced this

diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index ad07b80f758de12f96010b434d8eb8c6e1fd6bef..62bc9917f13a9e057b15f487b4b510954f900731 100644 (file)
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -151,6 +151,7 @@ bthandler(PG_FUNCTION_ARGS)
 void
 btbuildempty(Relation index)
 {
+       bool            allequalimage = _bt_allequalimage(index, false);
        Buffer          metabuf;
        Page            metapage;
 
@@ -169,7 +170,7 @@ btbuildempty(Relation index)
        START_CRIT_SECTION();
 
        metapage = BufferGetPage(metabuf);
-       _bt_initmetapage(metapage, P_NONE, 0, _bt_allequalimage(index, false));
+       _bt_initmetapage(metapage, P_NONE, 0, allequalimage);
        MarkBufferDirty(metabuf);
        log_newpage_buffer(metabuf, true);