RE: [Patch] Optimize dropping of relation buffers using dlist

The patch looks almost good except for the minor ones:

(1)
+    for (i = 0; i < nnodes; i++)
+    {
+        RelFileNodeBackend rnode = smgr_reln[i]->smgr_rnode;
+
+        rnodes[i] = rnode;
+    }

You can write:

+    for (i = 0; i < nnodes; i++)
+        rnodes[i] = smgr_reln[i]->smgr_rnode;


(2)
+        if (!accurate || j >= MAX_FORKNUM ||

The correct condition would be:

+        if (j <= MAX_FORKNUM ||

because j becomes MAX_FORKNUM + 1 if accurate sizes for all forks could be obtained.  If any fork's size is inaccurate,
jis <= MAX_FORKNUM when exiting the loop, so you don't need to test for accurate flag.
 


(3)
+        {
+            goto buffer_full_scan;
+            return;
+        }

return after goto cannot be reached, so this should just be:

+            goto buffer_full_scan;



Regards
Takayuki Tsunakawa