Use prefetch in pg_prewarm extension (#236)

* Use prefetch in pg_prewarm extension * Change prefetch order as suggested in review
neondatabase · Nov 21, 2022 · da50d99 · da50d99
1 parent 38009a2
commit da50d99
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Showing 2 changed files with 9 additions and 2 deletions.
diff --git a/contrib/pg_prewarm/pg_prewarm.c b/contrib/pg_prewarm/pg_prewarm.c
@@ -18,6 +18,7 @@
 #include "access/relation.h"
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "optimizer/cost.h"
 #include "storage/bufmgr.h"
 #include "storage/smgr.h"
 #include "utils/acl.h"
@@ -184,14 +185,19 @@ pg_prewarm(PG_FUNCTION_ARGS)
 	}
 	else if (ptype == PREWARM_BUFFER)
 	{
+		BlockNumber prefetch_block = first_block;
 		/*
 		 * In buffer mode, we actually pull the data into shared_buffers.
 		 */
 		for (block = first_block; block <= last_block; ++block)
 		{
-			Buffer		buf;
-
+			Buffer buf;
+			int prefetch_stop = block + Min(last_block - block + 1, seqscan_prefetch_buffers);
 			CHECK_FOR_INTERRUPTS();
+			while (prefetch_block < prefetch_stop)
+			{
+				PrefetchBuffer(rel, forkNumber, prefetch_block++);
+			}
 			buf = ReadBufferExtended(rel, forkNumber, block, RBM_NORMAL, NULL);
 			ReleaseBuffer(buf);
 			++blocks_done;

diff --git a/contrib/pg_prewarm/pg_prewarm.control b/contrib/pg_prewarm/pg_prewarm.control
@@ -3,3 +3,4 @@ comment = 'prewarm relation data'
 default_version = '1.2'
 module_pathname = '$libdir/pg_prewarm'
 relocatable = true
+trusted = true