v9-0001-Count-IO-time-for-temp-relation-writes.patch

From d17524cdeec3297eb7d08876fd7acc41e0f0f1b5 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Tue, 21 Mar 2023 16:00:55 -0400
Subject: [PATCH v9 1/4] Count IO time for temp relation writes

Both pgstat_database and pgBufferUsage count IO timing for reads of
temporary relation blocks into local buffers. However, both failed to
count write IO timing for flushes of dirty local buffers. Add this to
achieve parity.

Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20230321023451.7rzy4kjj2iktrg2r%40awork3.anarazel.de
---
 src/backend/storage/buffer/localbuf.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 3846d3eaca..3639296bc1 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -176,6 +176,8 @@ GetLocalVictimBuffer(void)
 	int			trycounter;
 	uint32		buf_state;
 	BufferDesc *bufHdr;
+	instr_time	io_start,
+				io_time;
 
 	ResourceOwnerEnlargeBuffers(CurrentResourceOwner);
 
@@ -239,6 +241,11 @@ GetLocalVictimBuffer(void)
 
 		PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
 
+		if (track_io_timing)
+			INSTR_TIME_SET_CURRENT(io_start);
+		else
+			INSTR_TIME_SET_ZERO(io_start);
+
 		/* And write... */
 		smgrwrite(oreln,
 				  BufTagGetForkNum(&bufHdr->tag),
@@ -252,6 +259,15 @@ GetLocalVictimBuffer(void)
 
 		/* Temporary table I/O does not use Buffer Access Strategies */
 		pgstat_count_io_op(IOOBJECT_TEMP_RELATION, IOCONTEXT_NORMAL, IOOP_WRITE);
+
+		if (track_io_timing)
+		{
+			INSTR_TIME_SET_CURRENT(io_time);
+			INSTR_TIME_SUBTRACT(io_time, io_start);
+			pgstat_count_buffer_write_time(INSTR_TIME_GET_MICROSEC(io_time));
+			INSTR_TIME_ADD(pgBufferUsage.blk_write_time, io_time);
+		}
+
 		pgBufferUsage.local_blks_written++;
 	}
 
-- 
2.37.2