bufmgr: Make buffer hit helper

Already two places count buffer hits, requiring quite a few lines of
code since we do accounting in so many places. Future commits will add
more locations, so refactor into a helper.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/zljergweqti7x67lg5ije2rzjusie37nslsnkjkkby4laqqbfw@3p3zu522yykv

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index ab9c2a4b9041d4663709b8bb1ddc030a43452752..fa85570a7912e12df38e2bc6ca8181c152f81fe2 100644 (file)
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -648,6 +648,11 @@ static inline BufferDesc *BufferAlloc(SMgrRelation smgr,
                                                                          bool *foundPtr, IOContext io_context);
 static bool AsyncReadBuffers(ReadBuffersOperation *operation, int *nblocks_progress);
 static void CheckReadBuffersOperation(ReadBuffersOperation *operation, bool is_complete);
+
+static pg_attribute_always_inline void TrackBufferHit(IOObject io_object,
+                                                                                                         IOContext io_context,
+                                                                                                         Relation rel, char persistence, SMgrRelation smgr,
+                                                                                                         ForkNumber forknum, BlockNumber blocknum);
 static Buffer GetVictimBuffer(BufferAccessStrategy strategy, IOContext io_context);
 static void FlushUnlockedBuffer(BufferDesc *buf, SMgrRelation reln,
                                                                IOObject io_object, IOContext io_context);
@@ -1243,18 +1248,14 @@ PinBufferForBlock(Relation rel,
                                                                           smgr->smgr_rlocator.backend);
 
        if (persistence == RELPERSISTENCE_TEMP)
-       {
                bufHdr = LocalBufferAlloc(smgr, forkNum, blockNum, foundPtr);
-               if (*foundPtr)
-                       pgBufferUsage.local_blks_hit++;
-       }
        else
-       {
                bufHdr = BufferAlloc(smgr, persistence, forkNum, blockNum,
                                                         strategy, foundPtr, io_context);
-               if (*foundPtr)
-                       pgBufferUsage.shared_blks_hit++;
-       }
+
+       if (*foundPtr)
+               TrackBufferHit(io_object, io_context, rel, persistence, smgr, forkNum, blockNum);
+
        if (rel)
        {
                /*
@@ -1263,21 +1264,6 @@ PinBufferForBlock(Relation rel,
                 * zeroed instead), the per-relation stats always count them.
                 */
                pgstat_count_buffer_read(rel);
-               if (*foundPtr)
-                       pgstat_count_buffer_hit(rel);
-       }
-       if (*foundPtr)
-       {
-               pgstat_count_io_op(io_object, io_context, IOOP_HIT, 1, 0);
-               if (VacuumCostActive)
-                       VacuumCostBalance += VacuumCostPageHit;
-
-               TRACE_POSTGRESQL_BUFFER_READ_DONE(forkNum, blockNum,
-                                                                                 smgr->smgr_rlocator.locator.spcOid,
-                                                                                 smgr->smgr_rlocator.locator.dbOid,
-                                                                                 smgr->smgr_rlocator.locator.relNumber,
-                                                                                 smgr->smgr_rlocator.backend,
-                                                                                 true);
        }
 
        return BufferDescriptorGetBuffer(bufHdr);
@@ -1712,6 +1698,37 @@ ReadBuffersCanStartIO(Buffer buffer, bool nowait)
        return ReadBuffersCanStartIOOnce(buffer, nowait);
 }
 
+/*
+ * We track various stats related to buffer hits. Because this is done in a
+ * few separate places, this helper exists for convenience.
+ */
+static pg_attribute_always_inline void
+TrackBufferHit(IOObject io_object, IOContext io_context,
+                          Relation rel, char persistence, SMgrRelation smgr,
+                          ForkNumber forknum, BlockNumber blocknum)
+{
+       TRACE_POSTGRESQL_BUFFER_READ_DONE(forknum,
+                                                                         blocknum,
+                                                                         smgr->smgr_rlocator.locator.spcOid,
+                                                                         smgr->smgr_rlocator.locator.dbOid,
+                                                                         smgr->smgr_rlocator.locator.relNumber,
+                                                                         smgr->smgr_rlocator.backend,
+                                                                         true);
+
+       if (persistence == RELPERSISTENCE_TEMP)
+               pgBufferUsage.local_blks_hit += 1;
+       else
+               pgBufferUsage.shared_blks_hit += 1;
+
+       pgstat_count_io_op(io_object, io_context, IOOP_HIT, 1, 0);
+
+       if (VacuumCostActive)
+               VacuumCostBalance += VacuumCostPageHit;
+
+       if (rel)
+               pgstat_count_buffer_hit(rel);
+}
+
 /*
  * Helper for WaitReadBuffers() that processes the results of a readv
  * operation, raising an error if necessary.
@@ -2007,25 +2024,8 @@ AsyncReadBuffers(ReadBuffersOperation *operation, int *nblocks_progress)
                 * must have started out as a miss in PinBufferForBlock(). The other
                 * backend will track this as a 'read'.
                 */
-               TRACE_POSTGRESQL_BUFFER_READ_DONE(forknum, blocknum,
-                                                                                 operation->smgr->smgr_rlocator.locator.spcOid,
-                                                                                 operation->smgr->smgr_rlocator.locator.dbOid,
-                                                                                 operation->smgr->smgr_rlocator.locator.relNumber,
-                                                                                 operation->smgr->smgr_rlocator.backend,
-                                                                                 true);
-
-               if (persistence == RELPERSISTENCE_TEMP)
-                       pgBufferUsage.local_blks_hit += 1;
-               else
-                       pgBufferUsage.shared_blks_hit += 1;
-
-               if (operation->rel)
-                       pgstat_count_buffer_hit(operation->rel);
-
-               pgstat_count_io_op(io_object, io_context, IOOP_HIT, 1, 0);
-
-               if (VacuumCostActive)
-                       VacuumCostBalance += VacuumCostPageHit;
+               TrackBufferHit(io_object, io_context, operation->rel, persistence,
+                                          operation->smgr, forknum, blocknum);
        }
        else
        {