diff options
| -rw-r--r-- | src/backend/storage/buffer/bufmgr.c | 40 |
1 files changed, 26 insertions, 14 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 8341a25e055..4d2c869860f 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.197 2005/10/15 02:49:24 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.198 2005/10/27 17:07:58 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -85,7 +85,8 @@ static volatile BufferDesc *PinCountWaitBuf = NULL; static bool PinBuffer(volatile BufferDesc *buf); static void PinBuffer_Locked(volatile BufferDesc *buf); -static void UnpinBuffer(volatile BufferDesc *buf, bool fixOwner, bool trashOK); +static void UnpinBuffer(volatile BufferDesc *buf, + bool fixOwner, bool normalAccess); static bool SyncOneBuffer(int buf_id, bool skip_pinned); static void WaitIO(volatile BufferDesc *buf); static bool StartBufferIO(volatile BufferDesc *buf, bool forInput); @@ -780,12 +781,18 @@ PinBuffer_Locked(volatile BufferDesc *buf) * This should be applied only to shared buffers, never local ones. * * Most but not all callers want CurrentResourceOwner to be adjusted. + * Those that don't should pass fixOwner = FALSE. + * + * normalAccess indicates that we are finishing a "normal" page access, + * that is, one requested by something outside the buffer subsystem. + * Passing FALSE means it's an internal access that should not update the + * buffer's usage count nor cause a change in the freelist. * * If we are releasing a buffer during VACUUM, and it's not been otherwise - * used recently, and trashOK is true, send the buffer to the freelist. + * used recently, and normalAccess is true, we send the buffer to the freelist. */ static void -UnpinBuffer(volatile BufferDesc *buf, bool fixOwner, bool trashOK) +UnpinBuffer(volatile BufferDesc *buf, bool fixOwner, bool normalAccess) { int b = buf->buf_id; @@ -797,7 +804,7 @@ UnpinBuffer(volatile BufferDesc *buf, bool fixOwner, bool trashOK) PrivateRefCount[b]--; if (PrivateRefCount[b] == 0) { - bool trash_buffer = false; + bool immed_free_buffer = false; /* I'd better not still hold any locks on the buffer */ Assert(!LWLockHeldByMe(buf->content_lock)); @@ -810,16 +817,21 @@ UnpinBuffer(volatile BufferDesc *buf, bool fixOwner, bool trashOK) Assert(buf->refcount > 0); buf->refcount--; - /* Mark the buffer recently used, unless we are in VACUUM */ - if (!strategy_hint_vacuum) + /* Update buffer usage info, unless this is an internal access */ + if (normalAccess) { - if (buf->usage_count < BM_MAX_USAGE_COUNT) - buf->usage_count++; + if (!strategy_hint_vacuum) + { + if (buf->usage_count < BM_MAX_USAGE_COUNT) + buf->usage_count++; + } + else + { + /* VACUUM accesses don't bump usage count, instead... */ + if (buf->refcount == 0 && buf->usage_count == 0) + immed_free_buffer = true; + } } - else if (trashOK && - buf->refcount == 0 && - buf->usage_count == 0) - trash_buffer = true; if ((buf->flags & BM_PIN_COUNT_WAITER) && buf->refcount == 1) @@ -839,7 +851,7 @@ UnpinBuffer(volatile BufferDesc *buf, bool fixOwner, bool trashOK) * freelist for near-term reuse. We put it at the tail so that it * won't be used before any invalid buffers that may exist. */ - if (trash_buffer) + if (immed_free_buffer) StrategyFreeBuffer(buf, false); } } |