diff options
Diffstat (limited to 'src/backend/storage/buffer/bufmgr.c')
| -rw-r--r-- | src/backend/storage/buffer/bufmgr.c | 85 |
1 files changed, 44 insertions, 41 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index ba79effe5db..53c01c844a5 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 1.174 2004/08/29 04:12:47 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.175 2004/08/29 05:06:47 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -58,7 +58,7 @@ bool zero_damaged_pages = false; #ifdef NOT_USED -bool ShowPinTrace = false; +bool ShowPinTrace = false; #endif long NDirectFileRead; /* some I/O's are direct file access. @@ -143,6 +143,7 @@ ReadBufferInternal(Relation reln, BlockNumber blockNum, { ReadBufferCount++; pgstat_count_buffer_read(&reln->pgstat_info, reln); + /* * lookup the buffer. IO_IN_PROGRESS is set if the requested * block is not currently in memory. @@ -174,11 +175,11 @@ ReadBufferInternal(Relation reln, BlockNumber blockNum, * it, if it's a shared buffer. * * Note: if smgrextend fails, we will end up with a buffer that is - * allocated but not marked BM_VALID. P_NEW will still select the same - * block number (because the relation didn't get any longer on disk) - * and so future attempts to extend the relation will find the same - * buffer (if it's not been recycled) but come right back here to try - * smgrextend again. + * allocated but not marked BM_VALID. P_NEW will still select the + * same block number (because the relation didn't get any longer on + * disk) and so future attempts to extend the relation will find the + * same buffer (if it's not been recycled) but come right back here to + * try smgrextend again. */ Assert(!(bufHdr->flags & BM_VALID)); @@ -196,10 +197,11 @@ ReadBufferInternal(Relation reln, BlockNumber blockNum, if (!PageHeaderIsValid((PageHeader) MAKE_PTR(bufHdr->data))) { /* - * During WAL recovery, the first access to any data page should - * overwrite the whole page from the WAL; so a clobbered page - * header is not reason to fail. Hence, when InRecovery we may - * always act as though zero_damaged_pages is ON. + * During WAL recovery, the first access to any data page + * should overwrite the whole page from the WAL; so a + * clobbered page header is not reason to fail. Hence, when + * InRecovery we may always act as though zero_damaged_pages + * is ON. */ if (zero_damaged_pages || InRecovery) { @@ -212,8 +214,8 @@ ReadBufferInternal(Relation reln, BlockNumber blockNum, else ereport(ERROR, (errcode(ERRCODE_DATA_CORRUPTED), - errmsg("invalid page header in block %u of relation \"%s\"", - blockNum, RelationGetRelationName(reln)))); + errmsg("invalid page header in block %u of relation \"%s\"", + blockNum, RelationGetRelationName(reln)))); } } @@ -348,9 +350,9 @@ BufferAlloc(Relation reln, * if someone were writing it. * * Note: it's okay to grab the io_in_progress lock while holding - * BufMgrLock. All code paths that acquire this lock pin the - * buffer first; since no one had it pinned (it just came off the - * free list), no one else can have the lock. + * BufMgrLock. All code paths that acquire this lock pin the + * buffer first; since no one had it pinned (it just came off + * the free list), no one else can have the lock. */ StartBufferIO(buf, false); @@ -364,23 +366,23 @@ BufferAlloc(Relation reln, /* * Somebody could have allocated another buffer for the same - * block we are about to read in. While we flush out the - * dirty buffer, we don't hold the lock and someone could have + * block we are about to read in. While we flush out the dirty + * buffer, we don't hold the lock and someone could have * allocated another buffer for the same block. The problem is * we haven't yet inserted the new tag into the buffer table. * So we need to check here. -ay 3/95 * - * Another reason we have to do this is to update cdb_found_index, - * since the CDB could have disappeared from B1/B2 list while - * we were writing. + * Another reason we have to do this is to update + * cdb_found_index, since the CDB could have disappeared from + * B1/B2 list while we were writing. */ buf2 = StrategyBufferLookup(&newTag, true, &cdb_found_index); if (buf2 != NULL) { /* - * Found it. Someone has already done what we were about to - * do. We'll just handle this as if it were found in the - * buffer pool in the first place. First, give up the + * Found it. Someone has already done what we were about + * to do. We'll just handle this as if it were found in + * the buffer pool in the first place. First, give up the * buffer we were planning to use. */ TerminateBufferIO(buf, 0); @@ -404,8 +406,9 @@ BufferAlloc(Relation reln, if (!(buf->flags & BM_VALID)) { /* - * If we get here, previous attempts to read the buffer - * must have failed ... but we shall bravely try again. + * If we get here, previous attempts to read the + * buffer must have failed ... but we shall + * bravely try again. */ *foundPtr = FALSE; StartBufferIO(buf, true); @@ -441,8 +444,8 @@ BufferAlloc(Relation reln, /* * Tell the buffer replacement strategy that we are replacing the - * buffer content. Then rename the buffer. Clearing BM_VALID here - * is necessary, clearing the dirtybits is just paranoia. + * buffer content. Then rename the buffer. Clearing BM_VALID here is + * necessary, clearing the dirtybits is just paranoia. */ StrategyReplaceBuffer(buf, &newTag, cdb_found_index, cdb_replace_index); buf->tag = newTag; @@ -685,9 +688,9 @@ BufferSync(int percent, int maxpages) NBuffers); /* - * If called by the background writer, we are usually asked to - * only write out some portion of dirty buffers now, to prevent - * the IO storm at checkpoint time. + * If called by the background writer, we are usually asked to only + * write out some portion of dirty buffers now, to prevent the IO + * storm at checkpoint time. */ if (percent > 0) { @@ -702,8 +705,8 @@ BufferSync(int percent, int maxpages) /* * Loop over buffers to be written. Note the BufMgrLock is held at - * loop top, but is released and reacquired within FlushBuffer, - * so we aren't holding it long. + * loop top, but is released and reacquired within FlushBuffer, so we + * aren't holding it long. */ for (i = 0; i < num_buffer_dirty; i++) { @@ -712,8 +715,8 @@ BufferSync(int percent, int maxpages) /* * Check it is still the same page and still needs writing. * - * We can check bufHdr->cntxDirty here *without* holding any lock - * on buffer context as long as we set this flag in access methods + * We can check bufHdr->cntxDirty here *without* holding any lock on + * buffer context as long as we set this flag in access methods * *before* logging changes with XLogInsert(): if someone will set * cntxDirty just after our check we don't worry because of our * checkpoint.redo points before log record for upcoming changes @@ -860,7 +863,7 @@ AtEOXact_Buffers(bool isCommit) if (isCommit) elog(WARNING, "buffer refcount leak: [%03d] " - "(rel=%u/%u/%u, blockNum=%u, flags=0x%x, refcount=%u %d)", + "(rel=%u/%u/%u, blockNum=%u, flags=0x%x, refcount=%u %d)", i, buf->tag.rnode.spcNode, buf->tag.rnode.dbNode, buf->tag.rnode.relNode, @@ -1009,12 +1012,12 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln) XLogFlush(recptr); /* - * Now it's safe to write buffer to disk. Note that no one else - * should have been able to write it while we were busy with - * locking and log flushing because caller has set the IO flag. + * Now it's safe to write buffer to disk. Note that no one else should + * have been able to write it while we were busy with locking and log + * flushing because caller has set the IO flag. * - * It would be better to clear BM_JUST_DIRTIED right here, but we'd - * have to reacquire the BufMgrLock and it doesn't seem worth it. + * It would be better to clear BM_JUST_DIRTIED right here, but we'd have + * to reacquire the BufMgrLock and it doesn't seem worth it. */ smgrwrite(reln, buf->tag.blockNum, |