diff options
Diffstat (limited to 'src/backend/access/transam/multixact.c')
| -rw-r--r-- | src/backend/access/transam/multixact.c | 50 |
1 files changed, 25 insertions, 25 deletions
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index 9e4ecdc3bba..c940e1d2b1e 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -4,15 +4,15 @@ * PostgreSQL multi-transaction-log manager * * The pg_multixact manager is a pg_clog-like manager that stores an array - * of TransactionIds for each MultiXactId. It is a fundamental part of the - * shared-row-lock implementation. A share-locked tuple stores a + * of TransactionIds for each MultiXactId. It is a fundamental part of the + * shared-row-lock implementation. A share-locked tuple stores a * MultiXactId in its Xmax, and a transaction that needs to wait for the * tuple to be unlocked can sleep on the potentially-several TransactionIds * that compose the MultiXactId. * * We use two SLRU areas, one for storing the offsets at which the data * starts for each MultiXactId in the other one. This trick allows us to - * store variable length arrays of TransactionIds. (We could alternatively + * store variable length arrays of TransactionIds. (We could alternatively * use one area containing counts and TransactionIds, with valid MultiXactId * values pointing at slots containing counts; but that way seems less robust * since it would get completely confused if someone inquired about a bogus @@ -32,7 +32,7 @@ * * Like clog.c, and unlike subtrans.c, we have to preserve state across * crashes and ensure that MXID and offset numbering increases monotonically - * across a crash. We do this in the same way as it's done for transaction + * across a crash. We do this in the same way as it's done for transaction * IDs: the WAL record is guaranteed to contain evidence of every MXID we * could need to worry about, and we just make sure that at the end of * replay, the next-MXID and next-offset counters are at least as large as @@ -64,13 +64,13 @@ /* - * Defines for MultiXactOffset page sizes. A page is the same BLCKSZ as is + * Defines for MultiXactOffset page sizes. A page is the same BLCKSZ as is * used everywhere else in Postgres. * * Note: because both MultiXactOffsets and TransactionIds are 32 bits and * wrap around at 0xFFFFFFFF, MultiXact page numbering also wraps around at * 0xFFFFFFFF/MULTIXACT_*_PER_PAGE, and segment numbering at - * 0xFFFFFFFF/MULTIXACT_*_PER_PAGE/SLRU_SEGMENTS_PER_PAGE. We need take no + * 0xFFFFFFFF/MULTIXACT_*_PER_PAGE/SLRU_SEGMENTS_PER_PAGE. We need take no * explicit notice of that fact in this module, except when comparing segment * and page numbers in TruncateMultiXact * (see MultiXact{Offset,Member}PagePrecedes). @@ -101,7 +101,7 @@ static SlruCtlData MultiXactMemberCtlData; #define MultiXactMemberCtl (&MultiXactMemberCtlData) /* - * MultiXact state shared across all backends. All this state is protected + * MultiXact state shared across all backends. All this state is protected * by MultiXactGenLock. (We also use MultiXactOffsetControlLock and * MultiXactMemberControlLock to guard accesses to the two sets of SLRU * buffers. For concurrency's sake, we avoid holding more than one of these @@ -343,7 +343,7 @@ MultiXactIdExpand(MultiXactId multi, TransactionId xid) /* * Determine which of the members of the MultiXactId are still running, * and use them to create a new one. (Removing dead members is just an - * optimization, but a useful one. Note we have the same race condition + * optimization, but a useful one. Note we have the same race condition * here as above: j could be 0 at the end of the loop.) */ newMembers = (TransactionId *) @@ -408,7 +408,7 @@ MultiXactIdIsRunning(MultiXactId multi) /* * This could be made faster by having another entry point in procarray.c, - * walking the PGPROC array only once for all the members. But in most + * walking the PGPROC array only once for all the members. But in most * cases nmembers should be small enough that it doesn't much matter. */ for (i = 0; i < nmembers; i++) @@ -527,7 +527,7 @@ MultiXactIdSetOldestMember(void) * The value to set is the oldest of nextMXact and all the valid per-backend * OldestMemberMXactId[] entries. Because of the locking we do, we can be * certain that no subsequent call to MultiXactIdSetOldestMember can set - * an OldestMemberMXactId[] entry older than what we compute here. Therefore + * an OldestMemberMXactId[] entry older than what we compute here. Therefore * there is no live transaction, now or later, that can be a member of any * MultiXactId older than the OldestVisibleMXactId we compute here. */ @@ -698,7 +698,7 @@ CreateMultiXactId(int nxids, TransactionId *xids) * heap_lock_tuple() to have put it there, and heap_lock_tuple() generates * an XLOG record that must follow ours. The normal LSN interlock between * the data page and that XLOG record will ensure that our XLOG record - * reaches disk first. If the SLRU members/offsets data reaches disk + * reaches disk first. If the SLRU members/offsets data reaches disk * sooner than the XLOG record, we do not care because we'll overwrite it * with zeroes unless the XLOG record is there too; see notes at top of * this file. @@ -805,7 +805,7 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset, * GetNewMultiXactId * Get the next MultiXactId. * - * Also, reserve the needed amount of space in the "members" area. The + * Also, reserve the needed amount of space in the "members" area. The * starting offset of the reserved space is returned in *offset. * * This may generate XLOG records for expansion of the offsets and/or members @@ -874,7 +874,7 @@ GetNewMultiXactId(int nxids, MultiXactOffset *offset) * until after file extension has succeeded! * * We don't care about MultiXactId wraparound here; it will be handled by - * the next iteration. But note that nextMXact may be InvalidMultiXactId + * the next iteration. But note that nextMXact may be InvalidMultiXactId * after this routine exits, so anyone else looking at the variable must * be prepared to deal with that. Similarly, nextOffset may be zero, but * we won't use that as the actual start offset of the next multixact. @@ -942,7 +942,7 @@ GetMultiXactIdMembers(MultiXactId multi, TransactionId **xids) * SLRU data if we did try to examine it. * * Conversely, an ID >= nextMXact shouldn't ever be seen here; if it is - * seen, it implies undetected ID wraparound has occurred. We just + * seen, it implies undetected ID wraparound has occurred. We just * silently assume that such an ID is no longer running. * * Shared lock is enough here since we aren't modifying any global state. @@ -958,7 +958,7 @@ GetMultiXactIdMembers(MultiXactId multi, TransactionId **xids) /* * Acquire the shared lock just long enough to grab the current counter - * values. We may need both nextMXact and nextOffset; see below. + * values. We may need both nextMXact and nextOffset; see below. */ LWLockAcquire(MultiXactGenLock, LW_SHARED); @@ -976,12 +976,12 @@ GetMultiXactIdMembers(MultiXactId multi, TransactionId **xids) /* * Find out the offset at which we need to start reading MultiXactMembers - * and the number of members in the multixact. We determine the latter as + * and the number of members in the multixact. We determine the latter as * the difference between this multixact's starting offset and the next * one's. However, there are some corner cases to worry about: * * 1. This multixact may be the latest one created, in which case there is - * no next one to look at. In this case the nextOffset value we just + * no next one to look at. In this case the nextOffset value we just * saved is the correct endpoint. * * 2. The next multixact may still be in process of being filled in: that @@ -992,11 +992,11 @@ GetMultiXactIdMembers(MultiXactId multi, TransactionId **xids) * (because we are careful to pre-zero offset pages). Because * GetNewMultiXactId will never return zero as the starting offset for a * multixact, when we read zero as the next multixact's offset, we know we - * have this case. We sleep for a bit and try again. + * have this case. We sleep for a bit and try again. * * 3. Because GetNewMultiXactId increments offset zero to offset one to * handle case #2, there is an ambiguity near the point of offset - * wraparound. If we see next multixact's offset is one, is that our + * wraparound. If we see next multixact's offset is one, is that our * multixact's actual endpoint, or did it end at zero with a subsequent * increment? We handle this using the knowledge that if the zero'th * member slot wasn't filled, it'll contain zero, and zero isn't a valid @@ -1388,7 +1388,7 @@ multixact_twophase_postabort(TransactionId xid, uint16 info, /* * Initialization of shared memory for MultiXact. We use two SLRU areas, - * thus double memory. Also, reserve space for the shared MultiXactState + * thus double memory. Also, reserve space for the shared MultiXactState * struct and the per-backend MultiXactId arrays (two of those, too). */ Size @@ -1448,7 +1448,7 @@ MultiXactShmemInit(void) /* * This func must be called ONCE on system install. It creates the initial - * MultiXact segments. (The MultiXacts directories are assumed to have been + * MultiXact segments. (The MultiXacts directories are assumed to have been * created by initdb, and MultiXactShmemInit must have been called already.) */ void @@ -1568,7 +1568,7 @@ TrimMultiXact(void) MultiXactOffsetCtl->shared->latest_page_number = pageno; /* - * Zero out the remainder of the current offsets page. See notes in + * Zero out the remainder of the current offsets page. See notes in * StartupCLOG() for motivation. */ entryno = MultiXactIdToOffsetEntry(multi); @@ -1598,7 +1598,7 @@ TrimMultiXact(void) MultiXactMemberCtl->shared->latest_page_number = pageno; /* - * Zero out the remainder of the current members page. See notes in + * Zero out the remainder of the current members page. See notes in * TrimCLOG() for motivation. */ entryno = MXOffsetToMemberEntry(offset); @@ -1799,7 +1799,7 @@ ExtendMultiXactMember(MultiXactOffset offset, int nmembers) * Remove all MultiXactOffset and MultiXactMember segments before the oldest * ones still of interest. * - * This is called only during checkpoints. We assume no more than one + * This is called only during checkpoints. We assume no more than one * backend does this at a time. * * XXX do we have any issues with needing to checkpoint here? @@ -1860,7 +1860,7 @@ TruncateMultiXact(void) return; /* - * We need to determine where to truncate MultiXactMember. If we found a + * We need to determine where to truncate MultiXactMember. If we found a * valid oldest MultiXactId, read its starting offset; otherwise we use * the nextOffset value we saved above. */ |