diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 65db2e48d88..85a7b285ec3 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -3210,8 +3210,7 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock) { char path[MAXPGPATH]; char tmppath[MAXPGPATH]; - char zbuffer_raw[XLOG_BLCKSZ + MAXIMUM_ALIGNOF]; - char *zbuffer; + PGAlignedXLogBlock zbuffer; XLogSegNo installed_segno; XLogSegNo max_segno; int fd; @@ -3263,17 +3262,13 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock) * fsync below) that all the indirect blocks are down on disk. Therefore, * fdatasync(2) or O_DSYNC will be sufficient to sync future writes to the * log file. - * - * Note: ensure the buffer is reasonably well-aligned; this may save a few - * cycles transferring data to the kernel. */ - zbuffer = (char *) MAXALIGN(zbuffer_raw); - memset(zbuffer, 0, XLOG_BLCKSZ); + memset(zbuffer.data, 0, XLOG_BLCKSZ); for (nbytes = 0; nbytes < wal_segment_size; nbytes += XLOG_BLCKSZ) { errno = 0; pgstat_report_wait_start(WAIT_EVENT_WAL_INIT_WRITE); - if ((int) write(fd, zbuffer, XLOG_BLCKSZ) != (int) XLOG_BLCKSZ) + if ((int) write(fd, zbuffer.data, XLOG_BLCKSZ) != (int) XLOG_BLCKSZ) { int save_errno = errno; @@ -3380,7 +3375,7 @@ XLogFileCopy(XLogSegNo destsegno, TimeLineID srcTLI, XLogSegNo srcsegno, { char path[MAXPGPATH]; char tmppath[MAXPGPATH]; - char buffer[XLOG_BLCKSZ]; + PGAlignedXLogBlock buffer; int srcfd; int fd; int nbytes; @@ -3423,7 +3418,7 @@ XLogFileCopy(XLogSegNo destsegno, TimeLineID srcTLI, XLogSegNo srcsegno, * zeros. */ if (nread < sizeof(buffer)) - memset(buffer, 0, sizeof(buffer)); + memset(buffer.data, 0, sizeof(buffer)); if (nread > 0) { @@ -3432,7 +3427,7 @@ XLogFileCopy(XLogSegNo destsegno, TimeLineID srcTLI, XLogSegNo srcsegno, if (nread > sizeof(buffer)) nread = sizeof(buffer); pgstat_report_wait_start(WAIT_EVENT_WAL_COPY_READ); - r = read(srcfd, buffer, nread); + r = read(srcfd, buffer.data, nread); if (r != nread) { if (r < 0) @@ -3450,7 +3445,7 @@ XLogFileCopy(XLogSegNo destsegno, TimeLineID srcTLI, XLogSegNo srcsegno, } errno = 0; pgstat_report_wait_start(WAIT_EVENT_WAL_COPY_WRITE); - if ((int) write(fd, buffer, sizeof(buffer)) != (int) sizeof(buffer)) + if ((int) write(fd, buffer.data, sizeof(buffer)) != (int) sizeof(buffer)) { int save_errno = errno; @@ -6540,8 +6535,11 @@ StartupXLOG(void) xlogreader->system_identifier = ControlFile->system_identifier; /* - * Allocate pages dedicated to WAL consistency checks, those had better be - * aligned. + * Allocate two page buffers dedicated to WAL consistency checks. We do + * it this way, rather than just making static arrays, for two reasons: + * (1) no need to waste the storage in most instantiations of the backend; + * (2) a static char array isn't guaranteed to have any particular + * alignment, whereas palloc() will provide MAXALIGN'd storage. */ replay_image_masked = (char *) palloc(BLCKSZ); master_image_masked = (char *) palloc(BLCKSZ); |