Use pg_pread() and pg_pwrite() in slru.c.
This avoids lseek() system calls at every SLRU I/O, as was
done for relation files in commit
Discussion:
Discussion:
@@ -669,7 +669,7 @@ SlruPhysicalReadPage(SlruCtl ctl, int pageno, int slotno)
SlruShared shared = ctl->shared;
int segno = pageno / SLRU_PAGES_PER_SEGMENT;
int rpageno = pageno % SLRU_PAGES_PER_SEGMENT;
- int offset = rpageno * BLCKSZ;
+ off_t offset = rpageno * BLCKSZ;
char path[MAXPGPATH];
int fd;
@@ -699,17 +699,9 @@ SlruPhysicalReadPage(SlruCtl ctl, int pageno, int slotno)
return true;
}
- if (lseek(fd, (off_t) offset, SEEK_SET) < 0)
- {
- slru_errcause = SLRU_SEEK_FAILED;
- slru_errno = errno;
- CloseTransientFile(fd);
- return false;
- }
-
errno = 0;
pgstat_report_wait_start(WAIT_EVENT_SLRU_READ);
- if (read(fd, shared->page_buffer[slotno], BLCKSZ) != BLCKSZ)
+ if (pg_pread(fd, shared->page_buffer[slotno], BLCKSZ, offset) != BLCKSZ)
{
pgstat_report_wait_end();
slru_errcause = SLRU_READ_FAILED;
@@ -749,7 +741,7 @@ SlruPhysicalWritePage(SlruCtl ctl, int pageno, int slotno, SlruFlush fdata)
SlruShared shared = ctl->shared;
int segno = pageno / SLRU_PAGES_PER_SEGMENT;
int rpageno = pageno % SLRU_PAGES_PER_SEGMENT;
- int offset = rpageno * BLCKSZ;
+ off_t offset = rpageno * BLCKSZ;
char path[MAXPGPATH];
int fd = -1;
@@ -862,18 +854,9 @@ SlruPhysicalWritePage(SlruCtl ctl, int pageno, int slotno, SlruFlush fdata)
}
}
- if (lseek(fd, (off_t) offset, SEEK_SET) < 0)
- {
- slru_errcause = SLRU_SEEK_FAILED;
- slru_errno = errno;
- if (!fdata)
- CloseTransientFile(fd);
- return false;
- }
-
errno = 0;
pgstat_report_wait_start(WAIT_EVENT_SLRU_WRITE);
- if (write(fd, shared->page_buffer[slotno], BLCKSZ) != BLCKSZ)
+ if (pg_pwrite(fd, shared->page_buffer[slotno], BLCKSZ, offset) != BLCKSZ)
{
pgstat_report_wait_end();
/* if write didn't set errno, assume problem is no disk space */
