diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 6f9c5513e3a..28daf72a503 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -562,11 +562,12 @@ typedef struct XLogCtlInsert char pad[PG_CACHE_LINE_SIZE]; /* - * fullPageWrites is the master copy used by all backends to determine - * whether to write full-page to WAL, instead of using process-local one. - * This is required because, when full_page_writes is changed by SIGHUP, - * we must WAL-log it before it actually affects WAL-logging by backends. - * Checkpointer sets at startup or after SIGHUP. + * fullPageWrites is the authoritative value used by all backends to + * determine whether to write full-page image to WAL. This shared value, + * instead of the process-local fullPageWrites, is required because, when + * full_page_writes is changed by SIGHUP, we must WAL-log it before it + * actually affects WAL-logging by backends. Checkpointer sets at startup + * or after SIGHUP. * * To read these fields, you must hold an insertion lock. To modify them, * you must hold ALL the locks. @@ -8366,8 +8367,9 @@ GetRedoRecPtr(void) /* * The possibly not up-to-date copy in XlogCtl is enough. Even if we - * grabbed a WAL insertion lock to read the master copy, someone might - * update it just after we've released the lock. + * grabbed a WAL insertion lock to read the authoritative value in + * Insert->RedoRecPtr, someone might update it just after we've released + * the lock. */ SpinLockAcquire(&XLogCtl->info_lck); ptr = XLogCtl->RedoRecPtr; |