diff options
Diffstat (limited to 'src/include/storage/proc.h')
| -rw-r--r-- | src/include/storage/proc.h | 35 |
1 files changed, 4 insertions, 31 deletions
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h index b78012ec2b6..11b514c9ae8 100644 --- a/src/include/storage/proc.h +++ b/src/include/storage/proc.h @@ -87,36 +87,8 @@ struct XidCache #define INVALID_PGPROCNO PG_INT32_MAX /* - * Flags for PGPROC.delayChkpt - * - * These flags can be used to delay the start or completion of a checkpoint - * for short periods. A flag is in effect if the corresponding bit is set in - * the PGPROC of any backend. - * - * For our purposes here, a checkpoint has three phases: (1) determine the - * location to which the redo pointer will be moved, (2) write all the - * data durably to disk, and (3) WAL-log the checkpoint. - * - * Setting DELAY_CHKPT_START prevents the system from moving from phase 1 - * to phase 2. This is useful when we are performing a WAL-logged modification - * of data that will be flushed to disk in phase 2. By setting this flag - * before writing WAL and clearing it after we've both written WAL and - * performed the corresponding modification, we ensure that if the WAL record - * is inserted prior to the new redo point, the corresponding data changes will - * also be flushed to disk before the checkpoint can complete. (In the - * extremely common case where the data being modified is in shared buffers - * and we acquire an exclusive content lock on the relevant buffers before - * writing WAL, this mechanism is not needed, because phase 2 will block - * until we release the content lock and then flush the modified data to - * disk.) - * - * Setting DELAY_CHKPT_COMPLETE prevents the system from moving from phase 2 - * to phase 3. This is useful if we are performing a WAL-logged operation that - * might invalidate buffers, such as relation truncation. In this case, we need - * to ensure that any buffers which were invalidated and thus not flushed by - * the checkpoint are actaully destroyed on disk. Replay can cope with a file - * or block that doesn't exist, but not with a block that has the wrong - * contents. + * Flags used only for type of internal functions + * GetVirtualXIDsDelayingChkptGuts and HaveVirtualXIDsDelayingChkptGuts. */ #define DELAY_CHKPT_START (1<<0) #define DELAY_CHKPT_COMPLETE (1<<1) @@ -226,11 +198,12 @@ struct PGPROC pg_atomic_uint64 waitStart; /* time at which wait for lock acquisition * started */ - int delayChkpt; /* for DELAY_CHKPT_* flags */ + bool delayChkpt; /* true if this proc delays checkpoint start */ uint8 statusFlags; /* this backend's status flags, see PROC_* * above. mirrored in * ProcGlobal->statusFlags[pgxactoff] */ + bool delayChkptEnd; /* true if this proc delays checkpoint end */ /* * Info to allow us to wait for synchronous replication, if needed. |