diff options
Diffstat (limited to 'src/backend/postmaster/bgwriter.c')
| -rw-r--r-- | src/backend/postmaster/bgwriter.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c index 7d19bf9f424..26650253361 100644 --- a/src/backend/postmaster/bgwriter.c +++ b/src/backend/postmaster/bgwriter.c @@ -2,7 +2,7 @@ * * bgwriter.c * - * The background writer (bgwriter) is new in Postgres 8.0. It attempts + * The background writer (bgwriter) is new as of Postgres 8.0. It attempts * to keep regular backends from having to write out dirty shared buffers * (which they would only do when needing to free a shared buffer to read in * another page). In the best scenario all writes from shared buffers will @@ -37,7 +37,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.34 2007/01/05 22:19:36 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.35 2007/01/17 00:17:20 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -103,8 +103,8 @@ typedef struct { RelFileNode rnode; - BlockNumber segno; - /* might add a request-type field later */ + BlockNumber segno; /* InvalidBlockNumber means "revoke" */ + /* might add a real request-type field later; not needed yet */ } BgWriterRequest; typedef struct @@ -695,6 +695,11 @@ RequestCheckpoint(bool waitforit, bool warnontime) * ForwardFsyncRequest * Forward a file-fsync request from a backend to the bgwriter * + * segno specifies which segment (not block!) of the relation needs to be + * fsync'd. If segno == InvalidBlockNumber, the meaning is to revoke any + * pending fsync requests for the entire relation (this message is sent + * when the relation is about to be deleted). + * * Whenever a backend is compelled to write directly to a relation * (which should be seldom, if the bgwriter is getting its job done), * the backend calls this routine to pass over knowledge that the relation |