diff options
Diffstat (limited to 'src/include/storage/relfilenode.h')
| -rw-r--r-- | src/include/storage/relfilenode.h | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/src/include/storage/relfilenode.h b/src/include/storage/relfilenode.h index 9638294b4a4..8ac8147ed93 100644 --- a/src/include/storage/relfilenode.h +++ b/src/include/storage/relfilenode.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/relfilenode.h,v 1.15 2008/01/01 19:45:59 momjian Exp $ + * $PostgreSQL: pgsql/src/include/storage/relfilenode.h,v 1.16 2008/08/11 11:05:11 heikki Exp $ * *------------------------------------------------------------------------- */ @@ -15,8 +15,25 @@ #define RELFILENODE_H /* + * The physical storage of a relation consists of one or more forks. The + * main fork is always created, but in addition to that there can be + * additional forks for storing various metadata. ForkNumber is used when + * we need to refer to a specific fork in a relation. + */ +typedef enum ForkNumber +{ + InvalidForkNumber = -1, + MAIN_FORKNUM = 0 + /* NOTE: change NUM_FORKS below when you add new forks */ +} ForkNumber; + +#define MAX_FORKNUM MAIN_FORKNUM + +/* * RelFileNode must provide all that we need to know to physically access - * a relation. + * a relation. Note, however, that a "physical" relation is comprised of + * multiple files on the filesystem, as each fork is stored as a separate + * file, and each fork can be divided into multiple segments. See md.c. * * spcNode identifies the tablespace of the relation. It corresponds to * pg_tablespace.oid. @@ -57,4 +74,13 @@ typedef struct RelFileNode (node1).dbNode == (node2).dbNode && \ (node1).spcNode == (node2).spcNode) +/* + * RelFileFork identifies a particular fork of a relation. + */ +typedef struct RelFileFork +{ + RelFileNode rnode; + ForkNumber forknum; +} RelFileFork; + #endif /* RELFILENODE_H */ |