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We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
90 lines
2.6 KiB
C
90 lines
2.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* relpath.h
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* Declarations for GetRelationPath() and friends
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*
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* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/common/relpath.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef RELPATH_H
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#define RELPATH_H
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/*
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* 'pgrminclude ignore' needed here because CppAsString2() does not throw
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* an error if the symbol is not defined.
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*/
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#include "catalog/catversion.h" /* pgrminclude ignore */
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/*
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* Name of major-version-specific tablespace subdirectories
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*/
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#define TABLESPACE_VERSION_DIRECTORY "PG_" PG_MAJORVERSION "_" \
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CppAsString2(CATALOG_VERSION_NO)
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/* Characters to allow for an OID in a relation path */
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#define OIDCHARS 10 /* max chars printed by %u */
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/*
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* Stuff for fork names.
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*
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* The physical storage of a relation consists of one or more forks.
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* The main fork is always created, but in addition to that there can be
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* additional forks for storing various metadata. ForkNumber is used when
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* we need to refer to a specific fork in a relation.
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*/
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typedef enum ForkNumber
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{
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InvalidForkNumber = -1,
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MAIN_FORKNUM = 0,
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FSM_FORKNUM,
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VISIBILITYMAP_FORKNUM,
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INIT_FORKNUM
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/*
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* NOTE: if you add a new fork, change MAX_FORKNUM and possibly
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* FORKNAMECHARS below, and update the forkNames array in
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* src/common/relpath.c
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*/
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} ForkNumber;
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#define MAX_FORKNUM INIT_FORKNUM
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#define FORKNAMECHARS 4 /* max chars for a fork name */
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extern PGDLLIMPORT const char *const forkNames[];
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extern ForkNumber forkname_to_number(const char *forkName);
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extern int forkname_chars(const char *str, ForkNumber *fork);
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/*
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* Stuff for computing filesystem pathnames for relations.
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*/
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extern char *GetDatabasePath(Oid dbOid, Oid spcOid);
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extern char *GetRelationPath(Oid dbOid, Oid spcOid, RelFileNumber relNumber,
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int backendId, ForkNumber forkNumber);
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/*
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* Wrapper macros for GetRelationPath. Beware of multiple
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* evaluation of the RelFileLocator or RelFileLocatorBackend argument!
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*/
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/* First argument is a RelFileLocator */
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#define relpathbackend(rlocator, backend, forknum) \
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GetRelationPath((rlocator).dbOid, (rlocator).spcOid, (rlocator).relNumber, \
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backend, forknum)
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/* First argument is a RelFileLocator */
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#define relpathperm(rlocator, forknum) \
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relpathbackend(rlocator, InvalidBackendId, forknum)
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/* First argument is a RelFileLocatorBackend */
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#define relpath(rlocator, forknum) \
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relpathbackend((rlocator).locator, (rlocator).backend, forknum)
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#endif /* RELPATH_H */
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