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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
67 lines
2.0 KiB
C
67 lines
2.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* sync.h
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* File synchronization management code.
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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/storage/sync.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef SYNC_H
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#define SYNC_H
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#include "storage/relfilelocator.h"
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/*
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* Type of sync request. These are used to manage the set of pending
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* requests to call a sync handler's sync or unlink functions at the next
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* checkpoint.
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*/
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typedef enum SyncRequestType
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{
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SYNC_REQUEST, /* schedule a call of sync function */
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SYNC_UNLINK_REQUEST, /* schedule a call of unlink function */
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SYNC_FORGET_REQUEST, /* forget all calls for a tag */
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SYNC_FILTER_REQUEST /* forget all calls satisfying match fn */
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} SyncRequestType;
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/*
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* Which set of functions to use to handle a given request. The values of
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* the enumerators must match the indexes of the function table in sync.c.
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*/
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typedef enum SyncRequestHandler
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{
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SYNC_HANDLER_MD = 0,
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SYNC_HANDLER_CLOG,
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SYNC_HANDLER_COMMIT_TS,
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SYNC_HANDLER_MULTIXACT_OFFSET,
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SYNC_HANDLER_MULTIXACT_MEMBER,
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SYNC_HANDLER_NONE
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} SyncRequestHandler;
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/*
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* A tag identifying a file. Currently it has the members required for md.c's
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* usage, but sync.c has no knowledge of the internal structure, and it is
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* liable to change as required by future handlers.
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*/
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typedef struct FileTag
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{
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int16 handler; /* SyncRequestHandler value, saving space */
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int16 forknum; /* ForkNumber, saving space */
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RelFileLocator rlocator;
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uint32 segno;
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} FileTag;
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extern void InitSync(void);
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extern void SyncPreCheckpoint(void);
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extern void SyncPostCheckpoint(void);
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extern void ProcessSyncRequests(void);
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extern void RememberSyncRequest(const FileTag *ftag, SyncRequestType type);
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extern bool RegisterSyncRequest(const FileTag *ftag, SyncRequestType type,
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bool retryOnError);
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#endif /* SYNC_H */
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