database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-10-25 13:17:41 +03:00
Code Activity

Refactor the fsync queue for wider use.

Browse Source 
Previously, md.c and checkpointer.c were tightly integrated so that
fsync calls could be handed off and processed in the background.
Introduce a system of callbacks and file tags, so that other modules
can hand off fsync work in the same way.

For now only md.c uses the new interface, but other users are being
proposed.  Since there may be use cases that are not strictly SMGR
implementations, use a new function table for sync handlers rather
than extending the traditional SMGR one.

Instead of using a bitmapset of segment numbers for each RelFileNode
in the checkpointer's hash table, make the segment number part of the
key.  This requires sending explicit "forget" requests for every
segment individually when relations are dropped, but suits the file
layout schemes of proposed future users better (ie sparse or high
segment numbers).

Author: Shawn Debnath and Thomas Munro
Reviewed-by: Thomas Munro, Andres Freund
Discussion: https://postgr.es/m/CAEepm=2gTANm=e3ARnJT=n0h8hf88wqmaZxk0JYkxw+b21fNrw@mail.gmail.com
This commit is contained in:
Thomas Munro
2019-04-04 21:56:03 +13:00
parent 33215d113d
commit 3eb77eba5a
18 changed files with 904 additions and 890 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
src/include/storage/sync.h Normal file
View File

@@ -0,0 +1,62 @@
/*-------------------------------------------------------------------------
*
* sync.h
* File synchronization management code.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/storage/sync.h
*
*-------------------------------------------------------------------------
*/
#ifndef SYNC_H
#define SYNC_H
#include "storage/relfilenode.h"
/*
* Type of sync request. These are used to manage the set of pending
* requests to call a sync handler's sync or unlink functions at the next
* checkpoint.
*/
typedef enum SyncRequestType
{
SYNC_REQUEST, /* schedule a call of sync function */
SYNC_UNLINK_REQUEST, /* schedule a call of unlink function */
SYNC_FORGET_REQUEST, /* forget all calls for a tag */
SYNC_FILTER_REQUEST /* forget all calls satisfying match fn */
} SyncRequestType;
/*
* Which set of functions to use to handle a given request. See the function
* table in sync.c.
*/
typedef enum SyncRequestHandler
{
SYNC_HANDLER_MD = 0 /* md smgr */
} SyncRequestHandler;
/*
* A tag identifying a file. Currently it has the members required for md.c's
* usage, but sync.c has no knowledge of the internal structure, and it is
* liable to change as required by future handlers.
*/
typedef struct FileTag
{
int16 handler; /* SyncRequstHandler value, saving space */
int16 forknum; /* ForkNumber, saving space */
RelFileNode rnode;
uint32 segno;
} FileTag;
extern void InitSync(void);
extern void SyncPreCheckpoint(void);
extern void SyncPostCheckpoint(void);
extern void ProcessSyncRequests(void);
extern void RememberSyncRequest(const FileTag *ftag, SyncRequestType type);
extern void EnableSyncRequestForwarding(void);
extern bool RegisterSyncRequest(const FileTag *ftag, SyncRequestType type,
bool retryOnError);
#endif /* SYNC_H */