mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-09-30 03:01:27 +02:00
95 lines
3.0 KiB
C
95 lines
3.0 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* walmethods.h
|
|
*
|
|
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
|
|
*
|
|
* IDENTIFICATION
|
|
* src/bin/pg_basebackup/walmethods.h
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
|
|
|
|
typedef void *Walfile;
|
|
|
|
typedef enum
|
|
{
|
|
CLOSE_NORMAL,
|
|
CLOSE_UNLINK,
|
|
CLOSE_NO_RENAME
|
|
} WalCloseMethod;
|
|
|
|
/*
|
|
* A WalWriteMethod structure represents the different methods used
|
|
* to write the streaming WAL as it's received.
|
|
*
|
|
* All methods that have a failure return indicator will set state
|
|
* allowing the getlasterror() method to return a suitable message.
|
|
* Commonly, errno is this state (or part of it); so callers must take
|
|
* care not to clobber errno between a failed method call and use of
|
|
* getlasterror() to retrieve the message.
|
|
*/
|
|
typedef struct WalWriteMethod WalWriteMethod;
|
|
struct WalWriteMethod
|
|
{
|
|
/*
|
|
* Open a target file. Returns Walfile, or NULL if open failed. If a temp
|
|
* suffix is specified, a file with that name will be opened, and then
|
|
* automatically renamed in close(). If pad_to_size is specified, the file
|
|
* will be padded with NUL up to that size, if supported by the Walmethod.
|
|
*/
|
|
Walfile (*open_for_write) (const char *pathname, const char *temp_suffix, size_t pad_to_size);
|
|
|
|
/*
|
|
* Close an open Walfile, using one or more methods for handling automatic
|
|
* unlinking etc. Returns 0 on success, other values for error.
|
|
*/
|
|
int (*close) (Walfile f, WalCloseMethod method);
|
|
|
|
/* Check if a file exist */
|
|
bool (*existsfile) (const char *pathname);
|
|
|
|
/* Return the size of a file, or -1 on failure. */
|
|
ssize_t (*get_file_size) (const char *pathname);
|
|
|
|
/*
|
|
* Write count number of bytes to the file, and return the number of bytes
|
|
* actually written or -1 for error.
|
|
*/
|
|
ssize_t (*write) (Walfile f, const void *buf, size_t count);
|
|
|
|
/* Return the current position in a file or -1 on error */
|
|
off_t (*get_current_pos) (Walfile f);
|
|
|
|
/*
|
|
* fsync the contents of the specified file. Returns 0 on success.
|
|
*/
|
|
int (*sync) (Walfile f);
|
|
|
|
/*
|
|
* Clean up the Walmethod, closing any shared resources. For methods like
|
|
* tar, this includes writing updated headers. Returns true if the
|
|
* close/write/sync of shared resources succeeded, otherwise returns false
|
|
* (but the resources are still closed).
|
|
*/
|
|
bool (*finish) (void);
|
|
|
|
/* Return a text for the last error in this Walfile */
|
|
const char *(*getlasterror) (void);
|
|
};
|
|
|
|
/*
|
|
* Available WAL methods:
|
|
* - WalDirectoryMethod - write WAL to regular files in a standard pg_wal
|
|
* - TarDirectoryMethod - write WAL to a tarfile corresponding to pg_wal
|
|
* (only implements the methods required for pg_basebackup,
|
|
* not all those required for pg_receivewal)
|
|
*/
|
|
WalWriteMethod *CreateWalDirectoryMethod(const char *basedir,
|
|
int compression, bool sync);
|
|
WalWriteMethod *CreateWalTarMethod(const char *tarbase, int compression, bool sync);
|
|
|
|
/* Cleanup routines for previously-created methods */
|
|
void FreeWalDirectoryMethod(void);
|
|
void FreeWalTarMethod(void);
|