mirror of https://github.com/postgres/postgres
A new callback named startup_cb, called shortly after a module is
loaded, is added. This makes possible the initialization of any
additional state data required by a module. This initial state data can
be saved in a ArchiveModuleState, that is now passed down to all the
callbacks that can be defined in a module. With this design, it is
possible to have a per-module state, aimed at opening the door to the
support of more than one archive module.
The initialization of the callbacks is changed so as
_PG_archive_module_init() does not anymore give in input a
ArchiveModuleCallbacks that a module has to fill in with callback
definitions. Instead, a module now needs to return a const
ArchiveModuleCallbacks.
All the structure and callback definitions of archive modules are moved
into their own header, named archive_module.h, from pgarch.h.
Command-based archiving follows the same line, with a new set of files
named shell_archive.{c,h}.
There are a few more items that are under discussion to improve the
design of archive modules, like the fact that basic_archive calls
sigsetjmp() by itself to define its own error handling flow. These will
be adjusted later, the changes done here cover already a good portion
of what has been discussed.
Any modules created for v15 will need to be adjusted to this new
design.
Author: Nathan Bossart
Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/20230130194810.6fztfgbn32e7qarj@awork3.anarazel.de
pull/128/head
Michael Paquier
3 years ago
parent
d2ea2d310d
commit
35739b87dc
@ -0,0 +1,18 @@ |
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#-------------------------------------------------------------------------
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#
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# Makefile--
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# Makefile for src/backend/archive
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#
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# IDENTIFICATION
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# src/backend/archive/Makefile
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#
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#-------------------------------------------------------------------------
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subdir = src/backend/archive
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top_builddir = ../../..
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include $(top_builddir)/src/Makefile.global |
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OBJS = \
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shell_archive.o
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include $(top_srcdir)/src/backend/common.mk |
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# Copyright (c) 2023, PostgreSQL Global Development Group |
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backend_sources += files( |
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'shell_archive.c' |
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) |
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/*-------------------------------------------------------------------------
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* |
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* archive_module.h |
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* Exports for archive modules. |
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* |
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* Copyright (c) 2022-2023, PostgreSQL Global Development Group |
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* |
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* src/include/archive/archive_module.h |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifndef _ARCHIVE_MODULE_H |
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#define _ARCHIVE_MODULE_H |
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/*
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* The value of the archive_library GUC. |
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*/ |
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extern PGDLLIMPORT char *XLogArchiveLibrary; |
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typedef struct ArchiveModuleState |
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{ |
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/*
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* Private data pointer for use by an archive module. This can be used to |
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* store state for the module that will be passed to each of its |
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* callbacks. |
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*/ |
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void *private_data; |
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} ArchiveModuleState; |
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/*
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* Archive module callbacks |
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* |
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* These callback functions should be defined by archive libraries and returned |
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* via _PG_archive_module_init(). ArchiveFileCB is the only required callback. |
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* For more information about the purpose of each callback, refer to the |
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* archive modules documentation. |
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*/ |
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typedef void (*ArchiveStartupCB) (ArchiveModuleState *state); |
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typedef bool (*ArchiveCheckConfiguredCB) (ArchiveModuleState *state); |
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typedef bool (*ArchiveFileCB) (ArchiveModuleState *state, const char *file, const char *path); |
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typedef void (*ArchiveShutdownCB) (ArchiveModuleState *state); |
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typedef struct ArchiveModuleCallbacks |
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{ |
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ArchiveStartupCB startup_cb; |
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ArchiveCheckConfiguredCB check_configured_cb; |
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ArchiveFileCB archive_file_cb; |
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ArchiveShutdownCB shutdown_cb; |
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} ArchiveModuleCallbacks; |
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/*
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* Type of the shared library symbol _PG_archive_module_init that is looked |
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* up when loading an archive library. |
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*/ |
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typedef const ArchiveModuleCallbacks *(*ArchiveModuleInit) (void); |
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extern PGDLLEXPORT const ArchiveModuleCallbacks *_PG_archive_module_init(void); |
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#endif /* _ARCHIVE_MODULE_H */ |
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/*-------------------------------------------------------------------------
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* |
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* shell_archive.h |
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* Exports for archiving via shell. |
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* |
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* Copyright (c) 2022-2023, PostgreSQL Global Development Group |
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* |
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* src/include/archive/shell_archive.h |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifndef _SHELL_ARCHIVE_H |
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#define _SHELL_ARCHIVE_H |
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#include "archive/archive_module.h" |
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/*
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* Since the logic for archiving via a shell command is in the core server |
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* and does not need to be loaded via a shared library, it has a special |
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* initialization function. |
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*/ |
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extern const ArchiveModuleCallbacks *shell_archive_init(void); |
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#endif /* _SHELL_ARCHIVE_H */ |
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