mirror of
https://github.com/postgres/postgres.git
synced 2025-05-11 05:41:32 +03:00
Move SnapBuild and SnapBuildOnDisk structs to snapshot_internal.h.
This commit moves the definitions of the SnapBuild and SnapBuildOnDisk structs, related to logical snapshots, to the snapshot_internal.h file. This change allows external tools, such as pg_logicalinspect (with an upcoming patch), to access and utilize the contents of logical snapshots. Author: Bertrand Drouvot Reviewed-by: Amit Kapila, Shveta Malik, Peter Smith Discussion: https://postgr.es/m/ZscuZ92uGh3wm4tW%40ip-10-97-1-34.eu-west-3.compute.internal
This commit is contained in:
Masahiko Sawada
parent
dbedc461b4
commit
e2fd615ecc
@ -134,6 +134,7 @@
|
|||||||
#include "replication/logical.h"
|
#include "replication/logical.h"
|
||||||
#include "replication/reorderbuffer.h"
|
#include "replication/reorderbuffer.h"
|
||||||
#include "replication/snapbuild.h"
|
#include "replication/snapbuild.h"
|
||||||
|
#include "replication/snapbuild_internal.h"
|
||||||
#include "storage/fd.h"
|
#include "storage/fd.h"
|
||||||
#include "storage/lmgr.h"
|
#include "storage/lmgr.h"
|
||||||
#include "storage/proc.h"
|
#include "storage/proc.h"
|
||||||
@ -143,146 +144,6 @@
|
|||||||
#include "utils/memutils.h"
|
#include "utils/memutils.h"
|
||||||
#include "utils/snapmgr.h"
|
#include "utils/snapmgr.h"
|
||||||
#include "utils/snapshot.h"
|
#include "utils/snapshot.h"
|
||||||
|
|
||||||
/*
|
|
||||||
* This struct contains the current state of the snapshot building
|
|
||||||
* machinery. Besides a forward declaration in the header, it is not exposed
|
|
||||||
* to the public, so we can easily change its contents.
|
|
||||||
*/
|
|
||||||
struct SnapBuild
|
|
||||||
{
|
|
||||||
/* how far are we along building our first full snapshot */
|
|
||||||
SnapBuildState state;
|
|
||||||
|
|
||||||
/* private memory context used to allocate memory for this module. */
|
|
||||||
MemoryContext context;
|
|
||||||
|
|
||||||
/* all transactions < than this have committed/aborted */
|
|
||||||
TransactionId xmin;
|
|
||||||
|
|
||||||
/* all transactions >= than this are uncommitted */
|
|
||||||
TransactionId xmax;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Don't replay commits from an LSN < this LSN. This can be set externally
|
|
||||||
* but it will also be advanced (never retreat) from within snapbuild.c.
|
|
||||||
*/
|
|
||||||
XLogRecPtr start_decoding_at;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* LSN at which two-phase decoding was enabled or LSN at which we found a
|
|
||||||
* consistent point at the time of slot creation.
|
|
||||||
*
|
|
||||||
* The prepared transactions, that were skipped because previously
|
|
||||||
* two-phase was not enabled or are not covered by initial snapshot, need
|
|
||||||
* to be sent later along with commit prepared and they must be before
|
|
||||||
* this point.
|
|
||||||
*/
|
|
||||||
XLogRecPtr two_phase_at;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Don't start decoding WAL until the "xl_running_xacts" information
|
|
||||||
* indicates there are no running xids with an xid smaller than this.
|
|
||||||
*/
|
|
||||||
TransactionId initial_xmin_horizon;
|
|
||||||
|
|
||||||
/* Indicates if we are building full snapshot or just catalog one. */
|
|
||||||
bool building_full_snapshot;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Indicates if we are using the snapshot builder for the creation of a
|
|
||||||
* logical replication slot. If it's true, the start point for decoding
|
|
||||||
* changes is not determined yet. So we skip snapshot restores to properly
|
|
||||||
* find the start point. See SnapBuildFindSnapshot() for details.
|
|
||||||
*/
|
|
||||||
bool in_slot_creation;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Snapshot that's valid to see the catalog state seen at this moment.
|
|
||||||
*/
|
|
||||||
Snapshot snapshot;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* LSN of the last location we are sure a snapshot has been serialized to.
|
|
||||||
*/
|
|
||||||
XLogRecPtr last_serialized_snapshot;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* The reorderbuffer we need to update with usable snapshots et al.
|
|
||||||
*/
|
|
||||||
ReorderBuffer *reorder;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* TransactionId at which the next phase of initial snapshot building will
|
|
||||||
* happen. InvalidTransactionId if not known (i.e. SNAPBUILD_START), or
|
|
||||||
* when no next phase necessary (SNAPBUILD_CONSISTENT).
|
|
||||||
*/
|
|
||||||
TransactionId next_phase_at;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Array of transactions which could have catalog changes that committed
|
|
||||||
* between xmin and xmax.
|
|
||||||
*/
|
|
||||||
struct
|
|
||||||
{
|
|
||||||
/* number of committed transactions */
|
|
||||||
size_t xcnt;
|
|
||||||
|
|
||||||
/* available space for committed transactions */
|
|
||||||
size_t xcnt_space;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Until we reach a CONSISTENT state, we record commits of all
|
|
||||||
* transactions, not just the catalog changing ones. Record when that
|
|
||||||
* changes so we know we cannot export a snapshot safely anymore.
|
|
||||||
*/
|
|
||||||
bool includes_all_transactions;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Array of committed transactions that have modified the catalog.
|
|
||||||
*
|
|
||||||
* As this array is frequently modified we do *not* keep it in
|
|
||||||
* xidComparator order. Instead we sort the array when building &
|
|
||||||
* distributing a snapshot.
|
|
||||||
*
|
|
||||||
* TODO: It's unclear whether that reasoning has much merit. Every
|
|
||||||
* time we add something here after becoming consistent will also
|
|
||||||
* require distributing a snapshot. Storing them sorted would
|
|
||||||
* potentially also make it easier to purge (but more complicated wrt
|
|
||||||
* wraparound?). Should be improved if sorting while building the
|
|
||||||
* snapshot shows up in profiles.
|
|
||||||
*/
|
|
||||||
TransactionId *xip;
|
|
||||||
} committed;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Array of transactions and subtransactions that had modified catalogs
|
|
||||||
* and were running when the snapshot was serialized.
|
|
||||||
*
|
|
||||||
* We normally rely on some WAL record types such as HEAP2_NEW_CID to know
|
|
||||||
* if the transaction has changed the catalog. But it could happen that
|
|
||||||
* the logical decoding decodes only the commit record of the transaction
|
|
||||||
* after restoring the previously serialized snapshot in which case we
|
|
||||||
* will miss adding the xid to the snapshot and end up looking at the
|
|
||||||
* catalogs with the wrong snapshot.
|
|
||||||
*
|
|
||||||
* Now to avoid the above problem, we serialize the transactions that had
|
|
||||||
* modified the catalogs and are still running at the time of snapshot
|
|
||||||
* serialization. We fill this array while restoring the snapshot and then
|
|
||||||
* refer it while decoding commit to ensure if the xact has modified the
|
|
||||||
* catalog. We discard this array when all the xids in the list become old
|
|
||||||
* enough to matter. See SnapBuildPurgeOlderTxn for details.
|
|
||||||
*/
|
|
||||||
struct
|
|
||||||
{
|
|
||||||
/* number of transactions */
|
|
||||||
size_t xcnt;
|
|
||||||
|
|
||||||
/* This array must be sorted in xidComparator order */
|
|
||||||
TransactionId *xip;
|
|
||||||
} catchange;
|
|
||||||
};
|
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* Starting a transaction -- which we need to do while exporting a snapshot --
|
* Starting a transaction -- which we need to do while exporting a snapshot --
|
||||||
* removes knowledge about the previously used resowner, so we save it here.
|
* removes knowledge about the previously used resowner, so we save it here.
|
||||||
@ -1557,40 +1418,6 @@ SnapBuildWaitSnapshot(xl_running_xacts *running, TransactionId cutoff)
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
/* -----------------------------------
|
|
||||||
* Snapshot serialization support
|
|
||||||
* -----------------------------------
|
|
||||||
*/
|
|
||||||
|
|
||||||
/*
|
|
||||||
* We store current state of struct SnapBuild on disk in the following manner:
|
|
||||||
*
|
|
||||||
* struct SnapBuildOnDisk;
|
|
||||||
* TransactionId * committed.xcnt; (*not xcnt_space*)
|
|
||||||
* TransactionId * catchange.xcnt;
|
|
||||||
*
|
|
||||||
*/
|
|
||||||
typedef struct SnapBuildOnDisk
|
|
||||||
{
|
|
||||||
/* first part of this struct needs to be version independent */
|
|
||||||
|
|
||||||
/* data not covered by checksum */
|
|
||||||
uint32 magic;
|
|
||||||
pg_crc32c checksum;
|
|
||||||
|
|
||||||
/* data covered by checksum */
|
|
||||||
|
|
||||||
/* version, in case we want to support pg_upgrade */
|
|
||||||
uint32 version;
|
|
||||||
/* how large is the on disk data, excluding the constant sized part */
|
|
||||||
uint32 length;
|
|
||||||
|
|
||||||
/* version dependent part */
|
|
||||||
SnapBuild builder;
|
|
||||||
|
|
||||||
/* variable amount of TransactionIds follows */
|
|
||||||
} SnapBuildOnDisk;
|
|
||||||
|
|
||||||
#define SnapBuildOnDiskConstantSize \
|
#define SnapBuildOnDiskConstantSize \
|
||||||
offsetof(SnapBuildOnDisk, builder)
|
offsetof(SnapBuildOnDisk, builder)
|
||||||
#define SnapBuildOnDiskNotChecksummedSize \
|
#define SnapBuildOnDiskNotChecksummedSize \
|
||||||
|
|||||||
@ -46,7 +46,7 @@ typedef enum
|
|||||||
SNAPBUILD_CONSISTENT = 2,
|
SNAPBUILD_CONSISTENT = 2,
|
||||||
} SnapBuildState;
|
} SnapBuildState;
|
||||||
|
|
||||||
/* forward declare so we don't have to expose the struct to the public */
|
/* forward declare so we don't have to include snapbuild_internal.h */
|
||||||
struct SnapBuild;
|
struct SnapBuild;
|
||||||
typedef struct SnapBuild SnapBuild;
|
typedef struct SnapBuild SnapBuild;
|
||||||
|
|
||||||
|
|||||||
196
src/include/replication/snapbuild_internal.h
Normal file
196
src/include/replication/snapbuild_internal.h
Normal file
@ -0,0 +1,196 @@
|
|||||||
|
/*-------------------------------------------------------------------------
|
||||||
|
*
|
||||||
|
* snapbuild_internal.h
|
||||||
|
* This file contains declarations for logical decoding utility
|
||||||
|
* functions for internal use.
|
||||||
|
*
|
||||||
|
* Copyright (c) 2024, PostgreSQL Global Development Group
|
||||||
|
*
|
||||||
|
* src/include/replication/snapbuild_internal.h
|
||||||
|
*
|
||||||
|
*-------------------------------------------------------------------------
|
||||||
|
*/
|
||||||
|
|
||||||
|
#ifndef SNAPBUILD_INTERNAL_H
|
||||||
|
#define SNAPBUILD_INTERNAL_H
|
||||||
|
|
||||||
|
#include "port/pg_crc32c.h"
|
||||||
|
#include "replication/reorderbuffer.h"
|
||||||
|
#include "replication/snapbuild.h"
|
||||||
|
|
||||||
|
/*
|
||||||
|
* This struct contains the current state of the snapshot building
|
||||||
|
* machinery. It is exposed to the public, so pay attention when changing its
|
||||||
|
* contents.
|
||||||
|
*/
|
||||||
|
struct SnapBuild
|
||||||
|
{
|
||||||
|
/* how far are we along building our first full snapshot */
|
||||||
|
SnapBuildState state;
|
||||||
|
|
||||||
|
/* private memory context used to allocate memory for this module. */
|
||||||
|
MemoryContext context;
|
||||||
|
|
||||||
|
/* all transactions < than this have committed/aborted */
|
||||||
|
TransactionId xmin;
|
||||||
|
|
||||||
|
/* all transactions >= than this are uncommitted */
|
||||||
|
TransactionId xmax;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Don't replay commits from an LSN < this LSN. This can be set externally
|
||||||
|
* but it will also be advanced (never retreat) from within snapbuild.c.
|
||||||
|
*/
|
||||||
|
XLogRecPtr start_decoding_at;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* LSN at which two-phase decoding was enabled or LSN at which we found a
|
||||||
|
* consistent point at the time of slot creation.
|
||||||
|
*
|
||||||
|
* The prepared transactions, that were skipped because previously
|
||||||
|
* two-phase was not enabled or are not covered by initial snapshot, need
|
||||||
|
* to be sent later along with commit prepared and they must be before
|
||||||
|
* this point.
|
||||||
|
*/
|
||||||
|
XLogRecPtr two_phase_at;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Don't start decoding WAL until the "xl_running_xacts" information
|
||||||
|
* indicates there are no running xids with an xid smaller than this.
|
||||||
|
*/
|
||||||
|
TransactionId initial_xmin_horizon;
|
||||||
|
|
||||||
|
/* Indicates if we are building full snapshot or just catalog one. */
|
||||||
|
bool building_full_snapshot;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Indicates if we are using the snapshot builder for the creation of a
|
||||||
|
* logical replication slot. If it's true, the start point for decoding
|
||||||
|
* changes is not determined yet. So we skip snapshot restores to properly
|
||||||
|
* find the start point. See SnapBuildFindSnapshot() for details.
|
||||||
|
*/
|
||||||
|
bool in_slot_creation;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Snapshot that's valid to see the catalog state seen at this moment.
|
||||||
|
*/
|
||||||
|
Snapshot snapshot;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* LSN of the last location we are sure a snapshot has been serialized to.
|
||||||
|
*/
|
||||||
|
XLogRecPtr last_serialized_snapshot;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* The reorderbuffer we need to update with usable snapshots et al.
|
||||||
|
*/
|
||||||
|
ReorderBuffer *reorder;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* TransactionId at which the next phase of initial snapshot building will
|
||||||
|
* happen. InvalidTransactionId if not known (i.e. SNAPBUILD_START), or
|
||||||
|
* when no next phase necessary (SNAPBUILD_CONSISTENT).
|
||||||
|
*/
|
||||||
|
TransactionId next_phase_at;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Array of transactions which could have catalog changes that committed
|
||||||
|
* between xmin and xmax.
|
||||||
|
*/
|
||||||
|
struct
|
||||||
|
{
|
||||||
|
/* number of committed transactions */
|
||||||
|
size_t xcnt;
|
||||||
|
|
||||||
|
/* available space for committed transactions */
|
||||||
|
size_t xcnt_space;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Until we reach a CONSISTENT state, we record commits of all
|
||||||
|
* transactions, not just the catalog changing ones. Record when that
|
||||||
|
* changes so we know we cannot export a snapshot safely anymore.
|
||||||
|
*/
|
||||||
|
bool includes_all_transactions;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Array of committed transactions that have modified the catalog.
|
||||||
|
*
|
||||||
|
* As this array is frequently modified we do *not* keep it in
|
||||||
|
* xidComparator order. Instead we sort the array when building &
|
||||||
|
* distributing a snapshot.
|
||||||
|
*
|
||||||
|
* TODO: It's unclear whether that reasoning has much merit. Every
|
||||||
|
* time we add something here after becoming consistent will also
|
||||||
|
* require distributing a snapshot. Storing them sorted would
|
||||||
|
* potentially also make it easier to purge (but more complicated wrt
|
||||||
|
* wraparound?). Should be improved if sorting while building the
|
||||||
|
* snapshot shows up in profiles.
|
||||||
|
*/
|
||||||
|
TransactionId *xip;
|
||||||
|
} committed;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Array of transactions and subtransactions that had modified catalogs
|
||||||
|
* and were running when the snapshot was serialized.
|
||||||
|
*
|
||||||
|
* We normally rely on some WAL record types such as HEAP2_NEW_CID to know
|
||||||
|
* if the transaction has changed the catalog. But it could happen that
|
||||||
|
* the logical decoding decodes only the commit record of the transaction
|
||||||
|
* after restoring the previously serialized snapshot in which case we
|
||||||
|
* will miss adding the xid to the snapshot and end up looking at the
|
||||||
|
* catalogs with the wrong snapshot.
|
||||||
|
*
|
||||||
|
* Now to avoid the above problem, we serialize the transactions that had
|
||||||
|
* modified the catalogs and are still running at the time of snapshot
|
||||||
|
* serialization. We fill this array while restoring the snapshot and then
|
||||||
|
* refer it while decoding commit to ensure if the xact has modified the
|
||||||
|
* catalog. We discard this array when all the xids in the list become old
|
||||||
|
* enough to matter. See SnapBuildPurgeOlderTxn for details.
|
||||||
|
*/
|
||||||
|
struct
|
||||||
|
{
|
||||||
|
/* number of transactions */
|
||||||
|
size_t xcnt;
|
||||||
|
|
||||||
|
/* This array must be sorted in xidComparator order */
|
||||||
|
TransactionId *xip;
|
||||||
|
} catchange;
|
||||||
|
};
|
||||||
|
|
||||||
|
/* -----------------------------------
|
||||||
|
* Snapshot serialization support
|
||||||
|
* -----------------------------------
|
||||||
|
*/
|
||||||
|
|
||||||
|
/*
|
||||||
|
* We store current state of struct SnapBuild on disk in the following manner:
|
||||||
|
*
|
||||||
|
* struct SnapBuildOnDisk;
|
||||||
|
* TransactionId * committed.xcnt; (*not xcnt_space*)
|
||||||
|
* TransactionId * catchange.xcnt;
|
||||||
|
*
|
||||||
|
* Check if the SnapBuildOnDiskConstantSize and SnapBuildOnDiskNotChecksummedSize
|
||||||
|
* macros need to be updated when modifying the SnapBuildOnDisk struct.
|
||||||
|
*/
|
||||||
|
typedef struct SnapBuildOnDisk
|
||||||
|
{
|
||||||
|
/* first part of this struct needs to be version independent */
|
||||||
|
|
||||||
|
/* data not covered by checksum */
|
||||||
|
uint32 magic;
|
||||||
|
pg_crc32c checksum;
|
||||||
|
|
||||||
|
/* data covered by checksum */
|
||||||
|
|
||||||
|
/* version, in case we want to support pg_upgrade */
|
||||||
|
uint32 version;
|
||||||
|
/* how large is the on disk data, excluding the constant sized part */
|
||||||
|
uint32 length;
|
||||||
|
|
||||||
|
/* version dependent part */
|
||||||
|
SnapBuild builder;
|
||||||
|
|
||||||
|
/* variable amount of TransactionIds follows */
|
||||||
|
} SnapBuildOnDisk;
|
||||||
|
|
||||||
|
#endif /* SNAPBUILD_INTERNAL_H */
|
||||||
Loading…
x
Reference in New Issue
Block a user