postgresql/src/include/access/xlogutils.h

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

119 lines
4.1 KiB
C
Raw Normal View History

XLOG (and related) changes: * Store two past checkpoint locations, not just one, in pg_control. On startup, we fall back to the older checkpoint if the newer one is unreadable. Also, a physical copy of the newest checkpoint record is kept in pg_control for possible use in disaster recovery (ie, complete loss of pg_xlog). Also add a version number for pg_control itself. Remove archdir from pg_control; it ought to be a GUC parameter, not a special case (not that it's implemented yet anyway). * Suppress successive checkpoint records when nothing has been entered in the WAL log since the last one. This is not so much to avoid I/O as to make it actually useful to keep track of the last two checkpoints. If the things are right next to each other then there's not a lot of redundancy gained... * Change CRC scheme to a true 64-bit CRC, not a pair of 32-bit CRCs on alternate bytes. Polynomial borrowed from ECMA DLT1 standard. * Fix XLOG record length handling so that it will work at BLCKSZ = 32k. * Change XID allocation to work more like OID allocation. (This is of dubious necessity, but I think it's a good idea anyway.) * Fix a number of minor bugs, such as off-by-one logic for XLOG file wraparound at the 4 gig mark. * Add documentation and clean up some coding infelicities; move file format declarations out to include files where planned contrib utilities can get at them. * Checkpoint will now occur every CHECKPOINT_SEGMENTS log segments or every CHECKPOINT_TIMEOUT seconds, whichever comes first. It is also possible to force a checkpoint by sending SIGUSR1 to the postmaster (undocumented feature...) * Defend against kill -9 postmaster by storing shmem block's key and ID in postmaster.pid lockfile, and checking at startup to ensure that no processes are still connected to old shmem block (if it still exists). * Switch backends to accept SIGQUIT rather than SIGUSR1 for emergency stop, for symmetry with postmaster and xlog utilities. Clean up signal handling in bootstrap.c so that xlog utilities launched by postmaster will react to signals better. * Standalone bootstrap now grabs lockfile in target directory, as added insurance against running it in parallel with live postmaster.
2001-03-13 02:17:06 +01:00
/*
* xlogutils.h
*
* Utilities for replaying WAL records.
XLOG (and related) changes: * Store two past checkpoint locations, not just one, in pg_control. On startup, we fall back to the older checkpoint if the newer one is unreadable. Also, a physical copy of the newest checkpoint record is kept in pg_control for possible use in disaster recovery (ie, complete loss of pg_xlog). Also add a version number for pg_control itself. Remove archdir from pg_control; it ought to be a GUC parameter, not a special case (not that it's implemented yet anyway). * Suppress successive checkpoint records when nothing has been entered in the WAL log since the last one. This is not so much to avoid I/O as to make it actually useful to keep track of the last two checkpoints. If the things are right next to each other then there's not a lot of redundancy gained... * Change CRC scheme to a true 64-bit CRC, not a pair of 32-bit CRCs on alternate bytes. Polynomial borrowed from ECMA DLT1 standard. * Fix XLOG record length handling so that it will work at BLCKSZ = 32k. * Change XID allocation to work more like OID allocation. (This is of dubious necessity, but I think it's a good idea anyway.) * Fix a number of minor bugs, such as off-by-one logic for XLOG file wraparound at the 4 gig mark. * Add documentation and clean up some coding infelicities; move file format declarations out to include files where planned contrib utilities can get at them. * Checkpoint will now occur every CHECKPOINT_SEGMENTS log segments or every CHECKPOINT_TIMEOUT seconds, whichever comes first. It is also possible to force a checkpoint by sending SIGUSR1 to the postmaster (undocumented feature...) * Defend against kill -9 postmaster by storing shmem block's key and ID in postmaster.pid lockfile, and checking at startup to ensure that no processes are still connected to old shmem block (if it still exists). * Switch backends to accept SIGQUIT rather than SIGUSR1 for emergency stop, for symmetry with postmaster and xlog utilities. Clean up signal handling in bootstrap.c so that xlog utilities launched by postmaster will react to signals better. * Standalone bootstrap now grabs lockfile in target directory, as added insurance against running it in parallel with live postmaster.
2001-03-13 02:17:06 +01:00
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
XLOG (and related) changes: * Store two past checkpoint locations, not just one, in pg_control. On startup, we fall back to the older checkpoint if the newer one is unreadable. Also, a physical copy of the newest checkpoint record is kept in pg_control for possible use in disaster recovery (ie, complete loss of pg_xlog). Also add a version number for pg_control itself. Remove archdir from pg_control; it ought to be a GUC parameter, not a special case (not that it's implemented yet anyway). * Suppress successive checkpoint records when nothing has been entered in the WAL log since the last one. This is not so much to avoid I/O as to make it actually useful to keep track of the last two checkpoints. If the things are right next to each other then there's not a lot of redundancy gained... * Change CRC scheme to a true 64-bit CRC, not a pair of 32-bit CRCs on alternate bytes. Polynomial borrowed from ECMA DLT1 standard. * Fix XLOG record length handling so that it will work at BLCKSZ = 32k. * Change XID allocation to work more like OID allocation. (This is of dubious necessity, but I think it's a good idea anyway.) * Fix a number of minor bugs, such as off-by-one logic for XLOG file wraparound at the 4 gig mark. * Add documentation and clean up some coding infelicities; move file format declarations out to include files where planned contrib utilities can get at them. * Checkpoint will now occur every CHECKPOINT_SEGMENTS log segments or every CHECKPOINT_TIMEOUT seconds, whichever comes first. It is also possible to force a checkpoint by sending SIGUSR1 to the postmaster (undocumented feature...) * Defend against kill -9 postmaster by storing shmem block's key and ID in postmaster.pid lockfile, and checking at startup to ensure that no processes are still connected to old shmem block (if it still exists). * Switch backends to accept SIGQUIT rather than SIGUSR1 for emergency stop, for symmetry with postmaster and xlog utilities. Clean up signal handling in bootstrap.c so that xlog utilities launched by postmaster will react to signals better. * Standalone bootstrap now grabs lockfile in target directory, as added insurance against running it in parallel with live postmaster.
2001-03-13 02:17:06 +01:00
* Portions Copyright (c) 1994, Regents of the University of California
*
2010-09-20 22:08:53 +02:00
* src/include/access/xlogutils.h
XLOG (and related) changes: * Store two past checkpoint locations, not just one, in pg_control. On startup, we fall back to the older checkpoint if the newer one is unreadable. Also, a physical copy of the newest checkpoint record is kept in pg_control for possible use in disaster recovery (ie, complete loss of pg_xlog). Also add a version number for pg_control itself. Remove archdir from pg_control; it ought to be a GUC parameter, not a special case (not that it's implemented yet anyway). * Suppress successive checkpoint records when nothing has been entered in the WAL log since the last one. This is not so much to avoid I/O as to make it actually useful to keep track of the last two checkpoints. If the things are right next to each other then there's not a lot of redundancy gained... * Change CRC scheme to a true 64-bit CRC, not a pair of 32-bit CRCs on alternate bytes. Polynomial borrowed from ECMA DLT1 standard. * Fix XLOG record length handling so that it will work at BLCKSZ = 32k. * Change XID allocation to work more like OID allocation. (This is of dubious necessity, but I think it's a good idea anyway.) * Fix a number of minor bugs, such as off-by-one logic for XLOG file wraparound at the 4 gig mark. * Add documentation and clean up some coding infelicities; move file format declarations out to include files where planned contrib utilities can get at them. * Checkpoint will now occur every CHECKPOINT_SEGMENTS log segments or every CHECKPOINT_TIMEOUT seconds, whichever comes first. It is also possible to force a checkpoint by sending SIGUSR1 to the postmaster (undocumented feature...) * Defend against kill -9 postmaster by storing shmem block's key and ID in postmaster.pid lockfile, and checking at startup to ensure that no processes are still connected to old shmem block (if it still exists). * Switch backends to accept SIGQUIT rather than SIGUSR1 for emergency stop, for symmetry with postmaster and xlog utilities. Clean up signal handling in bootstrap.c so that xlog utilities launched by postmaster will react to signals better. * Standalone bootstrap now grabs lockfile in target directory, as added insurance against running it in parallel with live postmaster.
2001-03-13 02:17:06 +01:00
*/
2000-10-25 02:49:14 +02:00
#ifndef XLOG_UTILS_H
2000-11-30 09:46:26 +01:00
#define XLOG_UTILS_H
2000-10-25 02:49:14 +02:00
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
#include "access/xlogreader.h"
#include "storage/bufmgr.h"
2000-10-25 02:49:14 +02:00
/*
* Prior to 8.4, all activity during recovery was carried out by the startup
* process. This local variable continues to be used in many parts of the
* code to indicate actions taken by RecoveryManagers. Other processes that
* potentially perform work during recovery should check RecoveryInProgress().
* See XLogCtl notes in xlog.c.
*/
extern PGDLLIMPORT bool InRecovery;
/*
* Like InRecovery, standbyState is only valid in the startup process.
* In all other processes it will have the value STANDBY_DISABLED (so
* InHotStandby will read as false).
*
* In DISABLED state, we're performing crash recovery or hot standby was
* disabled in postgresql.conf.
*
* In INITIALIZED state, we've run InitRecoveryTransactionEnvironment, but
* we haven't yet processed a RUNNING_XACTS or shutdown-checkpoint WAL record
* to initialize our primary-transaction tracking system.
*
* When the transaction tracking is initialized, we enter the SNAPSHOT_PENDING
* state. The tracked information might still be incomplete, so we can't allow
* connections yet, but redo functions must update the in-memory state when
* appropriate.
*
* In SNAPSHOT_READY mode, we have full knowledge of transactions that are
* (or were) running on the primary at the current WAL location. Snapshots
* can be taken, and read-only queries can be run.
*/
typedef enum
{
STANDBY_DISABLED,
STANDBY_INITIALIZED,
STANDBY_SNAPSHOT_PENDING,
STANDBY_SNAPSHOT_READY,
} HotStandbyState;
extern PGDLLIMPORT HotStandbyState standbyState;
#define InHotStandby (standbyState >= STANDBY_SNAPSHOT_PENDING)
2000-10-25 02:49:14 +02:00
extern bool XLogHaveInvalidPages(void);
extern void XLogCheckInvalidPages(void);
2000-10-28 18:21:00 +02:00
Change internal RelFileNode references to RelFileNumber or RelFileLocator. 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
2022-07-06 17:39:09 +02:00
extern void XLogDropRelation(RelFileLocator rlocator, ForkNumber forknum);
extern void XLogDropDatabase(Oid dbid);
Change internal RelFileNode references to RelFileNumber or RelFileLocator. 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
2022-07-06 17:39:09 +02:00
extern void XLogTruncateRelation(RelFileLocator rlocator, ForkNumber forkNum,
BlockNumber nblocks);
/* Result codes for XLogReadBufferForRedo[Extended] */
typedef enum
{
BLK_NEEDS_REDO, /* changes from WAL record need to be applied */
BLK_DONE, /* block is already up-to-date */
BLK_RESTORED, /* block was restored from a full-page image */
BLK_NOTFOUND, /* block was not found (and hence does not
* need to be replayed) */
} XLogRedoAction;
/* Private data of the read_local_xlog_page_no_wait callback. */
typedef struct ReadLocalXLogPageNoWaitPrivate
{
bool end_of_wal; /* true, when end of WAL is reached */
} ReadLocalXLogPageNoWaitPrivate;
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
extern XLogRedoAction XLogReadBufferForRedo(XLogReaderState *record,
uint8 block_id, Buffer *buf);
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
extern Buffer XLogInitBufferForRedo(XLogReaderState *record, uint8 block_id);
extern XLogRedoAction XLogReadBufferForRedoExtended(XLogReaderState *record,
uint8 block_id,
ReadBufferMode mode, bool get_cleanup_lock,
Buffer *buf);
Change internal RelFileNode references to RelFileNumber or RelFileLocator. 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
2022-07-06 17:39:09 +02:00
extern Buffer XLogReadBufferExtended(RelFileLocator rlocator, ForkNumber forknum,
Prefetch data referenced by the WAL, take II. Introduce a new GUC recovery_prefetch. When enabled, look ahead in the WAL and try to initiate asynchronous reading of referenced data blocks that are not yet cached in our buffer pool. For now, this is done with posix_fadvise(), which has several caveats. Since not all OSes have that system call, "try" is provided so that it can be enabled where available. Better mechanisms for asynchronous I/O are possible in later work. Set to "try" for now for test coverage. Default setting to be finalized before release. The GUC wal_decode_buffer_size limits the distance we can look ahead in bytes of decoded data. The existing GUC maintenance_io_concurrency is used to limit the number of concurrent I/Os allowed, based on pessimistic heuristics used to infer that I/Os have begun and completed. We'll also not look more than maintenance_io_concurrency * 4 block references ahead. Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> (earlier version) Reviewed-by: Andres Freund <andres@anarazel.de> (earlier version) Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> (earlier version) Tested-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> (earlier version) Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com> (earlier version) Tested-by: Dmitry Dolgov <9erthalion6@gmail.com> (earlier version) Tested-by: Sait Talha Nisanci <Sait.Nisanci@microsoft.com> (earlier version) Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
2022-04-07 09:28:40 +02:00
BlockNumber blkno, ReadBufferMode mode,
Buffer recent_buffer);
Change internal RelFileNode references to RelFileNumber or RelFileLocator. 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
2022-07-06 17:39:09 +02:00
extern Relation CreateFakeRelcacheEntry(RelFileLocator rlocator);
extern void FreeFakeRelcacheEntry(Relation fakerel);
extern int read_local_xlog_page(XLogReaderState *state,
XLogRecPtr targetPagePtr, int reqLen,
XLogRecPtr targetRecPtr, char *cur_page);
extern int read_local_xlog_page_no_wait(XLogReaderState *state,
XLogRecPtr targetPagePtr, int reqLen,
XLogRecPtr targetRecPtr,
char *cur_page);
extern void wal_segment_open(XLogReaderState *state,
XLogSegNo nextSegNo,
TimeLineID *tli_p);
extern void wal_segment_close(XLogReaderState *state);
extern void XLogReadDetermineTimeline(XLogReaderState *state,
Remove all use of ThisTimeLineID global variable outside of xlog.c All such code deals with this global variable in one of three ways. Sometimes the same functions use it in more than one of these ways at the same time. First, sometimes it's an implicit argument to one or more functions being called in xlog.c or elsewhere, and must be set to the appropriate value before calling those functions lest they misbehave. In those cases, it is now passed as an explicit argument instead. Second, sometimes it's used to obtain the current timeline after the end of recovery, i.e. the timeline to which WAL is being written and flushed. Such code now calls GetWALInsertionTimeLine() or relies on the new out parameter added to GetFlushRecPtr(). Third, sometimes it's used during recovery to store the current replay timeline. That can change, so such code must generally update the value before each use. It can still do that, but must now use a local variable instead. The net effect of these changes is to reduce by a fair amount the amount of code that is directly accessing this global variable. That's good, because history has shown that we don't always think clearly about which timeline ID it's supposed to contain at any given point in time, or indeed, whether it has been or needs to be initialized at any given point in the code. Patch by me, reviewed and tested by Michael Paquier, Amul Sul, and Álvaro Herrera. Discussion: https://postgr.es/m/CA+TgmobfAAqhfWa1kaFBBFvX+5CjM=7TE=n4r4Q1o2bjbGYBpA@mail.gmail.com
2021-11-05 17:50:01 +01:00
XLogRecPtr wantPage,
uint32 wantLength,
TimeLineID currTLI);
extern void WALReadRaiseError(WALReadError *errinfo);
2000-10-25 02:49:14 +02:00
#endif