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Index SLRUs by 64-bit integers rather than by 32-bit integers

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We've had repeated bugs in the area of handling SLRU wraparound in the past,
some of which have caused data loss. Switching to an indexing system for SLRUs
that does not wrap around should allow us to get rid of a whole bunch
of problems and improve the overall reliability of the system.

This particular patch however only changes the indexing and doesn't address
the wraparound per se. This is going to be done in the following patches.

Author: Maxim Orlov, Aleksander Alekseev, Alexander Korotkov, Teodor Sigaev
Author: Nikita Glukhov, Pavel Borisov, Yura Sokolov
Reviewed-by: Jacob Champion, Heikki Linnakangas, Alexander Korotkov
Reviewed-by: Japin Li, Pavel Borisov, Tom Lane, Peter Eisentraut, Andres Freund
Reviewed-by: Andrey Borodin, Dilip Kumar, Aleksander Alekseev
Discussion: https://postgr.es/m/CACG%3DezZe1NQSCnfHOr78AtAZxJZeCvxrts0ygrxYwe%3DpyyjVWA%40mail.gmail.com
Discussion: https://postgr.es/m/CAJ7c6TPDOYBYrnCAeyndkBktO0WG2xSdYduTF0nxq%2BvfkmTF5Q%40mail.gmail.com
This commit is contained in:
Alexander Korotkov
2023-11-29 01:39:55 +02:00
parent a916b47e23
commit 4ed8f0913b
18 changed files with 303 additions and 202 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
src/include/access/clog.h
View File

@ -31,7 +31,7 @@ typedef int XidStatus;
typedef struct xl_clog_truncate
{
int pageno;
int64 pageno;
TransactionId oldestXact;
Oid oldestXactDb;
} xl_clog_truncate;

2
src/include/access/commit_ts.h
View File

@ -60,7 +60,7 @@ typedef struct xl_commit_ts_set
typedef struct xl_commit_ts_truncate
{
int pageno;
int64 pageno;
TransactionId oldestXid;
} xl_commit_ts_truncate;

35
src/include/access/slru.h
View File

@ -64,7 +64,7 @@ typedef struct SlruSharedData
char **page_buffer;
SlruPageStatus *page_status;
bool *page_dirty;
int *page_number;
int64 *page_number;
int *page_lru_count;
LWLockPadded *buffer_locks;
@ -95,7 +95,7 @@ typedef struct SlruSharedData
* this is not critical data, since we use it only to avoid swapping out
* the latest page.
*/
int latest_page_number;
int64 latest_page_number;
/* SLRU's index for statistics purposes (might not be unique) */
int slru_stats_idx;
@ -127,7 +127,15 @@ typedef struct SlruCtlData
* the behavior of this callback has no functional implications.) Use
* SlruPagePrecedesUnitTests() in SLRUs meeting its criteria.
*/
bool (*PagePrecedes) (int, int);
bool (*PagePrecedes) (int64, int64);
/*
* If true, use long segment filenames formed from lower 48 bits of the
* segment number, e.g. pg_xact/000000001234. Otherwise, use short
* filenames formed from lower 16 bits of the segment number e.g.
* pg_xact/1234.
*/
bool long_segment_names;
/*
* Dir is set during SimpleLruInit and does not change thereafter. Since
@ -142,11 +150,12 @@ typedef SlruCtlData *SlruCtl;
extern Size SimpleLruShmemSize(int nslots, int nlsns);
extern void SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
LWLock *ctllock, const char *subdir, int tranche_id,
SyncRequestHandler sync_handler);
extern int SimpleLruZeroPage(SlruCtl ctl, int pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int pageno, bool write_ok,
SyncRequestHandler sync_handler,
bool long_segment_names);
extern int SimpleLruZeroPage(SlruCtl ctl, int64 pageno);
extern int SimpleLruReadPage(SlruCtl ctl, int64 pageno, bool write_ok,
TransactionId xid);
extern int SimpleLruReadPage_ReadOnly(SlruCtl ctl, int pageno,
extern int SimpleLruReadPage_ReadOnly(SlruCtl ctl, int64 pageno,
TransactionId xid);
extern void SimpleLruWritePage(SlruCtl ctl, int slotno);
extern void SimpleLruWriteAll(SlruCtl ctl, bool allow_redirtied);
@ -155,20 +164,20 @@ extern void SlruPagePrecedesUnitTests(SlruCtl ctl, int per_page);
#else
#define SlruPagePrecedesUnitTests(ctl, per_page) do {} while (0)
#endif
extern void SimpleLruTruncate(SlruCtl ctl, int cutoffPage);
extern bool SimpleLruDoesPhysicalPageExist(SlruCtl ctl, int pageno);
extern void SimpleLruTruncate(SlruCtl ctl, int64 cutoffPage);
extern bool SimpleLruDoesPhysicalPageExist(SlruCtl ctl, int64 pageno);
typedef bool (*SlruScanCallback) (SlruCtl ctl, char *filename, int segpage,
typedef bool (*SlruScanCallback) (SlruCtl ctl, char *filename, int64 segpage,
void *data);
extern bool SlruScanDirectory(SlruCtl ctl, SlruScanCallback callback, void *data);
extern void SlruDeleteSegment(SlruCtl ctl, int segno);
extern void SlruDeleteSegment(SlruCtl ctl, int64 segno);
extern int SlruSyncFileTag(SlruCtl ctl, const FileTag *ftag, char *path);
/* SlruScanDirectory public callbacks */
extern bool SlruScanDirCbReportPresence(SlruCtl ctl, char *filename,
int segpage, void *data);
extern bool SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int segpage,
int64 segpage, void *data);
extern bool SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage,
void *data);
#endif /* SLRU_H */