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postgresql/src/include/access/slru.h

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This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
/*
* slru.h
*
* Simple LRU
*
* Portions Copyright (c) 2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
Nested transactions. There is still much left to do, especially on the performance front, but with feature freeze upon us I think it's time to drive a stake in the ground and say that this will be in 7.5. Alvaro Herrera, with some help from Tom Lane.
2004-07-01 02:52:04 +02:00
* $PostgreSQL: pgsql/src/include/access/slru.h,v 1.7 2004/07/01 00:51:38 tgl Exp $
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
*/
#ifndef SLRU_H
#define SLRU_H
Nested transactions. There is still much left to do, especially on the performance front, but with feature freeze upon us I think it's time to drive a stake in the ground and say that this will be in 7.5. Alvaro Herrera, with some help from Tom Lane.
2004-07-01 02:52:04 +02:00
#include "access/xlog.h"
Per previous discussions, get rid of use of sync(2) in favor of explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
2004-05-31 05:48:10 +02:00
#include "storage/lwlock.h"
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
Per previous discussions, get rid of use of sync(2) in favor of explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
2004-05-31 05:48:10 +02:00
/* Opaque structs known only in slru.c */
typedef struct SlruSharedData *SlruShared;
typedef struct SlruFlushData *SlruFlush;
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
Code review for EXEC_BACKEND changes. Reduce the number of #ifdefs by about a third, make it work on non-Windows platforms again. (But perhaps I broke the WIN32 code, since I have no way to test that.) Fold all the paths that fork postmaster child processes to go through the single routine SubPostmasterMain, which takes care of resurrecting the state that would normally be inherited from the postmaster (including GUC variables). Clean up some places where there's no particularly good reason for the EXEC and non-EXEC cases to work differently. Take care of one or two FIXMEs that remained in the code.
2004-05-28 07:13:32 +02:00
/*
* SlruCtlData is an unshared structure that points to the active information
* in shared memory.
*/
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
typedef struct SlruCtlData
{
Per previous discussions, get rid of use of sync(2) in favor of explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
2004-05-31 05:48:10 +02:00
SlruShared shared;
LWLockId ControlLock;
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
Code review for EXEC_BACKEND changes. Reduce the number of #ifdefs by about a third, make it work on non-Windows platforms again. (But perhaps I broke the WIN32 code, since I have no way to test that.) Fold all the paths that fork postmaster child processes to go through the single routine SubPostmasterMain, which takes care of resurrecting the state that would normally be inherited from the postmaster (including GUC variables). Clean up some places where there's no particularly good reason for the EXEC and non-EXEC cases to work differently. Take care of one or two FIXMEs that remained in the code.
2004-05-28 07:13:32 +02:00
/*
Per previous discussions, get rid of use of sync(2) in favor of explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
2004-05-31 05:48:10 +02:00
* Dir is set during SimpleLruInit and does not change thereafter.
* Since it's always the same, it doesn't need to be in shared memory.
Code review for EXEC_BACKEND changes. Reduce the number of #ifdefs by about a third, make it work on non-Windows platforms again. (But perhaps I broke the WIN32 code, since I have no way to test that.) Fold all the paths that fork postmaster child processes to go through the single routine SubPostmasterMain, which takes care of resurrecting the state that would normally be inherited from the postmaster (including GUC variables). Clean up some places where there's no particularly good reason for the EXEC and non-EXEC cases to work differently. Take care of one or two FIXMEs that remained in the code.
2004-05-28 07:13:32 +02:00
*/
pgindent run.
2003-08-04 02:43:34 +02:00
char Dir[MAXPGPATH];
Code review for EXEC_BACKEND changes. Reduce the number of #ifdefs by about a third, make it work on non-Windows platforms again. (But perhaps I broke the WIN32 code, since I have no way to test that.) Fold all the paths that fork postmaster child processes to go through the single routine SubPostmasterMain, which takes care of resurrecting the state that would normally be inherited from the postmaster (including GUC variables). Clean up some places where there's no particularly good reason for the EXEC and non-EXEC cases to work differently. Take care of one or two FIXMEs that remained in the code.
2004-05-28 07:13:32 +02:00
/*
* Decide which of two page numbers is "older" for truncation purposes.
* We need to use comparison of TransactionIds here in order to do the
* right thing with wraparound XID arithmetic.
*/
pgindent run.
2003-08-04 02:43:34 +02:00
bool (*PagePrecedes) (int, int);
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
Another pgindent run with updated typedefs.
2003-08-08 23:42:59 +02:00
} SlruCtlData;
Per previous discussions, get rid of use of sync(2) in favor of explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
2004-05-31 05:48:10 +02:00
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
typedef SlruCtlData *SlruCtl;
Per previous discussions, get rid of use of sync(2) in favor of explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
2004-05-31 05:48:10 +02:00
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
extern int SimpleLruShmemSize(void);
extern void SimpleLruInit(SlruCtl ctl, const char *name, const char *subdir);
extern int SimpleLruZeroPage(SlruCtl ctl, int pageno);
Per previous discussions, get rid of use of sync(2) in favor of explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
2004-05-31 05:48:10 +02:00
extern char *SimpleLruReadPage(SlruCtl ctl, int pageno,
TransactionId xid, bool forwrite);
extern void SimpleLruWritePage(SlruCtl ctl, int slotno, SlruFlush fdata);
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
extern void SimpleLruSetLatestPage(SlruCtl ctl, int pageno);
extern void SimpleLruFlush(SlruCtl ctl, bool checkpoint);
extern void SimpleLruTruncate(SlruCtl ctl, int cutoffPage);
Nested transactions. There is still much left to do, especially on the performance front, but with feature freeze upon us I think it's time to drive a stake in the ground and say that this will be in 7.5. Alvaro Herrera, with some help from Tom Lane.
2004-07-01 02:52:04 +02:00
/* XLOG stuff */
#define CLOG_ZEROPAGE 0x00
#define SUBTRANS_ZEROPAGE 0x10
extern void slru_redo(XLogRecPtr lsn, XLogRecord *record);
extern void slru_undo(XLogRecPtr lsn, XLogRecord *record);
extern void slru_desc(char *buf, uint8 xl_info, char *rec);
This patch extracts page buffer pooling and the simple least-recently-used strategy from clog.c into slru.c. It doesn't change any visible behaviour and passes all regression tests plus a TruncateCLOG test done manually. Apart from refactoring I made a little change to SlruRecentlyUsed, formerly ClogRecentlyUsed: It now skips incrementing lru_counts, if slotno is already the LRU slot, thus saving a few CPU cycles. To make this work, lru_counts are initialised to 1 in SimpleLruInit. SimpleLru will be used by pg_subtrans (part of the nested transactions project), so the main purpose of this patch is to avoid future code duplication. Manfred Koizar
2003-06-12 00:37:46 +02:00
#endif /* SLRU_H */