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2467394ee1
There are various things left to do: contrib dbsize and oid2name modules need work, and so does the documentation. Also someone should think about COMMENT ON TABLESPACE and maybe RENAME TABLESPACE. Also initlocation is dead, it just doesn't know it yet. Gavin Sherry and Tom Lane.
216 lines
6.5 KiB
C
216 lines
6.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* buf_internals.h
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* Internal definitions for buffer manager and the buffer replacement
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* strategy.
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*
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*
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* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/storage/buf_internals.h,v 1.71 2004/06/18 06:14:13 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef BUFMGR_INTERNALS_H
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#define BUFMGR_INTERNALS_H
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#include "storage/backendid.h"
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#include "storage/buf.h"
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#include "storage/lmgr.h"
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#include "storage/lwlock.h"
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/*
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* Flags for buffer descriptors
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*/
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#define BM_DIRTY (1 << 0) /* data needs writing */
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#define BM_VALID (1 << 1) /* data is valid */
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#define BM_IO_IN_PROGRESS (1 << 2) /* read or write in progress */
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#define BM_IO_ERROR (1 << 3) /* previous I/O failed */
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#define BM_JUST_DIRTIED (1 << 4) /* dirtied since write started */
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#define BM_PIN_COUNT_WAITER (1 << 5) /* have waiter for sole pin */
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typedef bits16 BufFlags;
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/*
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* Buffer tag identifies which disk block the buffer contains.
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*
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* Note: the BufferTag data must be sufficient to determine where to write the
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* block, even during a "blind write" with no relcache entry. It's possible
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* that the backend flushing the buffer doesn't even believe the relation is
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* visible yet (its xact may have started before the xact that created the
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* rel). The storage manager must be able to cope anyway.
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*
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* Note: if there's any pad bytes in the struct, INIT_BUFFERTAG will have
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* to be fixed to zero them, since this struct is used as a hash key.
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*/
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typedef struct buftag
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{
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RelFileNode rnode; /* physical relation identifier */
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BlockNumber blockNum; /* blknum relative to begin of reln */
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} BufferTag;
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#define CLEAR_BUFFERTAG(a) \
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( \
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(a).rnode.spcNode = InvalidOid, \
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(a).rnode.dbNode = InvalidOid, \
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(a).rnode.relNode = InvalidOid, \
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(a).blockNum = InvalidBlockNumber \
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)
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#define INIT_BUFFERTAG(a,xx_reln,xx_blockNum) \
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( \
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(a).rnode = (xx_reln)->rd_node, \
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(a).blockNum = (xx_blockNum) \
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)
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#define BUFFERTAGS_EQUAL(a,b) \
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( \
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RelFileNodeEquals((a).rnode, (b).rnode) && \
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(a).blockNum == (b).blockNum \
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)
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/*
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* BufferDesc -- shared buffer cache metadata for a single
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* shared buffer descriptor.
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*/
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typedef struct sbufdesc
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{
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Buffer bufNext; /* link in freelist chain */
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SHMEM_OFFSET data; /* pointer to data in buf pool */
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/* tag and id must be together for table lookup (still true?) */
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BufferTag tag; /* file/block identifier */
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int buf_id; /* buffer's index number (from 0) */
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BufFlags flags; /* see bit definitions above */
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unsigned refcount; /* # of backends holding pins on buffer */
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LWLockId io_in_progress_lock; /* to wait for I/O to complete */
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LWLockId cntx_lock; /* to lock access to page context */
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bool cntxDirty; /* new way to mark block as dirty */
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/*
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* We can't physically remove items from a disk page if another
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* backend has the buffer pinned. Hence, a backend may need to wait
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* for all other pins to go away. This is signaled by storing its own
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* backend ID into wait_backend_id and setting flag bit
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* BM_PIN_COUNT_WAITER. At present, there can be only one such waiter
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* per buffer.
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*/
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BackendId wait_backend_id; /* backend ID of pin-count waiter */
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} BufferDesc;
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#define BufferDescriptorGetBuffer(bdesc) ((bdesc)->buf_id + 1)
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/*
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* Each backend has its own BufferLocks[] array holding flag bits
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* showing what locks it has set on each buffer.
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*
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* We have to free these locks during ereport(ERROR)...
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*/
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#define BL_IO_IN_PROGRESS (1 << 0) /* unimplemented */
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#define BL_PIN_COUNT_LOCK (1 << 1)
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/* entry for buffer lookup hashtable */
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typedef struct
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{
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BufferTag key; /* Tag of a disk page */
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int id; /* CDB id of associated CDB */
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} BufferLookupEnt;
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/*
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* Definitions for the buffer replacement strategy
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*/
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#define STRAT_LIST_UNUSED (-1)
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#define STRAT_LIST_B1 0
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#define STRAT_LIST_T1 1
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#define STRAT_LIST_T2 2
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#define STRAT_LIST_B2 3
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#define STRAT_NUM_LISTS 4
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/*
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* The Cache Directory Block (CDB) of the Adaptive Replacement Cache (ARC)
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*/
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typedef struct
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{
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int prev; /* list links */
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int next;
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short list; /* ID of list it is currently in */
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bool t1_vacuum; /* t => present only because of VACUUM */
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TransactionId t1_xid; /* the xid this entry went onto T1 */
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BufferTag buf_tag; /* page identifier */
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int buf_id; /* currently assigned data buffer, or -1 */
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} BufferStrategyCDB;
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/*
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* The shared ARC control information.
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*/
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typedef struct
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{
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int target_T1_size; /* What T1 size are we aiming for */
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int listUnusedCDB; /* All unused StrategyCDB */
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int listHead[STRAT_NUM_LISTS]; /* ARC lists B1, T1, T2 and B2 */
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int listTail[STRAT_NUM_LISTS];
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int listSize[STRAT_NUM_LISTS];
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Buffer listFreeBuffers; /* List of unused buffers */
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long num_lookup; /* Some hit statistics */
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long num_hit[STRAT_NUM_LISTS];
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time_t stat_report;
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/* Array of CDB's starts here */
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BufferStrategyCDB cdb[1]; /* VARIABLE SIZE ARRAY */
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} BufferStrategyControl;
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/* counters in buf_init.c */
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extern long int ReadBufferCount;
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extern long int ReadLocalBufferCount;
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extern long int BufferHitCount;
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extern long int LocalBufferHitCount;
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extern long int BufferFlushCount;
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extern long int LocalBufferFlushCount;
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/*
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* Bufmgr Interface:
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*/
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/* Internal routines: only called by bufmgr */
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/* freelist.c */
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extern BufferDesc *StrategyBufferLookup(BufferTag *tagPtr, bool recheck,
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int *cdb_found_index);
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extern BufferDesc *StrategyGetBuffer(int *cdb_replace_index);
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extern void StrategyReplaceBuffer(BufferDesc *buf, BufferTag *newTag,
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int cdb_found_index, int cdb_replace_index);
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extern void StrategyInvalidateBuffer(BufferDesc *buf);
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extern void StrategyHintVacuum(bool vacuum_active);
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extern int StrategyDirtyBufferList(BufferDesc **buffers, BufferTag *buftags,
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int max_buffers);
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extern void StrategyInitialize(bool init);
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/* buf_table.c */
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extern void InitBufTable(int size);
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extern int BufTableLookup(BufferTag *tagPtr);
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extern void BufTableInsert(BufferTag *tagPtr, int cdb_id);
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extern void BufTableDelete(BufferTag *tagPtr);
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/* bufmgr.c */
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extern BufferDesc *BufferDescriptors;
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extern bits8 *BufferLocks;
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/* localbuf.c */
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extern BufferDesc *LocalBufferDescriptors;
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extern BufferDesc *LocalBufferAlloc(Relation reln, BlockNumber blockNum,
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bool *foundPtr);
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extern void WriteLocalBuffer(Buffer buffer, bool release);
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extern void AtEOXact_LocalBuffers(bool isCommit);
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#endif /* BUFMGR_INTERNALS_H */
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