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499abb0c0f
existing lock manager and spinlocks: it understands exclusive vs shared lock but has few other fancy features. Replace most uses of spinlocks with lightweight locks. All remaining uses of spinlocks have very short lock hold times (a few dozen instructions), so tweak spinlock backoff code to work efficiently given this assumption. All per my proposal on pghackers 26-Sep-01.
126 lines
4.0 KiB
C
126 lines
4.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* transam.h
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* postgres transaction access method support code
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*
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*
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* Portions Copyright (c) 1996-2001, 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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* $Id: transam.h,v 1.41 2001/09/29 04:02:26 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef TRANSAM_H
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#define TRANSAM_H
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/* ----------------
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* Special transaction ID values
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*
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* BootstrapTransactionId is the XID for "bootstrap" operations, and
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* FrozenTransactionId is used for very old tuples. Both should
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* always be considered valid.
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*
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* FirstNormalTransactionId is the first "normal" transaction id.
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* ----------------
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*/
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#define InvalidTransactionId ((TransactionId) 0)
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#define BootstrapTransactionId ((TransactionId) 1)
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#define FrozenTransactionId ((TransactionId) 2)
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#define FirstNormalTransactionId ((TransactionId) 3)
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#define MaxTransactionId ((TransactionId) 0xFFFFFFFF)
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/* ----------------
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* transaction ID manipulation macros
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* ----------------
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*/
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#define TransactionIdIsValid(xid) ((xid) != InvalidTransactionId)
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#define TransactionIdIsNormal(xid) ((xid) >= FirstNormalTransactionId)
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#define TransactionIdEquals(id1, id2) ((id1) == (id2))
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#define TransactionIdStore(xid, dest) (*(dest) = (xid))
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#define StoreInvalidTransactionId(dest) (*(dest) = InvalidTransactionId)
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/* advance a transaction ID variable, handling wraparound correctly */
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#define TransactionIdAdvance(dest) \
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do { \
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(dest)++; \
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if ((dest) < FirstNormalTransactionId) \
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(dest) = FirstNormalTransactionId; \
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} while(0)
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/* ----------
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* Object ID (OID) zero is InvalidOid.
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*
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* OIDs 1-9999 are reserved for manual assignment (see the files
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* in src/include/catalog/).
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*
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* OIDS 10000-16383 are reserved for assignment by genbki.sh.
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*
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* OIDs beginning at 16384 are assigned at runtime from the OID
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* generator. (The first few of these will be assigned during initdb,
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* to objects created after the initial BKI script processing.)
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*
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* The choices of 10000 and 16384 are completely arbitrary, and can be moved
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* if we run low on OIDs in either category. Changing the macros below
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* should be sufficient to do this.
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*
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* NOTE: if the OID generator wraps around, we should skip over OIDs 0-16383
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* and resume with 16384. This minimizes the odds of OID conflict, by not
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* reassigning OIDs that might have been assigned during initdb.
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* ----------
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*/
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#define FirstGenBKIObjectId 10000
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#define BootstrapObjectIdData 16384
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/*
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* VariableCache is placed in shmem and used by
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* backends to get next available XID & OID.
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*/
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typedef struct VariableCacheData
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{
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TransactionId nextXid; /* next XID to assign */
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Oid nextOid; /* next OID to assign */
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uint32 oidCount; /* OIDs available before must do XLOG work */
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} VariableCacheData;
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typedef VariableCacheData *VariableCache;
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/* ----------------
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* extern declarations
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* ----------------
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*/
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/*
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* prototypes for functions in transam/transam.c
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*/
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extern void AmiTransactionOverride(bool flag);
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extern bool TransactionIdDidCommit(TransactionId transactionId);
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extern bool TransactionIdDidAbort(TransactionId transactionId);
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extern void TransactionIdCommit(TransactionId transactionId);
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extern void TransactionIdAbort(TransactionId transactionId);
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extern bool TransactionIdPrecedes(TransactionId id1, TransactionId id2);
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extern bool TransactionIdPrecedesOrEquals(TransactionId id1, TransactionId id2);
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extern bool TransactionIdFollows(TransactionId id1, TransactionId id2);
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extern bool TransactionIdFollowsOrEquals(TransactionId id1, TransactionId id2);
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/* in transam/varsup.c */
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extern TransactionId GetNewTransactionId(void);
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extern TransactionId ReadNewTransactionId(void);
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extern Oid GetNewObjectId(void);
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extern void CheckMaxObjectId(Oid assigned_oid);
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/* ----------------
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* global variable extern declarations
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* ----------------
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*/
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/* in xact.c */
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extern bool AMI_OVERRIDE;
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/* in varsup.c */
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extern VariableCache ShmemVariableCache;
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#endif /* TRAMSAM_H */
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