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No more #ifdef XLOG.

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This commit is contained in:
Vadim B. Mikheev
2000-11-30 08:46:26 +00:00
parent b16516b887
commit 81c8c244b2
36 changed files with 322 additions and 3983 deletions
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507
src/backend/access/transam/varsup.c
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@@ -1,290 +1,51 @@
/*-------------------------------------------------------------------------
*
* varsup.c
* postgres variable relation support routines
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
* postgres OID & XID variables support routines
*
* Copyright (c) 2000, PostgreSQL, Inc
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.33 2000/11/20 16:47:30 petere Exp $
* $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.34 2000/11/30 08:46:22 vadim Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#ifdef XLOG
#include "xlog_varsup.c"
#else
#include "access/heapam.h"
#include "catalog/catname.h"
#include "access/transam.h"
#include "storage/proc.h"
static void GetNewObjectIdBlock(Oid *oid_return, int oid_block_size);
static void VariableRelationGetNextOid(Oid *oid_return);
static void VariableRelationGetNextXid(TransactionId *xidP);
static void VariableRelationPutNextOid(Oid oid);
SPINLOCK OidGenLockId;
/* ---------------------
* spin lock for oid generation
* ---------------------
*/
int OidGenLockId;
extern SPINLOCK XidGenLockId;
extern void XLogPutNextOid(Oid nextOid);
/* ---------------------
* pointer to "variable cache" in shared memory (set up by shmem.c)
* ---------------------
*/
/* pointer to "variable cache" in shared memory (set up by shmem.c) */
VariableCache ShmemVariableCache = NULL;
/* ----------------------------------------------------------------
* variable relation query/update routines
* ----------------------------------------------------------------
*/
/* --------------------------------
* VariableRelationGetNextXid
* --------------------------------
*/
static void
VariableRelationGetNextXid(TransactionId *xidP)
{
Buffer buf;
VariableRelationContents var;
/* ----------------
* We assume that a spinlock has been acquired to guarantee
* exclusive access to the variable relation.
* ----------------
*/
/* ----------------
* do nothing before things are initialized
* ----------------
*/
if (!RelationIsValid(VariableRelation))
return;
/* ----------------
* read the variable page, get the the nextXid field and
* release the buffer
* ----------------
*/
buf = ReadBuffer(VariableRelation, 0);
if (!BufferIsValid(buf))
{
SpinRelease(OidGenLockId);
elog(ERROR, "VariableRelationGetNextXid: ReadBuffer failed");
}
var = (VariableRelationContents) BufferGetBlock(buf);
TransactionIdStore(var->nextXidData, xidP);
ReleaseBuffer(buf);
}
/* --------------------------------
* VariableRelationPutNextXid
* --------------------------------
*/
void
VariableRelationPutNextXid(TransactionId xid)
{
Buffer buf;
VariableRelationContents var;
/* ----------------
* We assume that a spinlock has been acquired to guarantee
* exclusive access to the variable relation.
* ----------------
*/
/* ----------------
* do nothing before things are initialized
* ----------------
*/
if (!RelationIsValid(VariableRelation))
return;
/* ----------------
* read the variable page, update the nextXid field and
* write the page back out to disk (with immediate write).
* ----------------
*/
buf = ReadBuffer(VariableRelation, 0);
if (!BufferIsValid(buf))
{
SpinRelease(OidGenLockId);
elog(ERROR, "VariableRelationPutNextXid: ReadBuffer failed");
}
var = (VariableRelationContents) BufferGetBlock(buf);
TransactionIdStore(xid, &(var->nextXidData));
FlushBuffer(buf, true, true);
}
/* --------------------------------
* VariableRelationGetNextOid
* --------------------------------
*/
static void
VariableRelationGetNextOid(Oid *oid_return)
{
Buffer buf;
VariableRelationContents var;
/* ----------------
* We assume that a spinlock has been acquired to guarantee
* exclusive access to the variable relation.
* ----------------
*/
/* ----------------
* if the variable relation is not initialized, then we
* assume we are running at bootstrap time and so we return
* an invalid object id (this path should never be taken, probably).
* ----------------
*/
if (!RelationIsValid(VariableRelation))
{
(*oid_return) = InvalidOid;
return;
}
/* ----------------
* read the variable page, get the the nextOid field and
* release the buffer
* ----------------
*/
buf = ReadBuffer(VariableRelation, 0);
if (!BufferIsValid(buf))
{
SpinRelease(OidGenLockId);
elog(ERROR, "VariableRelationGetNextOid: ReadBuffer failed");
}
var = (VariableRelationContents) BufferGetBlock(buf);
(*oid_return) = var->nextOid;
ReleaseBuffer(buf);
}
/* --------------------------------
* VariableRelationPutNextOid
* --------------------------------
*/
static void
VariableRelationPutNextOid(Oid oid)
{
Buffer buf;
VariableRelationContents var;
/* ----------------
* We assume that a spinlock has been acquired to guarantee
* exclusive access to the variable relation.
* ----------------
*/
/* ----------------
* do nothing before things are initialized
* ----------------
*/
if (!RelationIsValid(VariableRelation))
return;
/* ----------------
* read the variable page, update the nextXid field and
* write the page back out to disk.
* ----------------
*/
buf = ReadBuffer(VariableRelation, 0);
if (!BufferIsValid(buf))
{
SpinRelease(OidGenLockId);
elog(ERROR, "VariableRelationPutNextOid: ReadBuffer failed");
}
var = (VariableRelationContents) BufferGetBlock(buf);
var->nextOid = oid;
WriteBuffer(buf);
}
/* ----------------------------------------------------------------
* transaction id generation support
* ----------------------------------------------------------------
*/
/* ----------------
* GetNewTransactionId
*
* Transaction IDs are allocated via a cache in shared memory.
* Each time we need more IDs, we advance the "next XID" value
* in pg_variable by VAR_XID_PREFETCH and set the cache to
* show that many XIDs as available. Then, allocating those XIDs
* requires just a spinlock and not a buffer read/write cycle.
*
* Since the cache is shared across all backends, cached but unused
* XIDs are not lost when a backend exits, only when the postmaster
* quits or forces shared memory reinit. So we can afford to have
* a pretty big value of VAR_XID_PREFETCH.
*
* This code does not worry about initializing the transaction counter
* (see transam.c's InitializeTransactionLog() for that). We also
* ignore the possibility that the counter could someday wrap around.
* ----------------
*/
#define VAR_XID_PREFETCH 1024
void
GetNewTransactionId(TransactionId *xid)
{
/* ----------------
* during bootstrap initialization, we return the special
* bootstrap transaction id.
* ----------------
/*
* During bootstrap initialization, we return the special
* bootstrap transaction id.
*/
if (AMI_OVERRIDE)
{
TransactionIdStore(AmiTransactionId, xid);
*xid = AmiTransactionId;
return;
}
SpinAcquire(OidGenLockId); /* not good for concurrency... */
if (ShmemVariableCache->xid_count == 0)
{
TransactionId nextid;
VariableRelationGetNextXid(&nextid);
TransactionIdStore(nextid, &(ShmemVariableCache->nextXid));
ShmemVariableCache->xid_count = VAR_XID_PREFETCH;
TransactionIdAdd(&nextid, VAR_XID_PREFETCH);
VariableRelationPutNextXid(nextid);
}
TransactionIdStore(ShmemVariableCache->nextXid, xid);
TransactionIdAdd(&(ShmemVariableCache->nextXid), 1);
(ShmemVariableCache->xid_count)--;
SpinAcquire(XidGenLockId);
*xid = ShmemVariableCache->nextXid;
(ShmemVariableCache->nextXid)++;
if (MyProc != (PROC *) NULL)
MyProc->xid = *xid;
SpinRelease(OidGenLockId);
SpinRelease(XidGenLockId);
}
/*
@@ -294,30 +55,20 @@ void
ReadNewTransactionId(TransactionId *xid)
{
/* ----------------
* during bootstrap initialization, we return the special
* bootstrap transaction id.
* ----------------
/*
* During bootstrap initialization, we return the special
* bootstrap transaction id.
*/
if (AMI_OVERRIDE)
{
TransactionIdStore(AmiTransactionId, xid);
*xid = AmiTransactionId;
return;
}
SpinAcquire(OidGenLockId); /* not good for concurrency... */
SpinAcquire(XidGenLockId);
*xid = ShmemVariableCache->nextXid;
SpinRelease(XidGenLockId);
/*
* Note that we don't check is ShmemVariableCache->xid_count equal to
* 0 or not. This will work as long as we don't call
* ReadNewTransactionId() before GetNewTransactionId().
*/
if (ShmemVariableCache->nextXid == 0)
elog(ERROR, "ReadNewTransactionId: ShmemVariableCache->nextXid is not initialized");
TransactionIdStore(ShmemVariableCache->nextXid, xid);
SpinRelease(OidGenLockId);
}
/* ----------------------------------------------------------------
@@ -325,199 +76,67 @@ ReadNewTransactionId(TransactionId *xid)
* ----------------------------------------------------------------
*/
/* ----------------
* GetNewObjectIdBlock
*
* This support function is used to allocate a block of object ids
* of the given size.
* ----------------
*/
static void
GetNewObjectIdBlock(Oid *oid_return, /* place to return the first new
* object id */
int oid_block_size) /* number of oids desired */
{
Oid firstfreeoid;
Oid nextoid;
/* ----------------
* Obtain exclusive access to the variable relation page
* ----------------
*/
SpinAcquire(OidGenLockId);
/* ----------------
* get the "next" oid from the variable relation
* ----------------
*/
VariableRelationGetNextOid(&firstfreeoid);
/* ----------------
* Allocate the range of OIDs to be returned to the caller.
*
* There are two things going on here.
*
* One: in a virgin database pg_variable will initially contain zeroes,
* so we will read out firstfreeoid = InvalidOid. We want to start
* allocating OIDs at BootstrapObjectIdData instead (OIDs below that
* are reserved for static assignment in the initial catalog data).
*
* Two: if a database is run long enough, the OID counter will wrap
* around. We must not generate an invalid OID when that happens,
* and it seems wise not to generate anything in the reserved range.
* Therefore we advance to BootstrapObjectIdData in this case too.
*
* The comparison here assumes that Oid is an unsigned type.
*/
nextoid = firstfreeoid + oid_block_size;
if (! OidIsValid(firstfreeoid) || nextoid < firstfreeoid)
{
/* Initialization or wraparound time, force it up to safe range */
firstfreeoid = BootstrapObjectIdData;
nextoid = firstfreeoid + oid_block_size;
}
(*oid_return) = firstfreeoid;
/* ----------------
* Update the variable relation to show the block range as used.
* ----------------
*/
VariableRelationPutNextOid(nextoid);
/* ----------------
* Relinquish our lock on the variable relation page
* ----------------
*/
SpinRelease(OidGenLockId);
}
/* ----------------
* GetNewObjectId
*
* This function allocates and parses out object ids. Like
* GetNewTransactionId(), it "prefetches" 32 object ids by
* incrementing the nextOid stored in the var relation by 32 and then
* returning these id's one at a time until they are exhausted.
* This means we reduce the number of accesses to the variable
* relation by 32 for each backend.
*
* Note: 32 has no special significance. We don't want the
* number to be too large because when the backend
* terminates, we lose the oids we cached.
*
* Question: couldn't we use a shared-memory cache just like XIDs?
* That would allow a larger interval between pg_variable updates
* without cache losses. Note, however, that we can assign an OID
* without even a spinlock from the backend-local OID cache.
* Maybe two levels of caching would be good.
* ----------------
*/
#define VAR_OID_PREFETCH 32
static int prefetched_oid_count = 0;
static Oid next_prefetched_oid;
#define VAR_OID_PREFETCH 8192
static Oid lastSeenOid = InvalidOid;
void
GetNewObjectId(Oid *oid_return) /* place to return the new object id */
GetNewObjectId(Oid *oid_return)
{
/* ----------------
* if we run out of prefetched oids, then we get some
* more before handing them out to the caller.
* ----------------
*/
SpinAcquire(OidGenLockId);
if (prefetched_oid_count == 0)
/* If we run out of logged for use oids then we log more */
if (ShmemVariableCache->oidCount == 0)
{
int oid_block_size = VAR_OID_PREFETCH;
/* ----------------
* Make sure pg_variable is open.
* ----------------
*/
if (!RelationIsValid(VariableRelation))
VariableRelation = heap_openr(VariableRelationName, NoLock);
/* ----------------
* get a new block of prefetched object ids.
* ----------------
*/
GetNewObjectIdBlock(&next_prefetched_oid, oid_block_size);
/* ----------------
* now reset the prefetched_oid_count.
* ----------------
*/
prefetched_oid_count = oid_block_size;
XLogPutNextOid(ShmemVariableCache->nextOid + VAR_OID_PREFETCH);
ShmemVariableCache->oidCount = VAR_OID_PREFETCH;
}
/* ----------------
* return the next prefetched oid in the pointer passed by
* the user and decrement the prefetch count.
* ----------------
*/
if (PointerIsValid(oid_return))
(*oid_return) = next_prefetched_oid;
lastSeenOid = (*oid_return) = ShmemVariableCache->nextOid;
next_prefetched_oid++;
prefetched_oid_count--;
(ShmemVariableCache->nextOid)++;
(ShmemVariableCache->oidCount)--;
SpinRelease(OidGenLockId);
}
void
CheckMaxObjectId(Oid assigned_oid)
{
Oid temp_oid;
if (prefetched_oid_count == 0) /* make sure next/max is set, or
* reload */
GetNewObjectId(&temp_oid);
/* ----------------
* If we are below prefetched limits, do nothing
* ----------------
*/
if (assigned_oid < next_prefetched_oid)
if (lastSeenOid != InvalidOid && assigned_oid < lastSeenOid)
return;
/* ----------------
* If we are here, we are coming from a 'copy from' with oid's
*
* If we are in the prefetched oid range, just bump it up
* ----------------
*/
if (assigned_oid <= next_prefetched_oid + prefetched_oid_count - 1)
SpinAcquire(OidGenLockId);
if (assigned_oid < ShmemVariableCache->nextOid)
{
prefetched_oid_count -= assigned_oid - next_prefetched_oid + 1;
next_prefetched_oid = assigned_oid + 1;
lastSeenOid = ShmemVariableCache->nextOid - 1;
SpinRelease(OidGenLockId);
return;
}
/* ----------------
* We have exceeded the prefetch oid range
*
* We should lock the database and kill all other backends
* but we are loading oid's that we can not guarantee are unique
* anyway, so we must rely on the user
*
* We now:
* set the variable relation with the new max oid
* force the backend to reload its oid cache
*
* By reloading the oid cache, we don't have to update the variable
* relation every time when sequential OIDs are being loaded by COPY.
* ----------------
/* If we are in the logged oid range, just bump nextOid up */
if (assigned_oid <= ShmemVariableCache->nextOid +
ShmemVariableCache->oidCount - 1)
{
ShmemVariableCache->oidCount -=
assigned_oid - ShmemVariableCache->nextOid + 1;
ShmemVariableCache->nextOid = assigned_oid + 1;
SpinRelease(OidGenLockId);
return;
}
/*
* We have exceeded the logged oid range.
* We should lock the database and kill all other backends
* but we are loading oid's that we can not guarantee are unique
* anyway, so we must rely on the user.
*/
SpinAcquire(OidGenLockId);
VariableRelationPutNextOid(assigned_oid);
XLogPutNextOid(assigned_oid + VAR_OID_PREFETCH);
ShmemVariableCache->oidCount = VAR_OID_PREFETCH - 1;
ShmemVariableCache->nextOid = assigned_oid + 1;
SpinRelease(OidGenLockId);
prefetched_oid_count = 0; /* force reload */
GetNewObjectId(&temp_oid); /* cause target OID to be allocated */
}
#endif /* !XLOG */