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Diffstat (limited to 'src/backend/access/transam/transsup.c')
| -rw-r--r-- | src/backend/access/transam/transsup.c | 663 |
1 files changed, 663 insertions, 0 deletions
diff --git a/src/backend/access/transam/transsup.c b/src/backend/access/transam/transsup.c new file mode 100644 index 00000000000..a1e5b17ec13 --- /dev/null +++ b/src/backend/access/transam/transsup.c @@ -0,0 +1,663 @@ +/*------------------------------------------------------------------------- + * + * transsup.c-- + * postgres transaction access method support code + * + * Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * $Header: /cvsroot/pgsql/src/backend/access/transam/Attic/transsup.c,v 1.1.1.1 1996/07/09 06:21:13 scrappy Exp $ + * + * NOTES + * This file contains support functions for the high + * level access method interface routines found in transam.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include "machine.h" /* in port/ directory (needed for BLCKSZ) */ + +#include "storage/buf.h" +#include "storage/bufmgr.h" + +#include "utils/rel.h" +#include "utils/elog.h" +#include "utils/memutils.h" +#include "utils/nabstime.h" + +#include "catalog/heap.h" +#include "access/transam.h" /* where the declarations go */ +#include "access/xact.h" /* where the declarations go */ + +#include "storage/smgr.h" + +/* ---------------------------------------------------------------- + * general support routines + * ---------------------------------------------------------------- + */ + +/* -------------------------------- + * AmiTransactionOverride + * + * This function is used to manipulate the bootstrap flag. + * -------------------------------- + */ +void +AmiTransactionOverride(bool flag) +{ + AMI_OVERRIDE = flag; +} + +/* -------------------------------- + * TransComputeBlockNumber + * -------------------------------- + */ +void +TransComputeBlockNumber(Relation relation, /* relation to test */ + TransactionId transactionId, /* transaction id to test */ + BlockNumber *blockNumberOutP) +{ + long itemsPerBlock; + + /* ---------------- + * we calculate the block number of our transaction + * by dividing the transaction id by the number of + * transaction things per block. + * ---------------- + */ + if (relation == LogRelation) + itemsPerBlock = TP_NumXidStatusPerBlock; + else if (relation == TimeRelation) + itemsPerBlock = TP_NumTimePerBlock; + else + elog(WARN, "TransComputeBlockNumber: unknown relation"); + + /* ---------------- + * warning! if the transaction id's get too large + * then a BlockNumber may not be large enough to hold the results + * of our division. + * + * XXX this will all vanish soon when we implement an improved + * transaction id schema -cim 3/23/90 + * + * This has vanished now that xid's are 4 bytes (no longer 5). + * -mer 5/24/92 + * ---------------- + */ + (*blockNumberOutP) = transactionId / itemsPerBlock; +} + + +/* ---------------------------------------------------------------- + * trans block support routines + * ---------------------------------------------------------------- + */ + +/* -------------------------------- + * TransBlockGetLastTransactionIdStatus + * + * This returns the status and transaction id of the last + * transaction information recorded on the given TransBlock. + * -------------------------------- + */ + +XidStatus +TransBlockGetLastTransactionIdStatus(Block tblock, + TransactionId baseXid, + TransactionId *returnXidP) +{ + Index index; + Index maxIndex; + bits8 bit1; + bits8 bit2; + BitIndex offset; + XidStatus xstatus; + + /* ---------------- + * sanity check + * ---------------- + */ + Assert((tblock != NULL)); + + /* ---------------- + * search downward from the top of the block data, looking + * for the first Non-in progress transaction status. Since we + * are scanning backward, this will be last recorded transaction + * status on the block. + * ---------------- + */ + maxIndex = TP_NumXidStatusPerBlock; + for (index = maxIndex-1; index>=0; index--) { + offset = BitIndexOf(index); + bit1 = ((bits8) BitArrayBitIsSet((BitArray) tblock, offset++)) << 1; + bit2 = (bits8) BitArrayBitIsSet((BitArray) tblock, offset); + + xstatus = (bit1 | bit2) ; + + /* ---------------- + * here we have the status of some transaction, so test + * if the status is recorded as "in progress". If so, then + * we save the transaction id in the place specified by the caller. + * ---------------- + */ + if (xstatus != XID_INPROGRESS) { + if (returnXidP != NULL) { + TransactionIdStore(baseXid, returnXidP); + TransactionIdAdd(returnXidP, index); + } + break; + } + } + + /* ---------------- + * if we get here and index is 0 it means we couldn't find + * a non-inprogress transaction on the block. For now we just + * return this info to the user. They can check if the return + * status is "in progress" to know this condition has arisen. + * ---------------- + */ + if (index == 0) { + if (returnXidP != NULL) + TransactionIdStore(baseXid, returnXidP); + } + + /* ---------------- + * return the status to the user + * ---------------- + */ + return xstatus; +} + +/* -------------------------------- + * TransBlockGetXidStatus + * + * This returns the status of the desired transaction + * -------------------------------- + */ + +XidStatus +TransBlockGetXidStatus(Block tblock, + TransactionId transactionId) +{ + Index index; + bits8 bit1; + bits8 bit2; + BitIndex offset; + + /* ---------------- + * sanity check + * ---------------- + */ + if (tblock == NULL) { + return XID_INVALID; + } + + /* ---------------- + * calculate the index into the transaction data where + * our transaction status is located + * + * XXX this will be replaced soon when we move to the + * new transaction id scheme -cim 3/23/90 + * + * The old system has now been replaced. -mer 5/24/92 + * ---------------- + */ + index = transactionId % TP_NumXidStatusPerBlock; + + /* ---------------- + * get the data at the specified index + * ---------------- + */ + offset = BitIndexOf(index); + bit1 = ((bits8) BitArrayBitIsSet((BitArray) tblock, offset++)) << 1; + bit2 = (bits8) BitArrayBitIsSet((BitArray) tblock, offset); + + /* ---------------- + * return the transaction status to the caller + * ---------------- + */ + return (XidStatus) + (bit1 | bit2); +} + +/* -------------------------------- + * TransBlockSetXidStatus + * + * This sets the status of the desired transaction + * -------------------------------- + */ +void +TransBlockSetXidStatus(Block tblock, + TransactionId transactionId, + XidStatus xstatus) +{ + Index index; + BitIndex offset; + + /* ---------------- + * sanity check + * ---------------- + */ + if (tblock == NULL) + return; + + /* ---------------- + * calculate the index into the transaction data where + * we sould store our transaction status. + * + * XXX this will be replaced soon when we move to the + * new transaction id scheme -cim 3/23/90 + * + * The new scheme is here -mer 5/24/92 + * ---------------- + */ + index = transactionId % TP_NumXidStatusPerBlock; + + offset = BitIndexOf(index); + + /* ---------------- + * store the transaction value at the specified offset + * ---------------- + */ + switch(xstatus) { + case XID_COMMIT: /* set 10 */ + BitArraySetBit((BitArray) tblock, offset); + BitArrayClearBit((BitArray) tblock, offset + 1); + break; + case XID_ABORT: /* set 01 */ + BitArrayClearBit((BitArray) tblock, offset); + BitArraySetBit((BitArray) tblock, offset + 1); + break; + case XID_INPROGRESS: /* set 00 */ + BitArrayClearBit((BitArray) tblock, offset); + BitArrayClearBit((BitArray) tblock, offset + 1); + break; + default: + elog(NOTICE, + "TransBlockSetXidStatus: invalid status: %d (ignored)", + xstatus); + break; + } +} + +/* -------------------------------- + * TransBlockGetCommitTime + * + * This returns the transaction commit time for the + * specified transaction id in the trans block. + * -------------------------------- + */ +AbsoluteTime +TransBlockGetCommitTime(Block tblock, + TransactionId transactionId) +{ + Index index; + AbsoluteTime *timeArray; + + /* ---------------- + * sanity check + * ---------------- + */ + if (tblock == NULL) + return INVALID_ABSTIME; + + /* ---------------- + * calculate the index into the transaction data where + * our transaction commit time is located + * + * XXX this will be replaced soon when we move to the + * new transaction id scheme -cim 3/23/90 + * + * The new scheme is here. -mer 5/24/92 + * ---------------- + */ + index = transactionId % TP_NumTimePerBlock; + + /* ---------------- + * return the commit time to the caller + * ---------------- + */ + timeArray = (AbsoluteTime *) tblock; + return (AbsoluteTime) + timeArray[ index ]; +} + +/* -------------------------------- + * TransBlockSetCommitTime + * + * This sets the commit time of the specified transaction + * -------------------------------- + */ +void +TransBlockSetCommitTime(Block tblock, + TransactionId transactionId, + AbsoluteTime commitTime) +{ + Index index; + AbsoluteTime *timeArray; + + /* ---------------- + * sanity check + * ---------------- + */ + if (tblock == NULL) + return; + + + /* ---------------- + * calculate the index into the transaction data where + * we sould store our transaction status. + * + * XXX this will be replaced soon when we move to the + * new transaction id scheme -cim 3/23/90 + * + * The new scheme is here. -mer 5/24/92 + * ---------------- + */ + index = transactionId % TP_NumTimePerBlock; + + /* ---------------- + * store the transaction commit time at the specified index + * ---------------- + */ + timeArray = (AbsoluteTime *) tblock; + timeArray[ index ] = commitTime; +} + +/* ---------------------------------------------------------------- + * transam i/o support routines + * ---------------------------------------------------------------- + */ + +/* -------------------------------- + * TransBlockNumberGetXidStatus + * -------------------------------- + */ +XidStatus +TransBlockNumberGetXidStatus(Relation relation, + BlockNumber blockNumber, + TransactionId xid, + bool *failP) +{ + Buffer buffer; /* buffer associated with block */ + Block block; /* block containing xstatus */ + XidStatus xstatus; /* recorded status of xid */ + bool localfail; /* bool used if failP = NULL */ + + /* ---------------- + * SOMEDAY place a read lock on the log relation + * That someday is today 5 Aug 1991 -mer + * ---------------- + */ + RelationSetLockForRead(relation); + + /* ---------------- + * get the page containing the transaction information + * ---------------- + */ + buffer = ReadBuffer(relation, blockNumber); + block = BufferGetBlock(buffer); + + /* ---------------- + * get the status from the block. note, for now we always + * return false in failP. + * ---------------- + */ + if (failP == NULL) + failP = &localfail; + (*failP) = false; + + xstatus = TransBlockGetXidStatus(block, xid); + + /* ---------------- + * release the buffer and return the status + * ---------------- + */ + ReleaseBuffer(buffer); + + /* ---------------- + * SOMEDAY release our lock on the log relation + * ---------------- + */ + RelationUnsetLockForRead(relation); + + return + xstatus; +} + +/* -------------------------------- + * TransBlockNumberSetXidStatus + * -------------------------------- + */ +void +TransBlockNumberSetXidStatus(Relation relation, + BlockNumber blockNumber, + TransactionId xid, + XidStatus xstatus, + bool *failP) +{ + Buffer buffer; /* buffer associated with block */ + Block block; /* block containing xstatus */ + bool localfail; /* bool used if failP = NULL */ + + /* ---------------- + * SOMEDAY gain exclusive access to the log relation + * + * That someday is today 5 Aug 1991 -mer + * ---------------- + */ + RelationSetLockForWrite(relation); + + /* ---------------- + * get the block containing the transaction status + * ---------------- + */ + buffer = ReadBuffer(relation, blockNumber); + block = BufferGetBlock(buffer); + + /* ---------------- + * attempt to update the status of the transaction on the block. + * if we are successful, write the block. otherwise release the buffer. + * note, for now we always return false in failP. + * ---------------- + */ + if (failP == NULL) + failP = &localfail; + (*failP) = false; + + TransBlockSetXidStatus(block, xid, xstatus); + + if ((*failP) == false) + WriteBuffer(buffer); + else + ReleaseBuffer(buffer); + + /* ---------------- + * SOMEDAY release our lock on the log relation + * ---------------- + */ + RelationUnsetLockForWrite(relation); +} + +/* -------------------------------- + * TransBlockNumberGetCommitTime + * -------------------------------- + */ +AbsoluteTime +TransBlockNumberGetCommitTime(Relation relation, + BlockNumber blockNumber, + TransactionId xid, + bool *failP) +{ + Buffer buffer; /* buffer associated with block */ + Block block; /* block containing commit time */ + bool localfail; /* bool used if failP = NULL */ + AbsoluteTime xtime; /* commit time */ + + /* ---------------- + * SOMEDAY place a read lock on the time relation + * + * That someday is today 5 Aug. 1991 -mer + * ---------------- + */ + RelationSetLockForRead(relation); + + /* ---------------- + * get the block containing the transaction information + * ---------------- + */ + buffer = ReadBuffer(relation, blockNumber); + block = BufferGetBlock(buffer); + + /* ---------------- + * get the commit time from the block + * note, for now we always return false in failP. + * ---------------- + */ + if (failP == NULL) + failP = &localfail; + (*failP) = false; + + xtime = TransBlockGetCommitTime(block, xid); + + /* ---------------- + * release the buffer and return the commit time + * ---------------- + */ + ReleaseBuffer(buffer); + + /* ---------------- + * SOMEDAY release our lock on the time relation + * ---------------- + */ + RelationUnsetLockForRead(relation); + + if ((*failP) == false) + return xtime; + else + return INVALID_ABSTIME; + +} + +/* -------------------------------- + * TransBlockNumberSetCommitTime + * -------------------------------- + */ +void +TransBlockNumberSetCommitTime(Relation relation, + BlockNumber blockNumber, + TransactionId xid, + AbsoluteTime xtime, + bool *failP) +{ + Buffer buffer; /* buffer associated with block */ + Block block; /* block containing commit time */ + bool localfail; /* bool used if failP = NULL */ + + /* ---------------- + * SOMEDAY gain exclusive access to the time relation + * + * That someday is today 5 Aug. 1991 -mer + * ---------------- + */ + RelationSetLockForWrite(relation); + + /* ---------------- + * get the block containing our commit time + * ---------------- + */ + buffer = ReadBuffer(relation, blockNumber); + block = BufferGetBlock(buffer); + + /* ---------------- + * attempt to update the commit time of the transaction on the block. + * if we are successful, write the block. otherwise release the buffer. + * note, for now we always return false in failP. + * ---------------- + */ + if (failP == NULL) + failP = &localfail; + (*failP) = false; + + TransBlockSetCommitTime(block, xid, xtime); + + if ((*failP) == false) + WriteBuffer(buffer); + else + ReleaseBuffer(buffer); + + /* ---------------- + * SOMEDAY release our lock on the time relation + * ---------------- + */ + RelationUnsetLockForWrite(relation); + +} + +/* -------------------------------- + * TransGetLastRecordedTransaction + * -------------------------------- + */ +void +TransGetLastRecordedTransaction(Relation relation, + TransactionId xid, /* return: transaction id */ + bool *failP) +{ + BlockNumber blockNumber; /* block number */ + Buffer buffer; /* buffer associated with block */ + Block block; /* block containing xid status */ + BlockNumber n; /* number of blocks in the relation */ + TransactionId baseXid; + + (*failP) = false; + + /* ---------------- + * SOMEDAY gain exclusive access to the log relation + * + * That someday is today 5 Aug. 1991 -mer + * It looks to me like we only need to set a read lock here, despite + * the above comment about exclusive access. The block is never + * actually written into, we only check status bits. + * ---------------- + */ + RelationSetLockForRead(relation); + + /* ---------------- + * we assume the last block of the log contains the last + * recorded transaction. If the relation is empty we return + * failure to the user. + * ---------------- + */ + n = RelationGetNumberOfBlocks(relation); + if (n == 0) { + (*failP) = true; + return; + } + + /* ---------------- + * get the block containing the transaction information + * ---------------- + */ + blockNumber = n-1; + buffer = ReadBuffer(relation, blockNumber); + block = BufferGetBlock(buffer); + + /* ---------------- + * get the last xid on the block + * ---------------- + */ + baseXid = blockNumber * TP_NumXidStatusPerBlock; + +/* XXX ???? xid won't get returned! - AY '94 */ + (void) TransBlockGetLastTransactionIdStatus(block, baseXid, &xid); + + ReleaseBuffer(buffer); + + /* ---------------- + * SOMEDAY release our lock on the log relation + * ---------------- + */ + RelationUnsetLockForRead(relation); +} |