diff options
Diffstat (limited to 'src/backend/access/transam/transsup.c')
| -rw-r--r-- | src/backend/access/transam/transsup.c | 1065 |
1 files changed, 540 insertions, 525 deletions
diff --git a/src/backend/access/transam/transsup.c b/src/backend/access/transam/transsup.c index c3f1d4fc9fc..9809190c942 100644 --- a/src/backend/access/transam/transsup.c +++ b/src/backend/access/transam/transsup.c @@ -1,17 +1,17 @@ /*------------------------------------------------------------------------- * * transsup.c-- - * postgres transaction access method support code + * 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 1.9 1997/08/19 21:30:12 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/transam/Attic/transsup.c,v 1.10 1997/09/07 04:39:32 momjian Exp $ * * NOTES - * This file contains support functions for the high - * level access method interface routines found in transam.c + * This file contains support functions for the high + * level access method interface routines found in transam.c * *------------------------------------------------------------------------- */ @@ -23,644 +23,659 @@ #include <access/xact.h> #include <storage/lmgr.h> -static AbsoluteTime TransBlockGetCommitTime(Block tblock, - TransactionId transactionId); -static XidStatus TransBlockGetXidStatus(Block tblock, - TransactionId transactionId); -static void TransBlockSetCommitTime(Block tblock, - TransactionId transactionId, AbsoluteTime commitTime); -static void TransBlockSetXidStatus(Block tblock, - TransactionId transactionId, XidStatus xstatus); +static AbsoluteTime +TransBlockGetCommitTime(Block tblock, + TransactionId transactionId); +static XidStatus +TransBlockGetXidStatus(Block tblock, + TransactionId transactionId); +static void +TransBlockSetCommitTime(Block tblock, + TransactionId transactionId, AbsoluteTime commitTime); +static void +TransBlockSetXidStatus(Block tblock, + TransactionId transactionId, XidStatus xstatus); /* ---------------------------------------------------------------- - * general support routines + * general support routines * ---------------------------------------------------------------- */ /* -------------------------------- - * AmiTransactionOverride + * AmiTransactionOverride * - * This function is used to manipulate the bootstrap flag. + * This function is used to manipulate the bootstrap flag. * -------------------------------- */ void AmiTransactionOverride(bool flag) { - AMI_OVERRIDE = flag; + AMI_OVERRIDE = flag; } /* -------------------------------- - * TransComputeBlockNumber + * TransComputeBlockNumber * -------------------------------- */ void -TransComputeBlockNumber(Relation relation, /* relation to test */ - TransactionId transactionId, /* transaction id to test */ - BlockNumber *blockNumberOutP) +TransComputeBlockNumber(Relation relation, /* relation to test */ + TransactionId transactionId, /* transaction id to + * test */ + BlockNumber * blockNumberOutP) { - long itemsPerBlock = 0; - - /* ---------------- - * 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; + long itemsPerBlock = 0; + + /* ---------------- + * 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 + * trans block support routines * ---------------------------------------------------------------- */ /* -------------------------------- - * TransBlockGetLastTransactionIdStatus + * TransBlockGetLastTransactionIdStatus * - * This returns the status and transaction id of the last - * transaction information recorded on the given TransBlock. + * This returns the status and transaction id of the last + * transaction information recorded on the given TransBlock. * -------------------------------- */ #ifdef NOT_USED -static XidStatus +static XidStatus TransBlockGetLastTransactionIdStatus(Block tblock, - TransactionId baseXid, - TransactionId *returnXidP) + 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; index > 0; index--) { - offset = BitIndexOf(index-1); - 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 - 1); - } - break; + 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; index > 0; index--) + { + offset = BitIndexOf(index - 1); + 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 - 1); + } + 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; + + /* ---------------- + * 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; } + #endif /* -------------------------------- - * TransBlockGetXidStatus + * TransBlockGetXidStatus * - * This returns the status of the desired transaction + * This returns the status of the desired transaction * -------------------------------- */ -static XidStatus +static XidStatus TransBlockGetXidStatus(Block tblock, - TransactionId transactionId) + 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); + 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 + * TransBlockSetXidStatus * - * This sets the status of the desired transaction + * This sets the status of the desired transaction * -------------------------------- */ static void TransBlockSetXidStatus(Block tblock, - TransactionId transactionId, - XidStatus xstatus) + 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; - } + 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 + * TransBlockGetCommitTime * - * This returns the transaction commit time for the - * specified transaction id in the trans block. + * This returns the transaction commit time for the + * specified transaction id in the trans block. * -------------------------------- */ -static AbsoluteTime +static AbsoluteTime TransBlockGetCommitTime(Block tblock, - TransactionId transactionId) + 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 ]; + 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 + * TransBlockSetCommitTime * - * This sets the commit time of the specified transaction + * This sets the commit time of the specified transaction * -------------------------------- */ static void TransBlockSetCommitTime(Block tblock, - TransactionId transactionId, - AbsoluteTime commitTime) + 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; + 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 + * transam i/o support routines * ---------------------------------------------------------------- */ /* -------------------------------- - * TransBlockNumberGetXidStatus + * TransBlockNumberGetXidStatus * -------------------------------- */ XidStatus TransBlockNumberGetXidStatus(Relation relation, - BlockNumber blockNumber, - TransactionId xid, - bool *failP) + 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; + 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 + * TransBlockNumberSetXidStatus * -------------------------------- */ void TransBlockNumberSetXidStatus(Relation relation, - BlockNumber blockNumber, - TransactionId xid, - XidStatus xstatus, - bool *failP) + 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); + 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 + * TransBlockNumberGetCommitTime * -------------------------------- */ AbsoluteTime TransBlockNumberGetCommitTime(Relation relation, - BlockNumber blockNumber, - TransactionId xid, - bool *failP) + 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; - + 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 + * TransBlockNumberSetCommitTime * -------------------------------- */ void TransBlockNumberSetCommitTime(Relation relation, - BlockNumber blockNumber, - TransactionId xid, - AbsoluteTime xtime, - bool *failP) + 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); - + 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 + * TransGetLastRecordedTransaction * -------------------------------- */ #ifdef NOT_USED void TransGetLastRecordedTransaction(Relation relation, - TransactionId xid, /* return: transaction id */ - bool *failP) + 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; + 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 */ - TransBlockGetLastTransactionIdStatus(block, baseXid, &xid); - - ReleaseBuffer(buffer); - - /* ---------------- - * SOMEDAY release our lock on the log relation - * ---------------- - */ - RelationUnsetLockForRead(relation); + TransBlockGetLastTransactionIdStatus(block, baseXid, &xid); + + ReleaseBuffer(buffer); + + /* ---------------- + * SOMEDAY release our lock on the log relation + * ---------------- + */ + RelationUnsetLockForRead(relation); } + #endif |