diff options
Diffstat (limited to 'src/backend/access/transam/transsup.c')
| -rw-r--r-- | src/backend/access/transam/transsup.c | 134 |
1 files changed, 57 insertions, 77 deletions
diff --git a/src/backend/access/transam/transsup.c b/src/backend/access/transam/transsup.c index c433506eae6..0a44a018a9a 100644 --- a/src/backend/access/transam/transsup.c +++ b/src/backend/access/transam/transsup.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/transam/Attic/transsup.c,v 1.29 2001/03/22 03:59:17 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/transam/Attic/transsup.c,v 1.30 2001/03/22 06:16:10 momjian Exp $ * * NOTES * This file contains support functions for the high @@ -56,11 +56,9 @@ TransComputeBlockNumber(Relation relation, /* relation to test */ { long itemsPerBlock = 0; - /* ---------------- - * we calculate the block number of our transaction - * by dividing the transaction id by the number of - * transaction things per block. - * ---------------- + /* + * 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; @@ -109,18 +107,16 @@ TransBlockGetLastTransactionIdStatus(Block tblock, BitIndex offset; XidStatus xstatus; - /* ---------------- - * sanity check - * ---------------- + /* + * 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. - * ---------------- + /* + * 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--) @@ -131,11 +127,10 @@ TransBlockGetLastTransactionIdStatus(Block tblock, 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. - * ---------------- + /* + * 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) { @@ -148,12 +143,11 @@ TransBlockGetLastTransactionIdStatus(Block tblock, } } - /* ---------------- - * 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 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) { @@ -161,9 +155,8 @@ TransBlockGetLastTransactionIdStatus(Block tblock, TransactionIdStore(baseXid, returnXidP); } - /* ---------------- - * return the status to the user - * ---------------- + /* + * return the status to the user */ return xstatus; } @@ -200,17 +193,15 @@ TransBlockGetXidStatus(Block tblock, */ index = transactionId % TP_NumXidStatusPerBlock; - /* ---------------- - * get the data at the specified index - * ---------------- + /* + * 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 the transaction status to the caller */ return (XidStatus) (bit1 | bit2); } @@ -245,9 +236,8 @@ TransBlockSetXidStatus(Block tblock, offset = BitIndexOf(index); - /* ---------------- - * store the transaction value at the specified offset - * ---------------- + /* + * store the transaction value at the specified offset */ switch (xstatus) { @@ -291,18 +281,16 @@ TransBlockNumberGetXidStatus(Relation relation, XidStatus xstatus; /* recorded status of xid */ bool localfail; /* bool used if failP = NULL */ - /* ---------------- - * get the page containing the transaction information - * ---------------- + /* + * get the page containing the transaction information */ buffer = ReadBuffer(relation, blockNumber); LockBuffer(buffer, BUFFER_LOCK_SHARE); block = BufferGetBlock(buffer); - /* ---------------- - * get the status from the block. note, for now we always - * return false in failP. - * ---------------- + /* + * get the status from the block. note, for now we always return + * false in failP. */ if (failP == NULL) failP = &localfail; @@ -310,9 +298,8 @@ TransBlockNumberGetXidStatus(Relation relation, xstatus = TransBlockGetXidStatus(block, xid); - /* ---------------- - * release the buffer and return the status - * ---------------- + /* + * release the buffer and return the status */ LockBuffer(buffer, BUFFER_LOCK_UNLOCK); ReleaseBuffer(buffer); @@ -335,19 +322,17 @@ TransBlockNumberSetXidStatus(Relation relation, Block block; /* block containing xstatus */ bool localfail; /* bool used if failP = NULL */ - /* ---------------- - * get the block containing the transaction status - * ---------------- + /* + * get the block containing the transaction status */ buffer = ReadBuffer(relation, blockNumber); LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE); 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. - * ---------------- + /* + * 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; @@ -381,22 +366,20 @@ TransGetLastRecordedTransaction(Relation relation, (*failP) = false; - /* ---------------- - * SOMEDAY gain exclusive access to the log relation + /* + * 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. - * ---------------- + * 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. - * ---------------- + /* + * 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) @@ -405,17 +388,15 @@ TransGetLastRecordedTransaction(Relation relation, return; } - /* ---------------- - * get the block containing the transaction information - * ---------------- + /* + * get the block containing the transaction information */ blockNumber = n - 1; buffer = ReadBuffer(relation, blockNumber); block = BufferGetBlock(buffer); - /* ---------------- - * get the last xid on the block - * ---------------- + /* + * get the last xid on the block */ baseXid = blockNumber * TP_NumXidStatusPerBlock; @@ -424,9 +405,8 @@ TransGetLastRecordedTransaction(Relation relation, ReleaseBuffer(buffer); - /* ---------------- - * SOMEDAY release our lock on the log relation - * ---------------- + /* + * SOMEDAY release our lock on the log relation */ RelationUnsetLockForRead(relation); } |