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| 1 | +/*------------------------------------------------------------------------- |
| 2 | + * |
| 3 | + * xlog.c |
| 4 | + * |
| 5 | + * |
| 6 | + * Portions Copyright (c) 1996-2000, PostgreSQL, Inc |
| 7 | + * Portions Copyright (c) 1994, Regents of the University of California |
| 8 | + * |
| 9 | + *------------------------------------------------------------------------- |
| 10 | + */ |
| 11 | + |
| 12 | +#include "postgres.h" |
| 13 | + |
| 14 | +#include "access/xlog.h" |
| 15 | +#include "access/xact.h" |
| 16 | + |
| 17 | +#ifdef XLOG |
| 18 | + |
| 19 | +/* |
| 20 | + * Check if specified heap tuple was inserted by given |
| 21 | + * xaction/command and return |
| 22 | + * |
| 23 | + * - -1 if not |
| 24 | + * - 0 if there is no tuple at all |
| 25 | + * - 1 if yes |
| 26 | + */ |
| 27 | +int |
| 28 | +XLogIsOwnerOfTuple(RelFileNode hnode, ItemPointer iptr, |
| 29 | + TransactionId xid, CommandId cid) |
| 30 | +{ |
| 31 | + Relation reln; |
| 32 | + Buffer buffer; |
| 33 | + Page page; |
| 34 | + ItemId lp; |
| 35 | + HeapTupleHeader htup; |
| 36 | + |
| 37 | + reln = XLogOpenRelation(false, RM_HEAP_ID, hnode); |
| 38 | + if (!RelationIsValid(reln)) |
| 39 | + return(0); |
| 40 | + |
| 41 | + buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr)); |
| 42 | + if (!BufferIsValid(buffer)) |
| 43 | + return(0); |
| 44 | + |
| 45 | + LockBuffer(buffer, BUFFER_LOCK_SHARE); |
| 46 | + page = (Page) BufferGetPage(buffer); |
| 47 | + if (PageIsNew((PageHeader) page) || |
| 48 | + ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page)) |
| 49 | + { |
| 50 | + UnlockAndReleaseBuffer(buffer); |
| 51 | + return(0); |
| 52 | + } |
| 53 | + lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr)); |
| 54 | + if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp)) |
| 55 | + { |
| 56 | + UnlockAndReleaseBuffer(buffer); |
| 57 | + return(0); |
| 58 | + } |
| 59 | + |
| 60 | + htup = (HeapTupleHeader) PageGetItem(page, lp); |
| 61 | + |
| 62 | + if (PageGetSUI(page) != ThisStartUpID || htup->t_xmin != xid || htup->t_cmin != cid) |
| 63 | + { |
| 64 | + UnlockAndReleaseBuffer(buffer); |
| 65 | + return(-1); |
| 66 | + } |
| 67 | + |
| 68 | + UnlockAndReleaseBuffer(buffer); |
| 69 | + return(1); |
| 70 | +} |
| 71 | + |
| 72 | +/* |
| 73 | + * Check if exists valid (inserted by not aborted xaction) heap tuple |
| 74 | + * for given item pointer |
| 75 | + */ |
| 76 | +bool |
| 77 | +XLogIsValidTuple(RelFileNode hnode, ItemPointer iptr) |
| 78 | +{ |
| 79 | + Relation reln; |
| 80 | + Buffer buffer; |
| 81 | + Page page; |
| 82 | + ItemId lp; |
| 83 | + HeapTupleHeader htup; |
| 84 | + |
| 85 | + reln = XLogOpenRelation(false, RM_HEAP_ID, hnode); |
| 86 | + if (!RelationIsValid(reln)) |
| 87 | + return(false); |
| 88 | + |
| 89 | + buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr)); |
| 90 | + if (!BufferIsValid(buffer)) |
| 91 | + return(false); |
| 92 | + |
| 93 | + LockBuffer(buffer, BUFFER_LOCK_SHARE); |
| 94 | + page = (Page) BufferGetPage(buffer); |
| 95 | + if (PageIsNew((PageHeader) page) || |
| 96 | + ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page)) |
| 97 | + { |
| 98 | + UnlockAndReleaseBuffer(buffer); |
| 99 | + return(false); |
| 100 | + } |
| 101 | + lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr)); |
| 102 | + if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp)) |
| 103 | + { |
| 104 | + UnlockAndReleaseBuffer(buffer); |
| 105 | + return(false); |
| 106 | + } |
| 107 | + |
| 108 | + htup = (HeapTupleHeader) PageGetItem(page, lp); |
| 109 | + |
| 110 | + if (XLogIsAborted(PageGetSUI(page), htup->t_xmin)) |
| 111 | + { |
| 112 | + UnlockAndReleaseBuffer(buffer); |
| 113 | + return(false); |
| 114 | + } |
| 115 | + |
| 116 | + UnlockAndReleaseBuffer(buffer); |
| 117 | + return(true); |
| 118 | +} |
| 119 | + |
| 120 | +#endif |
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