|
| 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 | +#ifdefXLOG |
| 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(RelFileNodehnode,ItemPointeriptr, |
| 29 | +TransactionIdxid,CommandIdcid) |
| 30 | +{ |
| 31 | +Relationreln; |
| 32 | +Bufferbuffer; |
| 33 | +Pagepage; |
| 34 | +ItemIdlp; |
| 35 | +HeapTupleHeaderhtup; |
| 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(RelFileNodehnode,ItemPointeriptr) |
| 78 | +{ |
| 79 | +Relationreln; |
| 80 | +Bufferbuffer; |
| 81 | +Pagepage; |
| 82 | +ItemIdlp; |
| 83 | +HeapTupleHeaderhtup; |
| 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 |