|
3 | 3 | * |
4 | 4 | */ |
5 | 5 |
|
| 6 | +#include "postgres.h" |
| 7 | + |
| 8 | +#include "access/htup_details.h" |
| 9 | +#include "nodes/pg_list.h" |
| 10 | +#include "utils/memutils.h" /* MemoryContexts */ |
| 11 | + |
| 12 | +#include "common.h" |
6 | 13 | #include "sbuf.h" |
7 | 14 |
|
| 15 | +typedef struct |
| 16 | +{ |
| 17 | + StreamDataPackage header; |
| 18 | + int ntuples; |
| 19 | + char *curptr; |
| 20 | + char data[FLEXIBLE_ARRAY_MEMBER]; |
| 21 | +} TupleBuffer; |
| 22 | + |
| 23 | +#define TupleBufferMinSize offsetof(TupleBuffer, data) |
| 24 | +#define SDP_FREE_SPACE(buf) (StorageSize(buf) - (buf->curptr - &buf->data[0])) |
| 25 | + |
| 26 | +static List *freebufs = NIL; |
| 27 | + |
| 28 | +static int |
| 29 | +StorageSize(const TupleBuffer *buf) |
| 30 | +{ |
| 31 | + return (SDP_Size(buf) - TupleBufferMinSize); |
| 32 | +} |
| 33 | + |
| 34 | +bool |
| 35 | +SDP_IsEmpty(const StreamDataPackage *buffer) |
| 36 | +{ |
| 37 | + TupleBuffer *buf = (TupleBuffer *) buffer; |
| 38 | + |
| 39 | + Assert(buf->ntuples >= 0); |
| 40 | + Assert(SDP_FREE_SPACE(buf) >= 0); |
| 41 | + return buf->ntuples == 0; |
| 42 | +} |
| 43 | + |
| 44 | +int |
| 45 | +SDP_Actual_size(const StreamDataPackage *buffer) |
| 46 | +{ |
| 47 | + TupleBuffer *buf; |
| 48 | + |
| 49 | + if (buffer->datalen <= 1) |
| 50 | + return SDP_Size(buffer); |
| 51 | + Assert(IsSDPBuf(buffer)); |
| 52 | + |
| 53 | + buf = (TupleBuffer *) buffer; |
| 54 | + return SDP_Size(buf) - SDP_FREE_SPACE(buf); |
| 55 | +} |
| 56 | + |
| 57 | +/* |
| 58 | + * Check correctness of Stream Data Package |
| 59 | + */ |
| 60 | +bool |
| 61 | +IsSDPBuf(const StreamDataPackage *buffer) |
| 62 | +{ |
| 63 | + TupleBuffer *buf; |
| 64 | + |
| 65 | + if (buffer == NULL || buffer->datalen <= 1) |
| 66 | + return false; |
| 67 | + |
| 68 | + buf = (TupleBuffer *) buffer; |
| 69 | + |
| 70 | + if (buf->curptr == NULL || buf->ntuples < 0) |
| 71 | + return false; |
| 72 | + |
| 73 | + return true; |
| 74 | +} |
| 75 | + |
| 76 | +StreamDataPackage * |
| 77 | +SDP_Alloc(int size) |
| 78 | +{ |
| 79 | + ListCell *lc; |
| 80 | + TupleBuffer *buf = NULL; |
| 81 | + MemoryContext OldMemoryContext; |
| 82 | + |
| 83 | + OldMemoryContext = MemoryContextSwitchTo(memory_context); |
| 84 | + |
| 85 | + /* To avoid palloc/free overheads we can store buffers */ |
| 86 | + for (lc = list_head(freebufs); lc != NULL; lc = lnext(lc)) |
| 87 | + { |
| 88 | + TupleBuffer *freebuf = (TupleBuffer *) lfirst(lc); |
| 89 | + |
| 90 | + if (freebuf->header.datalen < size) |
| 91 | + continue; |
| 92 | + |
| 93 | + buf = freebuf; |
| 94 | + freebufs = list_delete_ptr(freebufs, freebuf); |
| 95 | + break; |
| 96 | + } |
| 97 | + |
| 98 | + if (buf == NULL) |
| 99 | + { |
| 100 | + size = Max((TupleBufferMinSize + size), DEFAULT_PACKAGE_SIZE); |
| 101 | + |
| 102 | + /* No one buffer can be found */ |
| 103 | + buf = palloc0(size + SDPHeaderSize); |
| 104 | + buf->header.datalen = size; |
| 105 | + } |
| 106 | + |
| 107 | + buf->header.index = -1; |
| 108 | + buf->curptr = &buf->data[0]; |
| 109 | + buf->ntuples = 0; |
| 110 | + MemoryContextSwitchTo(OldMemoryContext); |
| 111 | + return (StreamDataPackage *) buf; |
| 112 | +} |
| 113 | + |
| 114 | +/* |
| 115 | + * Return buffer to the free buffers list |
| 116 | + */ |
8 | 117 | void |
9 | | -initTupleBuffer(TupleBuffer *tbuf, size_t mem_size) |
| 118 | +SDP_Free(StreamDataPackage *buffer) |
| 119 | +{ |
| 120 | + TupleBuffer *buf = (TupleBuffer *) buffer; |
| 121 | + MemoryContext OldMemoryContext; |
| 122 | + |
| 123 | + OldMemoryContext = MemoryContextSwitchTo(memory_context); |
| 124 | + |
| 125 | + Assert(IsSDPBuf(buffer)); |
| 126 | + buf->curptr = NULL; |
| 127 | + buf->ntuples = -1; |
| 128 | + freebufs = lappend(freebufs, buf); |
| 129 | + |
| 130 | + MemoryContextSwitchTo(OldMemoryContext); |
| 131 | +} |
| 132 | + |
| 133 | +bool |
| 134 | +SDP_Store(StreamDataPackage *buffer, HeapTuple tuple) |
10 | 135 | { |
11 | | - tbuf->curptr = &tbuf->data; |
12 | | - /* Will corrected before send to DMQ for 'trim tails' purpose. */ |
13 | | - tbuf->size = mem_size; |
| 136 | + TupleBuffer *buf = (TupleBuffer *) buffer; |
| 137 | + HeapTuple dest; |
| 138 | + |
| 139 | + Assert(buf != NULL && tuple != NULL); |
| 140 | + /* Check that user not pass pointer to non-allocated buffer */ |
| 141 | + Assert(buf->curptr != NULL && buf->ntuples >= 0); |
| 142 | + |
| 143 | + if (SDP_FREE_SPACE(buf) < HEAPTUPLESIZE + tuple->t_len) |
| 144 | + return true; |
| 145 | + |
| 146 | + dest = (HeapTuple) buf->curptr; |
| 147 | + dest->t_len = tuple->t_len; |
| 148 | + dest->t_self = tuple->t_self; |
| 149 | + dest->t_tableOid = tuple->t_tableOid; |
| 150 | + dest->t_data = (HeapTupleHeader) ((char *) dest + HEAPTUPLESIZE); |
| 151 | + buf->curptr += HEAPTUPLESIZE; |
| 152 | + memcpy((char *) dest->t_data, (char *) tuple->t_data, tuple->t_len); |
| 153 | + |
| 154 | + buf->curptr += tuple->t_len; |
| 155 | + buf->ntuples++; |
| 156 | + Assert(SDP_FREE_SPACE(buf) >= 0); |
| 157 | + |
| 158 | + return false; |
| 159 | +} |
| 160 | + |
| 161 | +void |
| 162 | +SDP_PrepareToRead(StreamDataPackage *buffer) |
| 163 | +{ |
| 164 | + TupleBuffer *buf = (TupleBuffer *) buffer; |
| 165 | + |
| 166 | + Assert(IsSDPBuf(buffer)); |
| 167 | + buf->curptr = buf->data; |
| 168 | +} |
| 169 | + |
| 170 | +HeapTuple |
| 171 | +SDP_Get_tuple(StreamDataPackage *buffer) |
| 172 | +{ |
| 173 | + TupleBuffer *buf; |
| 174 | + HeapTuple tuple; |
| 175 | + |
| 176 | + Assert(IsSDPBuf(buffer)); |
| 177 | + |
| 178 | + if (SDP_IsEmpty(buffer)) |
| 179 | + return NULL; |
| 180 | + |
| 181 | + buf = (TupleBuffer *) buffer; |
| 182 | + tuple = (HeapTuple) buf->curptr; |
| 183 | + tuple->t_data = (HeapTupleHeader) ((char *) tuple + HEAPTUPLESIZE); |
| 184 | + |
| 185 | + buf->curptr += TupSize(tuple); |
| 186 | + buf->ntuples--; |
| 187 | + |
| 188 | + return tuple; |
14 | 189 | } |
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