| 1 | /*------------------------------------------------------------------------- |
| 2 | * |
| 3 | * heaptuple.c |
| 4 | * This file contains heap tuple accessor and mutator routines, as well |
| 5 | * as various tuple utilities. |
| 6 | * |
| 7 | * Some notes about varlenas and this code: |
| 8 | * |
| 9 | * Before Postgres 8.3 varlenas always had a 4-byte length header, and |
| 10 | * therefore always needed 4-byte alignment (at least). This wasted space |
| 11 | * for short varlenas, for example CHAR(1) took 5 bytes and could need up to |
| 12 | * 3 additional padding bytes for alignment. |
| 13 | * |
| 14 | * Now, a short varlena (up to 126 data bytes) is reduced to a 1-byte header |
| 15 | * and we don't align it. To hide this from datatype-specific functions that |
| 16 | * don't want to deal with it, such a datum is considered "toasted" and will |
| 17 | * be expanded back to the normal 4-byte-header format by pg_detoast_datum. |
| 18 | * (In performance-critical code paths we can use pg_detoast_datum_packed |
| 19 | * and the appropriate access macros to avoid that overhead.) Note that this |
| 20 | * conversion is performed directly in heap_form_tuple, without invoking |
| 21 | * tuptoaster.c. |
| 22 | * |
| 23 | * This change will break any code that assumes it needn't detoast values |
| 24 | * that have been put into a tuple but never sent to disk. Hopefully there |
| 25 | * are few such places. |
| 26 | * |
| 27 | * Varlenas still have alignment 'i' (or 'd') in pg_type/pg_attribute, since |
| 28 | * that's the normal requirement for the untoasted format. But we ignore that |
| 29 | * for the 1-byte-header format. This means that the actual start position |
| 30 | * of a varlena datum may vary depending on which format it has. To determine |
| 31 | * what is stored, we have to require that alignment padding bytes be zero. |
| 32 | * (Postgres actually has always zeroed them, but now it's required!) Since |
| 33 | * the first byte of a 1-byte-header varlena can never be zero, we can examine |
| 34 | * the first byte after the previous datum to tell if it's a pad byte or the |
| 35 | * start of a 1-byte-header varlena. |
| 36 | * |
| 37 | * Note that while formerly we could rely on the first varlena column of a |
| 38 | * system catalog to be at the offset suggested by the C struct for the |
| 39 | * catalog, this is now risky: it's only safe if the preceding field is |
| 40 | * word-aligned, so that there will never be any padding. |
| 41 | * |
| 42 | * We don't pack varlenas whose attstorage is 'p', since the data type |
| 43 | * isn't expecting to have to detoast values. This is used in particular |
| 44 | * by oidvector and int2vector, which are used in the system catalogs |
| 45 | * and we'd like to still refer to them via C struct offsets. |
| 46 | * |
| 47 | * |
| 48 | * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group |
| 49 | * Portions Copyright (c) 1994, Regents of the University of California |
| 50 | * |
| 51 | * |
| 52 | * IDENTIFICATION |
| 53 | * src/backend/access/common/heaptuple.c |
| 54 | * |
| 55 | *------------------------------------------------------------------------- |
| 56 | */ |
| 57 | |
| 58 | #include "postgres.h" |
| 59 | |
| 60 | #include "access/sysattr.h" |
| 61 | #include "access/tupdesc_details.h" |
| 62 | #include "access/tuptoaster.h" |
| 63 | #include "executor/tuptable.h" |
| 64 | #include "utils/expandeddatum.h" |
| 65 | |
| 66 | |
| 67 | /* Does att's datatype allow packing into the 1-byte-header varlena format? */ |
| 68 | #define ATT_IS_PACKABLE(att) \ |
| 69 | ((att)->attlen == -1 && (att)->attstorage != 'p') |
| 70 | /* Use this if it's already known varlena */ |
| 71 | #define VARLENA_ATT_IS_PACKABLE(att) \ |
| 72 | ((att)->attstorage != 'p') |
| 73 | |
| 74 | |
| 75 | /* ---------------------------------------------------------------- |
| 76 | * misc support routines |
| 77 | * ---------------------------------------------------------------- |
| 78 | */ |
| 79 | |
| 80 | /* |
| 81 | * Return the missing value of an attribute, or NULL if there isn't one. |
| 82 | */ |
| 83 | Datum |
| 84 | getmissingattr(TupleDesc tupleDesc, |
| 85 | int attnum, bool *isnull) |
| 86 | { |
| 87 | Form_pg_attribute att; |
| 88 | |
| 89 | Assert(attnum <= tupleDesc->natts); |
| 90 | Assert(attnum > 0); |
| 91 | |
| 92 | att = TupleDescAttr(tupleDesc, attnum - 1); |
| 93 | |
| 94 | if (att->atthasmissing) |
| 95 | { |
| 96 | AttrMissing *attrmiss; |
| 97 | |
| 98 | Assert(tupleDesc->constr); |
| 99 | Assert(tupleDesc->constr->missing); |
| 100 | |
| 101 | attrmiss = tupleDesc->constr->missing + (attnum - 1); |
| 102 | |
| 103 | if (attrmiss->am_present) |
| 104 | { |
| 105 | *isnull = false; |
| 106 | return attrmiss->am_value; |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | *isnull = true; |
| 111 | return PointerGetDatum(NULL); |
| 112 | } |
| 113 | |
| 114 | /* |
| 115 | * heap_compute_data_size |
| 116 | * Determine size of the data area of a tuple to be constructed |
| 117 | */ |
| 118 | Size |
| 119 | heap_compute_data_size(TupleDesc tupleDesc, |
| 120 | Datum *values, |
| 121 | bool *isnull) |
| 122 | { |
| 123 | Size data_length = 0; |
| 124 | int i; |
| 125 | int numberOfAttributes = tupleDesc->natts; |
| 126 | |
| 127 | for (i = 0; i < numberOfAttributes; i++) |
| 128 | { |
| 129 | Datum val; |
| 130 | Form_pg_attribute atti; |
| 131 | |
| 132 | if (isnull[i]) |
| 133 | continue; |
| 134 | |
| 135 | val = values[i]; |
| 136 | atti = TupleDescAttr(tupleDesc, i); |
| 137 | |
| 138 | if (ATT_IS_PACKABLE(atti) && |
| 139 | VARATT_CAN_MAKE_SHORT(DatumGetPointer(val))) |
| 140 | { |
| 141 | /* |
| 142 | * we're anticipating converting to a short varlena header, so |
| 143 | * adjust length and don't count any alignment |
| 144 | */ |
| 145 | data_length += VARATT_CONVERTED_SHORT_SIZE(DatumGetPointer(val)); |
| 146 | } |
| 147 | else if (atti->attlen == -1 && |
| 148 | VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(val))) |
| 149 | { |
| 150 | /* |
| 151 | * we want to flatten the expanded value so that the constructed |
| 152 | * tuple doesn't depend on it |
| 153 | */ |
| 154 | data_length = att_align_nominal(data_length, atti->attalign); |
| 155 | data_length += EOH_get_flat_size(DatumGetEOHP(val)); |
| 156 | } |
| 157 | else |
| 158 | { |
| 159 | data_length = att_align_datum(data_length, atti->attalign, |
| 160 | atti->attlen, val); |
| 161 | data_length = att_addlength_datum(data_length, atti->attlen, |
| 162 | val); |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | return data_length; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Per-attribute helper for heap_fill_tuple and other routines building tuples. |
| 171 | * |
| 172 | * Fill in either a data value or a bit in the null bitmask |
| 173 | */ |
| 174 | static inline void |
| 175 | fill_val(Form_pg_attribute att, |
| 176 | bits8 **bit, |
| 177 | int *bitmask, |
| 178 | char **dataP, |
| 179 | uint16 *infomask, |
| 180 | Datum datum, |
| 181 | bool isnull) |
| 182 | { |
| 183 | Size data_length; |
| 184 | char *data = *dataP; |
| 185 | |
| 186 | /* |
| 187 | * If we're building a null bitmap, set the appropriate bit for the |
| 188 | * current column value here. |
| 189 | */ |
| 190 | if (bit != NULL) |
| 191 | { |
| 192 | if (*bitmask != HIGHBIT) |
| 193 | *bitmask <<= 1; |
| 194 | else |
| 195 | { |
| 196 | *bit += 1; |
| 197 | **bit = 0x0; |
| 198 | *bitmask = 1; |
| 199 | } |
| 200 | |
| 201 | if (isnull) |
| 202 | { |
| 203 | *infomask |= HEAP_HASNULL; |
| 204 | return; |
| 205 | } |
| 206 | |
| 207 | **bit |= *bitmask; |
| 208 | } |
| 209 | |
| 210 | /* |
| 211 | * XXX we use the att_align macros on the pointer value itself, not on an |
| 212 | * offset. This is a bit of a hack. |
| 213 | */ |
| 214 | if (att->attbyval) |
| 215 | { |
| 216 | /* pass-by-value */ |
| 217 | data = (char *) att_align_nominal(data, att->attalign); |
| 218 | store_att_byval(data, datum, att->attlen); |
| 219 | data_length = att->attlen; |
| 220 | } |
| 221 | else if (att->attlen == -1) |
| 222 | { |
| 223 | /* varlena */ |
| 224 | Pointer val = DatumGetPointer(datum); |
| 225 | |
| 226 | *infomask |= HEAP_HASVARWIDTH; |
| 227 | if (VARATT_IS_EXTERNAL(val)) |
| 228 | { |
| 229 | if (VARATT_IS_EXTERNAL_EXPANDED(val)) |
| 230 | { |
| 231 | /* |
| 232 | * we want to flatten the expanded value so that the |
| 233 | * constructed tuple doesn't depend on it |
| 234 | */ |
| 235 | ExpandedObjectHeader *eoh = DatumGetEOHP(datum); |
| 236 | |
| 237 | data = (char *) att_align_nominal(data, |
| 238 | att->attalign); |
| 239 | data_length = EOH_get_flat_size(eoh); |
| 240 | EOH_flatten_into(eoh, data, data_length); |
| 241 | } |
| 242 | else |
| 243 | { |
| 244 | *infomask |= HEAP_HASEXTERNAL; |
| 245 | /* no alignment, since it's short by definition */ |
| 246 | data_length = VARSIZE_EXTERNAL(val); |
| 247 | memcpy(data, val, data_length); |
| 248 | } |
| 249 | } |
| 250 | else if (VARATT_IS_SHORT(val)) |
| 251 | { |
| 252 | /* no alignment for short varlenas */ |
| 253 | data_length = VARSIZE_SHORT(val); |
| 254 | memcpy(data, val, data_length); |
| 255 | } |
| 256 | else if (VARLENA_ATT_IS_PACKABLE(att) && |
| 257 | VARATT_CAN_MAKE_SHORT(val)) |
| 258 | { |
| 259 | /* convert to short varlena -- no alignment */ |
| 260 | data_length = VARATT_CONVERTED_SHORT_SIZE(val); |
| 261 | SET_VARSIZE_SHORT(data, data_length); |
| 262 | memcpy(data + 1, VARDATA(val), data_length - 1); |
| 263 | } |
| 264 | else |
| 265 | { |
| 266 | /* full 4-byte header varlena */ |
| 267 | data = (char *) att_align_nominal(data, |
| 268 | att->attalign); |
| 269 | data_length = VARSIZE(val); |
| 270 | memcpy(data, val, data_length); |
| 271 | } |
| 272 | } |
| 273 | else if (att->attlen == -2) |
| 274 | { |
| 275 | /* cstring ... never needs alignment */ |
| 276 | *infomask |= HEAP_HASVARWIDTH; |
| 277 | Assert(att->attalign == 'c'); |
| 278 | data_length = strlen(DatumGetCString(datum)) + 1; |
| 279 | memcpy(data, DatumGetPointer(datum), data_length); |
| 280 | } |
| 281 | else |
| 282 | { |
| 283 | /* fixed-length pass-by-reference */ |
| 284 | data = (char *) att_align_nominal(data, att->attalign); |
| 285 | Assert(att->attlen > 0); |
| 286 | data_length = att->attlen; |
| 287 | memcpy(data, DatumGetPointer(datum), data_length); |
| 288 | } |
| 289 | |
| 290 | data += data_length; |
| 291 | *dataP = data; |
| 292 | } |
| 293 | |
| 294 | /* |
| 295 | * heap_fill_tuple |
| 296 | * Load data portion of a tuple from values/isnull arrays |
| 297 | * |
| 298 | * We also fill the null bitmap (if any) and set the infomask bits |
| 299 | * that reflect the tuple's data contents. |
| 300 | * |
| 301 | * NOTE: it is now REQUIRED that the caller have pre-zeroed the data area. |
| 302 | */ |
| 303 | void |
| 304 | heap_fill_tuple(TupleDesc tupleDesc, |
| 305 | Datum *values, bool *isnull, |
| 306 | char *data, Size data_size, |
| 307 | uint16 *infomask, bits8 *bit) |
| 308 | { |
| 309 | bits8 *bitP; |
| 310 | int bitmask; |
| 311 | int i; |
| 312 | int numberOfAttributes = tupleDesc->natts; |
| 313 | |
| 314 | #ifdef USE_ASSERT_CHECKING |
| 315 | char *start = data; |
| 316 | #endif |
| 317 | |
| 318 | if (bit != NULL) |
| 319 | { |
| 320 | bitP = &bit[-1]; |
| 321 | bitmask = HIGHBIT; |
| 322 | } |
| 323 | else |
| 324 | { |
| 325 | /* just to keep compiler quiet */ |
| 326 | bitP = NULL; |
| 327 | bitmask = 0; |
| 328 | } |
| 329 | |
| 330 | *infomask &= ~(HEAP_HASNULL | HEAP_HASVARWIDTH | HEAP_HASEXTERNAL); |
| 331 | |
| 332 | for (i = 0; i < numberOfAttributes; i++) |
| 333 | { |
| 334 | Form_pg_attribute attr = TupleDescAttr(tupleDesc, i); |
| 335 | |
| 336 | fill_val(attr, |
| 337 | bitP ? &bitP : NULL, |
| 338 | &bitmask, |
| 339 | &data, |
| 340 | infomask, |
| 341 | values ? values[i] : PointerGetDatum(NULL), |
| 342 | isnull ? isnull[i] : true); |
| 343 | } |
| 344 | |
| 345 | Assert((data - start) == data_size); |
| 346 | } |
| 347 | |
| 348 | |
| 349 | /* ---------------------------------------------------------------- |
| 350 | * heap tuple interface |
| 351 | * ---------------------------------------------------------------- |
| 352 | */ |
| 353 | |
| 354 | /* ---------------- |
| 355 | * heap_attisnull - returns true iff tuple attribute is not present |
| 356 | * ---------------- |
| 357 | */ |
| 358 | bool |
| 359 | heap_attisnull(HeapTuple tup, int attnum, TupleDesc tupleDesc) |
| 360 | { |
| 361 | /* |
| 362 | * We allow a NULL tupledesc for relations not expected to have missing |
| 363 | * values, such as catalog relations and indexes. |
| 364 | */ |
| 365 | Assert(!tupleDesc || attnum <= tupleDesc->natts); |
| 366 | if (attnum > (int) HeapTupleHeaderGetNatts(tup->t_data)) |
| 367 | { |
| 368 | if (tupleDesc && TupleDescAttr(tupleDesc, attnum - 1)->atthasmissing) |
| 369 | return false; |
| 370 | else |
| 371 | return true; |
| 372 | } |
| 373 | |
| 374 | if (attnum > 0) |
| 375 | { |
| 376 | if (HeapTupleNoNulls(tup)) |
| 377 | return false; |
| 378 | return att_isnull(attnum - 1, tup->t_data->t_bits); |
| 379 | } |
| 380 | |
| 381 | switch (attnum) |
| 382 | { |
| 383 | case TableOidAttributeNumber: |
| 384 | case SelfItemPointerAttributeNumber: |
| 385 | case MinTransactionIdAttributeNumber: |
| 386 | case MinCommandIdAttributeNumber: |
| 387 | case MaxTransactionIdAttributeNumber: |
| 388 | case MaxCommandIdAttributeNumber: |
| 389 | /* these are never null */ |
| 390 | break; |
| 391 | |
| 392 | default: |
| 393 | elog(ERROR, "invalid attnum: %d" , attnum); |
| 394 | } |
| 395 | |
| 396 | return false; |
| 397 | } |
| 398 | |
| 399 | /* ---------------- |
| 400 | * nocachegetattr |
| 401 | * |
| 402 | * This only gets called from fastgetattr() macro, in cases where |
| 403 | * we can't use a cacheoffset and the value is not null. |
| 404 | * |
| 405 | * This caches attribute offsets in the attribute descriptor. |
| 406 | * |
| 407 | * An alternative way to speed things up would be to cache offsets |
| 408 | * with the tuple, but that seems more difficult unless you take |
| 409 | * the storage hit of actually putting those offsets into the |
| 410 | * tuple you send to disk. Yuck. |
| 411 | * |
| 412 | * This scheme will be slightly slower than that, but should |
| 413 | * perform well for queries which hit large #'s of tuples. After |
| 414 | * you cache the offsets once, examining all the other tuples using |
| 415 | * the same attribute descriptor will go much quicker. -cim 5/4/91 |
| 416 | * |
| 417 | * NOTE: if you need to change this code, see also heap_deform_tuple. |
| 418 | * Also see nocache_index_getattr, which is the same code for index |
| 419 | * tuples. |
| 420 | * ---------------- |
| 421 | */ |
| 422 | Datum |
| 423 | nocachegetattr(HeapTuple tuple, |
| 424 | int attnum, |
| 425 | TupleDesc tupleDesc) |
| 426 | { |
| 427 | HeapTupleHeader tup = tuple->t_data; |
| 428 | char *tp; /* ptr to data part of tuple */ |
| 429 | bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */ |
| 430 | bool slow = false; /* do we have to walk attrs? */ |
| 431 | int off; /* current offset within data */ |
| 432 | |
| 433 | /* ---------------- |
| 434 | * Three cases: |
| 435 | * |
| 436 | * 1: No nulls and no variable-width attributes. |
| 437 | * 2: Has a null or a var-width AFTER att. |
| 438 | * 3: Has nulls or var-widths BEFORE att. |
| 439 | * ---------------- |
| 440 | */ |
| 441 | |
| 442 | attnum--; |
| 443 | |
| 444 | if (!HeapTupleNoNulls(tuple)) |
| 445 | { |
| 446 | /* |
| 447 | * there's a null somewhere in the tuple |
| 448 | * |
| 449 | * check to see if any preceding bits are null... |
| 450 | */ |
| 451 | int byte = attnum >> 3; |
| 452 | int finalbit = attnum & 0x07; |
| 453 | |
| 454 | /* check for nulls "before" final bit of last byte */ |
| 455 | if ((~bp[byte]) & ((1 << finalbit) - 1)) |
| 456 | slow = true; |
| 457 | else |
| 458 | { |
| 459 | /* check for nulls in any "earlier" bytes */ |
| 460 | int i; |
| 461 | |
| 462 | for (i = 0; i < byte; i++) |
| 463 | { |
| 464 | if (bp[i] != 0xFF) |
| 465 | { |
| 466 | slow = true; |
| 467 | break; |
| 468 | } |
| 469 | } |
| 470 | } |
| 471 | } |
| 472 | |
| 473 | tp = (char *) tup + tup->t_hoff; |
| 474 | |
| 475 | if (!slow) |
| 476 | { |
| 477 | Form_pg_attribute att; |
| 478 | |
| 479 | /* |
| 480 | * If we get here, there are no nulls up to and including the target |
| 481 | * attribute. If we have a cached offset, we can use it. |
| 482 | */ |
| 483 | att = TupleDescAttr(tupleDesc, attnum); |
| 484 | if (att->attcacheoff >= 0) |
| 485 | return fetchatt(att, tp + att->attcacheoff); |
| 486 | |
| 487 | /* |
| 488 | * Otherwise, check for non-fixed-length attrs up to and including |
| 489 | * target. If there aren't any, it's safe to cheaply initialize the |
| 490 | * cached offsets for these attrs. |
| 491 | */ |
| 492 | if (HeapTupleHasVarWidth(tuple)) |
| 493 | { |
| 494 | int j; |
| 495 | |
| 496 | for (j = 0; j <= attnum; j++) |
| 497 | { |
| 498 | if (TupleDescAttr(tupleDesc, j)->attlen <= 0) |
| 499 | { |
| 500 | slow = true; |
| 501 | break; |
| 502 | } |
| 503 | } |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | if (!slow) |
| 508 | { |
| 509 | int natts = tupleDesc->natts; |
| 510 | int j = 1; |
| 511 | |
| 512 | /* |
| 513 | * If we get here, we have a tuple with no nulls or var-widths up to |
| 514 | * and including the target attribute, so we can use the cached offset |
| 515 | * ... only we don't have it yet, or we'd not have got here. Since |
| 516 | * it's cheap to compute offsets for fixed-width columns, we take the |
| 517 | * opportunity to initialize the cached offsets for *all* the leading |
| 518 | * fixed-width columns, in hope of avoiding future visits to this |
| 519 | * routine. |
| 520 | */ |
| 521 | TupleDescAttr(tupleDesc, 0)->attcacheoff = 0; |
| 522 | |
| 523 | /* we might have set some offsets in the slow path previously */ |
| 524 | while (j < natts && TupleDescAttr(tupleDesc, j)->attcacheoff > 0) |
| 525 | j++; |
| 526 | |
| 527 | off = TupleDescAttr(tupleDesc, j - 1)->attcacheoff + |
| 528 | TupleDescAttr(tupleDesc, j - 1)->attlen; |
| 529 | |
| 530 | for (; j < natts; j++) |
| 531 | { |
| 532 | Form_pg_attribute att = TupleDescAttr(tupleDesc, j); |
| 533 | |
| 534 | if (att->attlen <= 0) |
| 535 | break; |
| 536 | |
| 537 | off = att_align_nominal(off, att->attalign); |
| 538 | |
| 539 | att->attcacheoff = off; |
| 540 | |
| 541 | off += att->attlen; |
| 542 | } |
| 543 | |
| 544 | Assert(j > attnum); |
| 545 | |
| 546 | off = TupleDescAttr(tupleDesc, attnum)->attcacheoff; |
| 547 | } |
| 548 | else |
| 549 | { |
| 550 | bool usecache = true; |
| 551 | int i; |
| 552 | |
| 553 | /* |
| 554 | * Now we know that we have to walk the tuple CAREFULLY. But we still |
| 555 | * might be able to cache some offsets for next time. |
| 556 | * |
| 557 | * Note - This loop is a little tricky. For each non-null attribute, |
| 558 | * we have to first account for alignment padding before the attr, |
| 559 | * then advance over the attr based on its length. Nulls have no |
| 560 | * storage and no alignment padding either. We can use/set |
| 561 | * attcacheoff until we reach either a null or a var-width attribute. |
| 562 | */ |
| 563 | off = 0; |
| 564 | for (i = 0;; i++) /* loop exit is at "break" */ |
| 565 | { |
| 566 | Form_pg_attribute att = TupleDescAttr(tupleDesc, i); |
| 567 | |
| 568 | if (HeapTupleHasNulls(tuple) && att_isnull(i, bp)) |
| 569 | { |
| 570 | usecache = false; |
| 571 | continue; /* this cannot be the target att */ |
| 572 | } |
| 573 | |
| 574 | /* If we know the next offset, we can skip the rest */ |
| 575 | if (usecache && att->attcacheoff >= 0) |
| 576 | off = att->attcacheoff; |
| 577 | else if (att->attlen == -1) |
| 578 | { |
| 579 | /* |
| 580 | * We can only cache the offset for a varlena attribute if the |
| 581 | * offset is already suitably aligned, so that there would be |
| 582 | * no pad bytes in any case: then the offset will be valid for |
| 583 | * either an aligned or unaligned value. |
| 584 | */ |
| 585 | if (usecache && |
| 586 | off == att_align_nominal(off, att->attalign)) |
| 587 | att->attcacheoff = off; |
| 588 | else |
| 589 | { |
| 590 | off = att_align_pointer(off, att->attalign, -1, |
| 591 | tp + off); |
| 592 | usecache = false; |
| 593 | } |
| 594 | } |
| 595 | else |
| 596 | { |
| 597 | /* not varlena, so safe to use att_align_nominal */ |
| 598 | off = att_align_nominal(off, att->attalign); |
| 599 | |
| 600 | if (usecache) |
| 601 | att->attcacheoff = off; |
| 602 | } |
| 603 | |
| 604 | if (i == attnum) |
| 605 | break; |
| 606 | |
| 607 | off = att_addlength_pointer(off, att->attlen, tp + off); |
| 608 | |
| 609 | if (usecache && att->attlen <= 0) |
| 610 | usecache = false; |
| 611 | } |
| 612 | } |
| 613 | |
| 614 | return fetchatt(TupleDescAttr(tupleDesc, attnum), tp + off); |
| 615 | } |
| 616 | |
| 617 | /* ---------------- |
| 618 | * heap_getsysattr |
| 619 | * |
| 620 | * Fetch the value of a system attribute for a tuple. |
| 621 | * |
| 622 | * This is a support routine for the heap_getattr macro. The macro |
| 623 | * has already determined that the attnum refers to a system attribute. |
| 624 | * ---------------- |
| 625 | */ |
| 626 | Datum |
| 627 | heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull) |
| 628 | { |
| 629 | Datum result; |
| 630 | |
| 631 | Assert(tup); |
| 632 | |
| 633 | /* Currently, no sys attribute ever reads as NULL. */ |
| 634 | *isnull = false; |
| 635 | |
| 636 | switch (attnum) |
| 637 | { |
| 638 | case SelfItemPointerAttributeNumber: |
| 639 | /* pass-by-reference datatype */ |
| 640 | result = PointerGetDatum(&(tup->t_self)); |
| 641 | break; |
| 642 | case MinTransactionIdAttributeNumber: |
| 643 | result = TransactionIdGetDatum(HeapTupleHeaderGetRawXmin(tup->t_data)); |
| 644 | break; |
| 645 | case MaxTransactionIdAttributeNumber: |
| 646 | result = TransactionIdGetDatum(HeapTupleHeaderGetRawXmax(tup->t_data)); |
| 647 | break; |
| 648 | case MinCommandIdAttributeNumber: |
| 649 | case MaxCommandIdAttributeNumber: |
| 650 | |
| 651 | /* |
| 652 | * cmin and cmax are now both aliases for the same field, which |
| 653 | * can in fact also be a combo command id. XXX perhaps we should |
| 654 | * return the "real" cmin or cmax if possible, that is if we are |
| 655 | * inside the originating transaction? |
| 656 | */ |
| 657 | result = CommandIdGetDatum(HeapTupleHeaderGetRawCommandId(tup->t_data)); |
| 658 | break; |
| 659 | case TableOidAttributeNumber: |
| 660 | result = ObjectIdGetDatum(tup->t_tableOid); |
| 661 | break; |
| 662 | default: |
| 663 | elog(ERROR, "invalid attnum: %d" , attnum); |
| 664 | result = 0; /* keep compiler quiet */ |
| 665 | break; |
| 666 | } |
| 667 | return result; |
| 668 | } |
| 669 | |
| 670 | /* ---------------- |
| 671 | * heap_copytuple |
| 672 | * |
| 673 | * returns a copy of an entire tuple |
| 674 | * |
| 675 | * The HeapTuple struct, tuple header, and tuple data are all allocated |
| 676 | * as a single palloc() block. |
| 677 | * ---------------- |
| 678 | */ |
| 679 | HeapTuple |
| 680 | heap_copytuple(HeapTuple tuple) |
| 681 | { |
| 682 | HeapTuple newTuple; |
| 683 | |
| 684 | if (!HeapTupleIsValid(tuple) || tuple->t_data == NULL) |
| 685 | return NULL; |
| 686 | |
| 687 | newTuple = (HeapTuple) palloc(HEAPTUPLESIZE + tuple->t_len); |
| 688 | newTuple->t_len = tuple->t_len; |
| 689 | newTuple->t_self = tuple->t_self; |
| 690 | newTuple->t_tableOid = tuple->t_tableOid; |
| 691 | newTuple->t_data = (HeapTupleHeader) ((char *) newTuple + HEAPTUPLESIZE); |
| 692 | memcpy((char *) newTuple->t_data, (char *) tuple->t_data, tuple->t_len); |
| 693 | return newTuple; |
| 694 | } |
| 695 | |
| 696 | /* ---------------- |
| 697 | * heap_copytuple_with_tuple |
| 698 | * |
| 699 | * copy a tuple into a caller-supplied HeapTuple management struct |
| 700 | * |
| 701 | * Note that after calling this function, the "dest" HeapTuple will not be |
| 702 | * allocated as a single palloc() block (unlike with heap_copytuple()). |
| 703 | * ---------------- |
| 704 | */ |
| 705 | void |
| 706 | heap_copytuple_with_tuple(HeapTuple src, HeapTuple dest) |
| 707 | { |
| 708 | if (!HeapTupleIsValid(src) || src->t_data == NULL) |
| 709 | { |
| 710 | dest->t_data = NULL; |
| 711 | return; |
| 712 | } |
| 713 | |
| 714 | dest->t_len = src->t_len; |
| 715 | dest->t_self = src->t_self; |
| 716 | dest->t_tableOid = src->t_tableOid; |
| 717 | dest->t_data = (HeapTupleHeader) palloc(src->t_len); |
| 718 | memcpy((char *) dest->t_data, (char *) src->t_data, src->t_len); |
| 719 | } |
| 720 | |
| 721 | /* |
| 722 | * Expand a tuple which has less attributes than required. For each attribute |
| 723 | * not present in the sourceTuple, if there is a missing value that will be |
| 724 | * used. Otherwise the attribute will be set to NULL. |
| 725 | * |
| 726 | * The source tuple must have less attributes than the required number. |
| 727 | * |
| 728 | * Only one of targetHeapTuple and targetMinimalTuple may be supplied. The |
| 729 | * other argument must be NULL. |
| 730 | */ |
| 731 | static void |
| 732 | expand_tuple(HeapTuple *targetHeapTuple, |
| 733 | MinimalTuple *targetMinimalTuple, |
| 734 | HeapTuple sourceTuple, |
| 735 | TupleDesc tupleDesc) |
| 736 | { |
| 737 | AttrMissing *attrmiss = NULL; |
| 738 | int attnum; |
| 739 | int firstmissingnum = 0; |
| 740 | bool hasNulls = HeapTupleHasNulls(sourceTuple); |
| 741 | HeapTupleHeader ; |
| 742 | HeapTupleHeader = sourceTuple->t_data; |
| 743 | int sourceNatts = HeapTupleHeaderGetNatts(sourceTHeader); |
| 744 | int natts = tupleDesc->natts; |
| 745 | int sourceNullLen; |
| 746 | int targetNullLen; |
| 747 | Size sourceDataLen = sourceTuple->t_len - sourceTHeader->t_hoff; |
| 748 | Size targetDataLen; |
| 749 | Size len; |
| 750 | int hoff; |
| 751 | bits8 *nullBits = NULL; |
| 752 | int bitMask = 0; |
| 753 | char *targetData; |
| 754 | uint16 *infoMask; |
| 755 | |
| 756 | Assert((targetHeapTuple && !targetMinimalTuple) |
| 757 | || (!targetHeapTuple && targetMinimalTuple)); |
| 758 | |
| 759 | Assert(sourceNatts < natts); |
| 760 | |
| 761 | sourceNullLen = (hasNulls ? BITMAPLEN(sourceNatts) : 0); |
| 762 | |
| 763 | targetDataLen = sourceDataLen; |
| 764 | |
| 765 | if (tupleDesc->constr && |
| 766 | tupleDesc->constr->missing) |
| 767 | { |
| 768 | /* |
| 769 | * If there are missing values we want to put them into the tuple. |
| 770 | * Before that we have to compute the extra length for the values |
| 771 | * array and the variable length data. |
| 772 | */ |
| 773 | attrmiss = tupleDesc->constr->missing; |
| 774 | |
| 775 | /* |
| 776 | * Find the first item in attrmiss for which we don't have a value in |
| 777 | * the source. We can ignore all the missing entries before that. |
| 778 | */ |
| 779 | for (firstmissingnum = sourceNatts; |
| 780 | firstmissingnum < natts; |
| 781 | firstmissingnum++) |
| 782 | { |
| 783 | if (attrmiss[firstmissingnum].am_present) |
| 784 | break; |
| 785 | else |
| 786 | hasNulls = true; |
| 787 | } |
| 788 | |
| 789 | /* |
| 790 | * Now walk the missing attributes. If there is a missing value make |
| 791 | * space for it. Otherwise, it's going to be NULL. |
| 792 | */ |
| 793 | for (attnum = firstmissingnum; |
| 794 | attnum < natts; |
| 795 | attnum++) |
| 796 | { |
| 797 | if (attrmiss[attnum].am_present) |
| 798 | { |
| 799 | Form_pg_attribute att = TupleDescAttr(tupleDesc, attnum); |
| 800 | |
| 801 | targetDataLen = att_align_datum(targetDataLen, |
| 802 | att->attalign, |
| 803 | att->attlen, |
| 804 | attrmiss[attnum].am_value); |
| 805 | |
| 806 | targetDataLen = att_addlength_pointer(targetDataLen, |
| 807 | att->attlen, |
| 808 | attrmiss[attnum].am_value); |
| 809 | } |
| 810 | else |
| 811 | { |
| 812 | /* no missing value, so it must be null */ |
| 813 | hasNulls = true; |
| 814 | } |
| 815 | } |
| 816 | } /* end if have missing values */ |
| 817 | else |
| 818 | { |
| 819 | /* |
| 820 | * If there are no missing values at all then NULLS must be allowed, |
| 821 | * since some of the attributes are known to be absent. |
| 822 | */ |
| 823 | hasNulls = true; |
| 824 | } |
| 825 | |
| 826 | len = 0; |
| 827 | |
| 828 | if (hasNulls) |
| 829 | { |
| 830 | targetNullLen = BITMAPLEN(natts); |
| 831 | len += targetNullLen; |
| 832 | } |
| 833 | else |
| 834 | targetNullLen = 0; |
| 835 | |
| 836 | /* |
| 837 | * Allocate and zero the space needed. Note that the tuple body and |
| 838 | * HeapTupleData management structure are allocated in one chunk. |
| 839 | */ |
| 840 | if (targetHeapTuple) |
| 841 | { |
| 842 | len += offsetof(HeapTupleHeaderData, t_bits); |
| 843 | hoff = len = MAXALIGN(len); /* align user data safely */ |
| 844 | len += targetDataLen; |
| 845 | |
| 846 | *targetHeapTuple = (HeapTuple) palloc0(HEAPTUPLESIZE + len); |
| 847 | (*targetHeapTuple)->t_data |
| 848 | = targetTHeader |
| 849 | = (HeapTupleHeader) ((char *) *targetHeapTuple + HEAPTUPLESIZE); |
| 850 | (*targetHeapTuple)->t_len = len; |
| 851 | (*targetHeapTuple)->t_tableOid = sourceTuple->t_tableOid; |
| 852 | (*targetHeapTuple)->t_self = sourceTuple->t_self; |
| 853 | |
| 854 | targetTHeader->t_infomask = sourceTHeader->t_infomask; |
| 855 | targetTHeader->t_hoff = hoff; |
| 856 | HeapTupleHeaderSetNatts(targetTHeader, natts); |
| 857 | HeapTupleHeaderSetDatumLength(targetTHeader, len); |
| 858 | HeapTupleHeaderSetTypeId(targetTHeader, tupleDesc->tdtypeid); |
| 859 | HeapTupleHeaderSetTypMod(targetTHeader, tupleDesc->tdtypmod); |
| 860 | /* We also make sure that t_ctid is invalid unless explicitly set */ |
| 861 | ItemPointerSetInvalid(&(targetTHeader->t_ctid)); |
| 862 | if (targetNullLen > 0) |
| 863 | nullBits = (bits8 *) ((char *) (*targetHeapTuple)->t_data |
| 864 | + offsetof(HeapTupleHeaderData, t_bits)); |
| 865 | targetData = (char *) (*targetHeapTuple)->t_data + hoff; |
| 866 | infoMask = &(targetTHeader->t_infomask); |
| 867 | } |
| 868 | else |
| 869 | { |
| 870 | len += SizeofMinimalTupleHeader; |
| 871 | hoff = len = MAXALIGN(len); /* align user data safely */ |
| 872 | len += targetDataLen; |
| 873 | |
| 874 | *targetMinimalTuple = (MinimalTuple) palloc0(len); |
| 875 | (*targetMinimalTuple)->t_len = len; |
| 876 | (*targetMinimalTuple)->t_hoff = hoff + MINIMAL_TUPLE_OFFSET; |
| 877 | (*targetMinimalTuple)->t_infomask = sourceTHeader->t_infomask; |
| 878 | /* Same macro works for MinimalTuples */ |
| 879 | HeapTupleHeaderSetNatts(*targetMinimalTuple, natts); |
| 880 | if (targetNullLen > 0) |
| 881 | nullBits = (bits8 *) ((char *) *targetMinimalTuple |
| 882 | + offsetof(MinimalTupleData, t_bits)); |
| 883 | targetData = (char *) *targetMinimalTuple + hoff; |
| 884 | infoMask = &((*targetMinimalTuple)->t_infomask); |
| 885 | } |
| 886 | |
| 887 | if (targetNullLen > 0) |
| 888 | { |
| 889 | if (sourceNullLen > 0) |
| 890 | { |
| 891 | /* if bitmap pre-existed copy in - all is set */ |
| 892 | memcpy(nullBits, |
| 893 | ((char *) sourceTHeader) |
| 894 | + offsetof(HeapTupleHeaderData, t_bits), |
| 895 | sourceNullLen); |
| 896 | nullBits += sourceNullLen - 1; |
| 897 | } |
| 898 | else |
| 899 | { |
| 900 | sourceNullLen = BITMAPLEN(sourceNatts); |
| 901 | /* Set NOT NULL for all existing attributes */ |
| 902 | memset(nullBits, 0xff, sourceNullLen); |
| 903 | |
| 904 | nullBits += sourceNullLen - 1; |
| 905 | |
| 906 | if (sourceNatts & 0x07) |
| 907 | { |
| 908 | /* build the mask (inverted!) */ |
| 909 | bitMask = 0xff << (sourceNatts & 0x07); |
| 910 | /* Voila */ |
| 911 | *nullBits = ~bitMask; |
| 912 | } |
| 913 | } |
| 914 | |
| 915 | bitMask = (1 << ((sourceNatts - 1) & 0x07)); |
| 916 | } /* End if have null bitmap */ |
| 917 | |
| 918 | memcpy(targetData, |
| 919 | ((char *) sourceTuple->t_data) + sourceTHeader->t_hoff, |
| 920 | sourceDataLen); |
| 921 | |
| 922 | targetData += sourceDataLen; |
| 923 | |
| 924 | /* Now fill in the missing values */ |
| 925 | for (attnum = sourceNatts; attnum < natts; attnum++) |
| 926 | { |
| 927 | |
| 928 | Form_pg_attribute attr = TupleDescAttr(tupleDesc, attnum); |
| 929 | |
| 930 | if (attrmiss && attrmiss[attnum].am_present) |
| 931 | { |
| 932 | fill_val(attr, |
| 933 | nullBits ? &nullBits : NULL, |
| 934 | &bitMask, |
| 935 | &targetData, |
| 936 | infoMask, |
| 937 | attrmiss[attnum].am_value, |
| 938 | false); |
| 939 | } |
| 940 | else |
| 941 | { |
| 942 | fill_val(attr, |
| 943 | &nullBits, |
| 944 | &bitMask, |
| 945 | &targetData, |
| 946 | infoMask, |
| 947 | (Datum) 0, |
| 948 | true); |
| 949 | } |
| 950 | } /* end loop over missing attributes */ |
| 951 | } |
| 952 | |
| 953 | /* |
| 954 | * Fill in the missing values for a minimal HeapTuple |
| 955 | */ |
| 956 | MinimalTuple |
| 957 | minimal_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc) |
| 958 | { |
| 959 | MinimalTuple minimalTuple; |
| 960 | |
| 961 | expand_tuple(NULL, &minimalTuple, sourceTuple, tupleDesc); |
| 962 | return minimalTuple; |
| 963 | } |
| 964 | |
| 965 | /* |
| 966 | * Fill in the missing values for an ordinary HeapTuple |
| 967 | */ |
| 968 | HeapTuple |
| 969 | heap_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc) |
| 970 | { |
| 971 | HeapTuple heapTuple; |
| 972 | |
| 973 | expand_tuple(&heapTuple, NULL, sourceTuple, tupleDesc); |
| 974 | return heapTuple; |
| 975 | } |
| 976 | |
| 977 | /* ---------------- |
| 978 | * heap_copy_tuple_as_datum |
| 979 | * |
| 980 | * copy a tuple as a composite-type Datum |
| 981 | * ---------------- |
| 982 | */ |
| 983 | Datum |
| 984 | heap_copy_tuple_as_datum(HeapTuple tuple, TupleDesc tupleDesc) |
| 985 | { |
| 986 | HeapTupleHeader td; |
| 987 | |
| 988 | /* |
| 989 | * If the tuple contains any external TOAST pointers, we have to inline |
| 990 | * those fields to meet the conventions for composite-type Datums. |
| 991 | */ |
| 992 | if (HeapTupleHasExternal(tuple)) |
| 993 | return toast_flatten_tuple_to_datum(tuple->t_data, |
| 994 | tuple->t_len, |
| 995 | tupleDesc); |
| 996 | |
| 997 | /* |
| 998 | * Fast path for easy case: just make a palloc'd copy and insert the |
| 999 | * correct composite-Datum header fields (since those may not be set if |
| 1000 | * the given tuple came from disk, rather than from heap_form_tuple). |
| 1001 | */ |
| 1002 | td = (HeapTupleHeader) palloc(tuple->t_len); |
| 1003 | memcpy((char *) td, (char *) tuple->t_data, tuple->t_len); |
| 1004 | |
| 1005 | HeapTupleHeaderSetDatumLength(td, tuple->t_len); |
| 1006 | HeapTupleHeaderSetTypeId(td, tupleDesc->tdtypeid); |
| 1007 | HeapTupleHeaderSetTypMod(td, tupleDesc->tdtypmod); |
| 1008 | |
| 1009 | return PointerGetDatum(td); |
| 1010 | } |
| 1011 | |
| 1012 | /* |
| 1013 | * heap_form_tuple |
| 1014 | * construct a tuple from the given values[] and isnull[] arrays, |
| 1015 | * which are of the length indicated by tupleDescriptor->natts |
| 1016 | * |
| 1017 | * The result is allocated in the current memory context. |
| 1018 | */ |
| 1019 | HeapTuple |
| 1020 | heap_form_tuple(TupleDesc tupleDescriptor, |
| 1021 | Datum *values, |
| 1022 | bool *isnull) |
| 1023 | { |
| 1024 | HeapTuple tuple; /* return tuple */ |
| 1025 | HeapTupleHeader td; /* tuple data */ |
| 1026 | Size len, |
| 1027 | data_len; |
| 1028 | int hoff; |
| 1029 | bool hasnull = false; |
| 1030 | int numberOfAttributes = tupleDescriptor->natts; |
| 1031 | int i; |
| 1032 | |
| 1033 | if (numberOfAttributes > MaxTupleAttributeNumber) |
| 1034 | ereport(ERROR, |
| 1035 | (errcode(ERRCODE_TOO_MANY_COLUMNS), |
| 1036 | errmsg("number of columns (%d) exceeds limit (%d)" , |
| 1037 | numberOfAttributes, MaxTupleAttributeNumber))); |
| 1038 | |
| 1039 | /* |
| 1040 | * Check for nulls |
| 1041 | */ |
| 1042 | for (i = 0; i < numberOfAttributes; i++) |
| 1043 | { |
| 1044 | if (isnull[i]) |
| 1045 | { |
| 1046 | hasnull = true; |
| 1047 | break; |
| 1048 | } |
| 1049 | } |
| 1050 | |
| 1051 | /* |
| 1052 | * Determine total space needed |
| 1053 | */ |
| 1054 | len = offsetof(HeapTupleHeaderData, t_bits); |
| 1055 | |
| 1056 | if (hasnull) |
| 1057 | len += BITMAPLEN(numberOfAttributes); |
| 1058 | |
| 1059 | hoff = len = MAXALIGN(len); /* align user data safely */ |
| 1060 | |
| 1061 | data_len = heap_compute_data_size(tupleDescriptor, values, isnull); |
| 1062 | |
| 1063 | len += data_len; |
| 1064 | |
| 1065 | /* |
| 1066 | * Allocate and zero the space needed. Note that the tuple body and |
| 1067 | * HeapTupleData management structure are allocated in one chunk. |
| 1068 | */ |
| 1069 | tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + len); |
| 1070 | tuple->t_data = td = (HeapTupleHeader) ((char *) tuple + HEAPTUPLESIZE); |
| 1071 | |
| 1072 | /* |
| 1073 | * And fill in the information. Note we fill the Datum fields even though |
| 1074 | * this tuple may never become a Datum. This lets HeapTupleHeaderGetDatum |
| 1075 | * identify the tuple type if needed. |
| 1076 | */ |
| 1077 | tuple->t_len = len; |
| 1078 | ItemPointerSetInvalid(&(tuple->t_self)); |
| 1079 | tuple->t_tableOid = InvalidOid; |
| 1080 | |
| 1081 | HeapTupleHeaderSetDatumLength(td, len); |
| 1082 | HeapTupleHeaderSetTypeId(td, tupleDescriptor->tdtypeid); |
| 1083 | HeapTupleHeaderSetTypMod(td, tupleDescriptor->tdtypmod); |
| 1084 | /* We also make sure that t_ctid is invalid unless explicitly set */ |
| 1085 | ItemPointerSetInvalid(&(td->t_ctid)); |
| 1086 | |
| 1087 | HeapTupleHeaderSetNatts(td, numberOfAttributes); |
| 1088 | td->t_hoff = hoff; |
| 1089 | |
| 1090 | heap_fill_tuple(tupleDescriptor, |
| 1091 | values, |
| 1092 | isnull, |
| 1093 | (char *) td + hoff, |
| 1094 | data_len, |
| 1095 | &td->t_infomask, |
| 1096 | (hasnull ? td->t_bits : NULL)); |
| 1097 | |
| 1098 | return tuple; |
| 1099 | } |
| 1100 | |
| 1101 | /* |
| 1102 | * heap_modify_tuple |
| 1103 | * form a new tuple from an old tuple and a set of replacement values. |
| 1104 | * |
| 1105 | * The replValues, replIsnull, and doReplace arrays must be of the length |
| 1106 | * indicated by tupleDesc->natts. The new tuple is constructed using the data |
| 1107 | * from replValues/replIsnull at columns where doReplace is true, and using |
| 1108 | * the data from the old tuple at columns where doReplace is false. |
| 1109 | * |
| 1110 | * The result is allocated in the current memory context. |
| 1111 | */ |
| 1112 | HeapTuple |
| 1113 | heap_modify_tuple(HeapTuple tuple, |
| 1114 | TupleDesc tupleDesc, |
| 1115 | Datum *replValues, |
| 1116 | bool *replIsnull, |
| 1117 | bool *doReplace) |
| 1118 | { |
| 1119 | int numberOfAttributes = tupleDesc->natts; |
| 1120 | int attoff; |
| 1121 | Datum *values; |
| 1122 | bool *isnull; |
| 1123 | HeapTuple newTuple; |
| 1124 | |
| 1125 | /* |
| 1126 | * allocate and fill values and isnull arrays from either the tuple or the |
| 1127 | * repl information, as appropriate. |
| 1128 | * |
| 1129 | * NOTE: it's debatable whether to use heap_deform_tuple() here or just |
| 1130 | * heap_getattr() only the non-replaced columns. The latter could win if |
| 1131 | * there are many replaced columns and few non-replaced ones. However, |
| 1132 | * heap_deform_tuple costs only O(N) while the heap_getattr way would cost |
| 1133 | * O(N^2) if there are many non-replaced columns, so it seems better to |
| 1134 | * err on the side of linear cost. |
| 1135 | */ |
| 1136 | values = (Datum *) palloc(numberOfAttributes * sizeof(Datum)); |
| 1137 | isnull = (bool *) palloc(numberOfAttributes * sizeof(bool)); |
| 1138 | |
| 1139 | heap_deform_tuple(tuple, tupleDesc, values, isnull); |
| 1140 | |
| 1141 | for (attoff = 0; attoff < numberOfAttributes; attoff++) |
| 1142 | { |
| 1143 | if (doReplace[attoff]) |
| 1144 | { |
| 1145 | values[attoff] = replValues[attoff]; |
| 1146 | isnull[attoff] = replIsnull[attoff]; |
| 1147 | } |
| 1148 | } |
| 1149 | |
| 1150 | /* |
| 1151 | * create a new tuple from the values and isnull arrays |
| 1152 | */ |
| 1153 | newTuple = heap_form_tuple(tupleDesc, values, isnull); |
| 1154 | |
| 1155 | pfree(values); |
| 1156 | pfree(isnull); |
| 1157 | |
| 1158 | /* |
| 1159 | * copy the identification info of the old tuple: t_ctid, t_self |
| 1160 | */ |
| 1161 | newTuple->t_data->t_ctid = tuple->t_data->t_ctid; |
| 1162 | newTuple->t_self = tuple->t_self; |
| 1163 | newTuple->t_tableOid = tuple->t_tableOid; |
| 1164 | |
| 1165 | return newTuple; |
| 1166 | } |
| 1167 | |
| 1168 | /* |
| 1169 | * heap_modify_tuple_by_cols |
| 1170 | * form a new tuple from an old tuple and a set of replacement values. |
| 1171 | * |
| 1172 | * This is like heap_modify_tuple, except that instead of specifying which |
| 1173 | * column(s) to replace by a boolean map, an array of target column numbers |
| 1174 | * is used. This is often more convenient when a fixed number of columns |
| 1175 | * are to be replaced. The replCols, replValues, and replIsnull arrays must |
| 1176 | * be of length nCols. Target column numbers are indexed from 1. |
| 1177 | * |
| 1178 | * The result is allocated in the current memory context. |
| 1179 | */ |
| 1180 | HeapTuple |
| 1181 | heap_modify_tuple_by_cols(HeapTuple tuple, |
| 1182 | TupleDesc tupleDesc, |
| 1183 | int nCols, |
| 1184 | int *replCols, |
| 1185 | Datum *replValues, |
| 1186 | bool *replIsnull) |
| 1187 | { |
| 1188 | int numberOfAttributes = tupleDesc->natts; |
| 1189 | Datum *values; |
| 1190 | bool *isnull; |
| 1191 | HeapTuple newTuple; |
| 1192 | int i; |
| 1193 | |
| 1194 | /* |
| 1195 | * allocate and fill values and isnull arrays from the tuple, then replace |
| 1196 | * selected columns from the input arrays. |
| 1197 | */ |
| 1198 | values = (Datum *) palloc(numberOfAttributes * sizeof(Datum)); |
| 1199 | isnull = (bool *) palloc(numberOfAttributes * sizeof(bool)); |
| 1200 | |
| 1201 | heap_deform_tuple(tuple, tupleDesc, values, isnull); |
| 1202 | |
| 1203 | for (i = 0; i < nCols; i++) |
| 1204 | { |
| 1205 | int attnum = replCols[i]; |
| 1206 | |
| 1207 | if (attnum <= 0 || attnum > numberOfAttributes) |
| 1208 | elog(ERROR, "invalid column number %d" , attnum); |
| 1209 | values[attnum - 1] = replValues[i]; |
| 1210 | isnull[attnum - 1] = replIsnull[i]; |
| 1211 | } |
| 1212 | |
| 1213 | /* |
| 1214 | * create a new tuple from the values and isnull arrays |
| 1215 | */ |
| 1216 | newTuple = heap_form_tuple(tupleDesc, values, isnull); |
| 1217 | |
| 1218 | pfree(values); |
| 1219 | pfree(isnull); |
| 1220 | |
| 1221 | /* |
| 1222 | * copy the identification info of the old tuple: t_ctid, t_self |
| 1223 | */ |
| 1224 | newTuple->t_data->t_ctid = tuple->t_data->t_ctid; |
| 1225 | newTuple->t_self = tuple->t_self; |
| 1226 | newTuple->t_tableOid = tuple->t_tableOid; |
| 1227 | |
| 1228 | return newTuple; |
| 1229 | } |
| 1230 | |
| 1231 | /* |
| 1232 | * heap_deform_tuple |
| 1233 | * Given a tuple, extract data into values/isnull arrays; this is |
| 1234 | * the inverse of heap_form_tuple. |
| 1235 | * |
| 1236 | * Storage for the values/isnull arrays is provided by the caller; |
| 1237 | * it should be sized according to tupleDesc->natts not |
| 1238 | * HeapTupleHeaderGetNatts(tuple->t_data). |
| 1239 | * |
| 1240 | * Note that for pass-by-reference datatypes, the pointer placed |
| 1241 | * in the Datum will point into the given tuple. |
| 1242 | * |
| 1243 | * When all or most of a tuple's fields need to be extracted, |
| 1244 | * this routine will be significantly quicker than a loop around |
| 1245 | * heap_getattr; the loop will become O(N^2) as soon as any |
| 1246 | * noncacheable attribute offsets are involved. |
| 1247 | */ |
| 1248 | void |
| 1249 | heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc, |
| 1250 | Datum *values, bool *isnull) |
| 1251 | { |
| 1252 | HeapTupleHeader tup = tuple->t_data; |
| 1253 | bool hasnulls = HeapTupleHasNulls(tuple); |
| 1254 | int tdesc_natts = tupleDesc->natts; |
| 1255 | int natts; /* number of atts to extract */ |
| 1256 | int attnum; |
| 1257 | char *tp; /* ptr to tuple data */ |
| 1258 | uint32 off; /* offset in tuple data */ |
| 1259 | bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */ |
| 1260 | bool slow = false; /* can we use/set attcacheoff? */ |
| 1261 | |
| 1262 | natts = HeapTupleHeaderGetNatts(tup); |
| 1263 | |
| 1264 | /* |
| 1265 | * In inheritance situations, it is possible that the given tuple actually |
| 1266 | * has more fields than the caller is expecting. Don't run off the end of |
| 1267 | * the caller's arrays. |
| 1268 | */ |
| 1269 | natts = Min(natts, tdesc_natts); |
| 1270 | |
| 1271 | tp = (char *) tup + tup->t_hoff; |
| 1272 | |
| 1273 | off = 0; |
| 1274 | |
| 1275 | for (attnum = 0; attnum < natts; attnum++) |
| 1276 | { |
| 1277 | Form_pg_attribute thisatt = TupleDescAttr(tupleDesc, attnum); |
| 1278 | |
| 1279 | if (hasnulls && att_isnull(attnum, bp)) |
| 1280 | { |
| 1281 | values[attnum] = (Datum) 0; |
| 1282 | isnull[attnum] = true; |
| 1283 | slow = true; /* can't use attcacheoff anymore */ |
| 1284 | continue; |
| 1285 | } |
| 1286 | |
| 1287 | isnull[attnum] = false; |
| 1288 | |
| 1289 | if (!slow && thisatt->attcacheoff >= 0) |
| 1290 | off = thisatt->attcacheoff; |
| 1291 | else if (thisatt->attlen == -1) |
| 1292 | { |
| 1293 | /* |
| 1294 | * We can only cache the offset for a varlena attribute if the |
| 1295 | * offset is already suitably aligned, so that there would be no |
| 1296 | * pad bytes in any case: then the offset will be valid for either |
| 1297 | * an aligned or unaligned value. |
| 1298 | */ |
| 1299 | if (!slow && |
| 1300 | off == att_align_nominal(off, thisatt->attalign)) |
| 1301 | thisatt->attcacheoff = off; |
| 1302 | else |
| 1303 | { |
| 1304 | off = att_align_pointer(off, thisatt->attalign, -1, |
| 1305 | tp + off); |
| 1306 | slow = true; |
| 1307 | } |
| 1308 | } |
| 1309 | else |
| 1310 | { |
| 1311 | /* not varlena, so safe to use att_align_nominal */ |
| 1312 | off = att_align_nominal(off, thisatt->attalign); |
| 1313 | |
| 1314 | if (!slow) |
| 1315 | thisatt->attcacheoff = off; |
| 1316 | } |
| 1317 | |
| 1318 | values[attnum] = fetchatt(thisatt, tp + off); |
| 1319 | |
| 1320 | off = att_addlength_pointer(off, thisatt->attlen, tp + off); |
| 1321 | |
| 1322 | if (thisatt->attlen <= 0) |
| 1323 | slow = true; /* can't use attcacheoff anymore */ |
| 1324 | } |
| 1325 | |
| 1326 | /* |
| 1327 | * If tuple doesn't have all the atts indicated by tupleDesc, read the |
| 1328 | * rest as nulls or missing values as appropriate. |
| 1329 | */ |
| 1330 | for (; attnum < tdesc_natts; attnum++) |
| 1331 | values[attnum] = getmissingattr(tupleDesc, attnum + 1, &isnull[attnum]); |
| 1332 | } |
| 1333 | |
| 1334 | /* |
| 1335 | * heap_freetuple |
| 1336 | */ |
| 1337 | void |
| 1338 | heap_freetuple(HeapTuple htup) |
| 1339 | { |
| 1340 | pfree(htup); |
| 1341 | } |
| 1342 | |
| 1343 | |
| 1344 | /* |
| 1345 | * heap_form_minimal_tuple |
| 1346 | * construct a MinimalTuple from the given values[] and isnull[] arrays, |
| 1347 | * which are of the length indicated by tupleDescriptor->natts |
| 1348 | * |
| 1349 | * This is exactly like heap_form_tuple() except that the result is a |
| 1350 | * "minimal" tuple lacking a HeapTupleData header as well as room for system |
| 1351 | * columns. |
| 1352 | * |
| 1353 | * The result is allocated in the current memory context. |
| 1354 | */ |
| 1355 | MinimalTuple |
| 1356 | heap_form_minimal_tuple(TupleDesc tupleDescriptor, |
| 1357 | Datum *values, |
| 1358 | bool *isnull) |
| 1359 | { |
| 1360 | MinimalTuple tuple; /* return tuple */ |
| 1361 | Size len, |
| 1362 | data_len; |
| 1363 | int hoff; |
| 1364 | bool hasnull = false; |
| 1365 | int numberOfAttributes = tupleDescriptor->natts; |
| 1366 | int i; |
| 1367 | |
| 1368 | if (numberOfAttributes > MaxTupleAttributeNumber) |
| 1369 | ereport(ERROR, |
| 1370 | (errcode(ERRCODE_TOO_MANY_COLUMNS), |
| 1371 | errmsg("number of columns (%d) exceeds limit (%d)" , |
| 1372 | numberOfAttributes, MaxTupleAttributeNumber))); |
| 1373 | |
| 1374 | /* |
| 1375 | * Check for nulls |
| 1376 | */ |
| 1377 | for (i = 0; i < numberOfAttributes; i++) |
| 1378 | { |
| 1379 | if (isnull[i]) |
| 1380 | { |
| 1381 | hasnull = true; |
| 1382 | break; |
| 1383 | } |
| 1384 | } |
| 1385 | |
| 1386 | /* |
| 1387 | * Determine total space needed |
| 1388 | */ |
| 1389 | len = SizeofMinimalTupleHeader; |
| 1390 | |
| 1391 | if (hasnull) |
| 1392 | len += BITMAPLEN(numberOfAttributes); |
| 1393 | |
| 1394 | hoff = len = MAXALIGN(len); /* align user data safely */ |
| 1395 | |
| 1396 | data_len = heap_compute_data_size(tupleDescriptor, values, isnull); |
| 1397 | |
| 1398 | len += data_len; |
| 1399 | |
| 1400 | /* |
| 1401 | * Allocate and zero the space needed. |
| 1402 | */ |
| 1403 | tuple = (MinimalTuple) palloc0(len); |
| 1404 | |
| 1405 | /* |
| 1406 | * And fill in the information. |
| 1407 | */ |
| 1408 | tuple->t_len = len; |
| 1409 | HeapTupleHeaderSetNatts(tuple, numberOfAttributes); |
| 1410 | tuple->t_hoff = hoff + MINIMAL_TUPLE_OFFSET; |
| 1411 | |
| 1412 | heap_fill_tuple(tupleDescriptor, |
| 1413 | values, |
| 1414 | isnull, |
| 1415 | (char *) tuple + hoff, |
| 1416 | data_len, |
| 1417 | &tuple->t_infomask, |
| 1418 | (hasnull ? tuple->t_bits : NULL)); |
| 1419 | |
| 1420 | return tuple; |
| 1421 | } |
| 1422 | |
| 1423 | /* |
| 1424 | * heap_free_minimal_tuple |
| 1425 | */ |
| 1426 | void |
| 1427 | heap_free_minimal_tuple(MinimalTuple mtup) |
| 1428 | { |
| 1429 | pfree(mtup); |
| 1430 | } |
| 1431 | |
| 1432 | /* |
| 1433 | * heap_copy_minimal_tuple |
| 1434 | * copy a MinimalTuple |
| 1435 | * |
| 1436 | * The result is allocated in the current memory context. |
| 1437 | */ |
| 1438 | MinimalTuple |
| 1439 | heap_copy_minimal_tuple(MinimalTuple mtup) |
| 1440 | { |
| 1441 | MinimalTuple result; |
| 1442 | |
| 1443 | result = (MinimalTuple) palloc(mtup->t_len); |
| 1444 | memcpy(result, mtup, mtup->t_len); |
| 1445 | return result; |
| 1446 | } |
| 1447 | |
| 1448 | /* |
| 1449 | * heap_tuple_from_minimal_tuple |
| 1450 | * create a HeapTuple by copying from a MinimalTuple; |
| 1451 | * system columns are filled with zeroes |
| 1452 | * |
| 1453 | * The result is allocated in the current memory context. |
| 1454 | * The HeapTuple struct, tuple header, and tuple data are all allocated |
| 1455 | * as a single palloc() block. |
| 1456 | */ |
| 1457 | HeapTuple |
| 1458 | heap_tuple_from_minimal_tuple(MinimalTuple mtup) |
| 1459 | { |
| 1460 | HeapTuple result; |
| 1461 | uint32 len = mtup->t_len + MINIMAL_TUPLE_OFFSET; |
| 1462 | |
| 1463 | result = (HeapTuple) palloc(HEAPTUPLESIZE + len); |
| 1464 | result->t_len = len; |
| 1465 | ItemPointerSetInvalid(&(result->t_self)); |
| 1466 | result->t_tableOid = InvalidOid; |
| 1467 | result->t_data = (HeapTupleHeader) ((char *) result + HEAPTUPLESIZE); |
| 1468 | memcpy((char *) result->t_data + MINIMAL_TUPLE_OFFSET, mtup, mtup->t_len); |
| 1469 | memset(result->t_data, 0, offsetof(HeapTupleHeaderData, t_infomask2)); |
| 1470 | return result; |
| 1471 | } |
| 1472 | |
| 1473 | /* |
| 1474 | * minimal_tuple_from_heap_tuple |
| 1475 | * create a MinimalTuple by copying from a HeapTuple |
| 1476 | * |
| 1477 | * The result is allocated in the current memory context. |
| 1478 | */ |
| 1479 | MinimalTuple |
| 1480 | minimal_tuple_from_heap_tuple(HeapTuple htup) |
| 1481 | { |
| 1482 | MinimalTuple result; |
| 1483 | uint32 len; |
| 1484 | |
| 1485 | Assert(htup->t_len > MINIMAL_TUPLE_OFFSET); |
| 1486 | len = htup->t_len - MINIMAL_TUPLE_OFFSET; |
| 1487 | result = (MinimalTuple) palloc(len); |
| 1488 | memcpy(result, (char *) htup->t_data + MINIMAL_TUPLE_OFFSET, len); |
| 1489 | result->t_len = len; |
| 1490 | return result; |
| 1491 | } |
| 1492 | |
| 1493 | /* |
| 1494 | * This mainly exists so JIT can inline the definition, but it's also |
| 1495 | * sometimes useful in debugging sessions. |
| 1496 | */ |
| 1497 | size_t |
| 1498 | varsize_any(void *p) |
| 1499 | { |
| 1500 | return VARSIZE_ANY(p); |
| 1501 | } |
| 1502 | |