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Overview
Comment: | Fix further code and documentation issues in vdbesort.c. |
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SHA1: |
d03f5b8622d304f029f73c7cd0bee318 |
User & Date: | dan 2014-04-15 19:52:34.797 |
Context
2014-04-15
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20:52 | Fix some problems to do with OOM conditions in vdbesort.c. Some problems remain. (check-in: 2f94f9ce9b user: dan tags: threads) | |
19:52 | Fix further code and documentation issues in vdbesort.c. (check-in: d03f5b8622 user: dan tags: threads) | |
2014-04-14
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19:23 | Allow the sorter to begin returning data to the VDBE as soon as it is available, instead of waiting until all keys have been sorted. (check-in: cb0ab20c48 user: dan tags: threads) | |
Changes
Changes to src/vdbesort.c.
1 2 3 4 5 6 7 8 9 10 11 12 | /* ** 2011-07-09 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains code for the VdbeSorter object, used in concert with | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | /* ** 2011-07-09 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains code for the VdbeSorter object, used in concert with ** a VdbeCursor to sort large numbers of keys for CREATE INDEX statements ** or by SELECT statements with ORDER BY clauses that cannot be satisfied ** using indexes and without LIMIT clauses. ** ** The VdbeSorter object implements a multi-threaded external merge sort ** algorithm that is efficient even if the number of element being sorted ** exceeds the available memory. ** |
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53 54 55 56 57 58 59 | ** ** sqlite3VdbeSorterReset() Refurbish the VdbeSorter for reuse. This ** is like Close() followed by Init() only ** much faster. ** ** The interfaces above must be called in a particular order. Write() can ** only occur in between Init()/Reset() and Rewind(). Next(), Rowkey(), and | | > > > > > > > | | | | | | < > | | | | > | > > > > > > > > > > > > > > > > > > > | | > > > > > > > > > > > > > > > > > > > > > | < > > < > > > > | < | | | < | < < < < < < < < < < < < < < < < < | < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < | 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 | ** ** sqlite3VdbeSorterReset() Refurbish the VdbeSorter for reuse. This ** is like Close() followed by Init() only ** much faster. ** ** The interfaces above must be called in a particular order. Write() can ** only occur in between Init()/Reset() and Rewind(). Next(), Rowkey(), and ** Compare() can only occur in between Rewind() and Close()/Reset(). i.e. ** ** Init() ** for each record: Write() ** Rewind() ** Rowkey()/Compare() ** Next() ** Close() ** ** Algorithm: ** ** Records passed to the sorter via calls to Write() are initially held ** unsorted in main memory. Assuming the amount of memory used never exceeds ** a threshold, when Rewind() is called the set of records is sorted using ** an in-memory merge sort. In this case, no temporary files are required ** and subsequent calls to Rowkey(), Next() and Compare() read records ** directly from main memory. ** ** If the amount of space used to store records in main memory exceeds the ** threshold, then the set of records currently in memory are sorted and ** written to a temporary file in "Packed Memory Array" (PMA) format. ** A PMA created at this point is known as a "level-0 PMA". Higher levels ** of PMAs may be created by merging existing PMAs together - for example ** merging two or more level-0 PMAs together creates a level-1 PMA. ** ** The threshold for the amount of main memory to use before flushing ** records to a PMA is roughly the same as the limit configured for the ** page-cache of the main database. Specifically, the threshold is set to ** the value returned multiplied by "PRAGMA main.page_size" multipled by ** that returned by "PRAGMA main.cache_size", in bytes. ** ** If the sorter is running in single-threaded mode, then all PMAs generated ** are appended to a single temporary file. Or, if the sorter is running in ** multi-threaded mode then up to (N+1) temporary files may be opened, where ** N is the configured number of worker threads. In this case, instead of ** sorting the records and writing the PMA to a temporary file itself, the ** calling thread usually launches a worker thread to do so. Except, if ** there are already N worker threads running, the main thread does the work ** itself. ** ** The sorter is running in multi-threaded mode if (a) the library was built ** with pre-processor symbol SQLITE_MAX_WORKER_THREADS set to a value greater ** than zero, and (b) worker threads have been enabled at runtime by calling ** sqlite3_config(SQLITE_CONFIG_WORKER_THREADS, ...). ** ** When Rewind() is called, any data remaining in memory is flushed to a ** final PMA. So at this point the data is stored in some number of sorted ** PMAs within temporary files on disk. Within a single file sorter is ** running in single threaded mode, or distributed between one or more files ** for multi-threaded sorters. ** ** If there are fewer than SORTER_MAX_MERGE_COUNT PMAs in total and the ** sorter is running in single-threaded mode, then these PMAs are merged ** incrementally as keys are retreived from the sorter by the VDBE. See ** comments above object MergeEngine below for details. ** ** Or, if running in multi-threaded mode, then a background thread is ** launched to merge the existing PMAs. Once the background thread has ** merged T bytes of data into a single sorted PMA, the main thread ** begins reading keys from that PMA while the background thread proceeds ** with merging the next T bytes of data. And so on. ** ** Parameter T is set to half the value of the memory threshold used ** by Write() above to determine when to create a new PMA. ** ** If there are more than SORTER_MAX_MERGE_COUNT PMAs in total when ** Rewind() is called, then a hierarchy of incremental-merges is used. ** First, T bytes of data from the first SORTER_MAX_MERGE_COUNT PMAs on ** disk are merged together. Then T bytes of data from the second set, and ** so on, such that no operation ever merges more than SORTER_MAX_MERGE_COUNT ** PMAs at a time. This done is to improve locality. ** ** If running in multi-threaded mode and there are more than ** SORTER_MAX_MERGE_COUNT PMAs on disk when Rewind() is called, then more ** than one background thread may be created. Specifically, there may be ** one background thread for each temporary file on disk, and one background ** thread to merge the output of each of the others to a single PMA for ** the main thread to read from. */ #include "sqliteInt.h" #include "vdbeInt.h" /* ** If SQLITE_DEBUG_SORTER_THREADS is defined, this module outputs various ** messages to stderr that may be helpful in understanding the performance ** characteristics of the sorter in multi-threaded mode. */ #if 0 # define SQLITE_DEBUG_SORTER_THREADS 1 #endif /* ** Private objects used by the sorter */ typedef struct MergeEngine MergeEngine; /* Merge PMAs together */ typedef struct PmaReader PmaReader; /* Incrementally read one PMA */ typedef struct PmaWriter PmaWriter; /* Incrementally write one PMA */ typedef struct SorterRecord SorterRecord; /* A record being sorted */ typedef struct SortSubtask SortSubtask; /* A sub-task in the sort process */ typedef struct SorterFile SorterFile; /* Temporary file object wrapper */ typedef struct SorterList SorterList; /* In-memory list of records */ typedef struct IncrMerger IncrMerger; /* ** A container for a temp file handle and the current amount of data ** stored in the file. */ struct SorterFile { sqlite3_file *pFd; /* File handle */ i64 iEof; /* Bytes of data stored in pFd */ }; /* ** In memory linked list of records. */ struct SorterList { SorterRecord *pList; /* Linked list of records */ u8 *aMemory; /* If non-NULL, blob of memory for pList */ int szPMA; /* Size of pList as PMA in bytes */ }; /* ** The MergeEngine object is used to combine two or more smaller PMAs into ** one big PMA using a merge operation. Separate PMAs all need to be ** combined into one big PMA in order to be able to step through the sorted ** records in order. ** |
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264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 | */ struct MergeEngine { int nTree; /* Used size of aTree/aIter (power of 2) */ int *aTree; /* Current state of incremental merge */ PmaReader *aIter; /* Array of iterators to merge data from */ }; /* ** Main sorter structure. A single instance of this is allocated for each ** sorter cursor created by the VDBE. ** ** mxKeysize: ** As records are added to the sorter by calls to sqlite3VdbeSorterWrite(), ** this variable is updated so as to be set to the size on disk of the ** largest record in the sorter. */ struct VdbeSorter { int mnPmaSize; /* Minimum PMA size, in bytes */ int mxPmaSize; /* Maximum PMA size, in bytes. 0==no limit */ PmaReader *pReader; /* Read data from here after Rewind() */ MergeEngine *pMerger; /* Or here, if bUseThreads==0 */ | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | > | 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 | */ struct MergeEngine { int nTree; /* Used size of aTree/aIter (power of 2) */ int *aTree; /* Current state of incremental merge */ PmaReader *aIter; /* Array of iterators to merge data from */ }; /* ** Exactly VdbeSorter.nTask instances of this object are allocated ** as part of each VdbeSorter object. Instances are never allocated any ** other way. VdbeSorter.nTask is set to the number of worker threads allowed ** (see SQLITE_CONFIG_WORKER_THREADS) plus one (the main thread). ** ** Essentially, this structure contains all those fields of the VdbeSorter ** structure for which each thread requires a separate instance. For example, ** each thread requries its own UnpackedRecord object to unpack records in ** as part of comparison operations. ** ** Before a background thread is launched, variable bDone is set to 0. Then, ** right before it exits, the thread itself sets bDone to 1. This is used for ** two purposes: ** ** 1. When flushing the contents of memory to a level-0 PMA on disk, to ** attempt to select a SortSubtask for which there is not already an ** active background thread (since doing so causes the main thread ** to block until it finishes). ** ** 2. If SQLITE_DEBUG_SORTER_THREADS is defined, to determine if a call ** to sqlite3ThreadJoin() is likely to block. Cases that are likely to ** block provoke debugging output. ** ** In both cases, the effects of the main thread seeing (bDone==0) even ** after the thread has finished are not dire. So we don't worry about ** memory barriers and such here. */ struct SortSubtask { SQLiteThread *pThread; /* Background thread, if any */ int bDone; /* Set if thread is finished but not joined */ VdbeSorter *pSorter; /* Sorter that owns this sub-task */ UnpackedRecord *pUnpacked; /* Space to unpack a record */ SorterList list; /* List for thread to write to a PMA */ int nPMA; /* Number of PMAs currently in file */ SorterFile file; /* Temp file for level-0 PMAs */ SorterFile file2; /* Space for other PMAs */ }; /* ** Main sorter structure. A single instance of this is allocated for each ** sorter cursor created by the VDBE. ** ** mxKeysize: ** As records are added to the sorter by calls to sqlite3VdbeSorterWrite(), ** this variable is updated so as to be set to the size on disk of the ** largest record in the sorter. */ struct VdbeSorter { int mnPmaSize; /* Minimum PMA size, in bytes */ int mxPmaSize; /* Maximum PMA size, in bytes. 0==no limit */ int mxKeysize; /* Largest serialized key seen so far */ int pgsz; /* Main database page size */ PmaReader *pReader; /* Read data from here after Rewind() */ MergeEngine *pMerger; /* Or here, if bUseThreads==0 */ sqlite3 *db; /* Database connection */ KeyInfo *pKeyInfo; /* How to compare records */ UnpackedRecord *pUnpacked; /* Used by VdbeSorterCompare() */ SorterList list; /* List of in-memory records */ int iMemory; /* Offset of free space in list.aMemory */ int nMemory; /* Size of list.aMemory allocation in bytes */ u8 bUsePMA; /* True if one or more PMAs created */ u8 bUseThreads; /* True to use background threads */ u8 iPrev; /* Previous thread used to flush PMA */ |
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314 315 316 317 318 319 320 321 322 323 | }; /* ** Normally, a PmaReader object iterates through an existing PMA stored ** within a temp file. However, if the PmaReader.pIncr variable points to ** an object of the following type, it may be used to iterate/merge through ** multiple PMAs simultaneously. */ struct IncrMerger { SortSubtask *pTask; /* Task that owns this merger */ | > > > > > > > > > > > > > > > > > > > > > > > > > > < | 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 | }; /* ** Normally, a PmaReader object iterates through an existing PMA stored ** within a temp file. However, if the PmaReader.pIncr variable points to ** an object of the following type, it may be used to iterate/merge through ** multiple PMAs simultaneously. ** ** There are two types of IncrMerger object - single (bUseThread==0) and ** multi-threaded (bUseThread==1). ** ** A multi-threaded IncrMerger object uses two temporary files - aFile[0] ** and aFile[1]. Neither file is allowed to grow to more than mxSz bytes in ** size. When the IncrMerger is initialized, it reads enough data from ** pMerger to populate aFile[0]. It then sets variables within the ** corresponding PmaReader object to read from that file and kicks off ** a background thread to populate aFile[1] with the next mxSz bytes of ** sorted record data from pMerger. ** ** When the PmaReader reaches the end of aFile[0], it blocks until the ** background thread has finished populating aFile[1]. It then exchanges ** the contents of the aFile[0] and aFile[1] variables within this structure, ** sets the PmaReader fields to read from the new aFile[0] and kicks off ** another background thread to populate the new aFile[1]. And so on, until ** the contents of pMerger are exhausted. ** ** A single-threaded IncrMerger does not open any temporary files of its ** own. Instead, it has exclusive access to mxSz bytes of space beginning ** at offset iStartOff of file pTask->file2. And instead of using a ** background thread to prepare data for the PmaReader, with a single ** threaded IncrMerger the allocate part of pTask->file2 is "refilled" with ** keys from pMerger by the calling thread whenever the PmaReader runs out ** of data. */ struct IncrMerger { SortSubtask *pTask; /* Task that owns this merger */ MergeEngine *pMerger; /* Merge engine thread reads data from */ i64 iStartOff; /* Offset to start writing file at */ int mxSz; /* Maximum bytes of data to store */ int bEof; /* Set to true when merge is finished */ int bUseThread; /* True to use a bg thread for this object */ SorterFile aFile[2]; /* aFile[0] for reading, [1] for writing */ }; |
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350 351 352 353 354 355 356 | /* ** This object is the header on a single record while that record is being ** held in memory and prior to being written out as part of a PMA. ** ** How the linked list is connected depends on how memory is being managed ** by this module. If using a separate allocation for each in-memory record | | | | 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 | /* ** This object is the header on a single record while that record is being ** held in memory and prior to being written out as part of a PMA. ** ** How the linked list is connected depends on how memory is being managed ** by this module. If using a separate allocation for each in-memory record ** (VdbeSorter.list.aMemory==0), then the list is always connected using the ** SorterRecord.u.pNext pointers. ** ** Or, if using the single large allocation method (VdbeSorter.list.aMemory!=0), ** then while records are being accumulated the list is linked using the ** SorterRecord.u.iNext offset. This is because the aMemory[] array may ** be sqlite3Realloc()ed while records are being accumulated. Once the VM ** has finished passing records to the sorter, or when the in-memory buffer ** is full, the list is sorted. As part of the sorting process, it is ** converted to use the SorterRecord.u.pNext pointers. See function ** vdbeSorterSort() for details. |
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386 387 388 389 390 391 392 | ** page size in bytes. */ #define SORTER_MIN_WORKING 10 /* Maximum number of PMAs that a single MergeEngine can merge */ #define SORTER_MAX_MERGE_COUNT 16 static int vdbeIncrSwap(IncrMerger*); | | | 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 | ** page size in bytes. */ #define SORTER_MIN_WORKING 10 /* Maximum number of PMAs that a single MergeEngine can merge */ #define SORTER_MAX_MERGE_COUNT 16 static int vdbeIncrSwap(IncrMerger*); static void vdbeIncrFree(IncrMerger *); /* ** Free all memory belonging to the PmaReader object passed as the second ** argument. All structure fields are set to zero before returning. */ static void vdbePmaReaderClear(PmaReader *pIter){ sqlite3_free(pIter->aAlloc); |
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527 528 529 530 531 532 533 534 535 | sqlite3GetVarint(aVarint, pnOut); } } return SQLITE_OK; } static int vdbeSorterMapFile(SortSubtask *pTask, SorterFile *pFile, u8 **pp){ int rc = SQLITE_OK; | > > > > > > > > > | > > > > | < | > > > > | | | | | | | < | | | | | | | | | | | | | | | | | | < < > | | | | > > | 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 | sqlite3GetVarint(aVarint, pnOut); } } return SQLITE_OK; } /* ** Attempt to memory map file pFile. If successful, set *pp to point to the ** new mapping and return SQLITE_OK. If the mapping is not attempted ** (because the file is too large or the VFS layer is configured not to use ** mmap), return SQLITE_OK and set *pp to NULL. ** ** Or, if an error occurs, return an SQLite error code. The final value of ** *pp is undefined in this case. */ static int vdbeSorterMapFile(SortSubtask *pTask, SorterFile *pFile, u8 **pp){ int rc = SQLITE_OK; if( pFile->iEof<=(i64)(pTask->pSorter->db->nMaxSorterMmap) ){ rc = sqlite3OsFetch(pFile->pFd, 0, pFile->iEof, (void**)pp); } return rc; } /* ** Seek iterator pIter to offset iOff within file pFile. Return SQLITE_OK ** if successful, or an SQLite error code if an error occurs. */ static int vdbePmaReaderSeek( SortSubtask *pTask, /* Task context */ PmaReader *pIter, /* Iterate to populate */ SorterFile *pFile, /* Sorter file to read from */ i64 iOff /* Offset in pFile */ ){ int rc = SQLITE_OK; assert( pIter->pIncr==0 || pIter->pIncr->bEof==0 ); if( pIter->aMap ){ sqlite3OsUnfetch(pIter->pFile, 0, pIter->aMap); pIter->aMap = 0; } pIter->iReadOff = iOff; pIter->iEof = pFile->iEof; pIter->pFile = pFile->pFd; rc = vdbeSorterMapFile(pTask, pFile, &pIter->aMap); if( rc==SQLITE_OK && pIter->aMap==0 ){ int pgsz = pTask->pSorter->pgsz; int iBuf = pIter->iReadOff % pgsz; if( pIter->aBuffer==0 ){ pIter->aBuffer = (u8*)sqlite3Malloc(pgsz); if( pIter->aBuffer==0 ) rc = SQLITE_NOMEM; pIter->nBuffer = pgsz; } if( iBuf ){ int nRead = pgsz - iBuf; if( (pIter->iReadOff + nRead) > pIter->iEof ){ nRead = (int)(pIter->iEof - pIter->iReadOff); } rc = sqlite3OsRead( pIter->pFile, &pIter->aBuffer[iBuf], nRead, pIter->iReadOff ); assert( rc!=SQLITE_IOERR_SHORT_READ ); } } return rc; } /* ** Advance iterator pIter to the next key in its PMA. Return SQLITE_OK if ** no error occurs, or an SQLite error code if one does. */ static int vdbePmaReaderNext(PmaReader *pIter){ int rc = SQLITE_OK; /* Return Code */ u64 nRec = 0; /* Size of record in bytes */ if( pIter->iReadOff>=pIter->iEof ){ IncrMerger *pIncr = pIter->pIncr; int bEof = 1; if( pIncr ){ rc = vdbeIncrSwap(pIncr); if( rc==SQLITE_OK && pIncr->bEof==0 ){ rc = vdbePmaReaderSeek( pIncr->pTask, pIter, &pIncr->aFile[0], pIncr->iStartOff ); bEof = 0; } } if( bEof ){ /* This is an EOF condition */ vdbePmaReaderClear(pIter); |
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629 630 631 632 633 634 635 | static int vdbePmaReaderInit( SortSubtask *pTask, /* Task context */ SorterFile *pFile, /* Sorter file to read from */ i64 iStart, /* Start offset in pFile */ PmaReader *pIter, /* Iterator to populate */ i64 *pnByte /* IN/OUT: Increment this value by PMA size */ ){ | | < | < < < < < < < < < < < < | < < < < < < < < < < | < < < < < < < | < | 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 | static int vdbePmaReaderInit( SortSubtask *pTask, /* Task context */ SorterFile *pFile, /* Sorter file to read from */ i64 iStart, /* Start offset in pFile */ PmaReader *pIter, /* Iterator to populate */ i64 *pnByte /* IN/OUT: Increment this value by PMA size */ ){ int rc; assert( pFile->iEof>iStart ); assert( pIter->aAlloc==0 && pIter->nAlloc==0 ); assert( pIter->aBuffer==0 ); assert( pIter->aMap==0 ); rc = vdbePmaReaderSeek(pTask, pIter, pFile, iStart); if( rc==SQLITE_OK ){ u64 nByte; /* Size of PMA in bytes */ rc = vdbePmaReadVarint(pIter, &nByte); pIter->iEof = pIter->iReadOff + nByte; *pnByte += nByte; } if( rc==SQLITE_OK ){ rc = vdbePmaReaderNext(pIter); |
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702 703 704 705 706 707 708 | static int vdbeSorterCompare( SortSubtask *pTask, /* Subtask context (for pKeyInfo) */ const void *pKey1, int nKey1, /* Left side of comparison */ const void *pKey2, int nKey2 /* Right side of comparison */ ){ UnpackedRecord *r2 = pTask->pUnpacked; if( pKey2 ){ | | | 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 | static int vdbeSorterCompare( SortSubtask *pTask, /* Subtask context (for pKeyInfo) */ const void *pKey1, int nKey1, /* Left side of comparison */ const void *pKey2, int nKey2 /* Right side of comparison */ ){ UnpackedRecord *r2 = pTask->pUnpacked; if( pKey2 ){ sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2); } return sqlite3VdbeRecordCompare(nKey1, pKey1, r2, 0); } /* ** This function is called to compare two iterator keys when merging ** multiple b-tree segments. Parameter iOut is the index of the aTree[] |
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784 785 786 787 788 789 790 | sz = sizeof(VdbeSorter) + nWorker * sizeof(SortSubtask); pSorter = (VdbeSorter*)sqlite3DbMallocZero(db, sz + szKeyInfo); pCsr->pSorter = pSorter; if( pSorter==0 ){ rc = SQLITE_NOMEM; }else{ | | | < > < < < | 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 | sz = sizeof(VdbeSorter) + nWorker * sizeof(SortSubtask); pSorter = (VdbeSorter*)sqlite3DbMallocZero(db, sz + szKeyInfo); pCsr->pSorter = pSorter; if( pSorter==0 ){ rc = SQLITE_NOMEM; }else{ pSorter->pKeyInfo = pKeyInfo = (KeyInfo*)((u8*)pSorter + sz); memcpy(pKeyInfo, pCsr->pKeyInfo, szKeyInfo); pKeyInfo->db = 0; if( nField && nWorker==0 ) pKeyInfo->nField = nField; pSorter->pgsz = pgsz = sqlite3BtreeGetPageSize(db->aDb[0].pBt); pSorter->nTask = nWorker + 1; pSorter->bUseThreads = (pSorter->nTask>1); pSorter->db = db; for(i=0; i<pSorter->nTask; i++){ SortSubtask *pTask = &pSorter->aTask[i]; pTask->pSorter = pSorter; } if( !sqlite3TempInMemory(db) ){ pSorter->mnPmaSize = SORTER_MIN_WORKING * pgsz; mxCache = db->aDb[0].pSchema->cache_size; if( mxCache<SORTER_MIN_WORKING ) mxCache = SORTER_MIN_WORKING; |
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900 901 902 903 904 905 906 | # define vdbeSorterRewindDebug(x,y) # define vdbeSorterPopulateDebug(x,y) # define vdbeSorterBlockDebug(x,y,z) #endif #if SQLITE_MAX_WORKER_THREADS>0 /* | | | | | | | | | | | | | | | 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 | # define vdbeSorterRewindDebug(x,y) # define vdbeSorterPopulateDebug(x,y) # define vdbeSorterBlockDebug(x,y,z) #endif #if SQLITE_MAX_WORKER_THREADS>0 /* ** Join thread pTask->thread. */ static int vdbeSorterJoinThread(SortSubtask *pTask){ int rc = SQLITE_OK; if( pTask->pThread ){ #ifdef SQLITE_DEBUG_SORTER_THREADS int bDone = pTask->bDone; #endif void *pRet; vdbeSorterBlockDebug(pTask, !bDone, "enter"); rc = sqlite3ThreadJoin(pTask->pThread, &pRet); vdbeSorterBlockDebug(pTask, !bDone, "exit"); if( rc==SQLITE_OK ) rc = SQLITE_PTR_TO_INT(pRet); assert( pTask->bDone==1 ); pTask->bDone = 0; pTask->pThread = 0; } return rc; } /* ** Launch a background thread to run xTask(pIn). */ static int vdbeSorterCreateThread( SortSubtask *pTask, /* Thread will use this task object */ void *(*xTask)(void*), /* Routine to run in a separate thread */ void *pIn /* Argument passed into xTask() */ ){ assert( pTask->pThread==0 && pTask->bDone==0 ); return sqlite3ThreadCreate(&pTask->pThread, xTask, pIn); } /* ** Join all outstanding threads launched by SorterWrite() to create ** level-0 PMAs. */ static int vdbeSorterJoinAll(VdbeSorter *pSorter, int rcin){ int rc = rcin; int i; for(i=0; i<pSorter->nTask; i++){ SortSubtask *pTask = &pSorter->aTask[i]; int rc2 = vdbeSorterJoinThread(pTask); if( rc==SQLITE_OK ) rc = rc2; } return rc; } #else # define vdbeSorterJoinAll(x,rcin) (rcin) # define vdbeSorterJoinThread(pTask) SQLITE_OK #endif /* ** Allocate a new MergeEngine object with space for nIter iterators. */ static MergeEngine *vdbeMergeEngineNew(int nIter){ int N = 2; /* Smallest power of two >= nIter */ |
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985 986 987 988 989 990 991 992 993 994 995 996 997 998 | if( pMerger ){ for(i=0; i<pMerger->nTree; i++){ vdbePmaReaderClear(&pMerger->aIter[i]); } } sqlite3_free(pMerger); } /* ** Reset a sorting cursor back to its original empty state. */ void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){ int i; (void)vdbeSorterJoinAll(pSorter, SQLITE_OK); | > > > > > > > > > > > > > > > > > > | 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 | if( pMerger ){ for(i=0; i<pMerger->nTree; i++){ vdbePmaReaderClear(&pMerger->aIter[i]); } } sqlite3_free(pMerger); } /* ** Free all resources associated with the IncrMerger object indicated by ** the first argument. */ static void vdbeIncrFree(IncrMerger *pIncr){ if( pIncr ){ #if SQLITE_MAX_WORKER_THREADS>0 if( pIncr->bUseThread ){ vdbeSorterJoinThread(pIncr->pTask); if( pIncr->aFile[0].pFd ) sqlite3OsCloseFree(pIncr->aFile[0].pFd); if( pIncr->aFile[1].pFd ) sqlite3OsCloseFree(pIncr->aFile[1].pFd); } #endif vdbeMergeEngineFree(pIncr->pMerger); sqlite3_free(pIncr); } } /* ** Reset a sorting cursor back to its original empty state. */ void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){ int i; (void)vdbeSorterJoinAll(pSorter, SQLITE_OK); |
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1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 | if( rc==SQLITE_OK ){ i64 max = SQLITE_MAX_MMAP_SIZE; sqlite3OsFileControlHint( *ppFile, SQLITE_FCNTL_MMAP_SIZE, (void*)&max); } return rc; } static int vdbeSortAllocUnpacked(SortSubtask *pTask){ if( pTask->pUnpacked==0 ){ char *pFree; pTask->pUnpacked = sqlite3VdbeAllocUnpackedRecord( | > > > > > | | | 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 | if( rc==SQLITE_OK ){ i64 max = SQLITE_MAX_MMAP_SIZE; sqlite3OsFileControlHint( *ppFile, SQLITE_FCNTL_MMAP_SIZE, (void*)&max); } return rc; } /* ** If it has not already been allocated, allocate the UnpackedRecord ** structure at pTask->pUnpacked. Return SQLITE_OK if successful (or ** if no allocation was required), or SQLITE_NOMEM otherwise. */ static int vdbeSortAllocUnpacked(SortSubtask *pTask){ if( pTask->pUnpacked==0 ){ char *pFree; pTask->pUnpacked = sqlite3VdbeAllocUnpackedRecord( pTask->pSorter->pKeyInfo, 0, 0, &pFree ); assert( pTask->pUnpacked==(UnpackedRecord*)pFree ); if( pFree==0 ) return SQLITE_NOMEM; pTask->pUnpacked->nField = pTask->pSorter->pKeyInfo->nField; pTask->pUnpacked->errCode = 0; } return SQLITE_OK; } /* |
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1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 | ** in the PMA (not including the varint itself). ** ** * One or more records packed end-to-end in order of ascending keys. ** Each record consists of a varint followed by a blob of data (the ** key). The varint is the number of bytes in the blob of data. */ static int vdbeSorterListToPMA(SortSubtask *pTask, SorterList *pList){ int rc = SQLITE_OK; /* Return code */ PmaWriter writer; /* Object used to write to the file */ #ifdef SQLITE_DEBUG /* Set iSz to the expected size of file pTask->file after writing the PMA. ** This is used by an assert() statement at the end of this function. */ i64 iSz = pList->szPMA + sqlite3VarintLen(pList->szPMA) + pTask->file.iEof; #endif vdbeSorterWorkDebug(pTask, "enter"); memset(&writer, 0, sizeof(PmaWriter)); assert( pList->szPMA>0 ); /* If the first temporary PMA file has not been opened, open it now. */ if( pTask->file.pFd==0 ){ | > | | < < | | 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 | ** in the PMA (not including the varint itself). ** ** * One or more records packed end-to-end in order of ascending keys. ** Each record consists of a varint followed by a blob of data (the ** key). The varint is the number of bytes in the blob of data. */ static int vdbeSorterListToPMA(SortSubtask *pTask, SorterList *pList){ sqlite3 *db = pTask->pSorter->db; int rc = SQLITE_OK; /* Return code */ PmaWriter writer; /* Object used to write to the file */ #ifdef SQLITE_DEBUG /* Set iSz to the expected size of file pTask->file after writing the PMA. ** This is used by an assert() statement at the end of this function. */ i64 iSz = pList->szPMA + sqlite3VarintLen(pList->szPMA) + pTask->file.iEof; #endif vdbeSorterWorkDebug(pTask, "enter"); memset(&writer, 0, sizeof(PmaWriter)); assert( pList->szPMA>0 ); /* If the first temporary PMA file has not been opened, open it now. */ if( pTask->file.pFd==0 ){ rc = vdbeSorterOpenTempFile(db->pVfs, &pTask->file.pFd); assert( rc!=SQLITE_OK || pTask->file.pFd ); assert( pTask->file.iEof==0 ); assert( pTask->nPMA==0 ); } /* Try to get the file to memory map */ if( rc==SQLITE_OK ){ vdbeSorterExtendFile(db, pTask->file.pFd, pTask->file.iEof+pList->szPMA+9); } /* Sort the list */ if( rc==SQLITE_OK ){ rc = vdbeSorterSort(pTask, pList); } if( rc==SQLITE_OK ){ SorterRecord *p; SorterRecord *pNext = 0; vdbePmaWriterInit(pTask->file.pFd, &writer, pTask->pSorter->pgsz, pTask->file.iEof); pTask->nPMA++; vdbePmaWriteVarint(&writer, pList->szPMA); for(p=pList->pList; p; p=pNext){ pNext = p->u.pNext; vdbePmaWriteVarint(&writer, p->nVal); vdbePmaWriteBlob(&writer, SRVAL(p), p->nVal); |
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1409 1410 1411 1412 1413 1414 1415 | *pbEof = (pMerger->aIter[pMerger->aTree[1]].pFile==0); } return rc; } /* | | | | | 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 | *pbEof = (pMerger->aIter[pMerger->aTree[1]].pFile==0); } return rc; } /* ** The main routine for background threads that write level-0 PMAs. */ static void *vdbeSorterFlushThread(void *pCtx){ SortSubtask *pTask = (SortSubtask*)pCtx; int rc; /* Return code */ assert( pTask->bDone==0 ); rc = vdbeSorterListToPMA(pTask, &pTask->list); pTask->bDone = 1; return SQLITE_INT_TO_PTR(rc); } /* ** Flush the current contents of VdbeSorter.list to a new PMA, possibly ** using a background thread. */ |
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1449 1450 1451 1452 1453 1454 1455 | ** skip it. If the first (pSorter->nTask-1) sub-tasks are all still busy, ** fall back to using the final sub-task. The first (pSorter->nTask-1) ** sub-tasks are prefered as they use background threads - the final ** sub-task uses the main thread. */ for(i=0; i<nWorker; i++){ int iTest = (pSorter->iPrev + i + 1) % nWorker; pTask = &pSorter->aTask[iTest]; | | | | | | | 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 | ** skip it. If the first (pSorter->nTask-1) sub-tasks are all still busy, ** fall back to using the final sub-task. The first (pSorter->nTask-1) ** sub-tasks are prefered as they use background threads - the final ** sub-task uses the main thread. */ for(i=0; i<nWorker; i++){ int iTest = (pSorter->iPrev + i + 1) % nWorker; pTask = &pSorter->aTask[iTest]; if( pTask->bDone ){ rc = vdbeSorterJoinThread(pTask); } if( pTask->pThread==0 || rc!=SQLITE_OK ) break; } if( rc==SQLITE_OK ){ if( i==nWorker ){ /* Use the foreground thread for this operation */ rc = vdbeSorterListToPMA(&pSorter->aTask[nWorker], &pSorter->list); }else{ /* Launch a background thread for this operation */ u8 *aMem = pTask->list.aMemory; void *pCtx = (void*)pTask; assert( pTask->pThread==0 && pTask->bDone==0 ); assert( pTask->list.pList==0 ); assert( pTask->list.aMemory==0 || pSorter->list.aMemory!=0 ); pSorter->iPrev = (pTask - pSorter->aTask); pTask->list = pSorter->list; pSorter->list.pList = 0; pSorter->list.szPMA = 0; if( aMem ){ pSorter->list.aMemory = aMem; pSorter->nMemory = sqlite3MallocSize(aMem); }else{ pSorter->list.aMemory = sqlite3Malloc(pSorter->nMemory); if( !pSorter->list.aMemory ) return SQLITE_NOMEM; } rc = vdbeSorterCreateThread(pTask, vdbeSorterFlushThread, pCtx); } } return rc; #endif } |
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1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 | ** except that the number-of-bytes varint is omitted from the start. */ static int vdbeIncrPopulate(IncrMerger *pIncr){ int rc = SQLITE_OK; int rc2; i64 iStart = pIncr->iStartOff; SorterFile *pOut = &pIncr->aFile[1]; MergeEngine *pMerger = pIncr->pMerger; PmaWriter writer; assert( pIncr->bEof==0 ); | > | | | | > > > > > | < > > > | | > > > > > > > > > > > > > > > > > | | 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 | ** except that the number-of-bytes varint is omitted from the start. */ static int vdbeIncrPopulate(IncrMerger *pIncr){ int rc = SQLITE_OK; int rc2; i64 iStart = pIncr->iStartOff; SorterFile *pOut = &pIncr->aFile[1]; SortSubtask *pTask = pIncr->pTask; MergeEngine *pMerger = pIncr->pMerger; PmaWriter writer; assert( pIncr->bEof==0 ); vdbeSorterPopulateDebug(pTask, "enter"); vdbePmaWriterInit(pOut->pFd, &writer, pTask->pSorter->pgsz, iStart); while( rc==SQLITE_OK ){ int dummy; PmaReader *pReader = &pMerger->aIter[ pMerger->aTree[1] ]; int nKey = pReader->nKey; i64 iEof = writer.iWriteOff + writer.iBufEnd; /* Check if the output file is full or if the input has been exhausted. ** In either case exit the loop. */ if( pReader->pFile==0 ) break; if( (iEof + nKey + sqlite3VarintLen(nKey))>(iStart + pIncr->mxSz) ) break; /* Write the next key to the output. */ vdbePmaWriteVarint(&writer, nKey); vdbePmaWriteBlob(&writer, pReader->aKey, nKey); rc = vdbeSorterNext(pTask, pIncr->pMerger, &dummy); } rc2 = vdbePmaWriterFinish(&writer, &pOut->iEof); if( rc==SQLITE_OK ) rc = rc2; vdbeSorterPopulateDebug(pTask, "exit"); return rc; } #if SQLITE_MAX_WORKER_THREADS>0 /* ** The main routine for background threads that populate aFile[1] of ** multi-threaded IncrMerger objects. */ static void *vdbeIncrPopulateThread(void *pCtx){ IncrMerger *pIncr = (IncrMerger*)pCtx; void *pRet = SQLITE_INT_TO_PTR( vdbeIncrPopulate(pIncr) ); pIncr->pTask->bDone = 1; return pRet; } /* ** Launch a background thread to populate aFile[1] of pIncr. */ static int vdbeIncrBgPopulate(IncrMerger *pIncr){ void *p = (void*)pIncr; assert( pIncr->bUseThread ); return vdbeSorterCreateThread(pIncr->pTask, vdbeIncrPopulateThread, p); } #endif /* ** This function is called when the PmaReader corresponding to pIncr has ** finished reading the contents of aFile[0]. Its purpose is to "refill" ** aFile[0] such that the iterator should start rereading it from the ** beginning. ** ** For single-threaded objects, this is accomplished by literally reading ** keys from pIncr->pMerger and repopulating aFile[0]. ** ** For multi-threaded objects, all that is required is to wait until the ** background thread is finished (if it is not already) and then swap ** aFile[0] and aFile[1] in place. If the contents of pMerger have not ** been exhausted, this function also launches a new background thread ** to populate the new aFile[1]. ** ** SQLITE_OK is returned on success, or an SQLite error code otherwise. */ static int vdbeIncrSwap(IncrMerger *pIncr){ int rc = SQLITE_OK; #if SQLITE_MAX_WORKER_THREADS>0 if( pIncr->bUseThread ){ rc = vdbeSorterJoinThread(pIncr->pTask); if( rc==SQLITE_OK ){ SorterFile f0 = pIncr->aFile[0]; pIncr->aFile[0] = pIncr->aFile[1]; pIncr->aFile[1] = f0; } |
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1671 1672 1673 1674 1675 1676 1677 | pIncr->bEof = 1; } } return rc; } | > | < < < < < < < < < < < < | > > > | 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 | pIncr->bEof = 1; } } return rc; } /* ** Allocate and return a new IncrMerger object to read data from pMerger. */ static IncrMerger *vdbeIncrNew(SortSubtask *pTask, MergeEngine *pMerger){ IncrMerger *pIncr = sqlite3_malloc(sizeof(IncrMerger)); if( pIncr ){ memset(pIncr, 0, sizeof(IncrMerger)); pIncr->pMerger = pMerger; pIncr->pTask = pTask; pIncr->mxSz = MAX(pTask->pSorter->mxKeysize+9,pTask->pSorter->mxPmaSize/2); pTask->file2.iEof += pIncr->mxSz; } return pIncr; } /* ** Set the "use-threads" flag on object pIncr. */ static void vdbeIncrSetThreads(IncrMerger *pIncr, int bUseThread){ if( bUseThread ){ pIncr->bUseThread = 1; pIncr->pTask->file2.iEof -= pIncr->mxSz; } } |
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1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 | } static int vdbeIncrInit2(PmaReader *pIter, int eMode){ int rc = SQLITE_OK; IncrMerger *pIncr = pIter->pIncr; if( pIncr ){ SortSubtask *pTask = pIncr->pTask; rc = vdbeIncrInitMerger(pTask, pIncr->pMerger, eMode); /* Set up the required files for pIncr */ if( rc==SQLITE_OK ){ if( pIncr->bUseThread==0 ){ if( pTask->file2.pFd==0 ){ | > | | | | | 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 | } static int vdbeIncrInit2(PmaReader *pIter, int eMode){ int rc = SQLITE_OK; IncrMerger *pIncr = pIter->pIncr; if( pIncr ){ SortSubtask *pTask = pIncr->pTask; sqlite3 *db = pTask->pSorter->db; rc = vdbeIncrInitMerger(pTask, pIncr->pMerger, eMode); /* Set up the required files for pIncr */ if( rc==SQLITE_OK ){ if( pIncr->bUseThread==0 ){ if( pTask->file2.pFd==0 ){ rc = vdbeSorterOpenTempFile(db->pVfs, &pTask->file2.pFd); assert( pTask->file2.iEof>0 ); if( rc==SQLITE_OK ){ vdbeSorterExtendFile(db, pTask->file2.pFd, pTask->file2.iEof); pTask->file2.iEof = 0; } } if( rc==SQLITE_OK ){ pIncr->aFile[1].pFd = pTask->file2.pFd; pIncr->iStartOff = pTask->file2.iEof; pTask->file2.iEof += pIncr->mxSz; } }else{ rc = vdbeSorterOpenTempFile(db->pVfs, &pIncr->aFile[0].pFd); if( rc==SQLITE_OK ){ rc = vdbeSorterOpenTempFile(db->pVfs, &pIncr->aFile[1].pFd); } } } if( rc==SQLITE_OK && pIncr->bUseThread ){ /* Use the current thread */ assert( eMode==INCRINIT2_ROOT || eMode==INCRINIT2_TASK ); |
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1782 1783 1784 1785 1786 1787 1788 | return rc; } #if SQLITE_MAX_WORKER_THREADS>0 static void *vdbeIncrInit2Thread(void *pCtx){ PmaReader *pReader = (PmaReader*)pCtx; void *pRet = SQLITE_INT_TO_PTR( vdbeIncrInit2(pReader, INCRINIT2_TASK) ); | | | < < | 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 | return rc; } #if SQLITE_MAX_WORKER_THREADS>0 static void *vdbeIncrInit2Thread(void *pCtx){ PmaReader *pReader = (PmaReader*)pCtx; void *pRet = SQLITE_INT_TO_PTR( vdbeIncrInit2(pReader, INCRINIT2_TASK) ); pReader->pIncr->pTask->bDone = 1; return pRet; } static int vdbeIncrBgInit2(PmaReader *pIter){ void *pCtx = (void*)pIter; return vdbeSorterCreateThread(pIter->pIncr->pTask, vdbeIncrInit2Thread, pCtx); } #endif /* ** Allocate a new MergeEngine object to merge the contents of nPMA level-0 ** PMAs from pTask->file. If no error occurs, set *ppOut to point to ** the new object and return SQLITE_OK. Or, if an error does occur, set *ppOut |
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1881 1882 1883 1884 1885 1886 1887 | /* ** Populate iterator *pIter so that it may be used to iterate through all ** keys stored in all PMAs created by this sorter. */ static int vdbePmaReaderIncrInit(VdbeSorter *pSorter){ SortSubtask *pTask0 = &pSorter->aTask[0]; MergeEngine *pMain = 0; | | | 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 | /* ** Populate iterator *pIter so that it may be used to iterate through all ** keys stored in all PMAs created by this sorter. */ static int vdbePmaReaderIncrInit(VdbeSorter *pSorter){ SortSubtask *pTask0 = &pSorter->aTask[0]; MergeEngine *pMain = 0; sqlite3 *db = pTask0->pSorter->db; int rc = SQLITE_OK; int iTask; IncrBuilder *aMerge; const int nMerge = 32; aMerge = sqlite3DbMallocZero(db, sizeof(aMerge[0])*nMerge); if( aMerge==0 ) return SQLITE_NOMEM; |
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