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Overview
Comment: | Recognize the invariant that a Mem object cannot be MEM_Dyn and have a non-zero szMalloc at the same time. Enforce this with assert()s and exploit it in the sqlite3VdbeMemClearAndResize() routine for a performance increase. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
3b21cf2b284048da4b728a5d6ec89e5c |
User & Date: | drh 2014-09-19 22:30:49.809 |
Context
2014-09-19
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22:44 | Simplify two conditionals and add testcase() macros to the affinity transform logic in the comparison operators. (check-in: 544664cadf user: drh tags: trunk) | |
22:30 | Recognize the invariant that a Mem object cannot be MEM_Dyn and have a non-zero szMalloc at the same time. Enforce this with assert()s and exploit it in the sqlite3VdbeMemClearAndResize() routine for a performance increase. (check-in: 3b21cf2b28 user: drh tags: trunk) | |
22:01 | Tighten the conditions under which applyNumericAffinity() be called and add assert() statements to prove that it is never called otherwise. (check-in: e996ca32cb user: drh tags: trunk) | |
Changes
Changes to src/vdbemem.c.
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27 28 29 30 31 32 33 34 35 36 37 38 39 40 | */ int sqlite3VdbeCheckMemInvariants(Mem *p){ /* If MEM_Dyn is set then Mem.xDel!=0. ** Mem.xDel is might not be initialized if MEM_Dyn is clear. */ assert( (p->flags & MEM_Dyn)==0 || p->xDel!=0 ); /* Cannot be both MEM_Int and MEM_Real at the same time */ assert( (p->flags & (MEM_Int|MEM_Real))!=(MEM_Int|MEM_Real) ); /* The szMalloc field holds the correct memory allocation size */ assert( p->szMalloc==0 || p->szMalloc==sqlite3DbMallocSize(p->db,p->zMalloc) ); | > > > | 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | */ int sqlite3VdbeCheckMemInvariants(Mem *p){ /* If MEM_Dyn is set then Mem.xDel!=0. ** Mem.xDel is might not be initialized if MEM_Dyn is clear. */ assert( (p->flags & MEM_Dyn)==0 || p->xDel!=0 ); /* MEM_Dyn may only be set if Mem.szMalloc==0 */ assert( (p->flags & MEM_Dyn)==0 || p->szMalloc==0 ); /* Cannot be both MEM_Int and MEM_Real at the same time */ assert( (p->flags & (MEM_Int|MEM_Real))!=(MEM_Int|MEM_Real) ); /* The szMalloc field holds the correct memory allocation size */ assert( p->szMalloc==0 || p->szMalloc==sqlite3DbMallocSize(p->db,p->zMalloc) ); |
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160 161 162 163 164 165 166 | ** and MEM_Blob values may be discarded, MEM_Int, MEM_Real, and MEM_Null ** values are preserved. ** ** Return SQLITE_OK on success or an error code (probably SQLITE_NOMEM) ** if unable to complete the resizing. */ int sqlite3VdbeMemClearAndResize(Mem *pMem, int szNew){ | > | > | | < < | 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 | ** and MEM_Blob values may be discarded, MEM_Int, MEM_Real, and MEM_Null ** values are preserved. ** ** Return SQLITE_OK on success or an error code (probably SQLITE_NOMEM) ** if unable to complete the resizing. */ int sqlite3VdbeMemClearAndResize(Mem *pMem, int szNew){ assert( szNew>=0 ); if( pMem->szMalloc<szNew ){ return sqlite3VdbeMemGrow(pMem, szNew, 0); } assert( (pMem->flags & MEM_Dyn)==0 ); pMem->z = pMem->zMalloc; pMem->flags &= (MEM_Null|MEM_Int|MEM_Real); return SQLITE_OK; } /* ** Change pMem so that its MEM_Str or MEM_Blob value is stored in ** MEM.zMalloc, where it can be safely written. ** ** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails. */ int sqlite3VdbeMemMakeWriteable(Mem *pMem){ int f; assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) ); assert( (pMem->flags&MEM_RowSet)==0 ); |
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