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Overview
Comment: | Performance improvements in getAndInitPage(): omit the upper bound check on page number if the page is already in cache. (CVS 5716) |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
badd0873e6dffac9463b06a381b9f797 |
User & Date: | drh 2008-09-18 01:08:16.000 |
Context
2008-09-18
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11:18 | Changes to test script io.test to work on symbian. (CVS 5717) (check-in: 2b41c4959d user: danielk1977 tags: trunk) | |
01:08 | Performance improvements in getAndInitPage(): omit the upper bound check on page number if the page is already in cache. (CVS 5716) (check-in: badd0873e6 user: drh tags: trunk) | |
2008-09-17
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20:06 | Speed improvements for in-memory databases by omitting flag clearing on pages where it is impossible for the flag to be set and by avoiding assert()s on non-debugging builds. Ticket #3384. (CVS 5715) (check-in: a7fd9e622b user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
1 2 3 4 5 6 7 8 9 10 11 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | - + | /* ** 2004 April 6 ** ** 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. ** ************************************************************************* |
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1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 | 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 | + + + + + + + + + + + + + + + - - - - - - - - + | assert( pBt->pageSize>=512 && pBt->pageSize<=32768 ); pPage->maskPage = pBt->pageSize - 1; pPage->idxShift = 0; pPage->nCell = 0; pPage->isInit = 1; } /* ** Convert a DbPage obtained from the pager into a MemPage used by ** the btree layer. */ static MemPage *btreePageFromDbPage(DbPage *pDbPage, Pgno pgno, BtShared *pBt){ MemPage *pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage); pPage->aData = sqlite3PagerGetData(pDbPage); pPage->pDbPage = pDbPage; pPage->pBt = pBt; pPage->pgno = pgno; pPage->hdrOffset = pPage->pgno==1 ? 100 : 0; return pPage; } /* ** Get a page from the pager. Initialize the MemPage.pBt and ** MemPage.aData elements if needed. ** ** If the noContent flag is set, it means that we do not care about ** the content of the page at this time. So do not go to the disk ** to fetch the content. Just fill in the content with zeros for now. ** If in the future we call sqlite3PagerWrite() on this page, that ** means we have started to be concerned about content and the disk ** read should occur at that point. */ int sqlite3BtreeGetPage( BtShared *pBt, /* The btree */ Pgno pgno, /* Number of the page to fetch */ MemPage **ppPage, /* Return the page in this parameter */ int noContent /* Do not load page content if true */ ){ int rc; |
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1104 1105 1106 1107 1108 1109 1110 1111 1112 | 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 | + + + + + + + + + + + + + + + + + + + - - - - - - - - - - - - - - - - - - + + + + + + + + + + + + + + + + + + + + - - | static int getAndInitPage( BtShared *pBt, /* The database file */ Pgno pgno, /* Number of the page to get */ MemPage **ppPage, /* Write the page pointer here */ MemPage *pParent /* Parent of the page */ ){ int rc; DbPage *pDbPage; MemPage *pPage; assert( sqlite3_mutex_held(pBt->mutex) ); assert( !pParent || pParent->isInit ); if( pgno==0 ){ return SQLITE_CORRUPT_BKPT; } /* It is often the case that the page we want is already in cache. ** If so, get it directly. This saves us from having to call ** pagerPagecount() to make sure pgno is within limits, which results ** in a measureable performance improvements. */ pDbPage = sqlite3PagerLookup(pBt->pPager, pgno); if( pDbPage ){ /* Page is already in cache */ *ppPage = pPage = btreePageFromDbPage(pDbPage, pgno, pBt); rc = SQLITE_OK; }else{ /* Page not in cache. Acquire it. */ |
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