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| 1 /* |
| 2 ** 2007 May 7 |
| 3 ** |
| 4 ** The author disclaims copyright to this source code. In place of |
| 5 ** a legal notice, here is a blessing: |
| 6 ** |
| 7 ** May you do good and not evil. |
| 8 ** May you find forgiveness for yourself and forgive others. |
| 9 ** May you share freely, never taking more than you give. |
| 10 ** |
| 11 ************************************************************************* |
| 12 ** |
| 13 ** This file defines various limits of what SQLite can process. |
| 14 */ |
| 15 |
| 16 /* |
| 17 ** The maximum length of a TEXT or BLOB in bytes. This also |
| 18 ** limits the size of a row in a table or index. |
| 19 ** |
| 20 ** The hard limit is the ability of a 32-bit signed integer |
| 21 ** to count the size: 2^31-1 or 2147483647. |
| 22 */ |
| 23 #ifndef SQLITE_MAX_LENGTH |
| 24 # define SQLITE_MAX_LENGTH 1000000000 |
| 25 #endif |
| 26 |
| 27 /* |
| 28 ** This is the maximum number of |
| 29 ** |
| 30 ** * Columns in a table |
| 31 ** * Columns in an index |
| 32 ** * Columns in a view |
| 33 ** * Terms in the SET clause of an UPDATE statement |
| 34 ** * Terms in the result set of a SELECT statement |
| 35 ** * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement. |
| 36 ** * Terms in the VALUES clause of an INSERT statement |
| 37 ** |
| 38 ** The hard upper limit here is 32676. Most database people will |
| 39 ** tell you that in a well-normalized database, you usually should |
| 40 ** not have more than a dozen or so columns in any table. And if |
| 41 ** that is the case, there is no point in having more than a few |
| 42 ** dozen values in any of the other situations described above. |
| 43 */ |
| 44 #ifndef SQLITE_MAX_COLUMN |
| 45 # define SQLITE_MAX_COLUMN 2000 |
| 46 #endif |
| 47 |
| 48 /* |
| 49 ** The maximum length of a single SQL statement in bytes. |
| 50 ** |
| 51 ** It used to be the case that setting this value to zero would |
| 52 ** turn the limit off. That is no longer true. It is not possible |
| 53 ** to turn this limit off. |
| 54 */ |
| 55 #ifndef SQLITE_MAX_SQL_LENGTH |
| 56 # define SQLITE_MAX_SQL_LENGTH 1000000000 |
| 57 #endif |
| 58 |
| 59 /* |
| 60 ** The maximum depth of an expression tree. This is limited to |
| 61 ** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might |
| 62 ** want to place more severe limits on the complexity of an |
| 63 ** expression. |
| 64 ** |
| 65 ** A value of 0 used to mean that the limit was not enforced. |
| 66 ** But that is no longer true. The limit is now strictly enforced |
| 67 ** at all times. |
| 68 */ |
| 69 #ifndef SQLITE_MAX_EXPR_DEPTH |
| 70 # define SQLITE_MAX_EXPR_DEPTH 1000 |
| 71 #endif |
| 72 |
| 73 /* |
| 74 ** The maximum number of terms in a compound SELECT statement. |
| 75 ** The code generator for compound SELECT statements does one |
| 76 ** level of recursion for each term. A stack overflow can result |
| 77 ** if the number of terms is too large. In practice, most SQL |
| 78 ** never has more than 3 or 4 terms. Use a value of 0 to disable |
| 79 ** any limit on the number of terms in a compount SELECT. |
| 80 */ |
| 81 #ifndef SQLITE_MAX_COMPOUND_SELECT |
| 82 # define SQLITE_MAX_COMPOUND_SELECT 500 |
| 83 #endif |
| 84 |
| 85 /* |
| 86 ** The maximum number of opcodes in a VDBE program. |
| 87 ** Not currently enforced. |
| 88 */ |
| 89 #ifndef SQLITE_MAX_VDBE_OP |
| 90 # define SQLITE_MAX_VDBE_OP 25000 |
| 91 #endif |
| 92 |
| 93 /* |
| 94 ** The maximum number of arguments to an SQL function. |
| 95 */ |
| 96 #ifndef SQLITE_MAX_FUNCTION_ARG |
| 97 # define SQLITE_MAX_FUNCTION_ARG 127 |
| 98 #endif |
| 99 |
| 100 /* |
| 101 ** The maximum number of in-memory pages to use for the main database |
| 102 ** table and for temporary tables. The SQLITE_DEFAULT_CACHE_SIZE |
| 103 */ |
| 104 #ifndef SQLITE_DEFAULT_CACHE_SIZE |
| 105 # define SQLITE_DEFAULT_CACHE_SIZE 2000 |
| 106 #endif |
| 107 #ifndef SQLITE_DEFAULT_TEMP_CACHE_SIZE |
| 108 # define SQLITE_DEFAULT_TEMP_CACHE_SIZE 500 |
| 109 #endif |
| 110 |
| 111 /* |
| 112 ** The default number of frames to accumulate in the log file before |
| 113 ** checkpointing the database in WAL mode. |
| 114 */ |
| 115 #ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT |
| 116 # define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT 1000 |
| 117 #endif |
| 118 |
| 119 /* |
| 120 ** The maximum number of attached databases. This must be between 0 |
| 121 ** and 62. The upper bound on 62 is because a 64-bit integer bitmap |
| 122 ** is used internally to track attached databases. |
| 123 */ |
| 124 #ifndef SQLITE_MAX_ATTACHED |
| 125 # define SQLITE_MAX_ATTACHED 10 |
| 126 #endif |
| 127 |
| 128 |
| 129 /* |
| 130 ** The maximum value of a ?nnn wildcard that the parser will accept. |
| 131 */ |
| 132 #ifndef SQLITE_MAX_VARIABLE_NUMBER |
| 133 # define SQLITE_MAX_VARIABLE_NUMBER 999 |
| 134 #endif |
| 135 |
| 136 /* Maximum page size. The upper bound on this value is 65536. This a limit |
| 137 ** imposed by the use of 16-bit offsets within each page. |
| 138 ** |
| 139 ** Earlier versions of SQLite allowed the user to change this value at |
| 140 ** compile time. This is no longer permitted, on the grounds that it creates |
| 141 ** a library that is technically incompatible with an SQLite library |
| 142 ** compiled with a different limit. If a process operating on a database |
| 143 ** with a page-size of 65536 bytes crashes, then an instance of SQLite |
| 144 ** compiled with the default page-size limit will not be able to rollback |
| 145 ** the aborted transaction. This could lead to database corruption. |
| 146 */ |
| 147 #ifdef SQLITE_MAX_PAGE_SIZE |
| 148 # undef SQLITE_MAX_PAGE_SIZE |
| 149 #endif |
| 150 #define SQLITE_MAX_PAGE_SIZE 65536 |
| 151 |
| 152 |
| 153 /* |
| 154 ** The default size of a database page. |
| 155 */ |
| 156 #ifndef SQLITE_DEFAULT_PAGE_SIZE |
| 157 # define SQLITE_DEFAULT_PAGE_SIZE 1024 |
| 158 #endif |
| 159 #if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE |
| 160 # undef SQLITE_DEFAULT_PAGE_SIZE |
| 161 # define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE |
| 162 #endif |
| 163 |
| 164 /* |
| 165 ** Ordinarily, if no value is explicitly provided, SQLite creates databases |
| 166 ** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain |
| 167 ** device characteristics (sector-size and atomic write() support), |
| 168 ** SQLite may choose a larger value. This constant is the maximum value |
| 169 ** SQLite will choose on its own. |
| 170 */ |
| 171 #ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE |
| 172 # define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192 |
| 173 #endif |
| 174 #if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE |
| 175 # undef SQLITE_MAX_DEFAULT_PAGE_SIZE |
| 176 # define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE |
| 177 #endif |
| 178 |
| 179 |
| 180 /* |
| 181 ** Maximum number of pages in one database file. |
| 182 ** |
| 183 ** This is really just the default value for the max_page_count pragma. |
| 184 ** This value can be lowered (or raised) at run-time using that the |
| 185 ** max_page_count macro. |
| 186 */ |
| 187 #ifndef SQLITE_MAX_PAGE_COUNT |
| 188 # define SQLITE_MAX_PAGE_COUNT 1073741823 |
| 189 #endif |
| 190 |
| 191 /* |
| 192 ** Maximum length (in bytes) of the pattern in a LIKE or GLOB |
| 193 ** operator. |
| 194 */ |
| 195 #ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH |
| 196 # define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000 |
| 197 #endif |
| 198 |
| 199 /* |
| 200 ** Maximum depth of recursion for triggers. |
| 201 ** |
| 202 ** A value of 1 means that a trigger program will not be able to itself |
| 203 ** fire any triggers. A value of 0 means that no trigger programs at all |
| 204 ** may be executed. |
| 205 */ |
| 206 #ifndef SQLITE_MAX_TRIGGER_DEPTH |
| 207 # define SQLITE_MAX_TRIGGER_DEPTH 1000 |
| 208 #endif |
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