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 ** @(#) $Id: sqliteLimit.h,v 1.5 2007/12/13 21:54:11 drh Exp $ 16 */ 17 18 /* 19 ** The maximum length of a TEXT or BLOB in bytes. This also 20 ** limits the size of a row in a table or index. 21 ** 22 ** The hard limit is the ability of a 32-bit signed integer 23 ** to count the size: 2^31-1 or 2147483647. 24 */ 25 #ifndef SQLITE_MAX_LENGTH 26 # define SQLITE_MAX_LENGTH 1000000000 27 #endif 28 29 /* 30 ** This is the maximum number of 31 ** 32 ** * Columns in a table 33 ** * Columns in an index 34 ** * Columns in a view 35 ** * Terms in the SET clause of an UPDATE statement 36 ** * Terms in the result set of a SELECT statement 37 ** * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement. 38 ** * Terms in the VALUES clause of an INSERT statement 39 ** 40 ** The hard upper limit here is 32676. Most database people will 41 ** tell you that in a well-normalized database, you usually should 42 ** not have more than a dozen or so columns in any table. And if 43 ** that is the case, there is no point in having more than a few 44 ** dozen values in any of the other situations described above. 45 */ 46 #ifndef SQLITE_MAX_COLUMN 47 # define SQLITE_MAX_COLUMN 2000 48 #endif 49 50 /* 51 ** The maximum length of a single SQL statement in bytes. 52 ** The hard limit is 1 million. 53 */ 54 #ifndef SQLITE_MAX_SQL_LENGTH 55 # define SQLITE_MAX_SQL_LENGTH 1000000 56 #endif 57 58 /* 59 ** The maximum depth of an expression tree. This is limited to 60 ** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might 61 ** want to place more severe limits on the complexity of an 62 ** expression. A value of 0 (the default) means do not enforce 63 ** any limitation on expression tree depth. 64 */ 65 #ifndef SQLITE_MAX_EXPR_DEPTH 66 # define SQLITE_MAX_EXPR_DEPTH 1000 67 #endif 68 69 /* 70 ** The maximum number of terms in a compound SELECT statement. 71 ** The code generator for compound SELECT statements does one 72 ** level of recursion for each term. A stack overflow can result 73 ** if the number of terms is too large. In practice, most SQL 74 ** never has more than 3 or 4 terms. Use a value of 0 to disable 75 ** any limit on the number of terms in a compount SELECT. 76 */ 77 #ifndef SQLITE_MAX_COMPOUND_SELECT 78 # define SQLITE_MAX_COMPOUND_SELECT 500 79 #endif 80 81 /* 82 ** The maximum number of opcodes in a VDBE program. 83 ** Not currently enforced. 84 */ 85 #ifndef SQLITE_MAX_VDBE_OP 86 # define SQLITE_MAX_VDBE_OP 25000 87 #endif 88 89 /* 90 ** The maximum number of arguments to an SQL function. 91 */ 92 #ifndef SQLITE_MAX_FUNCTION_ARG 93 # define SQLITE_MAX_FUNCTION_ARG 100 94 #endif 95 96 /* 97 ** The maximum number of in-memory pages to use for the main database 98 ** table and for temporary tables. The SQLITE_DEFAULT_CACHE_SIZE 99 */ 100 #ifndef SQLITE_DEFAULT_CACHE_SIZE 101 # define SQLITE_DEFAULT_CACHE_SIZE 2000 102 #endif 103 #ifndef SQLITE_DEFAULT_TEMP_CACHE_SIZE 104 # define SQLITE_DEFAULT_TEMP_CACHE_SIZE 500 105 #endif 106 107 /* 108 ** The maximum number of attached databases. This must be at least 2 109 ** in order to support the main database file (0) and the file used to 110 ** hold temporary tables (1). And it must be less than 32 because 111 ** we use a bitmask of databases with a u32 in places (for example 112 ** the Parse.cookieMask field). 113 */ 114 #ifndef SQLITE_MAX_ATTACHED 115 # define SQLITE_MAX_ATTACHED 10 116 #endif 117 118 119 /* 120 ** The maximum value of a ?nnn wildcard that the parser will accept. 121 */ 122 #ifndef SQLITE_MAX_VARIABLE_NUMBER 123 # define SQLITE_MAX_VARIABLE_NUMBER 999 124 #endif 125 126 /* Maximum page size. The upper bound on this value is 32768. This a limit 127 ** imposed by the necessity of storing the value in a 2-byte unsigned integer 128 ** and the fact that the page size must be a power of 2. 129 */ 130 #ifndef SQLITE_MAX_PAGE_SIZE 131 # define SQLITE_MAX_PAGE_SIZE 32768 132 #endif 133 134 135 /* 136 ** The default size of a database page. 137 */ 138 #ifndef SQLITE_DEFAULT_PAGE_SIZE 139 # define SQLITE_DEFAULT_PAGE_SIZE 1024 140 #endif 141 #if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE 142 # undef SQLITE_DEFAULT_PAGE_SIZE 143 # define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE 144 #endif 145 146 /* 147 ** Ordinarily, if no value is explicitly provided, SQLite creates databases 148 ** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain 149 ** device characteristics (sector-size and atomic write() support), 150 ** SQLite may choose a larger value. This constant is the maximum value 151 ** SQLite will choose on its own. 152 */ 153 #ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE 154 # define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192 155 #endif 156 #if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE 157 # undef SQLITE_MAX_DEFAULT_PAGE_SIZE 158 # define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE 159 #endif 160 161 162 /* 163 ** Maximum number of pages in one database file. 164 ** 165 ** This is really just the default value for the max_page_count pragma. 166 ** This value can be lowered (or raised) at run-time using that the 167 ** max_page_count macro. 168 */ 169 #ifndef SQLITE_MAX_PAGE_COUNT 170 # define SQLITE_MAX_PAGE_COUNT 1073741823 171 #endif 172 173 /* 174 ** Maximum length (in bytes) of the pattern in a LIKE or GLOB 175 ** operator. 176 */ 177 #ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH 178 # define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000 179 #endif 180