000001 /* 000002 ** 2007 May 7 000003 ** 000004 ** The author disclaims copyright to this source code. In place of 000005 ** a legal notice, here is a blessing: 000006 ** 000007 ** May you do good and not evil. 000008 ** May you find forgiveness for yourself and forgive others. 000009 ** May you share freely, never taking more than you give. 000010 ** 000011 ************************************************************************* 000012 ** 000013 ** This file defines various limits of what SQLite can process. 000014 */ 000015 000016 /* 000017 ** The maximum length of a TEXT or BLOB in bytes. This also 000018 ** limits the size of a row in a table or index. 000019 ** 000020 ** The hard limit is the ability of a 32-bit signed integer 000021 ** to count the size: 2^31-1 or 2147483647. 000022 */ 000023 #ifndef SQLITE_MAX_LENGTH 000024 # define SQLITE_MAX_LENGTH 1000000000 000025 #endif 000026 000027 /* 000028 ** This is the maximum number of 000029 ** 000030 ** * Columns in a table 000031 ** * Columns in an index 000032 ** * Columns in a view 000033 ** * Terms in the SET clause of an UPDATE statement 000034 ** * Terms in the result set of a SELECT statement 000035 ** * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement. 000036 ** * Terms in the VALUES clause of an INSERT statement 000037 ** 000038 ** The hard upper limit here is 32676. Most database people will 000039 ** tell you that in a well-normalized database, you usually should 000040 ** not have more than a dozen or so columns in any table. And if 000041 ** that is the case, there is no point in having more than a few 000042 ** dozen values in any of the other situations described above. 000043 */ 000044 #ifndef SQLITE_MAX_COLUMN 000045 # define SQLITE_MAX_COLUMN 2000 000046 #endif 000047 000048 /* 000049 ** The maximum length of a single SQL statement in bytes. 000050 ** 000051 ** It used to be the case that setting this value to zero would 000052 ** turn the limit off. That is no longer true. It is not possible 000053 ** to turn this limit off. 000054 */ 000055 #ifndef SQLITE_MAX_SQL_LENGTH 000056 # define SQLITE_MAX_SQL_LENGTH 1000000000 000057 #endif 000058 000059 /* 000060 ** The maximum depth of an expression tree. This is limited to 000061 ** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might 000062 ** want to place more severe limits on the complexity of an 000063 ** expression. 000064 ** 000065 ** A value of 0 used to mean that the limit was not enforced. 000066 ** But that is no longer true. The limit is now strictly enforced 000067 ** at all times. 000068 */ 000069 #ifndef SQLITE_MAX_EXPR_DEPTH 000070 # define SQLITE_MAX_EXPR_DEPTH 1000 000071 #endif 000072 000073 /* 000074 ** The maximum number of terms in a compound SELECT statement. 000075 ** The code generator for compound SELECT statements does one 000076 ** level of recursion for each term. A stack overflow can result 000077 ** if the number of terms is too large. In practice, most SQL 000078 ** never has more than 3 or 4 terms. Use a value of 0 to disable 000079 ** any limit on the number of terms in a compount SELECT. 000080 */ 000081 #ifndef SQLITE_MAX_COMPOUND_SELECT 000082 # define SQLITE_MAX_COMPOUND_SELECT 500 000083 #endif 000084 000085 /* 000086 ** The maximum number of opcodes in a VDBE program. 000087 ** Not currently enforced. 000088 */ 000089 #ifndef SQLITE_MAX_VDBE_OP 000090 # define SQLITE_MAX_VDBE_OP 25000 000091 #endif 000092 000093 /* 000094 ** The maximum number of arguments to an SQL function. 000095 */ 000096 #ifndef SQLITE_MAX_FUNCTION_ARG 000097 # define SQLITE_MAX_FUNCTION_ARG 127 000098 #endif 000099 000100 /* 000101 ** The suggested maximum number of in-memory pages to use for 000102 ** the main database table and for temporary tables. 000103 ** 000104 ** IMPLEMENTATION-OF: R-30185-15359 The default suggested cache size is -2000, 000105 ** which means the cache size is limited to 2048000 bytes of memory. 000106 ** IMPLEMENTATION-OF: R-48205-43578 The default suggested cache size can be 000107 ** altered using the SQLITE_DEFAULT_CACHE_SIZE compile-time options. 000108 */ 000109 #ifndef SQLITE_DEFAULT_CACHE_SIZE 000110 # define SQLITE_DEFAULT_CACHE_SIZE -2000 000111 #endif 000112 000113 /* 000114 ** The default number of frames to accumulate in the log file before 000115 ** checkpointing the database in WAL mode. 000116 */ 000117 #ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT 000118 # define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT 1000 000119 #endif 000120 000121 /* 000122 ** The maximum number of attached databases. This must be between 0 000123 ** and 125. The upper bound of 125 is because the attached databases are 000124 ** counted using a signed 8-bit integer which has a maximum value of 127 000125 ** and we have to allow 2 extra counts for the "main" and "temp" databases. 000126 */ 000127 #ifndef SQLITE_MAX_ATTACHED 000128 # define SQLITE_MAX_ATTACHED 10 000129 #endif 000130 000131 000132 /* 000133 ** The maximum value of a ?nnn wildcard that the parser will accept. 000134 */ 000135 #ifndef SQLITE_MAX_VARIABLE_NUMBER 000136 # define SQLITE_MAX_VARIABLE_NUMBER 999 000137 #endif 000138 000139 /* Maximum page size. The upper bound on this value is 65536. This a limit 000140 ** imposed by the use of 16-bit offsets within each page. 000141 ** 000142 ** Earlier versions of SQLite allowed the user to change this value at 000143 ** compile time. This is no longer permitted, on the grounds that it creates 000144 ** a library that is technically incompatible with an SQLite library 000145 ** compiled with a different limit. If a process operating on a database 000146 ** with a page-size of 65536 bytes crashes, then an instance of SQLite 000147 ** compiled with the default page-size limit will not be able to rollback 000148 ** the aborted transaction. This could lead to database corruption. 000149 */ 000150 #ifdef SQLITE_MAX_PAGE_SIZE 000151 # undef SQLITE_MAX_PAGE_SIZE 000152 #endif 000153 #define SQLITE_MAX_PAGE_SIZE 65536 000154 000155 000156 /* 000157 ** The default size of a database page. 000158 */ 000159 #ifndef SQLITE_DEFAULT_PAGE_SIZE 000160 # define SQLITE_DEFAULT_PAGE_SIZE 4096 000161 #endif 000162 #if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE 000163 # undef SQLITE_DEFAULT_PAGE_SIZE 000164 # define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE 000165 #endif 000166 000167 /* 000168 ** Ordinarily, if no value is explicitly provided, SQLite creates databases 000169 ** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain 000170 ** device characteristics (sector-size and atomic write() support), 000171 ** SQLite may choose a larger value. This constant is the maximum value 000172 ** SQLite will choose on its own. 000173 */ 000174 #ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE 000175 # define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192 000176 #endif 000177 #if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE 000178 # undef SQLITE_MAX_DEFAULT_PAGE_SIZE 000179 # define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE 000180 #endif 000181 000182 000183 /* 000184 ** Maximum number of pages in one database file. 000185 ** 000186 ** This is really just the default value for the max_page_count pragma. 000187 ** This value can be lowered (or raised) at run-time using that the 000188 ** max_page_count macro. 000189 */ 000190 #ifndef SQLITE_MAX_PAGE_COUNT 000191 # define SQLITE_MAX_PAGE_COUNT 1073741823 000192 #endif 000193 000194 /* 000195 ** Maximum length (in bytes) of the pattern in a LIKE or GLOB 000196 ** operator. 000197 */ 000198 #ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH 000199 # define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000 000200 #endif 000201 000202 /* 000203 ** Maximum depth of recursion for triggers. 000204 ** 000205 ** A value of 1 means that a trigger program will not be able to itself 000206 ** fire any triggers. A value of 0 means that no trigger programs at all 000207 ** may be executed. 000208 */ 000209 #ifndef SQLITE_MAX_TRIGGER_DEPTH 000210 # define SQLITE_MAX_TRIGGER_DEPTH 1000 000211 #endif