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. A value of 0 means that there is no limit. 000064 */ 000065 #ifndef SQLITE_MAX_EXPR_DEPTH 000066 # define SQLITE_MAX_EXPR_DEPTH 1000 000067 #endif 000068 000069 /* 000070 ** The maximum number of terms in a compound SELECT statement. 000071 ** The code generator for compound SELECT statements does one 000072 ** level of recursion for each term. A stack overflow can result 000073 ** if the number of terms is too large. In practice, most SQL 000074 ** never has more than 3 or 4 terms. Use a value of 0 to disable 000075 ** any limit on the number of terms in a compound SELECT. 000076 */ 000077 #ifndef SQLITE_MAX_COMPOUND_SELECT 000078 # define SQLITE_MAX_COMPOUND_SELECT 500 000079 #endif 000080 000081 /* 000082 ** The maximum number of opcodes in a VDBE program. 000083 ** Not currently enforced. 000084 */ 000085 #ifndef SQLITE_MAX_VDBE_OP 000086 # define SQLITE_MAX_VDBE_OP 250000000 000087 #endif 000088 000089 /* 000090 ** The maximum number of arguments to an SQL function. 000091 */ 000092 #ifndef SQLITE_MAX_FUNCTION_ARG 000093 # define SQLITE_MAX_FUNCTION_ARG 127 000094 #endif 000095 000096 /* 000097 ** The suggested maximum number of in-memory pages to use for 000098 ** the main database table and for temporary tables. 000099 ** 000100 ** IMPLEMENTATION-OF: R-30185-15359 The default suggested cache size is -2000, 000101 ** which means the cache size is limited to 2048000 bytes of memory. 000102 ** IMPLEMENTATION-OF: R-48205-43578 The default suggested cache size can be 000103 ** altered using the SQLITE_DEFAULT_CACHE_SIZE compile-time options. 000104 */ 000105 #ifndef SQLITE_DEFAULT_CACHE_SIZE 000106 # define SQLITE_DEFAULT_CACHE_SIZE -2000 000107 #endif 000108 000109 /* 000110 ** The default number of frames to accumulate in the log file before 000111 ** checkpointing the database in WAL mode. 000112 */ 000113 #ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT 000114 # define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT 1000 000115 #endif 000116 000117 /* 000118 ** The maximum number of attached databases. This must be between 0 000119 ** and 125. The upper bound of 125 is because the attached databases are 000120 ** counted using a signed 8-bit integer which has a maximum value of 127 000121 ** and we have to allow 2 extra counts for the "main" and "temp" databases. 000122 */ 000123 #ifndef SQLITE_MAX_ATTACHED 000124 # define SQLITE_MAX_ATTACHED 10 000125 #endif 000126 000127 000128 /* 000129 ** The maximum value of a ?nnn wildcard that the parser will accept. 000130 ** If the value exceeds 32767 then extra space is required for the Expr 000131 ** structure. But otherwise, we believe that the number can be as large 000132 ** as a signed 32-bit integer can hold. 000133 */ 000134 #ifndef SQLITE_MAX_VARIABLE_NUMBER 000135 # define SQLITE_MAX_VARIABLE_NUMBER 32766 000136 #endif 000137 000138 /* Maximum page size. The upper bound on this value is 65536. This a limit 000139 ** imposed by the use of 16-bit offsets within each page. 000140 ** 000141 ** Earlier versions of SQLite allowed the user to change this value at 000142 ** compile time. This is no longer permitted, on the grounds that it creates 000143 ** a library that is technically incompatible with an SQLite library 000144 ** compiled with a different limit. If a process operating on a database 000145 ** with a page-size of 65536 bytes crashes, then an instance of SQLite 000146 ** compiled with the default page-size limit will not be able to rollback 000147 ** the aborted transaction. This could lead to database corruption. 000148 */ 000149 #ifdef SQLITE_MAX_PAGE_SIZE 000150 # undef SQLITE_MAX_PAGE_SIZE 000151 #endif 000152 #define SQLITE_MAX_PAGE_SIZE 65536 000153 000154 000155 /* 000156 ** The default size of a database page. 000157 */ 000158 #ifndef SQLITE_DEFAULT_PAGE_SIZE 000159 # define SQLITE_DEFAULT_PAGE_SIZE 4096 000160 #endif 000161 #if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE 000162 # undef SQLITE_DEFAULT_PAGE_SIZE 000163 # define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE 000164 #endif 000165 000166 /* 000167 ** Ordinarily, if no value is explicitly provided, SQLite creates databases 000168 ** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain 000169 ** device characteristics (sector-size and atomic write() support), 000170 ** SQLite may choose a larger value. This constant is the maximum value 000171 ** SQLite will choose on its own. 000172 */ 000173 #ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE 000174 # define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192 000175 #endif 000176 #if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE 000177 # undef SQLITE_MAX_DEFAULT_PAGE_SIZE 000178 # define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE 000179 #endif 000180 000181 000182 /* 000183 ** Maximum number of pages in one database file. 000184 ** 000185 ** This is really just the default value for the max_page_count pragma. 000186 ** This value can be lowered (or raised) at run-time using that the 000187 ** max_page_count macro. 000188 */ 000189 #ifndef SQLITE_MAX_PAGE_COUNT 000190 # define SQLITE_MAX_PAGE_COUNT 0xfffffffe /* 4294967294 */ 000191 #endif 000192 000193 /* 000194 ** Maximum length (in bytes) of the pattern in a LIKE or GLOB 000195 ** operator. 000196 */ 000197 #ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH 000198 # define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000 000199 #endif 000200 000201 /* 000202 ** Maximum depth of recursion for triggers. 000203 ** 000204 ** A value of 1 means that a trigger program will not be able to itself 000205 ** fire any triggers. A value of 0 means that no trigger programs at all 000206 ** may be executed. 000207 */ 000208 #ifndef SQLITE_MAX_TRIGGER_DEPTH 000209 # define SQLITE_MAX_TRIGGER_DEPTH 1000 000210 #endif