sqliteLimit.h
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- /*
- ** 2007 May 7
- **
- ** 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.
- **
- *************************************************************************
- **
- ** This file defines various limits of what SQLite can process.
- **
- ** @(#) $Id: sqliteLimit.h,v 1.8 2008/03/26 15:56:22 drh Exp $
- */
- /*
- ** The maximum length of a TEXT or BLOB in bytes. This also
- ** limits the size of a row in a table or index.
- **
- ** The hard limit is the ability of a 32-bit signed integer
- ** to count the size: 2^31-1 or 2147483647.
- */
- #ifndef SQLITE_MAX_LENGTH
- # define SQLITE_MAX_LENGTH 1000000000
- #endif
- /*
- ** This is the maximum number of
- **
- ** * Columns in a table
- ** * Columns in an index
- ** * Columns in a view
- ** * Terms in the SET clause of an UPDATE statement
- ** * Terms in the result set of a SELECT statement
- ** * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement.
- ** * Terms in the VALUES clause of an INSERT statement
- **
- ** The hard upper limit here is 32676. Most database people will
- ** tell you that in a well-normalized database, you usually should
- ** not have more than a dozen or so columns in any table. And if
- ** that is the case, there is no point in having more than a few
- ** dozen values in any of the other situations described above.
- */
- #ifndef SQLITE_MAX_COLUMN
- # define SQLITE_MAX_COLUMN 2000
- #endif
- /*
- ** The maximum length of a single SQL statement in bytes.
- **
- ** It used to be the case that setting this value to zero would
- ** turn the limit off. That is no longer true. It is not possible
- ** to turn this limit off.
- */
- #ifndef SQLITE_MAX_SQL_LENGTH
- # define SQLITE_MAX_SQL_LENGTH 1000000000
- #endif
- /*
- ** The maximum depth of an expression tree. This is limited to
- ** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might
- ** want to place more severe limits on the complexity of an
- ** expression.
- **
- ** A value of 0 used to mean that the limit was not enforced.
- ** But that is no longer true. The limit is now strictly enforced
- ** at all times.
- */
- #ifndef SQLITE_MAX_EXPR_DEPTH
- # define SQLITE_MAX_EXPR_DEPTH 1000
- #endif
- /*
- ** The maximum number of terms in a compound SELECT statement.
- ** The code generator for compound SELECT statements does one
- ** level of recursion for each term. A stack overflow can result
- ** if the number of terms is too large. In practice, most SQL
- ** never has more than 3 or 4 terms. Use a value of 0 to disable
- ** any limit on the number of terms in a compount SELECT.
- */
- #ifndef SQLITE_MAX_COMPOUND_SELECT
- # define SQLITE_MAX_COMPOUND_SELECT 500
- #endif
- /*
- ** The maximum number of opcodes in a VDBE program.
- ** Not currently enforced.
- */
- #ifndef SQLITE_MAX_VDBE_OP
- # define SQLITE_MAX_VDBE_OP 25000
- #endif
- /*
- ** The maximum number of arguments to an SQL function.
- */
- #ifndef SQLITE_MAX_FUNCTION_ARG
- # define SQLITE_MAX_FUNCTION_ARG 100
- #endif
- /*
- ** The maximum number of in-memory pages to use for the main database
- ** table and for temporary tables. The SQLITE_DEFAULT_CACHE_SIZE
- */
- #ifndef SQLITE_DEFAULT_CACHE_SIZE
- # define SQLITE_DEFAULT_CACHE_SIZE 2000
- #endif
- #ifndef SQLITE_DEFAULT_TEMP_CACHE_SIZE
- # define SQLITE_DEFAULT_TEMP_CACHE_SIZE 500
- #endif
- /*
- ** The maximum number of attached databases. This must be between 0
- ** and 30. The upper bound on 30 is because a 32-bit integer bitmap
- ** is used internally to track attached databases.
- */
- #ifndef SQLITE_MAX_ATTACHED
- # define SQLITE_MAX_ATTACHED 10
- #endif
- /*
- ** The maximum value of a ?nnn wildcard that the parser will accept.
- */
- #ifndef SQLITE_MAX_VARIABLE_NUMBER
- # define SQLITE_MAX_VARIABLE_NUMBER 999
- #endif
- /* Maximum page size. The upper bound on this value is 32768. This a limit
- ** imposed by the necessity of storing the value in a 2-byte unsigned integer
- ** and the fact that the page size must be a power of 2.
- */
- #ifndef SQLITE_MAX_PAGE_SIZE
- # define SQLITE_MAX_PAGE_SIZE 32768
- #endif
- /*
- ** The default size of a database page.
- */
- #ifndef SQLITE_DEFAULT_PAGE_SIZE
- # define SQLITE_DEFAULT_PAGE_SIZE 1024
- #endif
- #if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
- # undef SQLITE_DEFAULT_PAGE_SIZE
- # define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
- #endif
- /*
- ** Ordinarily, if no value is explicitly provided, SQLite creates databases
- ** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain
- ** device characteristics (sector-size and atomic write() support),
- ** SQLite may choose a larger value. This constant is the maximum value
- ** SQLite will choose on its own.
- */
- #ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE
- # define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192
- #endif
- #if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
- # undef SQLITE_MAX_DEFAULT_PAGE_SIZE
- # define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
- #endif
- /*
- ** Maximum number of pages in one database file.
- **
- ** This is really just the default value for the max_page_count pragma.
- ** This value can be lowered (or raised) at run-time using that the
- ** max_page_count macro.
- */
- #ifndef SQLITE_MAX_PAGE_COUNT
- # define SQLITE_MAX_PAGE_COUNT 1073741823
- #endif
- /*
- ** Maximum length (in bytes) of the pattern in a LIKE or GLOB
- ** operator.
- */
- #ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
- # define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
- #endif