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. A value of 0 means that there is no limit.
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 250000000
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 127
94#endif
95
96/*
97** The suggested maximum number of in-memory pages to use for
98** the main database table and for temporary tables.
99**
100** IMPLEMENTATION-OF: R-30185-15359 The default suggested cache size is -2000,
101** which means the cache size is limited to 2048000 bytes of memory.
102** IMPLEMENTATION-OF: R-48205-43578 The default suggested cache size can be
103** altered using the SQLITE_DEFAULT_CACHE_SIZE compile-time options.
104*/
105#ifndef SQLITE_DEFAULT_CACHE_SIZE
106# define SQLITE_DEFAULT_CACHE_SIZE -2000
107#endif
108
109/*
110** The default number of frames to accumulate in the log file before
111** checkpointing the database in WAL mode.
112*/
113#ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT
114# define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT 1000
115#endif
116
117/*
118** The maximum number of attached databases. This must be between 0
119** and 125. The upper bound of 125 is because the attached databases are
120** counted using a signed 8-bit integer which has a maximum value of 127
121** and we have to allow 2 extra counts for the "main" and "temp" databases.
122*/
123#ifndef SQLITE_MAX_ATTACHED
124# define SQLITE_MAX_ATTACHED 10
125#endif
126
127
128/*
129** The maximum value of a ?nnn wildcard that the parser will accept.
130** If the value exceeds 32767 then extra space is required for the Expr
131** structure. But otherwise, we believe that the number can be as large
132** as a signed 32-bit integer can hold.
133*/
134#ifndef SQLITE_MAX_VARIABLE_NUMBER
135# define SQLITE_MAX_VARIABLE_NUMBER 32766
136#endif
137
138/* Maximum page size. The upper bound on this value is 65536. This a limit
139** imposed by the use of 16-bit offsets within each page.
140**
141** Earlier versions of SQLite allowed the user to change this value at
142** compile time. This is no longer permitted, on the grounds that it creates
143** a library that is technically incompatible with an SQLite library
144** compiled with a different limit. If a process operating on a database
145** with a page-size of 65536 bytes crashes, then an instance of SQLite
146** compiled with the default page-size limit will not be able to rollback
147** the aborted transaction. This could lead to database corruption.
148*/
149#ifdef SQLITE_MAX_PAGE_SIZE
150# undef SQLITE_MAX_PAGE_SIZE
151#endif
152#define SQLITE_MAX_PAGE_SIZE 65536
153
154
155/*
156** The default size of a database page.
157*/
158#ifndef SQLITE_DEFAULT_PAGE_SIZE
159# define SQLITE_DEFAULT_PAGE_SIZE 4096
160#endif
161#if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
162# undef SQLITE_DEFAULT_PAGE_SIZE
163# define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
164#endif
165
166/*
167** Ordinarily, if no value is explicitly provided, SQLite creates databases
168** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain
169** device characteristics (sector-size and atomic write() support),
170** SQLite may choose a larger value. This constant is the maximum value
171** SQLite will choose on its own.
172*/
173#ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE
174# define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192
175#endif
176#if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
177# undef SQLITE_MAX_DEFAULT_PAGE_SIZE
178# define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
179#endif
180
181
182/*
183** Maximum number of pages in one database file.
184**
185** This is really just the default value for the max_page_count pragma.
186** This value can be lowered (or raised) at run-time using that the
187** max_page_count macro.
188*/
189#ifndef SQLITE_MAX_PAGE_COUNT
190# define SQLITE_MAX_PAGE_COUNT 1073741823
191#endif
192
193/*
194** Maximum length (in bytes) of the pattern in a LIKE or GLOB
195** operator.
196*/
197#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
198# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
199#endif
200
201/*
202** Maximum depth of recursion for triggers.
203**
204** A value of 1 means that a trigger program will not be able to itself
205** fire any triggers. A value of 0 means that no trigger programs at all
206** may be executed.
207*/
208#ifndef SQLITE_MAX_TRIGGER_DEPTH
209# define SQLITE_MAX_TRIGGER_DEPTH 1000
210#endif
211