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Overview
Comment: | Add documentation for unlikely(), likelihood() and the soft_heap_limit pragma. |
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Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: | dc4eae98aa016c4758a0c745ed4dc27d56c9d019 |
User & Date: | drh 2013-09-13 22:03:41 |
Context
2013-09-14
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16:09 | Merge the 3.8.0 branch changes into trunk. check-in: 18c0f01b0c user: drh tags: trunk | |
2013-09-13
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22:03 | Add documentation for unlikely(), likelihood() and the soft_heap_limit pragma. check-in: dc4eae98aa user: drh tags: trunk | |
14:52 | Add documentation for the fts4 unicode61 "tokenchars" and "separators" options. check-in: 00c7833d65 user: dan tags: trunk | |
Changes
Changes to pages/changes.in.
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proc chng {date desc {options {}}} { global nChng aChng set aChng($nChng) [list $date $desc $options] incr nChng } chng {2013-10-?? (3.8.1)} { <li>Add support for SQLITE_ENABLE_STAT4 <li>Add the [SQLITE_MINIMUM_FILE_DESCRIPTOR] compile-time option <li>Add the win32-longpath VFS on windows. } chng {2013-08-29 (3.8.0.1)} { <li>Fix an off-by-one error that caused quoted empty string at the end of a CRNL-terminated line of CSV input to be misread by the command-line shell. <li>Fix a query planner bug involving a LEFT JOIN with a BETWEEN or LIKE/GLOB constraint and then another INNER JOIN to the right that involves an OR constraint. |
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proc chng {date desc {options {}}} { global nChng aChng set aChng($nChng) [list $date $desc $options] incr nChng } chng {2013-10-?? (3.8.1)} { <li>Added the [unlikely()] and [likelihood()] SQL functions to be used as hints to the query planner. <li>Added the [soft_heap_limit pragma]. <li>Tweaked the query planner to take into account WHERE clause terms that cannot be used with indices. <li>Added support for SQLITE_ENABLE_STAT4 <li>Added the [SQLITE_MINIMUM_FILE_DESCRIPTOR] compile-time option <li>Added the win32-longpath VFS on windows. } chng {2013-08-29 (3.8.0.1)} { <li>Fix an off-by-one error that caused quoted empty string at the end of a CRNL-terminated line of CSV input to be misread by the command-line shell. <li>Fix a query planner bug involving a LEFT JOIN with a BETWEEN or LIKE/GLOB constraint and then another INNER JOIN to the right that involves an OR constraint. |
Changes to pages/lang.in.
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[LIKE] operator. When overriding the like() function, it may be important
to override both the two and three argument versions of the like()
function. Otherwise, different code may be called to implement the
[LIKE] operator depending on whether or not an ESCAPE clause was
specified.
}
funcdef {load_extension(X) load_extension(X,Y)} {} {
^The load_extension(X,Y) function loads [SQLite extensions] out of the shared
library file named X using the entry point Y. ^The result of load_extension()
is always a NULL. ^If Y is omitted then the default entry point name is used.
^The load_extension() function raises an exception if the extension fails to
load or initialize correctly.
................................................................................
^If the Y argument is omitted, trim(X) removes spaces from both ends of X.
}
funcdef {typeof(X)} {} {
^The typeof(X) function returns a string that indicates the [datatype] of
the expression X: "null", "integer", "real", "text", or "blob".
}
funcdef {unicode(X)} {} {
^The unicode(X) function returns the numeric unicode code point corresponding to
the first character of the string X. ^If the argument to unicode(X) is not a string
then the result is undefined.
}
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[LIKE] operator. When overriding the like() function, it may be important to override both the two and three argument versions of the like() function. Otherwise, different code may be called to implement the [LIKE] operator depending on whether or not an ESCAPE clause was specified. } funcdef {likelihood(X,Y)} {} { ^The likelihood(X,Y) function returns argument X unchanged. ^The value Y in likelihood(X,Y) must be a floating point constant between 0.0 and 1.0, inclusive. ^The likelihood(X) function is a no-op that the code generator optimizes away so that it consumes no CPU cycles at run-time. ^The purpose of the likelihood(X,Y) function is to provide a hint to the query planner that the argument X is a boolean that is true with a probability of approximately Y. ^The likelihood(X, 0.0625) function is equivalent to [unlikely](X). } funcdef {load_extension(X) load_extension(X,Y)} {} { ^The load_extension(X,Y) function loads [SQLite extensions] out of the shared library file named X using the entry point Y. ^The result of load_extension() is always a NULL. ^If Y is omitted then the default entry point name is used. ^The load_extension() function raises an exception if the extension fails to load or initialize correctly. ................................................................................ ^If the Y argument is omitted, trim(X) removes spaces from both ends of X. } funcdef {typeof(X)} {} { ^The typeof(X) function returns a string that indicates the [datatype] of the expression X: "null", "integer", "real", "text", or "blob". } funcdef {unlikely(X)} {} { ^The unlikely(X) function returns the argument X unchanged. ^The unlikely(X) function is a no-op that the code generator optimizes away so that it consumes no CPU cycles at run-time. ^The purpose of the unlikely(X) function is to provide a hint to the query planner that the argument X is a boolean value that is usually not true. ^The unlikely(X) function is equivalent to [likelihood](X, 0.0625). } funcdef {unicode(X)} {} { ^The unicode(X) function returns the numeric unicode code point corresponding to the first character of the string X. ^If the argument to unicode(X) is not a string then the result is undefined. } |
Changes to pages/pragma.in.
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<p><b>PRAGMA shrink_memory</b></p> <p>^This pragma causes the database connection on which it is invoked to free up as much memory as it can, by calling [sqlite3_db_release_memory()]. </p> } Pragma synchronous { <p>^(<b>PRAGMA synchronous; <br>PRAGMA synchronous = </b> <i>0 | OFF | 1 | NORMAL | 2 | FULL</i><b>;</b></p> <p>Query or change the setting of the "synchronous" flag.)^ |
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<p><b>PRAGMA shrink_memory</b></p> <p>^This pragma causes the database connection on which it is invoked to free up as much memory as it can, by calling [sqlite3_db_release_memory()]. </p> } Pragma soft_heap_limit { <p><b>PRAGMA soft_heap_limit<br> PRAGMA soft_heap_limit=</b><i>N</i></p> <p>^This pragma invokes the [sqlite3_soft_heap_limit64()] interface with the argument N, if N is specified and is a non-negative integer. ^The soft_heap_limit pragma always returns the same integer that would be returned by the [sqlite3_soft_heap_limit64](-1) C-language function. </p> } Pragma synchronous { <p>^(<b>PRAGMA synchronous; <br>PRAGMA synchronous = </b> <i>0 | OFF | 1 | NORMAL | 2 | FULL</i><b>;</b></p> <p>Query or change the setting of the "synchronous" flag.)^ |