diff options
Diffstat (limited to 'www/lang.tcl')
| -rw-r--r-- | www/lang.tcl | 61 |
1 files changed, 55 insertions, 6 deletions
diff --git a/www/lang.tcl b/www/lang.tcl index 6aabd1974..18f80fd5e 100644 --- a/www/lang.tcl +++ b/www/lang.tcl @@ -1,7 +1,7 @@ # # Run this Tcl script to generate the sqlite.html file. # -set rcsid {$Id: lang.tcl,v 1.27 2002/03/04 02:26:17 drh Exp $} +set rcsid {$Id: lang.tcl,v 1.28 2002/03/11 02:06:14 drh Exp $} puts {<html> <head> @@ -817,13 +817,19 @@ with caution.</p> <p>The current implementation supports the following pragmas:</p> <ul> -<li><p><b>PRAGMA cache_size = </b><i>Number-of-pages</i><b>;</b></p> - <p>Change the maximum number of database disk pages that SQLite - will hold in memory at once. Each page uses about 1.5K of RAM. - The default cache size is 100. If you are doing UPDATEs or DELETEs +<li><p><b>PRAGMA cache_size; + <br>PRAGMA cache_size = </b><i>Number-of-pages</i><b>;</b></p> + <p>Query or change the maximum number of database disk pages that SQLite + will hold in memory at once. Each page uses about 1.5K of memory. + The default cache size is 2000. If you are doing UPDATEs or DELETEs that change many rows of a database and you do not mind if SQLite uses more memory, you can increase the cache size for a possible speed - improvement.</p></li> + improvement.</p> + <p>When you change the cache size using the cache_size pragma, the + change only endures for the current session. The cache size reverts + to the default value when the database is closed and reopened. Use + the <b>default_cache_size</b> pragma to check the cache size permanently + </p></li> <li><p><b>PRAGMA count_changes = ON; <br>PRAGMA count_changes = OFF;</b></p> @@ -831,6 +837,39 @@ with caution.</p> be invoked once for each DELETE, INSERT, or UPDATE operation. The argument is the number of rows that were changed.</p> +<li><p><b>PRAGMA default_cache_size; + <br>PRAGMA default_cache_size = </b><i>Number-of-pages</i><b>;</b></p> + <p>Query or change the maximum number of database disk pages that SQLite + will hold in memory at once. Each page uses about 1.5K of memory. + This pragma works like the <b>cache_size</b> pragma with the addition + feature that it changes the cache size persistently. With this pragma, + you can set the cache size once and that setting is retained and reused + everytime you reopen the database.</p></li> + +<li><p><b>PRAGMA default_synchronous; + <br>PRAGMA default_synchronous = ON; + <br>PRAGMA default_synchronous = OFF;</b></p> + <p>Query or change the setting of the "synchronous" flag in + the database. When synchronous is on (the default), the SQLite database + engine will pause at critical moments to make sure that data has actually + be written to the disk surface. (In other words, it invokes the + equivalent of the <b>fsync()</b> system call.) In synchronous mode, + an SQLite database should be fully recoverable even if the operating + system crashes or power is interrupted unexpectedly. The penalty for + this assurance is that some database operations take longer because the + engine has to wait on the (relatively slow) disk drive. The alternative + is to turn synchronous off. With synchronous off, SQLite continues + processing as soon as it has handed data off to the operating system. + If the application running SQLite crashes, the data will be safe, but + the database could (in theory) become corrupted if the operating system + crashes or the computer suddenly loses power. On the other hand, some + operations are as much as 50 or more times faster with synchronous off. + </p> + <p>This pragma changes the synchronous mode persistently. Once changed, + the mode stays as set even if the database is closed and reopened. The + <b>synchronous</b> pragma does the same thing but only applies the setting + to the current session.</p> + <li><p><b>PRAGMA empty_result_callbacks = ON; <br>PRAGMA empty_result_callbacks = OFF;</b></p> <p>When on, the EMPTY_RESULT_CALLBACKS pragma causes the callback @@ -873,6 +912,16 @@ with caution.</p> a description of all problems. If everything is in order, "ok" is returned.</p> +<li><p><b>PRAGMA synchronous; + <br>PRAGMA synchronous = ON; + <br>PRAGMA synchronous = OFF;</b></p> + <p>Query or change the setting of the "synchronous" flag in + the database for the duration of the current database connect. + The synchronous flag reverts to its default value when the database + is closed and reopened. For additional information on the synchronous + flag, see the description of the <b>default_synchronous</b> pragma.</p> + </li> + <li><p><b>PRAGMA table_info(</b><i>table-name</i><b>);</b></p> <p>For each column in the named table, invoke the callback function once with information about that column, including the column name, |