Write ahead logging sqlite examples

To get temperature, subtract 0x and divide the decimal by For rainfall, as documented elsewhere, multiply by 0. The Code You can download the source code from here. It also decodes the hex-data into more meaningful values, and sends them to stdout as printf formatted strings.

Write ahead logging sqlite examples

Compiler Linkage Control 1. Overview For most purposes, SQLite can be built just fine using the default compilation options. However, if required, the compile-time options documented below can be used to omit SQLite features resulting write ahead logging sqlite examples a smaller compiled library size or to change the default values of some parameters.

Every effort has been made to ensure that the various combinations of compilation options work harmoniously and produce a working library.

Nevertheless, it is strongly recommended that the SQLite test-suite be executed to check for errors before using an SQLite library built with non-standard compilation options. Recommended Compile-time Options The following compile-time options are recommended for applications that are able to use them, in order to minimized the number of CPU cycles and the bytes of memory used by SQLite.

Not all of these compile-time options are usable by every application. It is impossible to test every possible combination of compile-time options for SQLite.

But the following set of compile-time options is one configuration that is always fully tested. This is the single compile-time option that makes the most difference in optimizing the performance of SQLite.

This compile-time option will accomplish that.

write ahead logging sqlite examples

Setting the maximum expression parse-tree depth to zero disables all checking of the expression parse-tree depth, which simplifies the code resulting in faster execution, and helps the parse tree to use less memory. By omitting the seldom-needed ability to return the declared type of columns from the result set of query, prepared statements can be made to consume less memory.

Omitting deprecated interfaces and features will not help SQLite to run any faster. It will reduce the library footprint, however. And it is the right thing to do. The progress handler callback counter must be checked in the inner loop of the bytecode engine.

By omitting this interface, a single conditional is removed from the inner loop of the bytecode enginehelping SQL statements to run slightly faster. Omitting the possibility of using shared cache allows many conditionals in performance-critical sections of the code to be eliminated.

This can give a noticable improvement in performance. Make use of alloca for dynamically allocating temporary stack space for use within a single function, on systems that support alloca.

write ahead logging sqlite examples

Without this option, temporary space is allocated from the heap. So these options do not make a huge difference. But in some design situations, every little bit helps. If this flag is missing or false, then fsync is always used.

This option is only applicable if the standard-library malloc is used. On Apple systems, "zone malloc" is used instead, and so this option is not applicable. This approach works but it is suboptimal.

If this option is missing or false, then SQLite substitutes its own home-grown implementation of strchrnul. If the target byte order cannot be determined at compile-time, then SQLite falls back to doing run-time checks, which always work, though with a small performance penalty.

For all versions of SQLite through 3. However, that might change in future releases of SQLite.#define SQLITE_PREPARE_PERSISTENT 0x01 These constants define various flags that can be passed into "prepFlags" parameter of the sqlite3_prepare_v3() and sqlite3_prepare16_v3() interfaces..

New flags may be added in future releases of SQLite. When write-ahead logging is not enabled (the default), it is not possible for reads and writes to occur on the database at the same time.

Before modifying the database, the writer implicitly acquires an exclusive lock on the database which prevents readers from accessing the database until the write is completed. Support for WAL on SQLite is available from version Some advantages of Write-Ahead Logging (WAL) are: WAL is significantly faster in most scenarios.

WAL provides more concurrency as readers do not block writers and a writer does not block readers. Reading and writing can proceed concurrently.

Yii ActiveRecord looks brilliantly simple and effective for drastically reducing the amount of custom SQL one has to write. It would be great to see more examples of using joins.

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The attheheels.com Nov 16,  · Learn about these advanced features of SQLite: WAL - Write-Ahead Logging, In-Memory DB, Triggers, Pragma statement, Foreign Keys, Full Text Searching, Indexi.

C/C++ Interface For SQLite Version 3