> Op 16 dec. 2019, om 22:38 heeft carsten.muencheberg > <carsten.muencheb...@native-instruments.de> het volgende geschreven: > > Hi, > I am working on a generic cache for prepared statements and would like to > make sure that I am not overlooking anything important. > > The cache is a simple map from an SQL string to a statement pointer. > > 1. When to call sqlite3_reset()? It looks like the safest and easiest > approach is to call sqlite3_reset() immediately after retrieving a statement > from the cache. Is there any disadvantage in regards to concurrency or > performance in keeping dozens or hundreds of statements alive in a non reset > state e.g. SELECT statements which have not stepped over all rows? > > 2. When to call sqlite3_clear_bindings()? If I understand correctly new > values can be bound without clearing old ones first, but calling > sqlite3_clear_bindings() can be a safeguard against accidentally executing a > statement with old values? > > 3. When to clear the cache? I read that in some cases statements are > automatically recompiled when a different value is bound to a parameter > inside the WHERE clause. What about SQLITE_ENABLE_STAT4 and ANALYZE, would it > make sense to clear the cache afterwards or can we trust SQLite to maintain > existing statements under all circumstances? > > 4. Other ideas, comments? > > Thanks in advance. > Carsten Hi, as nobody answers yet to the real questions, I just mention that a statement cache is in tclsqlite3.c. That may be a useful example. It is also in the apsw python interface. Regards, E. Pasma
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