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Cache param count and make statement cache more effective
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parent
6485b324d7
commit
a776f460e8
23
src/cache.rs
23
src/cache.rs
@ -5,6 +5,7 @@ use crate::{Connection, Result, Statement};
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use lru_cache::LruCache;
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use std::cell::RefCell;
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use std::ops::{Deref, DerefMut};
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use std::sync::Arc;
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impl Connection {
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/// Prepare a SQL statement for execution, returning a previously prepared
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@ -54,7 +55,7 @@ impl Connection {
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/// Prepared statements LRU cache.
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#[derive(Debug)]
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pub struct StatementCache(RefCell<LruCache<String, RawStatement>>);
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pub struct StatementCache(RefCell<LruCache<Arc<str>, RawStatement>>);
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/// Cacheable statement.
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///
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@ -125,12 +126,16 @@ impl StatementCache {
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conn: &'conn Connection,
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sql: &str,
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) -> Result<CachedStatement<'conn>> {
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let trimmed = sql.trim();
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let mut cache = self.0.borrow_mut();
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let stmt = match cache.remove(sql.trim()) {
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let stmt = match cache.remove(trimmed) {
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Some(raw_stmt) => Ok(Statement::new(conn, raw_stmt)),
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None => conn.prepare(sql),
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None => conn.prepare(trimmed),
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};
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stmt.map(|stmt| CachedStatement::new(stmt, self))
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stmt.map(|mut stmt| {
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stmt.stmt.set_statement_cache_key(trimmed);
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CachedStatement::new(stmt, self)
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})
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}
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// Return a statement to the cache.
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@ -140,10 +145,14 @@ impl StatementCache {
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}
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let mut cache = self.0.borrow_mut();
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stmt.clear_bindings();
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let sql = String::from_utf8_lossy(stmt.sql().unwrap().to_bytes())
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.trim()
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.to_string();
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if let Some(sql) = stmt.statement_cache_key() {
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cache.insert(sql, stmt);
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} else {
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debug_assert!(
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false,
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"bug in statement cache code, statement returned to cache that without key"
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);
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}
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}
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fn flush(&self) {
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@ -3,16 +3,32 @@ use super::unlock_notify;
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use super::StatementStatus;
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#[cfg(feature = "modern_sqlite")]
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use crate::util::SqliteMallocString;
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use std::cell::Cell;
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use std::ffi::CStr;
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use std::os::raw::c_int;
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use std::ptr;
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use std::sync::Arc;
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// Private newtype for raw sqlite3_stmts that finalize themselves when dropped.
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#[derive(Debug)]
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pub struct RawStatement {
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ptr: *mut ffi::sqlite3_stmt,
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tail: bool,
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// Cached indices of named parameters, computed on the fly.
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cache: crate::util::ParamIndexCache,
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// Cached count of named parameters, computed on first use.
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bind_parameter_count: Cell<Option<usize>>,
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// Cached SQL (trimmed) that we use as the key when we're in the statement
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// cache. This is None for statements which didn't come from the statement
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// cache.
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//
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// This is probably the same as `self.sql()` in most cases, but we don't
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// care either way -- It's a better cache key as it is anyway since it's the
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// actual source we got from rust.
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//
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// One example of a case where the result of `sqlite_sql` and the value in
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// `statement_cache_key` might differ is if the statement has a `tail`.
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statement_cache_key: Option<Arc<str>>,
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}
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impl RawStatement {
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@ -20,7 +36,9 @@ impl RawStatement {
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RawStatement {
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ptr: stmt,
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tail,
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bind_parameter_count: Cell::new(None),
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cache: Default::default(),
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statement_cache_key: None,
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}
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}
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@ -28,11 +46,20 @@ impl RawStatement {
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self.ptr.is_null()
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}
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pub(crate) fn set_statement_cache_key(&mut self, p: impl Into<Arc<str>>) {
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self.statement_cache_key = Some(p.into());
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}
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pub(crate) fn statement_cache_key(&self) -> Option<Arc<str>> {
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self.statement_cache_key.clone()
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}
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pub unsafe fn ptr(&self) -> *mut ffi::sqlite3_stmt {
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self.ptr
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}
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pub fn column_count(&self) -> usize {
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// Note: Can't cache this as it changes if the schema is altered.
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unsafe { ffi::sqlite3_column_count(self.ptr) as usize }
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}
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@ -94,7 +121,9 @@ impl RawStatement {
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}
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pub fn bind_parameter_count(&self) -> usize {
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unsafe { ffi::sqlite3_bind_parameter_count(self.ptr) as usize }
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crate::util::get_cached(&self.bind_parameter_count, || unsafe {
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ffi::sqlite3_bind_parameter_count(self.ptr) as usize
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})
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}
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pub fn bind_parameter_index(&self, name: &str) -> Option<usize> {
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@ -9,3 +9,18 @@ pub(crate) use small_cstr::SmallCString;
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mod sqlite_string;
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#[cfg(any(feature = "modern_sqlite", feature = "vtab"))]
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pub(crate) use sqlite_string::SqliteMallocString;
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#[inline]
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pub(crate) fn get_cached<T, F>(cache: &std::cell::Cell<Option<T>>, lookup: F) -> T
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where
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T: Copy,
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F: FnOnce() -> T,
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{
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if let Some(v) = cache.get() {
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v
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} else {
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let cb = lookup();
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cache.set(Some(cb));
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cb
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}
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}
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