Dedupe SQL arguments.

This isn't perfect -- we still need to clone in a couple of cases -- but it avoids us
passing duplicate strings down into SQLite whenever the same value is mentioned more
than once in a query.
This commit is contained in:
Richard Newman 2017-06-06 18:21:07 -07:00
parent a88375fc15
commit 7812a01ffe
2 changed files with 57 additions and 12 deletions

View file

@ -381,7 +381,7 @@ fn test_complex_or_join() {
`datoms` AS `datoms03` \
WHERE `datoms02`.a = 95 \
AND `datoms03`.a = 96 \
AND `datoms03`.v = $v2 \
AND `datoms03`.v = $v1 \
AND `datoms02`.v = `datoms03`.e) AS `c00`, \
`datoms` AS `datoms04`, \
`datoms` AS `datoms05` \
@ -391,8 +391,7 @@ fn test_complex_or_join() {
AND `c00`.`?page` = `datoms05`.e \
LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "http://foo.com/"),
make_arg("$v1", "Foo"),
make_arg("$v2", "Foo")]);
make_arg("$v1", "Foo")]);
}
#[test]

View file

@ -17,11 +17,14 @@ extern crate mentat_core;
use std::rc::Rc;
use std::collections::HashMap;
use ordered_float::OrderedFloat;
use mentat_core::{
ToMicros,
TypedValue,
Uuid,
};
pub use rusqlite::types::Value;
@ -95,7 +98,14 @@ pub struct SQLiteQueryBuilder {
arg_prefix: String,
arg_counter: i64,
args: Vec<(String, Rc<rusqlite::types::Value>)>,
// We can't just use an InternSet on the rusqlite::types::Value instances, because that
// includes f64, so it's not Hash or Eq.
// Instead we track UUID and String arguments separately, mapping them to their argument name,
// in order to dedupe. We'll add these to the regular argument vector later.
uuid_args: HashMap<Rc<Uuid>, String>, // From value to argument name.
string_args: HashMap<Rc<String>, String>, // From value to argument name.
args: Vec<(String, Rc<rusqlite::types::Value>)>, // (arg, value).
}
impl SQLiteQueryBuilder {
@ -108,13 +118,22 @@ impl SQLiteQueryBuilder {
sql: String::new(),
arg_prefix: prefix,
arg_counter: 0,
uuid_args: HashMap::default(),
string_args: HashMap::default(),
args: vec![],
}
}
fn push_static_arg(&mut self, val: Rc<rusqlite::types::Value>) {
fn next_argument_name(&mut self) -> String {
let arg = format!("{}{}", self.arg_prefix, self.arg_counter);
self.arg_counter = self.arg_counter + 1;
arg
}
fn push_static_arg(&mut self, val: Rc<rusqlite::types::Value>) {
// TODO: intern these, too.
let arg = self.next_argument_name();
self.push_named_arg(arg.as_str());
self.args.push((arg, val));
}
@ -147,18 +166,28 @@ impl QueryBuilder for SQLiteQueryBuilder {
self.push_sql(format!("{}", dt.to_micros()).as_str()); // TODO: argument instead?
},
&Uuid(ref u) => {
// Get a byte array.
let bytes = u.as_bytes().clone();
let v = Rc::new(rusqlite::types::Value::Blob(bytes.to_vec()));
self.push_static_arg(v);
if let Some(arg) = self.uuid_args.get(u).cloned() { // Why, borrow checker, why?!
self.push_named_arg(arg.as_str());
} else {
let arg = self.next_argument_name();
self.push_named_arg(arg.as_str());
self.uuid_args.insert(Rc::new(u.clone()), arg);
}
},
// These are both `Rc`. Unfortunately, we can't use that fact when
// turning these into rusqlite Values.
// However, we can check to see whether there's an existing var that matches…
&String(ref s) => {
let v = Rc::new(rusqlite::types::Value::Text(s.as_ref().clone()));
self.push_static_arg(v);
if let Some(arg) = self.string_args.get(s).cloned() {
self.push_named_arg(arg.as_str());
} else {
let arg = self.next_argument_name();
self.push_named_arg(arg.as_str());
self.string_args.insert(s.clone(), arg);
}
},
&Keyword(ref s) => {
// TODO: intern.
let v = Rc::new(rusqlite::types::Value::Text(s.as_ref().to_string()));
self.push_static_arg(v);
},
@ -190,9 +219,26 @@ impl QueryBuilder for SQLiteQueryBuilder {
}
fn finish(self) -> SQLQuery {
// We collected string and UUID arguments into separate maps so that we could
// dedupe them. Now we need to turn them into rusqlite Values.
let mut args = self.args;
let string_args = self.string_args.into_iter().map(|(val, arg)| {
(arg, Rc::new(rusqlite::types::Value::Text(val.as_ref().clone())))
});
let uuid_args = self.uuid_args.into_iter().map(|(val, arg)| {
// Get a byte array.
let bytes = val.as_bytes().clone();
(arg, Rc::new(rusqlite::types::Value::Blob(bytes.to_vec())))
});
args.extend(string_args);
args.extend(uuid_args);
// Get the args in the right order -- $v0, $v1…
args.sort_by(|&(ref k1, _), &(ref k2, _)| k1.cmp(k2));
SQLQuery {
sql: self.sql,
args: self.args,
args: args,
}
}
}