More efficient free list: avoid extending the file when updating the list of free pages

pmeunier

Jan 1, 2022, 11:06 AM

5NBCUZRB6HQHE4CMVI4QJKXNBYON5OGOVGAOJPDV3WGJVVQ55UKAC

Dependencies

[2] RLVQDUPY Fixing a double-free error introduced in 1.2.13
[3] E4MD6T3L Proofreading and commenting of this crate (massive bug fixes included)
[4] OP6SVMOD Resetting history
[5] OHG5NX6K Refactoring, drop and the Check trait

Change contents

replacement in sanakirja/src/environment/muttxn.rs at line 267

[3.9333]→[2.1345:1712](∅→∅),[2.1712]→[3.9590:9666](∅→∅),[3.9590]→[3.9590:9666](∅→∅),[3.9666]→[2.1713:1893](∅→∅)

let mut n = 0;
// Delete the pages allocated during this transaction
// from the free db. If these pages have been freed
// again, they will be reinserted below.
while let Some(p) = self.initial_allocated.pop() {
debug!("del initial {} {:x} {:x}", n, free_db.db, p);
btree::del(&mut self, &mut free_db, &p.to_le(), None)?;
if cfg!(debug_assertions) {
crate::debug::debug(&self, &[&free_db], &format!("/tmp/free_{}", n), true);
n += 1;

[3.9333]

[2.1893]

let mut changed = true;
// Fix point on the freed and allocated pages.
while changed {
changed = false;
// Delete the pages allocated during this transaction
// from the free db. If these pages have been freed
// again, they will be reinserted below.
while let Some(p) = self.initial_allocated.pop() {
btree::del(&mut self, &mut free_db, &p.to_le(), None)?;
changed = true;
edit in sanakirja/src/environment/muttxn.rs at line 278

[2.1915]→[3.9666:9684](∅→∅),[3.9666]→[3.9666:9684](∅→∅)

}
replacement in sanakirja/src/environment/muttxn.rs at line 279

[3.9685]→[3.11580:11879](∅→∅),[3.11580]→[3.11580:11879](∅→∅),[3.12459]→[3.12459:12656](∅→∅),[3.12656]→[2.1916:1974](∅→∅),[2.1974]→[3.12656:12735](∅→∅),[3.12656]→[3.12656:12735](∅→∅),[3.12735]→[2.1975:2167](∅→∅)

// Adding all the pages freed during the transaction to the
// tree of free pages. If this call to `btree::put` frees
// pages, add them again. This converges in at most log n
// iterations (where n is the total number of free pages).
while !self.free_pages.is_empty() || !self.free_owned_pages.is_empty() {
while let Some(p) = self.free_pages.pop() {
let p = p & !0xfff;
debug!("put free {} {:x}", n, p);
btree::put(&mut self, &mut free_db, &p.to_le(), &())?;
if cfg!(debug_assertions) {
crate::debug::debug(&self, &[&free_db], &format!("/tmp/free_{}", n), true);
n += 1;

[3.9685]

[2.2167]

// Adding all the pages freed during the transaction to the
// tree of free pages. If this call to `btree::put` frees
// pages, add them again. This converges in at most log n
// iterations (where n is the total number of free pages).
while !self.free_pages.is_empty() || !self.free_owned_pages.is_empty() {
while let Some(p) = self.free_pages.pop() {
let p = p & !0xfff;
btree::put(&mut self, &mut free_db, &p.to_le(), &())?;
changed = true;
replacement in sanakirja/src/environment/muttxn.rs at line 289

[2.2193]→[3.12735:12871](∅→∅),[3.12735]→[3.12735:12871](∅→∅),[3.12871]→[2.2194:2258](∅→∅),[2.2258]→[3.12871:12950](∅→∅),[3.12871]→[3.12871:12950](∅→∅),[3.12950]→[2.2259:2451](∅→∅)

}
while let Some(p) = self.free_owned_pages.pop() {
let p = p & !0xfff;
debug!("put owned free {} {:x}", n, p);
btree::put(&mut self, &mut free_db, &p.to_le(), &())?;
if cfg!(debug_assertions) {
crate::debug::debug(&self, &[&free_db], &format!("/tmp/free_{}", n), true);
n += 1;

[2.2193]

[2.2451]

while let Some(p) = self.free_owned_pages.pop() {
let p = p & !0xfff;
btree::put(&mut self, &mut free_db, &p.to_le(), &())?;
changed = true;
edit in sanakirja/src/environment/muttxn.rs at line 297

[2.2479]→[2.2479:3459](∅→∅)

// Delete the pages allocated during in the calls to
// `put` just above. Note that this is the same code
// as just before the `put`s. We need this duplication
// because doing this only here could potentially
// delete pages we just inserted, causing leaks.
//
// Conversely, doing it only above could result in
// pages being allocated in the calls to `put` above,
// and still counted as free.
while let Some(p) = self.initial_allocated.pop() {
debug!("del initial {} {:x} {:x}", n, free_db.db, p);
btree::del(&mut self, &mut free_db, &p.to_le(), None)?;
if cfg!(debug_assertions) {
crate::debug::debug(&self, &[&free_db], &format!("/tmp/free_{}", n), true);
n += 1;
}
}