Du kan inte välja fler än 25 ämnen
Ämnen måste starta med en bokstav eller siffra, kan innehålla bindestreck ('-') och vara max 35 tecken långa.
221 rader
5.1 KiB
221 rader
5.1 KiB
#pragma once
|
|
#include "fsized_map.h"
|
|
#include <chrono>
|
|
|
|
struct metadata_t{
|
|
bitops::regulated<uint64_t> record_cnt;
|
|
bitops::regulated<uint64_t> page_cnt;
|
|
bitops::regulated<uint64_t> delete_cnt;
|
|
bitops::regulated<uint64_t> last_page;
|
|
bitops::regulated<uint64_t> last_delete;
|
|
};
|
|
|
|
class database {
|
|
|
|
database(){}
|
|
|
|
public:
|
|
mmap_array<std::pair<bitops::regulated<uint64_t>, record>> records;
|
|
|
|
mmap_array<db_page> pages;
|
|
|
|
mmap_array<metadata_t> metadata;
|
|
|
|
mmap_array<size_t> delete_table;
|
|
|
|
database(
|
|
const std::string& records,
|
|
const std::string& pages,
|
|
const std::string& deletions,
|
|
const std::string& meta,
|
|
const size_t& record_cnt = 4096,
|
|
const size_t& page_cnt = 4096,
|
|
const size_t& delete_cnt = 512
|
|
)
|
|
: records{record_cnt, records}
|
|
, pages{page_cnt, pages}
|
|
, metadata{(size_t)1, meta}
|
|
, delete_table{delete_cnt, deletions}
|
|
{}
|
|
|
|
static database&& create(const std::string dir, size_t page_nb) {
|
|
database ret{
|
|
dir+"records",
|
|
dir+"pages",
|
|
dir+"deleted",
|
|
dir+"meta",
|
|
page_nb+page_nb/2,
|
|
page_nb,
|
|
page_nb/8
|
|
};
|
|
|
|
for(auto& n : ret.records)
|
|
{
|
|
n.second.timestamp = 0;
|
|
n.second.offset = 0;
|
|
}
|
|
|
|
for(auto& n : ret.delete_table)
|
|
{
|
|
n = std::numeric_limits<size_t>::max();
|
|
}
|
|
|
|
(*ret.metadata).last_page = 0;
|
|
(*ret.metadata).last_delete = 0;
|
|
(*ret.metadata).record_cnt = page_nb+page_nb/2;
|
|
(*ret.metadata).page_cnt = page_nb;
|
|
(*ret.metadata).delete_cnt = page_nb/8;
|
|
|
|
#pragma GCC diagnostic push
|
|
#pragma GCC diagnostic ignored "-Wreturn-local-addr"
|
|
return std::move(ret);
|
|
#pragma GCC diagnostic pop
|
|
}
|
|
|
|
static database&& open(const std::string dir) {
|
|
mmap_array<metadata_t> tmp{(size_t)1, dir+"meta"};
|
|
|
|
database ret{
|
|
dir+"records",
|
|
dir+"pages",
|
|
dir+"deleted",
|
|
dir+"meta",
|
|
(*tmp).record_cnt,
|
|
(*tmp).page_cnt,
|
|
(*tmp).delete_cnt
|
|
};
|
|
|
|
tmp.clear();
|
|
|
|
#pragma GCC diagnostic push
|
|
#pragma GCC diagnostic ignored "-Wreturn-local-addr"
|
|
return std::move(ret);
|
|
#pragma GCC diagnostic pop
|
|
}
|
|
|
|
void write(const record_identifier& target, const db_page& value){
|
|
uint64_t page = std::numeric_limits<uint64_t>::max();;
|
|
size_t off = std::numeric_limits<size_t>::max();
|
|
if(metadata[0].last_delete>0)
|
|
{
|
|
off = (*metadata).last_delete;
|
|
page = delete_table[off-1];
|
|
} else {
|
|
page = (*metadata).last_page;
|
|
if(page>=pages.size()) {
|
|
throw std::runtime_error("PAGE STARVATION! MUST EXIT NOW");
|
|
}
|
|
}
|
|
|
|
if(page == std::numeric_limits<uint64_t>::max())
|
|
{
|
|
throw std::runtime_error("PAGE ERROR! MUST EXIT NOW");
|
|
}
|
|
|
|
pages[page] = value;
|
|
|
|
uint64_t hashed = std::hash<record_identifier>{}(target);
|
|
uint64_t hashed_roll = hashed;
|
|
bool succeed = false;
|
|
|
|
|
|
uint64_t ts = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::system_clock::now().time_since_epoch()).count();
|
|
std::pair<bitops::regulated<uint64_t>,record> tmp{0, record{}};
|
|
tmp.first = hashed;
|
|
tmp.second.record_head.split = target;
|
|
tmp.second.timestamp = ts;
|
|
tmp.second.offset = page;
|
|
do{
|
|
uint64_t pos = hashed_roll % records.size();
|
|
|
|
switch (static_cast<uint64_t>(records[pos].second.timestamp)) {
|
|
case 0:
|
|
[[fallthrough]];
|
|
case std::numeric_limits<uint64_t>::max():
|
|
records[pos] = tmp;
|
|
succeed = true;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
hashed_roll++;
|
|
}while(!succeed);
|
|
|
|
if(off != std::numeric_limits<size_t>::max())
|
|
{
|
|
(*metadata).last_delete += -1;
|
|
delete_table[off] = std::numeric_limits<size_t>::max();
|
|
} else {
|
|
(*metadata).last_page += (size_t)1;
|
|
}
|
|
}
|
|
|
|
std::pair<uint64_t, db_page> read(const record_identifier& target) {
|
|
std::pair<uint64_t, db_page> ret;
|
|
ret.first = 0;
|
|
ret.second.fill(0);
|
|
|
|
uint64_t hashed = std::hash<record_identifier>{}(target);
|
|
uint64_t hashed_roll = hashed;
|
|
|
|
do{
|
|
uint64_t pos = hashed_roll % records.size();
|
|
|
|
auto& value = records[pos].second;
|
|
switch (static_cast<uint64_t>(value.timestamp)) {
|
|
case 0:
|
|
return ret;
|
|
case std::numeric_limits<uint64_t>::max():
|
|
break;
|
|
default:
|
|
if(records[pos].first == hashed)
|
|
if(std::hash<record_identifier>{}(value.record_head.split) == hashed)
|
|
{
|
|
if(ret.first<value.timestamp)
|
|
{
|
|
ret.first = value.timestamp;
|
|
ret.second = pages[value.offset];
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
hashed_roll++;
|
|
}while(true);
|
|
return ret;
|
|
}
|
|
|
|
void remove(const record_identifier& target) {
|
|
uint64_t hashed = std::hash<record_identifier>{}(target);
|
|
uint64_t hashed_roll = hashed;
|
|
|
|
do{
|
|
uint64_t pos = hashed_roll % records.size();
|
|
|
|
auto& value = records[pos].second;
|
|
switch (static_cast<uint64_t>(value.timestamp)) {
|
|
case 0:
|
|
return;
|
|
case std::numeric_limits<uint64_t>::max():
|
|
break;
|
|
default:
|
|
if(records[pos].first == hashed)
|
|
if(std::hash<record_identifier>{}(value.record_head.split) == hashed)
|
|
{
|
|
value.timestamp = std::numeric_limits<uint64_t>::max();
|
|
(*metadata).last_delete+=1;
|
|
delete_table[(*metadata).last_delete-1] = value.offset;
|
|
value.offset = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
hashed_roll++;
|
|
}while(true); // return only happens on hitting a case 0
|
|
}
|
|
|
|
void rollback(const record_identifier&) {
|
|
|
|
}
|
|
};
|