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stasis-aries-wal/stasis/operations/lsmIterators.h
Sears Russell a639d461b8 fail a bit earlier on error
2008-10-27 23:32:45 +00:00

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#ifndef _LSMITERATORS_H__
#define _LSMITERATORS_H__
#include "stasis/page.h"
#include "stasis/bufferManager.h"
#include "stasis/page/compression/compression.h"
#include "stasis/page/compression/tuple.h"
/**
@file
This file contains a number of C++ STL-style iterators that are
used during the LSM tree merges.
*/
/**
@todo get rid of these undefs once compensation.h has been removed...
*/
#undef end
#undef begin
namespace rose {
template <class ITERA, class ITERB, class ROW> class mergeIterator;
template <class ITERA, class ITERB, class ROW>
inline const byte * toByteArray(mergeIterator<ITERA,ITERB,ROW> * const t);
template <class ITER, class ROW> class versioningIterator;
template <class ITER, class ROW>
inline const byte * toByteArray(versioningIterator<ITER,ROW> * const t);
template <class STLITER, class ROW> class stlSetIterator;
template <class STLITER, class ROW>
inline const byte * toByteArray(stlSetIterator<STLITER,ROW> * const t);
/**
Scans over another iterator, checking for tombstones, and garbage collecting old tuples.
*/
template <class ROW, class ITER>
class gcIterator {
public:
explicit gcIterator(ITER * i, ITER * iend, epoch_t beginning_of_time, column_number_t ts_col)
: i_(i),
newest_(),
current_(),
have_newest_(0),
have_current_(0),
went_back_(0),
at_end_(0),
//newTS_(-1),
iend_(iend),
freeIt(0),
beginning_of_time_(beginning_of_time),
ts_col_(ts_col) {
get_next();
if(have_newest_) {
have_current_ = true; // needed by ++.
++(*this);
// assert(have_current_); // Should pass; commented out for perf.
}
}
explicit gcIterator()
: i_(0),
newest_(),
current_(),
have_newest_(false),
have_current_(false),
at_end_(true),
freeIt(0),
beginning_of_time_(0),
ts_col_(0) {}
explicit gcIterator(gcIterator& t)
: i_(new ITER(*(t.i_))),
newest_(t.newest_),
current_(t.current_),
have_newest_(t.have_newest_),
have_current_(t.have_current_),
went_back_(t.went_back_),
at_end_(t.at_end_),
iend_(t.iend_),
freeIt(1),
beginning_of_time_(t.beginning_of_time_),
ts_col_(t.ts_col_) { }
~gcIterator() {
if (freeIt) {
delete i_;
}
}
ROW & operator*() {
// Both should pass, comment out for perf
//assert(!went_back_);
//assert(have_current_);
return current_;
}
bool get_next() {
// assert(!went_back_);
// assert(!at_end_);
while(!have_newest_) {
have_newest_ = true;
newest_ = **i_;
if(ts_col_ != INVALID_COL) {
epoch_t newest_time = *(epoch_t*)newest_.get(ts_col_);
while(1) {
++(*i_);
if(*i_ == *iend_) { at_end_=true; return true; }
if(!myTupCmp(newest_,**i_)) { break; }
if(newest_time >= beginning_of_time_) { break; }
epoch_t this_time = *(epoch_t*)(**i_).get(ts_col_);
if(this_time > newest_time) {
newest_= **i_;
newest_time = this_time;
}
}
// is it a tombstone we can forget?
if (newest_time & 0x1 && newest_time < beginning_of_time_) {
have_newest_ = 0;
}
} else {
++(*i_);
if(*i_ == *iend_) { at_end_=true; return false; }
}
}
return true; // newest_;
}
inline bool operator==(const gcIterator &a) const {
// return (*i_) == (*a.i_);
if((!have_current_) && at_end_) { return a.at_end_; }
return false;
}
inline bool operator!=(const gcIterator &a) const {
// return (*i_) != (*a.i_);
return !(*this == a);
}
inline void operator++() {
if(went_back_) {
went_back_ = false;
} else {
// assert(have_current_);
if(have_newest_) {
current_ = newest_;
have_current_ = have_newest_;
have_newest_ = false;
if(!at_end_) {
get_next();
}
} else {
// assert(at_end_);
have_current_ = false;
}
}
}
inline void operator--() {
// assert(!went_back_);
went_back_ = true;
}
/* inline gcIterator* end() {
return new gcIterator(i_->end());
} */
private:
bool myTupCmp(const ROW &a, const ROW &b) {
/* for(int i = 0; i < cnt; i++) {
if(a.get(i) != b.get(i)) {
return 0;
}
}*/
if(ROW::NN > 0) if(*a.get0() != *b.get0()) { if(0 != ts_col_) return 0; }
if(ROW::NN > 1) if(*a.get1() != *b.get1()) { if(1 != ts_col_) return 0; }
if(ROW::NN > 2) if(*a.get2() != *b.get2()) { if(2 != ts_col_) return 0; }
if(ROW::NN > 3) if(*a.get3() != *b.get3()) { if(3 != ts_col_) return 0; }
if(ROW::NN > 4) if(*a.get4() != *b.get4()) { if(4 != ts_col_) return 0; }
if(ROW::NN > 5) if(*a.get5() != *b.get5()) { if(5 != ts_col_) return 0; }
if(ROW::NN > 6) if(*a.get6() != *b.get6()) { if(6 != ts_col_) return 0; }
if(ROW::NN > 7) if(*a.get7() != *b.get7()) { if(7 != ts_col_) return 0; }
if(ROW::NN > 8) if(*a.get8() != *b.get8()) { if(8 != ts_col_) return 0; }
if(ROW::NN > 9) if(*a.get9() != *b.get9()) { if(9 != ts_col_) return 0; }
if(ROW::NN > 10) if(*a.get10() != *b.get10()) { if(10 != ts_col_) return 0; }
if(ROW::NN > 11) if(*a.get11() != *b.get11()) { if(11 != ts_col_) return 0; }
if(ROW::NN > 12) if(*a.get12() != *b.get12()) { if(12 != ts_col_) return 0; }
if(ROW::NN > 13) if(*a.get13() != *b.get13()) { if(13 != ts_col_) return 0; }
if(ROW::NN > 14) if(*a.get14() != *b.get14()) { if(14 != ts_col_) return 0; }
if(ROW::NN > 15) if(*a.get15() != *b.get15()) { if(15 != ts_col_) return 0; }
if(ROW::NN > 16) if(*a.get16() != *b.get16()) { if(16 != ts_col_) return 0; }
if(ROW::NN > 17) if(*a.get17() != *b.get17()) { if(17 != ts_col_) return 0; }
if(ROW::NN > 18) if(*a.get18() != *b.get18()) { if(18 != ts_col_) return 0; }
if(ROW::NN > 19) if(*a.get19() != *b.get19()) { if(19 != ts_col_) return 0; }
return 1;
}
//explicit gcIterator() { abort(); }
void operator=(gcIterator & t) { abort(); }
int operator-(gcIterator & t) { abort(); }
ITER * i_;
ROW newest_;
ROW current_;
bool have_newest_;
bool have_current_;
bool went_back_;
bool at_end_;
// epoch_t newTS_;
ITER * iend_;
bool freeIt;
epoch_t beginning_of_time_;
column_number_t ts_col_;
};
//---------------------------------------------------------------------------
/**
Scans through an LSM tree's leaf pages, each tuple in the tree, in
order. This iterator is designed for maximum forward scan
performance, and does not support all STL operations.
*/
template <class ROW, class PAGELAYOUT>
class treeIterator {
private:
inline void init_helper() {
if(!lsmIterator_) {
currentPage_ = 0;
pageid_ = -1;
p_ = 0;
} else if(!lsmTreeIterator_next(-1, lsmIterator_)) {
currentPage_ = 0;
pageid_ = -1;
p_ = 0;
} else {
pageid_t * pid_tmp;
pageid_t ** hack = &pid_tmp;
lsmTreeIterator_value(-1,lsmIterator_,(byte**)hack);
pageid_ = *pid_tmp;
p_ = loadPage(-1,pageid_);
currentPage_ = (PAGELAYOUT*)p_->impl;
assert(currentPage_);
}
}
public:
explicit treeIterator(recordid tree, ROW &scratch, int keylen) :
tree_(tree),
scratch_(scratch),
keylen_(keylen),
lsmIterator_(lsmTreeIterator_open(-1,tree)),
slot_(0)
{
init_helper();
}
// typedef recordid handle;
class treeIteratorHandle {
public:
treeIteratorHandle() : r_(NULLRID) {}
treeIteratorHandle(const recordid r) : r_(r) {}
/* const treeIteratorHandle & operator=(const recordid *r) {
r_ = *r;
return this;
} */
treeIteratorHandle * operator=(const recordid &r) {
r_ = r;
return this;
}
recordid r_;
};
typedef treeIteratorHandle* handle;
explicit treeIterator(recordid tree) :
tree_(tree),
scratch_(),
keylen_(ROW::sizeofBytes()),
lsmIterator_(lsmTreeIterator_open(-1,tree)),
slot_(0)
{
init_helper();
}
explicit treeIterator(treeIteratorHandle* tree) :
tree_(tree?tree->r_:NULLRID),
scratch_(),
keylen_(ROW::sizeofBytes()),
lsmIterator_(lsmTreeIterator_open(-1,tree?tree->r_:NULLRID)),
slot_(0)
{
init_helper();
}
explicit treeIterator(treeIterator& t) :
tree_(t.tree_),
scratch_(t.scratch_),
keylen_(t.keylen_),
lsmIterator_(t.lsmIterator_?lsmTreeIterator_copy(-1,t.lsmIterator_):0),
slot_(t.slot_),
pageid_(t.pageid_),
p_((Page*)((t.p_)?loadPage(-1,t.p_->id):0)),
currentPage_((PAGELAYOUT*)((p_)?p_->impl:0)) {
}
~treeIterator() {
if(lsmIterator_) {
lsmTreeIterator_close(-1, lsmIterator_);
}
if(p_) {
releasePage(p_);
p_ = 0;
}
}
ROW & operator*() {
ROW* readTuple = currentPage_->recordRead(-1,slot_, &scratch_);
if(!readTuple) {
releasePage(p_);
p_=0;
if(lsmTreeIterator_next(-1,lsmIterator_)) {
pageid_t *pid_tmp;
slot_ = 0;
pageid_t **hack = &pid_tmp;
lsmTreeIterator_value(-1,lsmIterator_,(byte**)hack);
pageid_ = *pid_tmp;
p_ = loadPage(-1,pageid_);
currentPage_ = (PAGELAYOUT*)p_->impl;
readTuple = currentPage_->recordRead(-1,slot_, &scratch_);
// assert(readTuple);
} else {
// past end of iterator! "end" should contain the pageid of the
// last leaf, and 1+ numslots on that page.
abort();
}
}
/* for(int c = 0; c < (scratch_).column_count(); c++) {
assert(*(byte*)(scratch_).get(c) || !*(byte*)(scratch_).get(c));
} */
return scratch_;
}
inline bool operator==(const treeIterator &a) const {
return (slot_ == a.slot_ && pageid_ == a.pageid_)/* || !(lsmIterator_ && a.lsmIterator_)*/ ;
}
inline bool operator!=(const treeIterator &a) const {
return !(*this==a);
}
inline void operator++() {
slot_++;
}
inline void operator--() {
// This iterator consumes its input, and only partially supports
// "==". "--" is just for book keeping, so we don't need to worry
// about setting the other state.
slot_--;
}
inline treeIterator* end() {
treeIterator* t = new treeIterator(tree_,scratch_,keylen_);
if(t->p_) {
releasePage(t->p_);
t->p_=0;
}
t->currentPage_ = 0;
pageid_t pid = TlsmLastPage(-1,tree_);
if(pid != -1) {
t->pageid_= pid;
Page * p = loadPage(-1, t->pageid_);
PAGELAYOUT * lastPage = (PAGELAYOUT*)p->impl;
t->slot_ = 0;
while(lastPage->recordRead(-1,t->slot_,&scratch_)) { t->slot_++; }
releasePage(p);
} else {
// begin == end already; we're done.
}
return t;
}
private:
explicit treeIterator() { abort(); }
void operator=(treeIterator & t) { abort(); }
int operator-(treeIterator & t) { abort(); }
recordid tree_;
ROW scratch_;
int keylen_;
lladdIterator_t * lsmIterator_;
slot_index_t slot_;
pageid_t pageid_;
Page * p_;
PAGELAYOUT * currentPage_;
};
/**
This iterator takes two otehr iterators as arguments, and merges
their output, dropping duplicate entries.
It does not understand versioning or tombstones.
*/
template<class ITERA, class ITERB, class ROW>
class mergeIterator {
private:
static const int A = 0;
static const int B = 1;
static const int NONE = -1;
static const int BOTH = -2;
inline int calcCurr(int oldcur) {
int cur;
if(oldcur == NONE) { return NONE; }
if(a_ == aend_) {
if(b_ == bend_) {
cur = NONE;
} else {
cur = B;
}
} else {
if(b_ == bend_) {
cur = A;
} else {
if((*a_) < (*b_)) {
cur = A;
} else if((*a_) == (*b_)) {
cur = BOTH;
} else {
cur = B;
}
}
}
return cur;
}
public:
mergeIterator(ITERA & a, ITERB & b, ITERA & aend, ITERB & bend) :
off_(0),
a_(a),
b_(b),
aend_(aend),
bend_(bend),
curr_(calcCurr(A)),
before_eof_(0)
{}
explicit mergeIterator(mergeIterator &i) :
off_(i.off_),
a_(i.a_),
b_(i.b_),
aend_(i.aend_),
bend_(i.bend_),
curr_(i.curr_),
before_eof_(i.before_eof_)
{ }
const ROW& operator* () {
if(curr_ == A) { return *a_; }
if(curr_ == B || curr_ == BOTH) { return *b_; }
abort();
curr_ = calcCurr(A);
if(curr_ == A) { return *a_; }
if(curr_ == B || curr_ == BOTH) { return *b_; }
abort();
}
void seekEnd() {
curr_ = NONE;
}
// XXX Only works if exactly one of the comparators is derived from end.
inline bool operator==(const mergeIterator &o) const {
if(curr_ == NONE && o.curr_ == NONE) {
return 1;
} else if(curr_ != NONE && o.curr_ != NONE) {
return (a_ == o.a_) && (b_ == o.b_);
}
return 0;
}
inline bool operator!=(const mergeIterator &o) const {
return !(*this == o);
}
inline void operator++() {
off_++;
if(curr_ == BOTH) {
++a_;
++b_;
} else {
if(curr_ == A) { ++a_; }
if(curr_ == B) { ++b_; }
}
curr_ = calcCurr(curr_);
}
inline void operator--() {
off_--;
if(curr_ == BOTH) {
--a_;
--b_;
} else {
if(curr_ == A) { --a_; }
if(curr_ == B) { --b_; }
}
if(curr_ == NONE) {
before_eof_ = 1;
} else {
before_eof_ = 0;
}
}
inline int operator-(mergeIterator&i) {
return off_ - i.off_;
}
inline void operator=(mergeIterator const &i) {
off_ = i.off_;
a_ = i.a_;
b_ = i.b_;
aend_ = i.aend_;
bend_ = i.bend_;
curr_ = i.curr_;
before_eof_ = i.before_eof;
}
inline unsigned int offset() { return off_; }
private:
unsigned int off_;
ITERA a_;
ITERB b_;
ITERA aend_;
ITERB bend_;
int curr_;
int before_eof_;
friend const byte*
toByteArray<ITERA,ITERB,ROW>(mergeIterator<ITERA,ITERB,ROW> * const t);
};
/**
This iterator takes an iterator that produces rows with versioning
information. The rows should be sorted based on value, then sorted by
version, with the newest value first.
*/
template<class ITER, class ROW>
class versioningIterator {
public:
versioningIterator(ITER & a, ITER & aend,
int beginning_of_time) :
a_(a),
aend_(aend),
check_tombstone_(0),
tombstone_(),
off_(0)
{}
explicit versioningIterator(versioningIterator &i) :
a_(i.a_),
aend_(i.aend_),
check_tombstone_(i.check_tombstone_),
tombstone_(i.tombstone_),
off_(i.off_)
{}
const ROW& operator* () {
return *a_;
}
void seekEnd() {
a_.seekEnd();// = aend_; // XXX good idea?
}
inline bool operator==(const versioningIterator &o) const {
return a_ == o.a_;
}
inline bool operator!=(const versioningIterator &o) const {
return !(*this == o);
}
inline void operator++() {
if(check_tombstone_) {
do {
++a_;
} while(a_ != aend_ && *a_ == tombstone_);
} else {
++a_;
}
if(a_ != aend_ && (*a_).tombstone()) {
tombstone_.copyFrom(*a_);
check_tombstone_ = 1;
} else {
check_tombstone_ = 0;
}
off_++;
}
inline void operator--() {
--a_;
// need to remember that we backed up so that ++ can work...
// the cursor is always positioned on a live value, and -- can
// only be followed by ++, so this should do the right thing.
check_tombstone_ = 0;
off_--;
}
inline int operator-(versioningIterator&i) {
return off_ - i.off_;
}
inline void operator=(versioningIterator const &i) {
a_ = i.a_;
aend_ = i.aend_;
check_tombstone_ = i.check_tombstone_;
tombstone_ = i.tombstone_;
// scratch_ = *a_;
off_ = i.off_;
}
inline unsigned int offset() { return off_; }
private:
ITER a_;
ITER aend_;
int check_tombstone_;
ROW tombstone_;
off_t off_;
friend const byte*
toByteArray<ITER,ROW>(versioningIterator<ITER,ROW> * const t);
};
/**
This iterator takes an iterator that produces rows with versioning
information. The rows should be sorted based on value, then sorted by
version, with the newest value first.
*/
template<class SET,class ROW> class stlSetIterator {
private:
typedef typename SET::iterator STLITER;
public:
typedef SET * handle;
stlSetIterator( SET * s ) : it_(s->begin()), itend_(s->end()) {}
stlSetIterator( STLITER& it, STLITER& itend ) : it_(it), itend_(itend) {}
explicit stlSetIterator(stlSetIterator &i) : it_(i.it_), itend_(i.itend_){}
const ROW& operator* () { return *it_; }
void seekEnd() {
it_ = itend_; // XXX good idea?
}
stlSetIterator * end() { return new stlSetIterator(itend_,itend_); }
inline bool operator==(const stlSetIterator &o) const {
return it_ == o.it_;
}
inline bool operator!=(const stlSetIterator &o) const {
return !(*this == o);
}
inline void operator++() {
++it_;
}
inline void operator--() {
--it_;
}
inline int operator-(stlSetIterator&i) {
return it_ - i.it_;
}
inline void operator=(stlSetIterator const &i) {
it_ = i.it_;
itend_ = i.itend_;
}
private:
STLITER it_;
STLITER itend_;
friend const byte*
toByteArray<SET,ROW>(stlSetIterator<SET,ROW> * const t);
};
template <class SET,class ROW>
inline const byte * toByteArray(stlSetIterator<SET,ROW> * const t) {
return (*(t->it_)).toByteArray();
}
/** Produce a byte array from the value stored at t's current
position */
template <class ITERA, class ITERB, class ROW>
inline const byte * toByteArray(mergeIterator<ITERA,ITERB,ROW> * const t) {
if(t->curr_ == t->A) {
return toByteArray(&t->a_);
} else if(t->curr_ == t->B || t->curr_ == t->BOTH) {
return toByteArray(&t->b_);
}
abort();
}
/** Produce a byte array from the value stored at t's current
position */
template <class ITER, class ROW>
inline const byte * toByteArray(versioningIterator<ITER,ROW> * const t) {
return toByteArray(&t->a_);
}
#ifdef DEFINED_VAL_T
template <class PAGELAYOUT>
inline const byte* toByteArray(treeIterator<val_t,PAGELAYOUT> *const t) {
return (const byte*)&(**t);
}
#endif
template <class PAGELAYOUT,class ROW>
inline const byte* toByteArray(treeIterator<ROW,PAGELAYOUT> *const t) {
return (**t).toByteArray();
}
}
#endif // _LSMITERATORS_H__
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