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optimize FST.readLastTargetArc (speeds up primary key lookups) 

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1074881 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Michael McCandless 2011-02-26 17:11:08 +00:00
parent 2e1eb3ee86
commit d79e5ce8ca
2 changed files with 61 additions and 16 deletions
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66
lucene/src/java/org/apache/lucene/util/automaton/fst/FST.java
View File

@ -99,7 +99,7 @@ public class FST<T> {
public int arcWithOutputCount;
// If arc has this label then that arc is final/accepted
public static int END_LABEL = -1;
public static final int END_LABEL = -1;
public final static class Arc<T> {
public int label;
@ -297,8 +297,6 @@ public class FST<T> {
final int v;
if (inputType == INPUT_TYPE.BYTE1) {
v = in.readByte()&0xFF;
} else if (inputType == INPUT_TYPE.BYTE2) {
v = in.readVInt();
} else {
v = in.readVInt();
}
@ -478,6 +476,59 @@ public class FST<T> {
return arc;
}
/** Follows the <code>follow</code> arc and reads the last
* arc of its target; this changes the provided
* <code>arc</code> (2nd arg) in-place and returns it.
*
* @return Returns the second argument
* (<code>arc</code>). */
public Arc<T> readLastTargetArc(Arc<T> follow, Arc<T> arc) throws IOException {
//System.out.println("readLast");
if (!targetHasArcs(follow)) {
//System.out.println(" end node");
assert follow.isFinal();
arc.label = -1;
arc.output = follow.nextFinalOutput;
arc.flags = BIT_LAST_ARC;
return arc;
} else {
final BytesReader in = getBytesReader(follow.target);
arc.flags = in.readByte();
if (arc.flag(BIT_ARCS_AS_FIXED_ARRAY)) {
// array: jump straight to end
arc.numArcs = in.readVInt();
arc.bytesPerArc = in.readByte() & 0xFF;
//System.out.println(" array numArcs=" + arc.numArcs + " bpa=" + arc.bytesPerArc);
arc.posArcsStart = in.pos;
arc.arcIdx = arc.numArcs - 2;
} else {
// non-array: linear scan
arc.bytesPerArc = 0;
//System.out.println(" scan");
while(!arc.isLast()) {
// skip this arc:
readLabel(in);
if (arc.flag(BIT_ARC_HAS_OUTPUT)) {
outputs.read(in);
}
if (arc.flag(BIT_ARC_HAS_FINAL_OUTPUT)) {
outputs.read(in);
}
if (arc.flag(BIT_STOP_NODE)) {
} else if (arc.flag(BIT_TARGET_NEXT)) {
} else {
in.pos -= 4;
}
arc.flags = in.readByte();
}
arc.nextArc = in.pos+1;
}
readNextRealArc(arc);
assert arc.isLast();
return arc;
}
}
/**
* Follow the <code>follow</code> arc and read the first arc of its target;
* this changes the provided <code>arc</code> (2nd arg) in-place and returns
@ -518,15 +569,13 @@ public class FST<T> {
arc.numArcs = in.readVInt();
arc.bytesPerArc = in.readByte() & 0xFF;
arc.arcIdx = -1;
arc.posArcsStart = in.pos;
arc.nextArc = arc.posArcsStart = in.pos;
//System.out.println(" bytesPer=" + arc.bytesPerArc + " numArcs=" + arc.numArcs + " arcsStart=" + pos);
} else {
in.pos++;
arc.nextArc = address;
arc.bytesPerArc = 0;
}
arc.nextArc = in.pos;
arc.label = 0;
return readNextArc(arc);
return readNextRealArc(arc);
}
/**
@ -598,6 +647,7 @@ public class FST<T> {
if (arc.bytesPerArc != 0) {
// arcs are at fixed entries
arc.arcIdx++;
assert arc.arcIdx < arc.numArcs;
in = getBytesReader(arc.posArcsStart - arc.arcIdx*arc.bytesPerArc);
} else {
// arcs are packed

9
lucene/src/java/org/apache/lucene/util/automaton/fst/FSTEnum.java
View File

@ -274,7 +274,7 @@ abstract class FSTEnum<T> {
while(true) {
//System.out.println(" cycle upto=" + upto + " arc.label=" + arc.label + " (" + (char) arc.label + ") targetLabel=" + targetLabel + " isLast?=" + arc.isLast());
if (arc.bytesPerArc != 0 && arc.label != -1) {
if (arc.bytesPerArc != 0 && arc.label != FST.END_LABEL) {
// Arcs are fixed array -- use binary search to find
// the target.
@ -465,12 +465,7 @@ abstract class FSTEnum<T> {
}
incr();
final FST.Arc<T> nextArc = getArc(upto);
fst.readFirstTargetArc(arc, nextArc);
arc = nextArc;
while(!arc.isLast()) {
fst.readNextArc(arc);
}
arc = fst.readLastTargetArc(arc, getArc(upto));
}
}