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https://github.com/FirebirdSQL/firebird.git
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Frontported improvement #7494 : Firebird performance issue - non necessary index reads.
Also, fixed unregistered bug when scan of multi-segmented descending index with partial match and greater-than condition could miss some records.
This commit is contained in:
Vlad Khorsun
parent
dd4c28ffcf
commit
88a434dacc
171
src/jrd/btr.cpp
171
src/jrd/btr.cpp
@ -198,13 +198,13 @@ static ULONG fast_load(thread_db*, IndexCreation&, SelectivityList&);
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static index_root_page* fetch_root(thread_db*, WIN*, const jrd_rel*, const RelationPages*);
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static UCHAR* find_node_start_point(btree_page*, temporary_key*, UCHAR*, USHORT*,
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bool, bool, bool = false, RecordNumber = NO_VALUE);
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bool, int, bool = false, RecordNumber = NO_VALUE);
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static UCHAR* find_area_start_point(btree_page*, const temporary_key*, UCHAR*,
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USHORT*, bool, bool, RecordNumber = NO_VALUE);
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USHORT*, bool, int, RecordNumber = NO_VALUE);
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static ULONG find_page(btree_page*, const temporary_key*, const index_desc*, RecordNumber = NO_VALUE,
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bool = false);
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int = 0);
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static contents garbage_collect(thread_db*, WIN*, ULONG);
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static void generate_jump_nodes(thread_db*, btree_page*, JumpNodeList*, USHORT,
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@ -717,28 +717,36 @@ static void checkForLowerKeySkip(bool& skipLowerKey,
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}
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else
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{
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// Check if we have a duplicate node (for the same page)
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if (node.prefix < lower.key_length)
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if ((lower.key_length == node.prefix + node.length) ||
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((lower.key_length <= node.prefix + node.length) && partLower))
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{
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if (node.prefix + node.length == lower.key_length)
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skipLowerKey = (memcmp(node.data, lower.key_data + node.prefix, node.length) == 0);
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else
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skipLowerKey = false;
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}
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else if ((node.prefix == lower.key_length) && node.length)
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{
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// In case of multi-segment check segment-number else
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// it's a different key
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if (partLower)
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const UCHAR* p = node.data, *q = lower.key_data + node.prefix;
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const UCHAR* const end = lower.key_data + lower.key_length;
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while (q < end)
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{
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const USHORT segnum = idx.idx_count - (UCHAR)((idx.idx_flags & idx_descending) ?
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(*node.data) ^ -1 : *node.data);
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if (*p++ != *q++)
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{
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skipLowerKey = false;
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break;
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}
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}
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if ((q >= end) && (p < node.data + node.length) && skipLowerKey && partLower)
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{
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const bool descending = idx.idx_flags & idx_descending;
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// since key length always is multiplier of (STUFF_COUNT + 1) (for partial
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// compound keys) and we passed lower key completely then p pointed
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// us to the next segment number and we can use this fact to calculate
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// how many segments is equal to lower key
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const USHORT segnum = idx.idx_count - (UCHAR) (descending ? ((*p) ^ -1) : *p);
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if (segnum < retrieval->irb_lower_count)
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skipLowerKey = false;
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}
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else
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skipLowerKey = false;
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}
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else {
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skipLowerKey = false;
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}
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}
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}
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@ -809,35 +817,7 @@ void BTR_evaluate(thread_db* tdbb, const IndexRetrieval* retrieval, RecordBitmap
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{
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IndexNode node;
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node.readNode(pointer, true);
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if ((lower->key_length == node.prefix + node.length) ||
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((lower->key_length <= node.prefix + node.length) && partLower))
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{
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const UCHAR* p = node.data, *q = lower->key_data + node.prefix;
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const UCHAR* const end = lower->key_data + lower->key_length;
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while (q < end)
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{
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if (*p++ != *q++)
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{
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skipLowerKey = false;
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break;
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}
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}
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if ((q >= end) && (p < node.data + node.length) && skipLowerKey && partLower)
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{
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// since key length always is multiplier of (STUFF_COUNT + 1) (for partial
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// compound keys) and we passed lower key completely then p pointed
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// us to the next segment number and we can use this fact to calculate
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// how many segments is equal to lower key
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const USHORT segnum = idx.idx_count - (UCHAR) (descending ? ((*p) ^ -1) : *p);
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if (segnum < retrieval->irb_lower_count)
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skipLowerKey = false;
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}
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}
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else
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skipLowerKey = false;
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checkForLowerKeySkip(skipLowerKey, partLower, node, *lower, idx, retrieval);
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}
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}
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else
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@ -922,7 +902,7 @@ void BTR_evaluate(thread_db* tdbb, const IndexRetrieval* retrieval, RecordBitmap
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UCHAR* BTR_find_leaf(btree_page* bucket, temporary_key* key, UCHAR* value,
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USHORT* return_value, bool descending, bool retrieval)
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USHORT* return_value, bool descending, int retrieval)
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{
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/**************************************
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*
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@ -4313,7 +4293,7 @@ static index_root_page* fetch_root(thread_db* tdbb, WIN* window, const jrd_rel*
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static UCHAR* find_node_start_point(btree_page* bucket, temporary_key* key,
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UCHAR* value,
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USHORT* return_value, bool descending,
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bool retrieval, bool pointer_by_marker,
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int retrieval, bool pointer_by_marker,
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RecordNumber find_record_number)
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{
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/**************************************
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@ -4389,9 +4369,21 @@ static UCHAR* find_node_start_point(btree_page* bucket, temporary_key* key,
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{
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while (true)
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{
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if (q == nodeEnd || (retrieval && p == key_end))
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if (q == nodeEnd)
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goto done;
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if (retrieval && p == key_end)
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{
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if ((retrieval & irb_partial) && !(retrieval & irb_starting))
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{
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// check segment
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const bool sameSegment = ((p - STUFF_COUNT > key->key_data) && p[-(STUFF_COUNT + 1)] == *q);
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if (sameSegment)
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break;
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}
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goto done;
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}
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if (p == key_end || *p > *q)
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break;
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@ -4451,7 +4443,7 @@ done:
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static UCHAR* find_area_start_point(btree_page* bucket, const temporary_key* key,
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UCHAR* value,
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USHORT* return_prefix, bool descending,
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bool retrieval, RecordNumber find_record_number)
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int retrieval, RecordNumber find_record_number)
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{
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/**************************************
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*
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@ -4557,7 +4549,17 @@ static UCHAR* find_area_start_point(btree_page* bucket, const temporary_key* key
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if (retrieval && keyPointer == keyEnd)
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{
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done = true;
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if ((retrieval & irb_partial) && !(retrieval & irb_starting))
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{
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// check segment
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const bool sameSegment = ((keyPointer - STUFF_COUNT > key->key_data) && keyPointer[-(STUFF_COUNT + 1)] == *q);
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if (!sameSegment)
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done = true;
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}
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else
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{
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done = true;
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}
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break;
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}
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@ -4664,7 +4666,7 @@ static UCHAR* find_area_start_point(btree_page* bucket, const temporary_key* key
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static ULONG find_page(btree_page* bucket, const temporary_key* key,
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const index_desc* idx, RecordNumber find_record_number,
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bool retrieval)
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int retrieval)
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{
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/**************************************
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*
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@ -6486,7 +6488,6 @@ static bool scan(thread_db* tdbb, UCHAR* pointer, RecordBitmap** bitmap, RecordB
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// stuff the key to the stuff boundary
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ULONG count;
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USHORT flag = retrieval->irb_generic;
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bool partialEquality = false;
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if ((flag & irb_partial) && (flag & irb_equality) &&
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!(flag & irb_starting) && !(flag & irb_descending))
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@ -6497,7 +6498,6 @@ static bool scan(thread_db* tdbb, UCHAR* pointer, RecordBitmap** bitmap, RecordB
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key->key_data[key->key_length + i] = 0;
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count += key->key_length;
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partialEquality = true;
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}
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else
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count = key->key_length;
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@ -6507,13 +6507,13 @@ static bool scan(thread_db* tdbb, UCHAR* pointer, RecordBitmap** bitmap, RecordB
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count -= key->key_length;
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const bool descending = (flag & irb_descending);
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const bool equality = (flag & irb_equality);
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const bool ignoreNulls = (flag & irb_ignore_null_value_key) && (idx->idx_count == 1);
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bool done = false;
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bool ignore = false;
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const bool skipUpperKey = (flag & irb_exclude_upper);
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const bool partLower = (retrieval->irb_lower_count < idx->idx_count);
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const bool partUpper = (retrieval->irb_upper_count < idx->idx_count);
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USHORT upperPrefix = prefix;
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// reset irb_equality flag passed for optimization
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flag &= ~(irb_equality | irb_ignore_null_value_key);
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@ -6555,7 +6555,7 @@ static bool scan(thread_db* tdbb, UCHAR* pointer, RecordBitmap** bitmap, RecordB
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else if (node.prefix <= prefix)
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{
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prefix = node.prefix;
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upperPrefix = prefix;
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USHORT byteInSegment = prefix % (STUFF_COUNT + 1);
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p = key->key_data + prefix;
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const UCHAR* q = node.data;
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USHORT l = node.length;
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@ -6563,49 +6563,52 @@ static bool scan(thread_db* tdbb, UCHAR* pointer, RecordBitmap** bitmap, RecordB
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{
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if (skipUpperKey && partUpper)
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{
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if (upperPrefix >= key->key_length)
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if (p >= end_key && byteInSegment == 0)
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{
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const USHORT segnum =
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idx->idx_count - (UCHAR)(descending ? ((*q) ^ -1) : *q) + 1;
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if (segnum >= retrieval->irb_upper_count)
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if (segnum > retrieval->irb_upper_count)
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return false;
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if (segnum == retrieval->irb_upper_count && !descending)
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return false;
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}
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if (*p == *q)
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upperPrefix++;
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if (++byteInSegment > STUFF_COUNT)
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byteInSegment = 0;
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}
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if (p >= end_key)
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{
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if (flag)
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{
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if (partialEquality)
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// Check if current node bytes is from the same segment as
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// last byte of the key. If not, we have equality at that
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// segment. Else, for ascending index, node is greater than
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// the key and scan should be stopped.
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// For descending index, the node is less than the key and
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// scan shoud be continued.
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if ((flag & irb_partial) && !(flag & irb_starting))
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{
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// node have no more data, it is equality
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if (q >= node.data + node.length)
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break;
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if ((p - STUFF_COUNT > key->key_data) && (p[-(STUFF_COUNT + 1)] == *q))
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{
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if (descending)
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break;
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// node contains more bytes than a key, check numbers
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// of last key segment and current node segment.
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fb_assert(!descending);
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fb_assert(p - STUFF_COUNT - 1 >= key->key_data);
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const USHORT keySeg = idx->idx_count - p[-STUFF_COUNT - 1];
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const USHORT nodeSeg = idx->idx_count - *q;
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fb_assert(keySeg <= nodeSeg);
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// If current segment at node is the same as last segment
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// of the key then node > key.
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if (keySeg == nodeSeg)
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return false;
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}
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// If node segment belongs to the key segments then key contains
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// null or empty string and node contains some data.
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if (nodeSeg < retrieval->irb_upper_count)
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return false;
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if (equality)
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{
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const USHORT nodeSeg = idx->idx_count - (UCHAR) (descending ? ((*q) ^ -1) : *q);
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// If node segment belongs to the key segments then key contains
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// null or empty string and node contains some data.
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if (nodeSeg < retrieval->irb_upper_count)
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return false;
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}
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}
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break;
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}
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@ -37,7 +37,7 @@ bool BTR_description(Jrd::thread_db*, Jrd::jrd_rel*, Ods::index_root_page*, Jrd:
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bool BTR_check_condition(Jrd::thread_db*, Jrd::index_desc*, Jrd::Record*);
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DSC* BTR_eval_expression(Jrd::thread_db*, Jrd::index_desc*, Jrd::Record*, bool&);
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void BTR_evaluate(Jrd::thread_db*, const Jrd::IndexRetrieval*, Jrd::RecordBitmap**, Jrd::RecordBitmap*);
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UCHAR* BTR_find_leaf(Ods::btree_page*, Jrd::temporary_key*, UCHAR*, USHORT*, bool, bool);
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UCHAR* BTR_find_leaf(Ods::btree_page*, Jrd::temporary_key*, UCHAR*, USHORT*, bool, int);
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Ods::btree_page* BTR_find_page(Jrd::thread_db*, const Jrd::IndexRetrieval*, Jrd::win*, Jrd::index_desc*,
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Jrd::temporary_key*, Jrd::temporary_key*, bool = true);
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void BTR_insert(Jrd::thread_db*, Jrd::win*, Jrd::index_insertion*);
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