Tony Brusseau created DERBY-6093:
------------------------------------
Summary: dramatically worse query plan for prepared stamement vs
calling directly
Key: DERBY-6093
URL: https://issues.apache.org/jira/browse/DERBY-6093
Project: Derby
Issue Type: Bug
Components: Store
Affects Versions: 10.9.1.0
Environment: Linux
Reporter: Tony Brusseau
If I run a count query given all the parameters directly, then the query
executes in .05s, however, if I send it across as a prepared statement, then
the query takes 40s to run (because is does a complete table scan on a table
with 15m rows).
The query looks like:
SELECT COUNT(*)
FROM KB.FORMULA_ENTRIES fe1, KB.FORMULA_ENTRIES fe2
WHERE
(fe1.arg_0_term = 1407374883620920) AND (fe1.arg_num = 1) AND (fe1.arg_term =
1407374883574780) AND (fe1.formula_type = 0)
AND (fe1.formula_id = fe2.formula_id) AND (fe2.arg_0_term = 1407374883620920)
AND (fe2.arg_num = 2) AND (fe2.arg_term = 1407374883663337) AND
(fe2.formula_type = 0)
or the prepared version like:
SELECT COUNT(*)
FROM KB.FORMULA_ENTRIES fe1
, KB.FORMULA_ENTRIES fe2
WHERE
(fe1.arg_0_term = ?) AND (fe1.arg_num = ?) AND (fe1.arg_term = ?) AND
(fe1.formula_type = ?)
AND (fe1.formula_id = fe2.formula_id) AND (fe2.arg_0_term = ?) AND (fe2.arg_num
= ?) AND (fe2.arg_term = ?) AND (fe2.formula_type = ?)
The table is defined as:
DROP TABLE KB.FORMULA_ENTRIES;
CREATE TABLE KB.FORMULA_ENTRIES
(
formula_entries_id BIGINT NOT NULL,)
formula_id BIGINT NOT NULL,
arg_0_term BIGINT NOT NULL,
arg_term BIGINT NOT NULL,
arg_num INTEGER NOT NULL,
formula_type SMALLINT NOT NULL
);
ALTER TABLE kb.formula_entries ADD CONSTRAINT kb_formula_entries_pk PRIMARY KEY
(formula_entries_id);
ALTER TABLE kb.formula_entries ADD CONSTRAINT kb_fomula_entries_formula_id_fk
FOREIGN KEY (formula_id) REFERENCES kb.formula_term (term_id) ON DELETE
CASCADE;
CREATE INDEX kb_formula_entries_formula_term_type ON kb.formula_entries
(arg_term, formula_type);
CREATE INDEX kb_formula_entries_formula_term_arg0_type ON kb.formula_entries
(arg_term, arg_0_term, formula_type);
CREATE INDEX kb_formula_entries_formula_term_num_type ON kb.formula_entries
(arg_term, arg_num, formula_type);
CREATE INDEX kb_formula_entries_formula_term_arg0_num_type ON
kb.formula_entries (arg_term, arg_0_term, arg_num, formula_type);
The good query plan looks (when *not* sent as a prepared statements) looks like:
Tue Feb 26 16:15:21 CST 2013 Thread[DRDAConnThread_5,5,main] (XID = 40971291),
(SESSIONID = 7), SELECT COUNT(*)
FROM KB.FORMULA_ENTRIES fe1, KB.FORMULA_ENTRIES fe2
WHERE
(fe1.arg_0_term = 1407374883620920) AND (fe1.arg_num = 1) AND (fe1.arg_term =
1407374883574780) AND (fe1.formula_type = 0)
AND (fe1.formula_id = fe2.formula_id) AND (fe2.arg_0_term = 1407374883620920)
AND (fe2.arg_num = 2) AND (fe2.arg_term = 1407374883663337) AND
(fe2.formula_type = 0) ******* Project-Restrict ResultSet (10):
Number of opens = 1
Rows seen = 1
Rows filtered = 0
restriction = false
projection = true
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
restriction time (milliseconds) = 0
projection time (milliseconds) = 0
optimizer estimated row count: 1.00
optimizer estimated cost: 7184.99
Source result set:
Scalar Aggregate ResultSet:
Number of opens = 1
Rows input = 3863
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 7184.99
Index Key Optimization = false
Source result set:
Project-Restrict ResultSet (9):
Number of opens = 1
Rows seen = 3863
Rows filtered = 0
restriction = false
projection = true
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
restriction time (milliseconds) = 0
projection time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 7184.99
Source result set:
Nested Loop Join ResultSet:
Number of opens = 1
Rows seen from the left = 3863
Rows seen from the right = 3863
Rows filtered = 0
Rows returned = 3863
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 7184.99
Left result set:
Project-Restrict ResultSet (5):
Number of opens = 1
Rows seen = 3865
Rows filtered = 2
restriction = true
projection = true
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
restriction time (milliseconds) = 0
projection time (milliseconds) = 0
optimizer estimated row count: 35.89
optimizer estimated cost: 6785.98
Source result set:
Index Row to Base Row ResultSet for
FORMULA_ENTRIES:
Number of opens = 1
Rows seen = 3865
Columns accessed from heap = {1, 2, 3,
4, 5}
constructor time (milliseconds)
= 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count:
35.89
optimizer estimated cost:
6785.98
Index Scan ResultSet for
FORMULA_ENTRIES using index KB_FORMULA_ENTRIES_FORMULA_TERM_TYPE at read
committed isolation level using instantaneous share row locking chosen by the
optimizer
Number of opens = 1
Rows seen = 3865
Rows filtered = 0
Fetch Size = 16
constructor time
(milliseconds) = 0
open time
(milliseconds) = 0
next time
(milliseconds) = 0
close time
(milliseconds) = 0
next time in
milliseconds/row = 0
scan information:
Bit set of columns
fetched=All
Number of columns
fetched=3
Number of deleted rows
visited=0
Number of pages
visited=7
Number of rows
qualified=3865
Number of rows
visited=3866
Scan type=btree
Tree height=3
start position:
>= on first 2
column(s).
Ordered null
semantics on the following columns:
0 1
stop position:
> on first 2
column(s).
Ordered null
semantics on the following columns:
0 1
qualifiers:
None
optimizer estimated row
count: 35.89
optimizer estimated
cost: 6785.98
Right result set:
Project-Restrict ResultSet (8):
Number of opens = 3863
Rows seen = 15452
Rows filtered = 11589
restriction = true
projection = true
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
restriction time (milliseconds) = 0
projection time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 399.01
Source result set:
Index Row to Base Row ResultSet for
FORMULA_ENTRIES:
Number of opens = 3863
Rows seen = 15452
Columns accessed from heap = {1, 2, 3,
4, 5}
constructor time (milliseconds)
= 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count:
0.00
optimizer estimated cost: 399.01
Index Scan ResultSet for
FORMULA_ENTRIES using constraint KB_FOMULA_ENTRIES_FORMULA_ID_FK at read
committed isolation level using instantaneous share row locking chosen by the
optimizer
Number of opens = 3863
Rows seen = 15452
Rows filtered = 0
Fetch Size = 16
constructor time
(milliseconds) = 0
open time
(milliseconds) = 0
next time
(milliseconds) = 0
close time
(milliseconds) = 0
next time in
milliseconds/row = 0
scan information:
Bit set of columns
fetched=All
Number of columns
fetched=2
Number of deleted rows
visited=0
Number of pages
visited=11606
Number of rows
qualified=15452
Number of rows
visited=19315
Scan type=btree
Tree height=3
start position:
>= on first 1
column(s).
Ordered null
semantics on the following columns:
0
stop position:
> on first 1
column(s).
Ordered null
semantics on the following columns:
0
qualifiers:
None
optimizer estimated row
count: 0.00
optimizer estimated
cost: 399.01
The bad query plan looks (when sent as a prepared statements) looks like:
Tue Feb 26 16:09:35 CST 2013 Thread[DRDAConnThread_4,5,main] (XID = 40971265),
(SESSIONID = 5), SELECT COUNT(*)
FROM KB.FORMULA_ENTRIES fe1
, KB.FORMULA_ENTRIES fe2
WHERE
(fe1.arg_0_term = ?) AND (fe1.arg_num = ?) AND (fe1.arg_term = ?) AND
(fe1.formula_type = ?)
AND (fe1.formula_id = fe2.formula_id) AND (fe2.arg_0_term = ?) AND (fe2.arg_num
= ?) AND (fe2.arg_term = ?) AND (fe2.formula_type = ?) ******* Project-Restrict
ResultSet (9):
Number of opens = 1
Rows seen = 1
Rows filtered = 0
restriction = false
projection = true
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
restriction time (milliseconds) = 0
projection time (milliseconds) = 0
optimizer estimated row count: 1.00
optimizer estimated cost: 43.36
Source result set:
Scalar Aggregate ResultSet:
Number of opens = 1
Rows input = 3863
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 43.36
Index Key Optimization = false
Source result set:
Project-Restrict ResultSet (8):
Number of opens = 1
Rows seen = 3863
Rows filtered = 0
restriction = false
projection = true
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
restriction time (milliseconds) = 0
projection time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 43.36
Source result set:
Nested Loop Join ResultSet:
Number of opens = 1
Rows seen from the left = 3863
Rows seen from the right = 3863
Rows filtered = 0
Rows returned = 3863
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 43.36
Left result set:
Index Row to Base Row ResultSet for
FORMULA_ENTRIES:
Number of opens = 1
Rows seen = 3863
Columns accessed from heap = {1, 2, 3, 4, 5}
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count: 2.98
optimizer estimated cost: 10.89
Index Scan ResultSet for
FORMULA_ENTRIES using index KB_FORMULA_ENTRIES_FORMULA_TERM_ARG0_NUM_TYPE at
read committed isolation level using instantaneous share row locking chosen by
the optimizer
Number of opens = 1
Rows seen = 3863
Rows filtered = 0
Fetch Size = 16
constructor time (milliseconds)
= 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
next time in milliseconds/row = 0
scan information:
Bit set of columns fetched=All
Number of columns fetched=5
Number of deleted rows visited=0
Number of pages visited=8
Number of rows qualified=3863
Number of rows visited=3864
Scan type=btree
Tree height=3
start position:
>= on first 4 column(s).
Ordered null semantics
on the following columns:
stop position:
> on first 4 column(s).
Ordered null semantics
on the following columns:
qualifiers:
None
optimizer estimated row count:
2.98
optimizer estimated cost: 10.89
Right result set:
Project-Restrict ResultSet (7):
Number of opens = 3863
Rows seen = 14922769
Rows filtered = 14918906
restriction = true
projection = true
constructor time (milliseconds) = 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
restriction time (milliseconds) = 0
projection time (milliseconds) = 0
optimizer estimated row count: 0.00
optimizer estimated cost: 32.47
Source result set:
Index Row to Base Row ResultSet for
FORMULA_ENTRIES:
Number of opens = 3863
Rows seen = 14922769
Columns accessed from heap = {1, 2, 3,
4, 5}
constructor time (milliseconds)
= 0
open time (milliseconds) = 0
next time (milliseconds) = 0
close time (milliseconds) = 0
optimizer estimated row count:
0.00
optimizer estimated cost: 32.47
Index Scan ResultSet for
FORMULA_ENTRIES using index KB_FORMULA_ENTRIES_FORMULA_TERM_ARG0_NUM_TYPE at
read committed isolation level using instantaneous share row locking chosen by
the optimizer
Number of opens = 3863
Rows seen = 14922769
Rows filtered = 0
Fetch Size = 16
constructor time
(milliseconds) = 0
open time
(milliseconds) = 0
next time
(milliseconds) = 0
close time
(milliseconds) = 0
next time in
milliseconds/row = 0
scan information:
Bit set of columns
fetched=All
Number of columns
fetched=5
Number of deleted rows
visited=0
Number of pages
visited=34767
Number of rows
qualified=14922769
Number of rows
visited=14926632
Scan type=btree
Tree height=3
start position:
>= on first 4
column(s).
Ordered null
semantics on the following columns:
stop position:
> on first 4
column(s).
Ordered null
semantics on the following columns:
qualifiers:
None
optimizer estimated row
count: 0.00
optimizer estimated
cost: 32.47
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