268 lines
8.5 KiB
Plaintext
268 lines
8.5 KiB
Plaintext
# 2009 March 04
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#
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# The author disclaims copyright to this source code. In place of
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# a legal notice, here is a blessing:
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#
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# May you do good and not evil.
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# May you find forgiveness for yourself and forgive others.
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# May you share freely, never taking more than you give.
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#
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#***********************************************************************
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#
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# $Id: notify2.test,v 1.7 2009/03/30 11:59:31 drh Exp $
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set testdir [file dirname $argv0]
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source $testdir/tester.tcl
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if {[run_thread_tests]==0} { finish_test ; return }
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ifcapable !unlock_notify||!shared_cache { finish_test ; return }
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# The tests in this file test the sqlite3_blocking_step() function in
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# test_thread.c. sqlite3_blocking_step() is not an SQLite API function,
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# it is just a demonstration of how the sqlite3_unlock_notify() function
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# can be used to synchronize multi-threaded access to SQLite databases
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# in shared-cache mode.
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#
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# Since the implementation of sqlite3_blocking_step() is included on the
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# website as example code, it is important to test that it works.
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#
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# notify2-1.*:
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#
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# This test uses $nThread threads. Each thread opens the main database
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# and attaches two other databases. Each database contains a single table.
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#
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# Each thread repeats transactions over and over for 20 seconds. Each
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# transaction consists of 3 operations. Each operation is either a read
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# or a write of one of the tables. The read operations verify an invariant
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# to make sure that things are working as expected. If an SQLITE_LOCKED
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# error is returned the current transaction is rolled back immediately.
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#
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# This exercise is repeated twice, once using sqlite3_step(), and the
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# other using sqlite3_blocking_step(). The results are compared to ensure
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# that sqlite3_blocking_step() resulted in higher transaction throughput.
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#
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db close
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set ::enable_shared_cache [sqlite3_enable_shared_cache 1]
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# Number of threads to run simultaneously.
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#
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set nThread 6
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set nSecond 5
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# The Tcl script executed by each of the $nThread threads used by this test.
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#
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set ThreadProgram {
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# Proc used by threads to execute SQL.
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#
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proc execsql_blocking {db zSql} {
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set lRes [list]
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set rc SQLITE_OK
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set sql $zSql
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while {$rc=="SQLITE_OK" && $zSql ne ""} {
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set STMT [$::xPrepare $db $zSql -1 zSql]
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while {[set rc [$::xStep $STMT]] eq "SQLITE_ROW"} {
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for {set i 0} {$i < [sqlite3_column_count $STMT]} {incr i} {
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lappend lRes [sqlite3_column_text $STMT 0]
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}
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}
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set rc [sqlite3_finalize $STMT]
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}
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if {$rc != "SQLITE_OK"} { error "$rc $sql [sqlite3_errmsg $db]" }
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return $lRes
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}
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proc execsql_retry {db sql} {
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set msg "SQLITE_LOCKED blah..."
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while { [string match SQLITE_LOCKED* $msg] } {
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catch { execsql_blocking $db $sql } msg
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}
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}
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proc select_one {args} {
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set n [llength $args]
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lindex $args [expr int($n*rand())]
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}
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proc opendb {} {
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# Open a database connection. Attach the two auxillary databases.
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set ::DB [sqlite3_open test.db]
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execsql_retry $::DB { ATTACH 'test2.db' AS aux2; }
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execsql_retry $::DB { ATTACH 'test3.db' AS aux3; }
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}
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opendb
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#after 2000
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# This loop runs for ~20 seconds.
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#
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set iStart [clock_seconds]
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set nOp 0
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set nAttempt 0
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while { ([clock_seconds]-$iStart) < $nSecond } {
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# Each transaction does 3 operations. Each operation is either a read
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# or write of a randomly selected table (t1, t2 or t3). Set the variables
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# $SQL(1), $SQL(2) and $SQL(3) to the SQL commands used to implement
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# each operation.
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#
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for {set ii 1} {$ii <= 3} {incr ii} {
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foreach {tbl database} [select_one {t1 main} {t2 aux2} {t3 aux3}] {}
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set SQL($ii) [string map [list xxx $tbl yyy $database] [select_one {
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SELECT
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(SELECT b FROM xxx WHERE a=(SELECT max(a) FROM xxx))==total(a)
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FROM xxx WHERE a!=(SELECT max(a) FROM xxx);
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} {
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DELETE FROM xxx WHERE a<(SELECT max(a)-100 FROM xxx);
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INSERT INTO xxx SELECT NULL, total(a) FROM xxx;
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} {
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CREATE INDEX IF NOT EXISTS yyy.xxx_i ON xxx(b);
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} {
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DROP INDEX IF EXISTS yyy.xxx_i;
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}
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]]
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}
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# Execute the SQL transaction.
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#
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incr nAttempt
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set rc [catch { execsql_blocking $::DB "
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BEGIN;
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$SQL(1);
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$SQL(2);
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$SQL(3);
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COMMIT;
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"
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} msg]
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if {$rc && [string match "SQLITE_LOCKED*" $msg]
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|| [string match "SQLITE_SCHEMA*" $msg]
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} {
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# Hit an SQLITE_LOCKED error. Rollback the current transaction.
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set rc [catch { execsql_blocking $::DB ROLLBACK } msg]
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if {$rc && [string match "SQLITE_LOCKED*" $msg]} {
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sqlite3_close $::DB
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opendb
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}
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} elseif {$rc} {
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# Hit some other kind of error. This is a malfunction.
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error $msg
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} else {
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# No error occurred. Check that any SELECT statements in the transaction
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# returned "1". Otherwise, the invariant was false, indicating that
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# some malfunction has occurred.
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foreach r $msg { if {$r != 1} { puts "Invariant check failed: $msg" } }
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incr nOp
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}
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}
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# Close the database connection and return 0.
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#
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sqlite3_close $::DB
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list $nOp $nAttempt
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}
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foreach {iTest xStep xPrepare} {
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1 sqlite3_blocking_step sqlite3_blocking_prepare_v2
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2 sqlite3_step sqlite3_nonblocking_prepare_v2
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} {
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forcedelete test.db test2.db test3.db
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set ThreadSetup "set xStep $xStep;set xPrepare $xPrepare;set nSecond $nSecond"
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# Set up the database schema used by this test. Each thread opens file
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# test.db as the main database, then attaches files test2.db and test3.db
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# as auxillary databases. Each file contains a single table (t1, t2 and t3, in
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# files test.db, test2.db and test3.db, respectively).
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#
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do_test notify2-$iTest.1.1 {
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sqlite3 db test.db
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execsql {
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ATTACH 'test2.db' AS aux2;
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ATTACH 'test3.db' AS aux3;
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CREATE TABLE main.t1(a INTEGER PRIMARY KEY, b);
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CREATE TABLE aux2.t2(a INTEGER PRIMARY KEY, b);
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CREATE TABLE aux3.t3(a INTEGER PRIMARY KEY, b);
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INSERT INTO t1 SELECT NULL, 0;
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INSERT INTO t2 SELECT NULL, 0;
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INSERT INTO t3 SELECT NULL, 0;
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}
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} {}
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do_test notify2-$iTest.1.2 {
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db close
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} {}
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# Launch $nThread threads. Then wait for them to finish.
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#
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puts "Running $xStep test for $nSecond seconds"
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unset -nocomplain finished
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for {set ii 0} {$ii < $nThread} {incr ii} {
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thread_spawn finished($ii) $ThreadSetup $ThreadProgram
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}
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for {set ii 0} {$ii < $nThread} {incr ii} {
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do_test notify2-$iTest.2.$ii {
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if {![info exists finished($ii)]} { vwait finished($ii) }
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incr anSuccess($xStep) [lindex $finished($ii) 0]
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incr anAttempt($xStep) [lindex $finished($ii) 1]
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expr 0
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} {0}
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}
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# Count the total number of succesful writes.
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do_test notify2-$iTest.3.1 {
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sqlite3 db test.db
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execsql {
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ATTACH 'test2.db' AS aux2;
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ATTACH 'test3.db' AS aux3;
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}
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set anWrite($xStep) [execsql {
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SELECT (SELECT max(a) FROM t1)
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+ (SELECT max(a) FROM t2)
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+ (SELECT max(a) FROM t3)
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}]
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db close
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} {}
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}
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# The following tests checks to make sure sqlite3_blocking_step() is
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# faster than sqlite3_step(). "Faster" in this case means uses fewer
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# CPU cycles. This is not always the same as faster in wall-clock time
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# for this type of test. The number of CPU cycles per transaction is
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# roughly proportional to the number of attempts made (i.e. one plus the
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# number of SQLITE_BUSY or SQLITE_LOCKED errors that require the transaction
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# to be retried). So this test just measures that a greater percentage of
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# transactions attempted using blocking_step() succeed.
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#
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# The blocking_step() function is almost always faster on multi-core and is
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# usually faster on single-core. But sometimes, by chance, step() will be
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# faster on a single core, in which case the
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# following test will fail.
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#
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puts "The following test seeks to demonstrate that the sqlite3_unlock_notify()"
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puts "interface helps multi-core systems to run more efficiently. This test"
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puts "sometimes fails on single-core machines."
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puts [array get anWrite]
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do_test notify2-3 {
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set blocking [expr {
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double($anSuccess(sqlite3_blocking_step)) /
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double($anAttempt(sqlite3_blocking_step))
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}]
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set non [expr {
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double($anSuccess(sqlite3_step)) /
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double($anAttempt(sqlite3_step))
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}]
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puts -nonewline [format " blocking: %.1f%% non-blocking %.1f%% ..." \
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[expr $blocking*100.0] [expr $non*100.0]]
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expr {$blocking > $non}
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} {1}
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sqlite3_enable_shared_cache $::enable_shared_cache
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finish_test
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