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It describes a speed comparison between +archaic versions of SQLite, MySQL and PostgreSQL. +<p> +The numbers here have become meaningless. This page has been retained only +as an historical artifact. +</b></font> + +<h3>Executive Summary</h3> + +<p>A series of tests were run to measure the relative performance of +SQLite 2.7.6, PostgreSQL 7.1.3, and MySQL 3.23.41. +The following are general +conclusions drawn from these experiments: +</p> + +<ul> +<li><p> + SQLite 2.7.6 is significantly faster (sometimes as much as 10 or + 20 times faster) than the default PostgreSQL 7.1.3 installation + on RedHat 7.2 for most common operations. +</p></li> +<li><p> + SQLite 2.7.6 is often faster (sometimes + more than twice as fast) than MySQL 3.23.41 + for most common operations. +</p></li> +<li><p> + SQLite does not execute CREATE INDEX or DROP TABLE as fast as + the other databases. But this is not seen as a problem because + those are infrequent operations. +</p></li> +<li><p> + SQLite works best if you group multiple operations together into + a single transaction. +</p></li> +</ul> + +<p> +The results presented here come with the following caveats: +</p> + +<ul> +<li><p> + These tests did not attempt to measure multi-user performance or + optimization of complex queries involving multiple joins and subqueries. +</p></li> +<li><p> + These tests are on a relatively small (approximately 14 megabyte) database. + They do not measure how well the database engines scale to larger problems. +</p></li> +</ul> + +<h3>Test Environment</h3> + +<p> +The platform used for these tests is a 1.6GHz Athlon with 1GB or memory +and an IDE disk drive. The operating system is RedHat Linux 7.2 with +a stock kernel. +</p> + +<p> +The PostgreSQL and MySQL servers used were as delivered by default on +RedHat 7.2. (PostgreSQL version 7.1.3 and MySQL version 3.23.41.) +No effort was made to tune these engines. Note in particular +the default MySQL configuration on RedHat 7.2 does not support +transactions. Not having to support transactions gives MySQL a +big speed advantage, but SQLite is still able to hold its own on most +tests. +</p> + +<p> +I am told that the default PostgreSQL configuration in RedHat 7.3 +is unnecessarily conservative (it is designed to +work on a machine with 8MB of RAM) and that PostgreSQL could +be made to run a lot faster with some knowledgeable configuration +tuning. +Matt Sergeant reports that he has tuned his PostgreSQL installation +and rerun the tests shown below. His results show that +PostgreSQL and MySQL run at about the same speed. For Matt's +results, visit +</p> + +<blockquote> +Obsolete URL: http://www.sergeant.org/sqlite_vs_pgsync.html +</blockquote> + +<p> +SQLite was tested in the same configuration that it appears +on the website. It was compiled with -O6 optimization and with +the -DNDEBUG=1 switch which disables the many "assert()" statements +in the SQLite code. The -DNDEBUG=1 compiler option roughly doubles +the speed of SQLite. +</p> + +<p> +All tests are conducted on an otherwise quiescent machine. +A simple Tcl script was used to generate and run all the tests. +A copy of this Tcl script can be found in the SQLite source tree +in the file <b>tools/speedtest.tcl</b>. +</p> + +<p> +The times reported on all tests represent wall-clock time +in seconds. Two separate time values are reported for SQLite. +The first value is for SQLite in its default configuration with +full disk synchronization turned on. With synchronization turned +on, SQLite executes +an <b>fsync()</b> system call (or the equivalent) at key points +to make certain that critical data has +actually been written to the disk drive surface. Synchronization +is necessary to guarantee the integrity of the database if the +operating system crashes or the computer powers down unexpectedly +in the middle of a database update. The second time reported for SQLite is +when synchronization is turned off. With synchronization off, +SQLite is sometimes much faster, but there is a risk that an +operating system crash or an unexpected power failure could +damage the database. Generally speaking, the synchronous SQLite +times are for comparison against PostgreSQL (which is also +synchronous) and the asynchronous SQLite times are for +comparison against the asynchronous MySQL engine. +</p> + +<h3>Test 1: 1000 INSERTs</h3> +<blockquote> +CREATE TABLE t1(a INTEGER, b INTEGER, c VARCHAR(100));<br> +INSERT INTO t1 VALUES(1,13153,'thirteen thousand one hundred fifty three');<br> +INSERT INTO t1 VALUES(2,75560,'seventy five thousand five hundred sixty');<br> +<i>... 995 lines omitted</i><br> +INSERT INTO t1 VALUES(998,66289,'sixty six thousand two hundred eighty nine');<br> +INSERT INTO t1 VALUES(999,24322,'twenty four thousand three hundred twenty two');<br> +INSERT INTO t1 VALUES(1000,94142,'ninety four thousand one hundred forty two');<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 4.373</td></tr> +<tr><td>MySQL:</td><td align="right"> 0.114</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 13.061</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.223</td></tr> +</table> + +<p> +Because it does not have a central server to coordinate access, +SQLite must close and reopen the database file, and thus invalidate +its cache, for each transaction. In this test, each SQL statement +is a separate transaction so the database file must be opened and closed +and the cache must be flushed 1000 times. In spite of this, the asynchronous +version of SQLite is still nearly as fast as MySQL. Notice how much slower +the synchronous version is, however. SQLite calls <b>fsync()</b> after +each synchronous transaction to make sure that all data is safely on +the disk surface before continuing. For most of the 13 seconds in the +synchronous test, SQLite was sitting idle waiting on disk I/O to complete.</p> + + +<h3>Test 2: 25000 INSERTs in a transaction</h3> +<blockquote> +BEGIN;<br> +CREATE TABLE t2(a INTEGER, b INTEGER, c VARCHAR(100));<br> +INSERT INTO t2 VALUES(1,59672,'fifty nine thousand six hundred seventy two');<br> +<i>... 24997 lines omitted</i><br> +INSERT INTO t2 VALUES(24999,89569,'eighty nine thousand five hundred sixty nine');<br> +INSERT INTO t2 VALUES(25000,94666,'ninety four thousand six hundred sixty six');<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 4.900</td></tr> +<tr><td>MySQL:</td><td align="right"> 2.184</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 0.914</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.757</td></tr> +</table> + +<p> +When all the INSERTs are put in a transaction, SQLite no longer has to +close and reopen the database or invalidate its cache between each statement. +It also does not +have to do any fsync()s until the very end. When unshackled in +this way, SQLite is much faster than either PostgreSQL and MySQL. +</p> + +<h3>Test 3: 25000 INSERTs into an indexed table</h3> +<blockquote> +BEGIN;<br> +CREATE TABLE t3(a INTEGER, b INTEGER, c VARCHAR(100));<br> +CREATE INDEX i3 ON t3(c);<br> +<i>... 24998 lines omitted</i><br> +INSERT INTO t3 VALUES(24999,88509,'eighty eight thousand five hundred nine');<br> +INSERT INTO t3 VALUES(25000,84791,'eighty four thousand seven hundred ninety one');<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 8.175</td></tr> +<tr><td>MySQL:</td><td align="right"> 3.197</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 1.555</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 1.402</td></tr> +</table> + +<p> +There were reports that SQLite did not perform as well on an indexed table. +This test was recently added to disprove those rumors. It is true that +SQLite is not as fast at creating new index entries as the other engines +(see Test 6 below) but its overall speed is still better. +</p> + +<h3>Test 4: 100 SELECTs without an index</h3> +<blockquote> +BEGIN;<br> +SELECT count(*), avg(b) FROM t2 WHERE b>=0 AND b<1000;<br> +SELECT count(*), avg(b) FROM t2 WHERE b>=100 AND b<1100;<br> +<i>... 96 lines omitted</i><br> +SELECT count(*), avg(b) FROM t2 WHERE b>=9800 AND b<10800;<br> +SELECT count(*), avg(b) FROM t2 WHERE b>=9900 AND b<10900;<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 3.629</td></tr> +<tr><td>MySQL:</td><td align="right"> 2.760</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 2.494</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 2.526</td></tr> +</table> + + +<p> +This test does 100 queries on a 25000 entry table without an index, +thus requiring a full table scan. Prior versions of SQLite used to +be slower than PostgreSQL and MySQL on this test, but recent performance +enhancements have increased its speed so that it is now the fastest +of the group. +</p> + +<h3>Test 5: 100 SELECTs on a string comparison</h3> +<blockquote> +BEGIN;<br> +SELECT count(*), avg(b) FROM t2 WHERE c LIKE '%one%';<br> +SELECT count(*), avg(b) FROM t2 WHERE c LIKE '%two%';<br> +<i>... 96 lines omitted</i><br> +SELECT count(*), avg(b) FROM t2 WHERE c LIKE '%ninety nine%';<br> +SELECT count(*), avg(b) FROM t2 WHERE c LIKE '%one hundred%';<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 13.409</td></tr> +<tr><td>MySQL:</td><td align="right"> 4.640</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 3.362</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 3.372</td></tr> +</table> + +<p> +This test still does 100 full table scans but it uses +uses string comparisons instead of numerical comparisons. +SQLite is over three times faster than PostgreSQL here and about 30% +faster than MySQL. +</p> + +<h3>Test 6: Creating an index</h3> +<blockquote> +CREATE INDEX i2a ON t2(a);<br>CREATE INDEX i2b ON t2(b); +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 0.381</td></tr> +<tr><td>MySQL:</td><td align="right"> 0.318</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 0.777</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.659</td></tr> +</table> + +<p> +SQLite is slower at creating new indices. This is not a huge problem +(since new indices are not created very often) but it is something that +is being worked on. Hopefully, future versions of SQLite will do better +here. +</p> + +<h3>Test 7: 5000 SELECTs with an index</h3> +<blockquote> +SELECT count(*), avg(b) FROM t2 WHERE b>=0 AND b<100;<br> +SELECT count(*), avg(b) FROM t2 WHERE b>=100 AND b<200;<br> +SELECT count(*), avg(b) FROM t2 WHERE b>=200 AND b<300;<br> +<i>... 4994 lines omitted</i><br> +SELECT count(*), avg(b) FROM t2 WHERE b>=499700 AND b<499800;<br> +SELECT count(*), avg(b) FROM t2 WHERE b>=499800 AND b<499900;<br> +SELECT count(*), avg(b) FROM t2 WHERE b>=499900 AND b<500000;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 4.614</td></tr> +<tr><td>MySQL:</td><td align="right"> 1.270</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 1.121</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 1.162</td></tr> +</table> + +<p> +All three database engines run faster when they have indices to work with. +But SQLite is still the fastest. +</p> + +<h3>Test 8: 1000 UPDATEs without an index</h3> +<blockquote> +BEGIN;<br> +UPDATE t1 SET b=b*2 WHERE a>=0 AND a<10;<br> +UPDATE t1 SET b=b*2 WHERE a>=10 AND a<20;<br> +<i>... 996 lines omitted</i><br> +UPDATE t1 SET b=b*2 WHERE a>=9980 AND a<9990;<br> +UPDATE t1 SET b=b*2 WHERE a>=9990 AND a<10000;<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 1.739</td></tr> +<tr><td>MySQL:</td><td align="right"> 8.410</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 0.637</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.638</td></tr> +</table> + +<p> +For this particular UPDATE test, MySQL is consistently +five or ten times +slower than PostgreSQL and SQLite. I do not know why. MySQL is +normally a very fast engine. Perhaps this problem has been addressed +in later versions of MySQL. +</p> + +<h3>Test 9: 25000 UPDATEs with an index</h3> +<blockquote> +BEGIN;<br> +UPDATE t2 SET b=468026 WHERE a=1;<br> +UPDATE t2 SET b=121928 WHERE a=2;<br> +<i>... 24996 lines omitted</i><br> +UPDATE t2 SET b=35065 WHERE a=24999;<br> +UPDATE t2 SET b=347393 WHERE a=25000;<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 18.797</td></tr> +<tr><td>MySQL:</td><td align="right"> 8.134</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 3.520</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 3.104</td></tr> +</table> + +<p> +As recently as version 2.7.0, SQLite ran at about the same speed as +MySQL on this test. But recent optimizations to SQLite have more +than doubled speed of UPDATEs. +</p> + +<h3>Test 10: 25000 text UPDATEs with an index</h3> +<blockquote> +BEGIN;<br> +UPDATE t2 SET c='one hundred forty eight thousand three hundred eighty two' WHERE a=1;<br> +UPDATE t2 SET c='three hundred sixty six thousand five hundred two' WHERE a=2;<br> +<i>... 24996 lines omitted</i><br> +UPDATE t2 SET c='three hundred eighty three thousand ninety nine' WHERE a=24999;<br> +UPDATE t2 SET c='two hundred fifty six thousand eight hundred thirty' WHERE a=25000;<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 48.133</td></tr> +<tr><td>MySQL:</td><td align="right"> 6.982</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 2.408</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 1.725</td></tr> +</table> + +<p> +Here again, version 2.7.0 of SQLite used to run at about the same speed +as MySQL. But now version 2.7.6 is over two times faster than MySQL and +over twenty times faster than PostgreSQL. +</p> + +<p> +In fairness to PostgreSQL, it started thrashing on this test. A +knowledgeable administrator might be able to get PostgreSQL to run a lot +faster here by tweaking and tuning the server a little. +</p> + +<h3>Test 11: INSERTs from a SELECT</h3> +<blockquote> +BEGIN;<br>INSERT INTO t1 SELECT b,a,c FROM t2;<br>INSERT INTO t2 SELECT b,a,c FROM t1;<br>COMMIT; +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 61.364</td></tr> +<tr><td>MySQL:</td><td align="right"> 1.537</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 2.787</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 1.599</td></tr> +</table> + +<p> +The asynchronous SQLite is just a shade slower than MySQL on this test. +(MySQL seems to be especially adept at INSERT...SELECT statements.) +The PostgreSQL engine is still thrashing - most of the 61 seconds it used +were spent waiting on disk I/O. +</p> + +<h3>Test 12: DELETE without an index</h3> +<blockquote> +DELETE FROM t2 WHERE c LIKE '%fifty%'; +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 1.509</td></tr> +<tr><td>MySQL:</td><td align="right"> 0.975</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 4.004</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.560</td></tr> +</table> + +<p> +The synchronous version of SQLite is the slowest of the group in this test, +but the asynchronous version is the fastest. +The difference is the extra time needed to execute fsync(). +</p> + +<h3>Test 13: DELETE with an index</h3> +<blockquote> +DELETE FROM t2 WHERE a>10 AND a<20000; +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 1.316</td></tr> +<tr><td>MySQL:</td><td align="right"> 2.262</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 2.068</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.752</td></tr> +</table> + +<p> +This test is significant because it is one of the few where +PostgreSQL is faster than MySQL. The asynchronous SQLite is, +however, faster then both the other two. +</p> + +<h3>Test 14: A big INSERT after a big DELETE</h3> +<blockquote> +INSERT INTO t2 SELECT * FROM t1; +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 13.168</td></tr> +<tr><td>MySQL:</td><td align="right"> 1.815</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 3.210</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 1.485</td></tr> +</table> + +<p> +Some older versions of SQLite (prior to version 2.4.0) +would show decreasing performance after a +sequence of DELETEs followed by new INSERTs. As this test shows, the +problem has now been resolved. +</p> + +<h3>Test 15: A big DELETE followed by many small INSERTs</h3> +<blockquote> +BEGIN;<br> +DELETE FROM t1;<br> +INSERT INTO t1 VALUES(1,10719,'ten thousand seven hundred nineteen');<br> +<i>... 11997 lines omitted</i><br> +INSERT INTO t1 VALUES(11999,72836,'seventy two thousand eight hundred thirty six');<br> +INSERT INTO t1 VALUES(12000,64231,'sixty four thousand two hundred thirty one');<br> +COMMIT;<br> + +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 4.556</td></tr> +<tr><td>MySQL:</td><td align="right"> 1.704</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 0.618</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.406</td></tr> +</table> + +<p> +SQLite is very good at doing INSERTs within a transaction, which probably +explains why it is so much faster than the other databases at this test. +</p> + +<h3>Test 16: DROP TABLE</h3> +<blockquote> +DROP TABLE t1;<br>DROP TABLE t2;<br>DROP TABLE t3; +</blockquote><table border=0 cellpadding=0 cellspacing=0> +<tr><td>PostgreSQL:</td><td align="right"> 0.135</td></tr> +<tr><td>MySQL:</td><td align="right"> 0.015</td></tr> +<tr><td>SQLite 2.7.6:</td><td align="right"> 0.939</td></tr> +<tr><td>SQLite 2.7.6 (nosync):</td><td align="right"> 0.254</td></tr> +</table> + +<p> +SQLite is slower than the other databases when it comes to dropping tables. +This probably is because when SQLite drops a table, it has to go through and +erase the records in the database file that deal with that table. MySQL and +PostgreSQL, on the other hand, use separate files to represent each table +so they can drop a table simply by deleting a file, which is much faster. +</p> + +<p> +On the other hand, dropping tables is not a very common operation +so if SQLite takes a little longer, that is not seen as a big problem. +</p> +<p align="center"><small><i>This page last modified on <a href="https://sqlite.org/docsrc/honeypot" id="mtimelink" data-href="https://sqlite.org/docsrc/finfo/pages/speed.in?m=5496b6bdd5">2023-01-02 14:22:42</a> UTC </small></i></p> + |