Newer JVMs are faster. Upgrading to the latest version of your JVM can provide a "free" boost to performance. On the Windows platform, switching from the default Client JVM to the Server JVM using the <code>-server</code> command-line option improves performance at the cost of a slight increase in start-up time.
Newer JVMs are faster. Upgrading to the latest version of your JVM can provide a "free" boost to performance. Switching from the default Client JVM to the Server JVM using the <code>-server</code> command-line option improves performance at the cost of a slight increase in start-up time.
@performance_1404_h3
@performance_1404_h3
Virus Scanners
Virus Scanners
@performance_1405_p
@performance_1405_p
Some virus scanners scan files every time they are accessed. It is very important for performance that database files are not scanned for viruses. The database engine does never interprets the data stored in the files as programs, that means even if somebody would store a virus in a database file, this would be harmless (when the virus does not run, it cannot spread). Some virus scanners allow to exclude files by suffix. Make sure files ending with .db are not scanned.
Some virus scanners scan files every time they are accessed. It is very important for performance that database files are not scanned for viruses. The database engine does never interpret the data stored in the files as programs, that means even if somebody would store a virus in a database file, this would be harmless (when the virus does not run, it cannot spread). Some virus scanners allow to exclude files by suffix. Ensure files ending with .db are not scanned.
@performance_1406_h3
@performance_1406_h3
Using the Trace Options
Using the Trace Options
@performance_1407_p
@performance_1407_p
If the main performance hot spots are in the database engine, in many cases the performance can be optimized by creating additional indexes, or changing the schema. Sometimes the application does not directly generate the SQL statements, for example if an O/R mapping tool is used. To view the SQL statements and JDBC API calls, you can use the trace options. For more information, see <a href="features.html#trace_options">Using the Trace Options</a> .
If the performance hot spots are in the database engine, in many cases the performance can be optimized by creating additional indexes, or changing the schema. Sometimes the application does not directly generate the SQL statements, for example if an O/R mapping tool is used. To view the SQL statements and JDBC API calls, you can use the trace options. For more information, see <a href="features.html#trace_options">Using the Trace Options</a> .
@performance_1408_h3
@performance_1408_h3
Index Usage
Index Usage
...
@@ -8980,13 +8980,16 @@ Add option to enable TCP_NODELAY using Socket.setTcpNoDelay(true).
...
@@ -8980,13 +8980,16 @@ Add option to enable TCP_NODELAY using Socket.setTcpNoDelay(true).
@roadmap_1417_li
@roadmap_1417_li
Maybe disallow = within database names (jdbc:h2:mem:MODE=DB2 means database name MODE=DB2).
Maybe disallow = within database names (jdbc:h2:mem:MODE=DB2 means database name MODE=DB2).
@roadmap_1418_h2
@roadmap_1418_li
Fast alter table add column.
@roadmap_1419_h2
Not Planned
Not Planned
@roadmap_1419_li
@roadmap_1420_li
HSQLDB (did) support this: select id i from test where i<0 (other databases don't). Supporting it may break compatibility.
HSQLDB (did) support this: select id i from test where i<0 (other databases don't). Supporting it may break compatibility.
@roadmap_1420_li
@roadmap_1421_li
String.intern (so that Strings can be compared with ==) will not be used because some VMs have problems when used extensively.
String.intern (so that Strings can be compared with ==) will not be used because some VMs have problems when used extensively.
#Newer JVMs are faster. Upgrading to the latest version of your JVM can provide a "free" boost to performance. On the Windows platform, switching from the default Client JVM to the Server JVM using the <code>-server</code> command-line option improves performance at the cost of a slight increase in start-up time.
#Newer JVMs are faster. Upgrading to the latest version of your JVM can provide a "free" boost to performance. Switching from the default Client JVM to the Server JVM using the <code>-server</code> command-line option improves performance at the cost of a slight increase in start-up time.
@performance_1404_h3
@performance_1404_h3
#Virus Scanners
#Virus Scanners
@performance_1405_p
@performance_1405_p
#Some virus scanners scan files every time they are accessed. It is very important for performance that database files are not scanned for viruses. The database engine does never interprets the data stored in the files as programs, that means even if somebody would store a virus in a database file, this would be harmless (when the virus does not run, it cannot spread). Some virus scanners allow to exclude files by suffix. Make sure files ending with .db are not scanned.
#Some virus scanners scan files every time they are accessed. It is very important for performance that database files are not scanned for viruses. The database engine does never interpret the data stored in the files as programs, that means even if somebody would store a virus in a database file, this would be harmless (when the virus does not run, it cannot spread). Some virus scanners allow to exclude files by suffix. Ensure files ending with .db are not scanned.
@performance_1406_h3
@performance_1406_h3
トレースオプションを使用する
トレースオプションを使用する
@performance_1407_p
@performance_1407_p
#If the main performance hot spots are in the database engine, in many cases the performance can be optimized by creating additional indexes, or changing the schema. Sometimes the application does not directly generate the SQL statements, for example if an O/R mapping tool is used. To view the SQL statements and JDBC API calls, you can use the trace options. For more information, see <a href="features.html#trace_options">Using the Trace Options</a> .
#If the performance hot spots are in the database engine, in many cases the performance can be optimized by creating additional indexes, or changing the schema. Sometimes the application does not directly generate the SQL statements, for example if an O/R mapping tool is used. To view the SQL statements and JDBC API calls, you can use the trace options. For more information, see <a href="features.html#trace_options">Using the Trace Options</a> .
@performance_1408_h3
@performance_1408_h3
#Index Usage
#Index Usage
...
@@ -8980,13 +8980,16 @@ SQLコマンドがコマンドエリアに表示されます。
...
@@ -8980,13 +8980,16 @@ SQLコマンドがコマンドエリアに表示されます。
@roadmap_1417_li
@roadmap_1417_li
#Maybe disallow = within database names (jdbc:h2:mem:MODE=DB2 means database name MODE=DB2).
#Maybe disallow = within database names (jdbc:h2:mem:MODE=DB2 means database name MODE=DB2).
@roadmap_1418_h2
@roadmap_1418_li
#Fast alter table add column.
@roadmap_1419_h2
#Not Planned
#Not Planned
@roadmap_1419_li
@roadmap_1420_li
#HSQLDB (did) support this: select id i from test where i<0 (other databases don't). Supporting it may break compatibility.
#HSQLDB (did) support this: select id i from test where i<0 (other databases don't). Supporting it may break compatibility.
@roadmap_1420_li
@roadmap_1421_li
#String.intern (so that Strings can be compared with ==) will not be used because some VMs have problems when used extensively.
#String.intern (so that Strings can be compared with ==) will not be used because some VMs have problems when used extensively.
@@ -2500,11 +2500,11 @@ performance_1399_p=Now convert the .trace.db file using the ConvertTraceFile too
...
@@ -2500,11 +2500,11 @@ performance_1399_p=Now convert the .trace.db file using the ConvertTraceFile too
performance_1400_p=The generated file <code>test.sql</code> will contain the SQL statements as well as the following profiling data (results vary)\:
performance_1400_p=The generated file <code>test.sql</code> will contain the SQL statements as well as the following profiling data (results vary)\:
performance_1401_h2=Database Performance Tuning
performance_1401_h2=Database Performance Tuning
performance_1402_h3=Use a Modern JVM
performance_1402_h3=Use a Modern JVM
performance_1403_p=Newer JVMs are faster. Upgrading to the latest version of your JVM can provide a "free" boost to performance. On the Windows platform, switching from the default Client JVM to the Server JVM using the <code>-server</code> command-line option improves performance at the cost of a slight increase in start-up time.
performance_1403_p=Newer JVMs are faster. Upgrading to the latest version of your JVM can provide a "free" boost to performance. Switching from the default Client JVM to the Server JVM using the <code>-server</code> command-line option improves performance at the cost of a slight increase in start-up time.
performance_1404_h3=Virus Scanners
performance_1404_h3=Virus Scanners
performance_1405_p=Some virus scanners scan files every time they are accessed. It is very important for performance that database files are not scanned for viruses. The database engine does never interprets the data stored in the files as programs, that means even if somebody would store a virus in a database file, this would be harmless (when the virus does not run, it cannot spread). Some virus scanners allow to exclude files by suffix. Make sure files ending with .db are not scanned.
performance_1405_p=Some virus scanners scan files every time they are accessed. It is very important for performance that database files are not scanned for viruses. The database engine does never interpret the data stored in the files as programs, that means even if somebody would store a virus in a database file, this would be harmless (when the virus does not run, it cannot spread). Some virus scanners allow to exclude files by suffix. Ensure files ending with .db are not scanned.
performance_1406_h3=Using the Trace Options
performance_1406_h3=Using the Trace Options
performance_1407_p=If the main performance hot spots are in the database engine, in many cases the performance can be optimized by creating additional indexes, or changing the schema. Sometimes the application does not directly generate the SQL statements, for example if an O/R mapping tool is used. To view the SQL statements and JDBC API calls, you can use the trace options. For more information, see <a href\="features.html\#trace_options">Using the Trace Options</a> .
performance_1407_p=If the performance hot spots are in the database engine, in many cases the performance can be optimized by creating additional indexes, or changing the schema. Sometimes the application does not directly generate the SQL statements, for example if an O/R mapping tool is used. To view the SQL statements and JDBC API calls, you can use the trace options. For more information, see <a href\="features.html\#trace_options">Using the Trace Options</a> .
performance_1408_h3=Index Usage
performance_1408_h3=Index Usage
performance_1409_p=This database uses indexes to improve the performance of SELECT, UPDATE and DELETE statements. If a column is used in the WHERE clause of a query, and if an index exists on this column, then the index can be used. Multi-column indexes are used if all or the first columns of the index are used. Both equality lookup and range scans are supported. Indexes are used to order result sets, but only if the condition uses the same index or no index at all. The results are sorted in memory if required. Indexes are created automatically for primary key and unique constraints. Indexes are also created for foreign key constraints, if required. For other columns, indexes need to be created manually using the CREATE INDEX statement.
performance_1409_p=This database uses indexes to improve the performance of SELECT, UPDATE and DELETE statements. If a column is used in the WHERE clause of a query, and if an index exists on this column, then the index can be used. Multi-column indexes are used if all or the first columns of the index are used. Both equality lookup and range scans are supported. Indexes are used to order result sets, but only if the condition uses the same index or no index at all. The results are sorted in memory if required. Indexes are created automatically for primary key and unique constraints. Indexes are also created for foreign key constraints, if required. For other columns, indexes need to be created manually using the CREATE INDEX statement.
performance_1410_h3=Optimizer
performance_1410_h3=Optimizer
...
@@ -2990,9 +2990,10 @@ roadmap_1414_li=Issue 107\: Prefer using the ORDER BY index if LIMIT is used.
...
@@ -2990,9 +2990,10 @@ roadmap_1414_li=Issue 107\: Prefer using the ORDER BY index if LIMIT is used.
roadmap_1415_li=Support reading sequences using DatabaseMetaData.getTables(null, null, null, new String[]{"SEQUENCE"}). See PostgreSQL.
roadmap_1415_li=Support reading sequences using DatabaseMetaData.getTables(null, null, null, new String[]{"SEQUENCE"}). See PostgreSQL.
roadmap_1416_li=Add option to enable TCP_NODELAY using Socket.setTcpNoDelay(true).
roadmap_1416_li=Add option to enable TCP_NODELAY using Socket.setTcpNoDelay(true).
roadmap_1417_li=Maybe disallow \=within database names (jdbc\:h2\:mem\:MODE\=DB2 means database name MODE\=DB2).
roadmap_1417_li=Maybe disallow \=within database names (jdbc\:h2\:mem\:MODE\=DB2 means database name MODE\=DB2).
roadmap_1418_h2=Not Planned
roadmap_1418_li=Fast alter table add column.
roadmap_1419_li=HSQLDB (did) support this\:select id i from test where i<0 (other databases don't). Supporting it may break compatibility.
roadmap_1419_h2=Not Planned
roadmap_1420_li=String.intern (so that Strings can be compared with \=\=) will not be used because some VMs have problems when used extensively.
roadmap_1420_li=HSQLDB (did) support this\:select id i from test where i<0 (other databases don't). Supporting it may break compatibility.
roadmap_1421_li=String.intern (so that Strings can be compared with \=\=) will not be used because some VMs have problems when used extensively.