@@ -8078,78 +8078,84 @@ In-memory indexes are automatically used for in-memory databases, but can also b
In-memory hash indexes are backed by a hash table and are usually faster than regular indexes. However, hash indexes only supports direct lookup (<code>WHERE ID = ?</code>) but not range scan (<code>WHERE ID < ?</code>). To use hash indexes, use HASH as in: <code>CREATE UNIQUE HASH INDEX</code> and <code>CREATE TABLE ...(ID INT PRIMARY KEY HASH,...)</code>.
@performance_1429_h3
Optimization Examples
Use Prepared Statements
@performance_1430_p
See <code>src/test/org/h2/samples/optimizations.sql</code> for a few examples of queries that benefit from special optimizations built into the database.
If possible, use prepared statements with parameters. Avoid generating SQL statements with a variable size IN(...) list. Instead, use arrays as in the following example:
@performance_1431_h3
Cache Size and Type
Optimization Examples
@performance_1432_p
By default the cache size of H2 is quite small. Consider using a larger cache size, or enable the second level soft reference cache. See also <a href="features.html#cache_settings">Cache Settings</a>.
See <code>src/test/org/h2/samples/optimizations.sql</code> for a few examples of queries that benefit from special optimizations built into the database.
@performance_1433_h3
Data Types
Cache Size and Type
@performance_1434_p
By default the cache size of H2 is quite small. Consider using a larger cache size, or enable the second level soft reference cache. See also <a href="features.html#cache_settings">Cache Settings</a>.
@performance_1435_h3
Data Types
@performance_1436_p
Each data type has different storage and performance characteristics:
@performance_1435_li
@performance_1437_li
The <code>DECIMAL/NUMERIC</code> type is slower and requires more storage than the <code>REAL</code> and <code>DOUBLE</code> types.
@performance_1436_li
@performance_1438_li
Text types are slower to read, write, and compare than numeric types and generally require more storage.
@performance_1437_li
@performance_1439_li
See <a href="advanced.html#large_objects">Large Objects</a> for information on <code>BINARY</code> vs. <code>BLOB</code> and <code>VARCHAR</code> vs. <code>CLOB</code> performance.
@performance_1438_li
@performance_1440_li
Parsing and formatting takes longer for the <code>TIME</code>, <code>DATE</code>, and <code>TIMESTAMP</code> types than the numeric types.
@performance_1439_code
@performance_1441_code
SMALLINT/TINYINT/BOOLEAN
@performance_1440_li
@performance_1442_li
are not significantly smaller or faster to work with than <code>INTEGER</code> in most modes.
@performance_1441_h3
@performance_1443_h3
Sorted Insert Optimization
@performance_1442_p
@performance_1444_p
To reduce disk space usage and speed up table creation, an optimization for sorted inserts is available. When used, b-tree pages are split at the insertion point. To use this optimization, add <code>SORTED</code> before the <code>SELECT</code> statement:
@performance_1443_h2
@performance_1445_h2
Using the Built-In Profiler
@performance_1444_p
@performance_1446_p
A very simple Java profiler is built-in. To use it, use the following template:
@performance_1445_h2
@performance_1447_h2
Fast Database Import
@performance_1446_p
@performance_1448_p
To speed up large imports, consider using the following options temporarily:
@performance_1447_code
@performance_1449_code
SET CACHE_SIZE
@performance_1448_li
@performance_1450_li
(a large cache is faster)
@performance_1449_code
@performance_1451_code
SET LOCK_MODE 0
@performance_1450_li
@performance_1452_li
(disable locking)
@performance_1451_code
@performance_1453_code
SET UNDO_LOG 0
@performance_1452_li
@performance_1454_li
(disable the session undo log)
@performance_1453_p
@performance_1455_p
These options can be set in the database URL: <code>jdbc:h2:~/test;CACHE_SIZE=65536;LOCK_MODE=0;UNDO_LOG=0</code>. Most of those options are not recommended for regular use, that means you need to reset them after use.
# In-memory hash indexes are backed by a hash table and are usually faster than regular indexes. However, hash indexes only supports direct lookup (<code>WHERE ID = ?</code>) but not range scan (<code>WHERE ID < ?</code>). To use hash indexes, use HASH as in: <code>CREATE UNIQUE HASH INDEX</code> and <code>CREATE TABLE ...(ID INT PRIMARY KEY HASH,...)</code>.
@performance_1429_h3
#Optimization Examples
#Use Prepared Statements
@performance_1430_p
# See <code>src/test/org/h2/samples/optimizations.sql</code> for a few examples of queries that benefit from special optimizations built into the database.
# If possible, use prepared statements with parameters. Avoid generating SQL statements with a variable size IN(...) list. Instead, use arrays as in the following example:
@performance_1431_h3
#Cache Size and Type
#Optimization Examples
@performance_1432_p
# By default the cache size of H2 is quite small. Consider using a larger cache size, or enable the second level soft reference cache. See also <a href="features.html#cache_settings">Cache Settings</a>.
# See <code>src/test/org/h2/samples/optimizations.sql</code> for a few examples of queries that benefit from special optimizations built into the database.
@performance_1433_h3
データ型
#Cache Size and Type #データ型
@performance_1434_p
# By default the cache size of H2 is quite small. Consider using a larger cache size, or enable the second level soft reference cache. See also <a href="features.html#cache_settings">Cache Settings</a>.
@performance_1435_h3
データ型
@performance_1436_p
# Each data type has different storage and performance characteristics:
@performance_1435_li
@performance_1437_li
#The <code>DECIMAL/NUMERIC</code> type is slower and requires more storage than the <code>REAL</code> and <code>DOUBLE</code> types.
@performance_1436_li
@performance_1438_li
#Text types are slower to read, write, and compare than numeric types and generally require more storage.
@performance_1437_li
@performance_1439_li
#See <a href="advanced.html#large_objects">Large Objects</a> for information on <code>BINARY</code> vs. <code>BLOB</code> and <code>VARCHAR</code> vs. <code>CLOB</code> performance.
@performance_1438_li
@performance_1440_li
#Parsing and formatting takes longer for the <code>TIME</code>, <code>DATE</code>, and <code>TIMESTAMP</code> types than the numeric types.
@performance_1439_code
@performance_1441_code
#SMALLINT/TINYINT/BOOLEAN
@performance_1440_li
@performance_1442_li
# are not significantly smaller or faster to work with than <code>INTEGER</code> in most modes.
@performance_1441_h3
@performance_1443_h3
#Sorted Insert Optimization
@performance_1442_p
@performance_1444_p
# To reduce disk space usage and speed up table creation, an optimization for sorted inserts is available. When used, b-tree pages are split at the insertion point. To use this optimization, add <code>SORTED</code> before the <code>SELECT</code> statement:
@performance_1443_h2
@performance_1445_h2
#Using the Built-In Profiler
@performance_1444_p
@performance_1446_p
# A very simple Java profiler is built-in. To use it, use the following template:
@performance_1445_h2
@performance_1447_h2
#Fast Database Import
@performance_1446_p
@performance_1448_p
# To speed up large imports, consider using the following options temporarily:
@performance_1447_code
@performance_1449_code
#SET CACHE_SIZE
@performance_1448_li
@performance_1450_li
# (a large cache is faster)
@performance_1449_code
@performance_1451_code
#SET LOCK_MODE 0
@performance_1450_li
@performance_1452_li
# (disable locking)
@performance_1451_code
@performance_1453_code
#SET UNDO_LOG 0
@performance_1452_li
@performance_1454_li
# (disable the session undo log)
@performance_1453_p
@performance_1455_p
# These options can be set in the database URL: <code>jdbc:h2:~/test;CACHE_SIZE=65536;LOCK_MODE=0;UNDO_LOG=0</code>. Most of those options are not recommended for regular use, that means you need to reset them after use.
performance_1426_p=\ Using in-memory indexes, specially in-memory hash indexes, can speed up queries and data manipulation.
performance_1427_p=In-memory indexes are automatically used for in-memory databases, but can also be created for persistent databases using <code>CREATE MEMORY TABLE</code>. In many cases, the rows itself will also be kept in-memory. Please note this may cause memory problems for large tables.
performance_1428_p=\ In-memory hash indexes are backed by a hash table and are usually faster than regular indexes. However, hash indexes only supports direct lookup (<code>WHERE ID \=?</code>) but not range scan (<code>WHERE ID < ?</code>). To use hash indexes, use HASH as in\:<code>CREATE UNIQUE HASH INDEX</code> and <code>CREATE TABLE ...(ID INT PRIMARY KEY HASH,...)</code>.
performance_1429_h3=Optimization Examples
performance_1430_p=\ See <code>src/test/org/h2/samples/optimizations.sql</code> for a few examples of queries that benefit from special optimizations built into the database.
performance_1431_h3=Cache Size and Type
performance_1432_p=\ By default the cache size of H2 is quite small. Consider using a larger cache size, or enable the second level soft reference cache. See also <a href\="features.html\#cache_settings">Cache Settings</a>.
performance_1433_h3=Data Types
performance_1434_p=\ Each data type has different storage and performance characteristics\:
performance_1435_li=The <code>DECIMAL/NUMERIC</code> type is slower and requires more storage than the <code>REAL</code> and <code>DOUBLE</code> types.
performance_1436_li=Text types are slower to read, write, and compare than numeric types and generally require more storage.
performance_1437_li=See <a href\="advanced.html\#large_objects">Large Objects</a> for information on <code>BINARY</code> vs. <code>BLOB</code> and <code>VARCHAR</code> vs. <code>CLOB</code> performance.
performance_1438_li=Parsing and formatting takes longer for the <code>TIME</code>, <code>DATE</code>, and <code>TIMESTAMP</code> types than the numeric types.
performance_1439_code=SMALLINT/TINYINT/BOOLEAN
performance_1440_li=\ are not significantly smaller or faster to work with than <code>INTEGER</code> in most modes.
performance_1441_h3=Sorted Insert Optimization
performance_1442_p=\ To reduce disk space usage and speed up table creation, an optimization for sorted inserts is available. When used, b-tree pages are split at the insertion point. To use this optimization, add <code>SORTED</code> before the <code>SELECT</code> statement\:
performance_1443_h2=Using the Built-In Profiler
performance_1444_p=\ A very simple Java profiler is built-in. To use it, use the following template\:
performance_1445_h2=Fast Database Import
performance_1446_p=\ To speed up large imports, consider using the following options temporarily\:
performance_1447_code=SET CACHE_SIZE
performance_1448_li=\ (a large cache is faster)
performance_1449_code=SET LOCK_MODE 0
performance_1450_li=\ (disable locking)
performance_1451_code=SET UNDO_LOG 0
performance_1452_li=\ (disable the session undo log)
performance_1453_p=\ These options can be set in the database URL\:<code>jdbc\:h2\:~/test;CACHE_SIZE\=65536;LOCK_MODE\=0;UNDO_LOG\=0</code>. Most of those options are not recommended for regular use, that means you need to reset them after use.
performance_1429_h3=Use Prepared Statements
performance_1430_p=\ If possible, use prepared statements with parameters. Avoid generating SQL statements with a variable size IN(...) list. Instead, use arrays as in the following example\:
performance_1431_h3=Optimization Examples
performance_1432_p=\ See <code>src/test/org/h2/samples/optimizations.sql</code> for a few examples of queries that benefit from special optimizations built into the database.
performance_1433_h3=Cache Size and Type
performance_1434_p=\ By default the cache size of H2 is quite small. Consider using a larger cache size, or enable the second level soft reference cache. See also <a href\="features.html\#cache_settings">Cache Settings</a>.
performance_1435_h3=Data Types
performance_1436_p=\ Each data type has different storage and performance characteristics\:
performance_1437_li=The <code>DECIMAL/NUMERIC</code> type is slower and requires more storage than the <code>REAL</code> and <code>DOUBLE</code> types.
performance_1438_li=Text types are slower to read, write, and compare than numeric types and generally require more storage.
performance_1439_li=See <a href\="advanced.html\#large_objects">Large Objects</a> for information on <code>BINARY</code> vs. <code>BLOB</code> and <code>VARCHAR</code> vs. <code>CLOB</code> performance.
performance_1440_li=Parsing and formatting takes longer for the <code>TIME</code>, <code>DATE</code>, and <code>TIMESTAMP</code> types than the numeric types.
performance_1441_code=SMALLINT/TINYINT/BOOLEAN
performance_1442_li=\ are not significantly smaller or faster to work with than <code>INTEGER</code> in most modes.
performance_1443_h3=Sorted Insert Optimization
performance_1444_p=\ To reduce disk space usage and speed up table creation, an optimization for sorted inserts is available. When used, b-tree pages are split at the insertion point. To use this optimization, add <code>SORTED</code> before the <code>SELECT</code> statement\:
performance_1445_h2=Using the Built-In Profiler
performance_1446_p=\ A very simple Java profiler is built-in. To use it, use the following template\:
performance_1447_h2=Fast Database Import
performance_1448_p=\ To speed up large imports, consider using the following options temporarily\:
performance_1449_code=SET CACHE_SIZE
performance_1450_li=\ (a large cache is faster)
performance_1451_code=SET LOCK_MODE 0
performance_1452_li=\ (disable locking)
performance_1453_code=SET UNDO_LOG 0
performance_1454_li=\ (disable the session undo log)
performance_1455_p=\ These options can be set in the database URL\:<code>jdbc\:h2\:~/test;CACHE_SIZE\=65536;LOCK_MODE\=0;UNDO_LOG\=0</code>. Most of those options are not recommended for regular use, that means you need to reset them after use.
quickstart_1000_h1=Quickstart
quickstart_1001_a=\ Embedding H2 in an Application
