sysproperties.java

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    /**
     * System property <code>h2.objectCacheMaxPerElementSize</code> (default:
     * 4096).<br />
     * Maximum size of an object in the cache.
     */
    public static final int OBJECT_CACHE_MAX_PER_ELEMENT_SIZE = getIntSetting("h2.objectCacheMaxPerElementSize", 4096);

    /**
     * System property <code>h2.objectCacheSize</code> (default: 1024).<br />
     * Maximum size of an object in the cache.
     */
    public static final int OBJECT_CACHE_SIZE = getIntSetting("h2.objectCacheSize", 1024);

    /**
     * System property <code>h2.optimizeDropDependencies</code> (default:
     * true).<br />
     * Improve the performance of DROP and DROP ALL OBJECTS by quicker scanning
     * if other objects depend on this object.
     */
    public static final boolean OPTIMIZE_DROP_DEPENDENCIES = getBooleanSetting("h2.optimizeDropDependencies", true);

    /**
     * System property <code>h2.optimizeDistinct</code> (default: true).<br />
     * Improve the performance of simple DISTINCT queries if an index is
     * available for the given column. The optimization is used if:
     * <ul>
     * <li>The select is a single column query without condition </li>
     * <li>The query contains only one table, and no group by </li>
     * <li>There is only one table involved </li>
     * <li>There is an ascending index on the column </li>
     * <li>The selectivity of the column is below 20 </li>
     * </ul>
     */
    public static final boolean OPTIMIZE_DISTINCT = getBooleanSetting("h2.optimizeDistinct", true);

    /**
     * System property <code>h2.optimizeEvaluatableSubqueries</code> (default:
     * true).<br />
     * Optimize subqueries that are not dependent on the outer query.
     */
    public static final boolean OPTIMIZE_EVALUATABLE_SUBQUERIES = getBooleanSetting("h2.optimizeEvaluatableSubqueries", true);

    /**
     * System property <code>h2.optimizeGroupSorted</code> (default: false).<br />
     * Optimize GROUP BY queries if an index can be used that matches the group
     * by columns.
     */
    public static final boolean OPTIMIZE_GROUP_SORTED = getBooleanSetting("h2.optimizeGroupSorted", false);

    /**
     * System property <code>h2.optimizeIn</code> (default: true).<br />
     * Optimize IN(...) comparisons.
     */
    public static final boolean OPTIMIZE_IN = getBooleanSetting("h2.optimizeIn", true);

    /**
     * System property <code>h2.optimizeInJoin</code> (default: false).<br />
     * Optimize IN(...) comparisons by converting them to inner joins.
     */
    // TODO change in version 1.1
    public static final boolean OPTIMIZE_IN_JOIN = getBooleanSetting("h2.optimizeInJoin", false);

    /**
     * System property <code>h2.optimizeMinMax</code> (default: true).<br />
     * Optimize MIN and MAX aggregate functions.
     */
    public static final boolean OPTIMIZE_MIN_MAX = getBooleanSetting("h2.optimizeMinMax", true);

    /**
     * System property <code>h2.optimizeSubqueryCache</code> (default: true).<br />
     * Cache subquery results.
     */
    public static final boolean OPTIMIZE_SUBQUERY_CACHE = getBooleanSetting("h2.optimizeSubqueryCache", true);

    /**
     * System property <code>h2.optimizeNot</code> (default: true).<br />
     * Optimize NOT conditions by removing the NOT and inverting the condition.
     */
    public static final boolean OPTIMIZE_NOT = getBooleanSetting("h2.optimizeNot", true);

    /**
     * System property <code>h2.optimizeTwoEquals</code> (default: true).<br />
     * Optimize expressions of the form A=B AND B=1. In this case, AND A=1 is
     * added so an index on A can be used.
     */
    public static final boolean OPTIMIZE_TWO_EQUALS = getBooleanSetting("h2.optimizeTwoEquals", true);

    /**
     * System property <code>h2.overflowExceptions</code> (default: true).<br />
     * Throw an exception on integer overflows.
     */
    public static final boolean OVERFLOW_EXCEPTIONS = getBooleanSetting("h2.overflowExceptions", true);

    /**
     * System property <code>h2.recompileAlways</code> (default: false).<br />
     * Always recompile prepared statements.
     */
    public static final boolean RECOMPILE_ALWAYS = getBooleanSetting("h2.recompileAlways", false);

    /**
     * System property <code>h2.redoBufferSize</code> (default: 262144).<br />
     * Size of the redo buffer (used at startup when recovering).
     */
    public static final int REDO_BUFFER_SIZE = getIntSetting("h2.redoBufferSize", 256 * 1024);

    /**
     * System property <code>h2.reuseSpaceAfter</code> (default: 16).<br />
     * Reuse space in database files after this many pages are free.
     */
    public static final int REUSE_SPACE_AFTER = getIntSetting("h2.reuseSpaceAfter", 32);

    /**
     * System property <code>h2.reuseSpaceQuickly</code> (default: true).<br />
     * Reuse space in database files quickly.
     */
    public static final boolean REUSE_SPACE_QUICKLY = getBooleanSetting("h2.reuseSpaceQuickly", true);

    /**
     * System property <code>h2.runFinalize</code> (default: true).<br />
     * Run finalizers to detect unclosed connections.
     */
    public static boolean runFinalize = getBooleanSetting("h2.runFinalize", true);

    /**
     * System property <code>h2.scriptDirectory</code> (default: empty
     * string).<br />
     * Relative or absolute directory where the script files are stored to or
     * read from.
     */
    public static String scriptDirectory = getStringSetting("h2.scriptDirectory", "");

    /**
     * System property <code>h2.serverCachedObjects</code> (default: 64).<br />
     * TCP Server: number of cached objects per session.
     */
    public static final int SERVER_CACHED_OBJECTS = getIntSetting("h2.serverCachedObjects", 64);

    /**
     * System property <code>h2.serverResultSetFetchSize</code> (default: 100).<br />
     * The default result set fetch size when using the server mode.
     */
    public static final int SERVER_RESULT_SET_FETCH_SIZE = getIntSetting("h2.serverResultSetFetchSize", 100);

    /**
     * System property <code>h2.traceIO</code> (default: false).<br />
     * Trace all I/O operations.
     */
    public static final boolean TRACE_IO = getBooleanSetting("h2.traceIO", false);

    /**
     * System property <code>h2.largeResultBufferSize</code> (default: 4096).<br />
     * Buffer size for large result sets. Set this value to 0 to disable the buffer.
     */
    public static final int LARGE_RESULT_BUFFER_SIZE = getIntSetting("h2.largeResultBufferSize", 4 * 1024);

    /**
     * System property <code>h2.collatorCacheSize</code> (default: 10000).<br />
     * The cache size for collation keys (in elements). Used when a collator has
     * been set for the database.
     */
    public static final int COLLATOR_CACHE_SIZE = getCollatorCacheSize();

    private static String baseDir = getStringSetting("h2.baseDir", null);

    private static boolean getBooleanSetting(String name, boolean defaultValue) {
        String s = getProperty(name);
        if (s != null) {
            try {
                return Boolean.valueOf(s).booleanValue();
            } catch (NumberFormatException e) {
            }
        }
        return defaultValue;
    }

    private static String getProperty(String name) {
        try {
            return System.getProperty(name);
        } catch (SecurityException e) {
            // applets may not do that - ignore
            return null;
        }
    }

    /**
     * INTERNAL
     */
    public static String getStringSetting(String name, String defaultValue) {
        String s = getProperty(name);
        return s == null ? defaultValue : s;
    }

    /**
     * INTERNAL
     */
    public static int getIntSetting(String name, int defaultValue) {
        String s = getProperty(name);
        if (s != null) {
            try {
                return Integer.decode(s).intValue();
            } catch (NumberFormatException e) {
            }
        }
        return defaultValue;
    }

    /**
     * INTERNAL
     */
    public static void setBaseDir(String dir) {
        if (!dir.endsWith("/")) {
            dir += "/";
        }
        baseDir = dir;
    }

    /**
     * INTERNAL
     */
    public static String getBaseDir() {
        return baseDir;
    }

    /**
     * INTERNAL
     */
    public static int getMaxQueryTimeout() {
        return getIntSetting(H2_MAX_QUERY_TIMEOUT, 0);
    }

    /**
     * INTERNAL
     */
    public static int getLogFileDeleteDelay() {
        return getIntSetting(H2_LOG_DELETE_DELAY, 0);
    }

    /**
     * INTERNAL
     */
    public static int getCollatorCacheSize() {
        return getIntSetting(H2_COLLATOR_CACHE_SIZE, 32000);
    }
}