. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 5.5.4. SET STATISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . section describes how to create indexes, activate and deactivate them, delete them and collect statistics (recalculate selectivity) for them. 5.5.1. CREATE INDEX Used for Creating an index for a table state and rebuilding it ALTER INDEX IDX_UPDATER ACTIVE; See also CREATE INDEX, DROP INDEX, SET STATISTICS Chapter 5. Data Definition (DDL) Statements 127 5.5.3. DROP INDEX Used for Deleting an index

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 5.5.4. SET STATISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SIGN SQRT The aggregate functions SUM, AVG, MAX and MIN work with DECFLOAT data, as do all the statistics aggregates (including but not limited to STDDEV or CORR). Special Functions for DECFLOAT Firebird section describes how to create indexes, activate and deactivate them, delete them and collect statistics (recalculate selectivity) for them. 5.5.1. CREATE INDEX Used for Creating an index for a table

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.2. Committing Or Rolling Back. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . rollback or neither (c, r, or n)? 6.2. Committing Or Rolling Back When a limbo transaction has been detected, the DBA has the option of committing or rolling back one or more of the transactions reported as my_employee transaction is not in limbo -transaction 388 is active unknown ISC error 0 When committing or rolling back all limbo transactions, the -⁠pr[ompt] option can be specified. It is, however, not permitted

the following structure: MONS$STAT_ID The statistic id. MONS$STAT_GROUP The statistic group. Statistics are gathered for the following groups: • 0: The database as a whole. • 1: Attachments. • 2: It is possible that not all of these have been written back to disc. To inspect the current statistics for the database as a whole, we would use the following query in isql: tux> isql employee Database: 522 Interpretation of the above statistics is exactly the same as for the database as a whole. We can further diagnose the statistics by individual transactions, as follows: SQL> SELECT

..................................................................................... 142 SET STATISTICS .............................................................................................. CREATE INDEX, ALTER INDEX. SET STATISTICS Назначение: Пересчёт селективности индекса. Доступно в: DSQL, ESQL. Операторы DDL 143 Синтаксис: SET STATISTICS INDEX indexname; Таблица 4.16. Параметры оператора SET STATISTICS Параметр Описание indexname Имя индекса. Оператор SET STATISTICS пересчитывает значение селективности для указанного индекса. Селективность

SHADOW, SHARED, SINGULAR, SIZE, SNAPSHOT, SORT, STABILITY, STARTING, STARTS, STATEMENT, STATISTICS, SUB_TYPE, SUSPEND, TRANSACTION, UNCOMMITTED, WAIT, WORK и WRITE. • Более не зарезервированные ROLE SCHEMA SEGMENT SHADOW SHARED SINGULAR SIZE SNAPSHOT SORT STABILITY STARTING STARTS STATEMENT STATISTICS SUB_TYPE SUSPEND TRANSACTION TYPE UNCOMMITTED WAIT WEEKDAY WORK WRITE YEARDAY Более не резервируемые 'ACTIVE' 110 Руководство по языку SQL ELSE 'INACTIVE' END AS VARCHAR(10)) INDEX_ACTIVE, RI.RDB$STATISTICS INDEX_STATISTIC FROM RDB$INDICES RI JOIN RDB$RELATION_CONSTRAINTS RC ON RC.RDB$RELATION_NAME

-m(erge) The command line switch -m2, has been added in Firebird 2.0 and can be used to send the statistics and plans to the same output file that receives the input from the -o(utput) switch. In earlier DIALECT -- set sql dialect to SET STATs -- toggle display of performance statistics SET TIME -- toggle display of timestamp with DATE values SET TERM DIALECT -- set sql dialect to SET STATs -- toggle display of performance statistics SET TIME -- toggle display of timestamp with DATE values SET TERM

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 5.5.4. SET STATISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . schalten und neu aufbauen ALTER INDEX IDX_UPDATER ACTIVE; Siehe auch CREATE INDEX, DROP INDEX, SET STATISTICS 5.5.3. DROP INDEX Verwendet für Einen Index löschen (löschen) Verfügbar in DSQL, ESQL Syntax INDEX 5.5.4. SET STATISTICS Verwendet für Neuberechnung der Selektivität eines Index Verfügbar in DSQL, ESQL Syntax SET STATISTICS INDEX indexname Tabelle 34. SET STATISTICS-Anweisungsparameter

. . . . . . . . . . . . . . 15 5.2. Generators as “usage counters” for SPs to provide basic statistics . . . . . . . . . . . . . . . . . . . . . . . . 15 5.3. Generators to simulate “Select count(*) this does work safely and exactly). 5.2. Generators as “usage counters” for SPs to provide basic statistics Imagine you just built a fantastic new feature into your database with a stored procedure. Now