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- Why Cannot I Use Some Functions?
- What Is the Function of the dsc_ora_ext Schema Generated After Migration to the Target Database?
- What Should I Do If Data Collection Fails or Is Slow Due to the Small Values of Certain Oracle SGA Parameters?
- What Should I Do If Data Collection Fails and a Message SNAPSHOT TOO OLD Is Displayed?
- What Is the Mapping Between the GaussDB Versions Displayed on the UGO Console and Self-built GaussDB Versions?
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Database Connections
- What Should I Do If I Cannot Connect to the Source Oracle Database During Database Evaluation Project Creation?
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Evaluation Project
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- How Does UGO Collect Data from Source Databases?
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- What Are the Possible Causes for an Object Collection Failure?
- In GaussDB, How Do I Configure a Search Path If A Statement Without Schema Name Fails To Be Executed?
- What Is Native Compatibility, Conversion Compatibility, Partial Compatibility, or Incompatibility?
- What Is the Relationship Between Migration Risk (Top 10 risk SQL) and Risky SQL Summary?
- What Are Reconstruction Statistics and How Are Reconstruction Points Measured?
- What Should I Do If An Object Collection Error (Closed Connection) Is Displayed During Evaluation Project Creation?
- What Should I Do If "ErrorCode=4036" Is Displayed During Evaluation Project Creation?
- What Should I Do If "ErrorCode=17002" Is Displayed During Evaluation Project Creation?
- What Do I Do If the Assessment Task Is Connected but the Pre-check Fails?
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Migration Project
- Why Is There No Available Evaluation Project During Migration Project Creation?
- When Should I Use the Conversion Config Function?
- What Should I Do If SQL Modifications Failed to Be Saved During Object Correction?
- How Do I Solve ERROR: syntax error at or near "@"?
- What Are the Possible Causes for an Object Verification Failure?
- What Are the Impacts of GUC Parameter Settings of GaussDB on Migration?
- How Do I Set GaussDB GUC Parameters?
- Why Is the Number of Indexes Different After Oracle Data is Migrated to GaussDB?
- What Should I Do If There Are ctid, xc_node_id, and tableoid Columns in GaussDB?
- Why Is Data Inconsistent When SELECT Statements Without ORDER BY Are Used for Query in Distributed GaussDB?
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GUC Parameters of GaussDB (MySQL-Compatible Mode)
For GaussDB databases compatible with MySQL syntax, you can set the GUC parameters to enhance the compatibility. For details, see Table 1.
GaussDB provides many operation parameters. Configurations of these parameters affect the behavior of the database system. Before changing these parameters, learn the impact of these parameters on the database. Otherwise, unexpected results may occur.
MySQL-Compatible Configuration Item |
Compatibility Configuration Item |
Compatibility Configuration Item Name |
Supported Database |
Enable |
---|---|---|---|---|
b_format_behavior_compat_options |
enable_set_variables |
Takes effect only for session variables of centralized GaussDB instances. |
Centralized |
Yes |
b_format_version |
5.7 |
Specifies database platform compatibility configuration items. |
Centralized/Distributed 505.0 |
Yes |
b_format_dev_version |
s1 |
Specifies the compatible minor version of the database platform. |
Centralized/Distributed 505.0 |
Yes |
s2 |
Specifies the compatible minor version of the database platform. |
Centralized/Distributed 505.1 |
Yes |
Set the b_format_dev_version parameter as follows:
- For GaussDB V2.0-8.0 Enterprise Edition, set the value to s1.
- For GaussDB V2.0-8.100 Enterprise Edition, set the value to s2.
For details about the versions, see What Is the Mapping Between the GaussDB Versions Displayed on the UGO Console and Self-built GaussDB Versions?
- The S1 compatibility configuration item affects the following content:
- NEW() function, last_day() function, date_sub(date, INTERVAL expr unit), datediff(expr1, expr2), day()/dayofmonth(), and dayname()
- dayofweek(), dayofyear(), extract(unit FROM date), from_days(days), from_unixtime(unix_timestamp[,format]), get_format({DATE | TIME | DATETIME | TIMESTAMP}, {'EUR' | 'USA' | 'JIS' | 'ISO' | 'INTERNAL'}), hour(), makedate(year,dayofyear), microsecond(), minute(), month(), monthname(), period_add(period, month_number)
- TIMESTAMPDIFF, yearweek(date[, mode]), year(), weekofyear(date), weekday(), week(date[, mode]), utc_timestamp(), utc_time(), period_diff(p1,p2), second().
- quarter(), str_to_date(str, format), subdate(expr, days), time_format(time, format), ifnull(expr1, expr2), database(), current_date, current_time, current_timestamp
- round(arg1, arg2), localtime([precision]), localtimestamp, dbtimezone, timenow(), numtodsinterval(num, interval_unit), numtoyminterval(num, interval_unit)
- new_time(date, timezone1,timezone2), sysdate([precision]), add_months(d,n), months_between(d1, d2), convert_tz(dt, from_tz, to_tz)
- adddate(date, INTERVAL expr unit), date_format(date, format)
- The S2 compatibility configuration item affects:
- Compatibility behaviors controlled by s1.
- The following functions:
- When data is imported to the AUTO_INCREMENT column or the BATCH INSERT execution plan is inserted, if 0, NULL, and determined values are used together, the auto-increment count is updated immediately when the determined value is inserted, the subsequent 0 or NULL increases automatically based on the determined value.
- The like operator does not report an error when an escape character is at the end of the matching string.
- The priorities of the sorting rules for character sets and character orders are changed.
- The following syntax:
- The CREATE TABLE table_name LIKE source_table syntax is supported.
- The syntaxes CREATE TABLE table_name LIKE source_table and CREATE TABLE table_name (LIKE source_table) cannot specify INCLUDING and EXCLUDING options. By default, INCLUDING ALL is specified.
- The LOAD DATA syntax is supported. Some syntax functions in gs_loader that are consistent with the LOAD DATA syntax will change.
- The collate clause can be specified by set names.
- The syntax for changing table names, such as ALTER TABLE and RENAME TABLE, is involved. For example, if the character string corresponding to the new table name starts with #MySQL50# and is followed by other characters, #MySQL50# will be ignored.
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