Add the guc parameter lightdb_arch_mode, and there are two values. classic means that the current data system is not a distributed architecture. dist means that the current data system is a distributed architecture, under this architecture, the table created with create table defaults to a distributed table. see Compatibility.

lt_check is a LightDB check sha256sum tool. Ensure that the files in the LightDB installation directory are complete. see lt_check.

Added detection for unconditional and pageless queries. see LightDB DML Specification Check.

In the following scenarios, a prompt message is printed indicating that the user should use pagination/where:

for example:

lightdb@lt_test=# set lightdb_best_practice_level to 'warn';
SET
lightdb@lt_test=# set lightdb_best_practice_mode to 'no_paging';
SET
lightdb@lt_test=# create table dc_np_t1(c_a int primary key, c_b varchar, gmt_create timestamp null, gmt_modified timestamp null);
CREATE TABLE
lightdb@lt_test=# SELECT * from dc_np_t1;
WARNING:  LightDB DML check warning! select sql not where/limit/offset clause!
 c_a | c_b | gmt_create | gmt_modified 
-----+-----+------------+--------------
(0 rows)

Check the correctness of each item in the checklist. It can be used to detect whether there are risks in operating system parameters, LightDB installation file sha256sum, LightDB version number, etc. If there are risks, give a risk report. see check_list.

Support database() functions can be used in both oracle and postgres modes. The database() function is placed in the extension ltfce. see ltfce.

for example:

lightdb@postgres=# select database();
 database 
----------
 public
(1 row)
lightdb@postgres=# \c test_createdb_oracle
You are now connected to database "test_createdb_oracle" as user "lightdb".
lightdb@test_createdb_oracle=# show lightdb_dblevel_syntax_compatible_type;
 lightdb_dblevel_syntax_compatible_type 
----------------------------------------
 Oracle
(1 row)
lightdb@test_createdb_oracle=#  select database();
 database 
----------
 public
(1 row)

Archive log cleaning optimization. see lightdb_archive_dir.

Add walminer extension to mine all the useful information of wal logs to provide LightDB data recovery support. The database log level configuration needs to be greater than minimal. see lt_walminer.

Supports single-instance multi-mode. see CREATE DATABASE.

for example:

lightdb@postgres=# create database test_createdb_oracle with lightdb_syntax_compatible_type oracle;
CREATE DATABASE
lightdb@postgres=# \c test_createdb_oracle
You are now connected to database "test_createdb_oracle" as user "lightdb".
lightdb@test_createdb_oracle=# show lightdb_dblevel_syntax_compatible_type;
 lightdb_dblevel_syntax_compatible_type 
----------------------------------------
 Oracle
(1 row)

Add the lightdb_aborted_rollback parameter to support the error reporting of the current statement in the transaction and rollback the entire transaction. see lightdb_aborted_rollback.

Before adding this feature,for example:

lightdb@lt_test=# begin;
BEGIN
lightdb@lt_test=*# create table aborted_rollback(name varchar(100));
CREATE TABLE
lightdb@lt_test=*# insert into aborted_rollback1 values(1);
ERROR:  relation "aborted_rollback1" does not exist
LINE 1: insert into aborted_rollback1 values(1);
                    ^
lightdb@lt_test=!# insert into aborted_rollback1 values(1);
ERROR:  current transaction is aborted, commands ignored until end of transaction block
lightdb@lt_test=!# commit;
ROLLBACK

After adding this feature,for example:

lightdb@lt_test=# set lightdb_aborted_rollback to on;
SET
lightdb@lt_test=# begin;
BEGIN
lightdb@lt_test=*# create table aborted_rollback(name varchar(100));
CREATE TABLE
lightdb@lt_test=*# insert into aborted_rollback1 values(1);
ERROR:  relation "aborted_rollback1" does not exist
LINE 1: insert into aborted_rollback1 values(1);
                    ^
ERROR:  current transaction is aborted, "insert into aborted_rollback1 values(1);" causes transaction rollback.

Solve the problem of type mismatch when the unknown type participates in the operation. see optional.

for example:

lightdb@lt_test=# select '1'+1;
 ?column? 
----------
        2
(1 row)

Note: Operator overloading may affect the return value of the expression. For example, for an expression such as select '1' * 1, it previously returned an int type, but now it returns a numeric type.

The problem of high CPU usage in optimizing the lt_cron process. see lt_cron.

Add an option table_exists_action, to tell lt_restore what to do if the table it is tring to create already exists. table_exists_action has four options: skip,append, truncate or replace. see lt_restore.

lt_upgrade supports package upgrade. see lt_upgrade.

lt_upgradecheck supports cross-version upgrade. see lt_upgrade_check.

Statement level rollback optimization, This feature is supported in both Oracle and MySQL modes. Statement level rollback is enabled, and the performance loss is about 5%. see lt_statement_rollback_enable.

ltdts_ora is a data synchronization tool for synchronizing Oracle data to LightDB. see ltdts_ora.

ltdts_mysql is a data synchronization tool for synchronizing MySQL|MariaDB data to LightDB. see ltdts_mysql.

lt_patch enhancements, and many of new parameters shown below have been added. see lt_patch.

Use lt_dump and lt_restore tools to implement backup and recovery of distributed clusters:

Use lt_probackup tools to implement backup and recovery of distributed clusters. see lt_distributed_probackup.

Oracle compatibility enhancements, and many of new features shown below have been added.