Review the following replication considerations for MemSQL targets:
When InitialSync loads data from temporary text files to MemSQL targets by using the MySQL ODBC driver, it requires audit log tables to process any SQL expressions that are defined for the source tables. You must generate the audit log tables even if the source tables with SQL expressions are mapped in SQL Apply mode.
If the global.insert_buffer_size runtime parameter is set to the default value of 0 to dynamically determine the appropriate number of operations that can be buffered for the target type, the Applier buffers only 1 operation because of the MySQL ODBC driver restrictions. This setting causes the Applier to apply each SQL change operation from the source to the target instead of accumulating these changes in the internal buffer first. Enter a value other than the default value only at the request of Informatica Global Customer Support.
MemSQL does not support the following DDL operations:
ALTER TABLE operations that change a column constraint from NULL to NOT NULL
ALTER TABLE operations that change primary keys or unique indexes
If you enable DDL replication for a replication configuration that has a MemSQL target and determine that unsupported DDL operations might occur on the source database, set all of the following runtime parameters to 1 to avoid Applier failures: apply.skip_create_index_failed_ddl, apply.skip_drop_index_failed_ddl, and apply.skip_alter_column_failed_ddl.
Ensure that distribution by tables is set in one of the following ways:
On the
Map Columns
tab, select the
Distribute by tables
option.
On the
Map Tables
tab, click
Settings
to open the
Customize Settings for the Selected Tables
window. In the
Distribute By
column, select
Tables
.
For MemSQL targets, the default option is distribution by rows.
Ensure that each Applier or InitialSync thread does not process more than 19 tables simultaneously by adjusting the values of the