Updates executed in Oracle don't appear in TimesTen

Question

Hello. I'm evaluating Oracle + Timesten cache group feature and got the following problem. I performed init scripts on Oracle, created both Oracle and TimesTen users (the have the same names and passwords), created test table (named sub), grid and global dynamic async write cache group from this table. Then I perform an insert query and see changes in Oracle. But when I perform insert query on Oracle I don't see the inserted data from TimesTen. Here is the full set of commands I perform to create cache group
As instance administrator I create user (tengri) and cache administrator (tengriadm):
Command> create user tengri identified by tengri;
User created.
Command> create user tengriadm identified by tengriadm;
User created.
Command> GRANT CREATE SESSION, CACHE_MANAGER, CREATE ANY TABLE TO tengriadm;
As cache manager user (tengriadm) I create grid, cache group, start replication and attach node to grid:
Command> call ttCacheUidPwdSet('tengriadm','tengriadm');
Command> call ttGridCreate('ttGrid');
Command> call ttGridNameSet('ttGrid');
Command> CREATE DYNAMIC ASYNCHRONOUS WRITETHROUGH GLOBAL CACHE GROUP ttGroup
FROM tengri.sub (
id integer not null primary key,
msisdn varchar(32) not null,
name varchar (64),
balance integer,
short_num varchar (32),
address varchar (512),
type integer not null,
is_locked integer not null,
charging_profile_id integer,
cos_id integer,
currency_id integer,
language_id integer
Command> call ttRepStart;
Command> call ttGridAttach(1,'tt1','10.50.3.160',5001);
As instance administrator:
Command> grant select, update, insert, delete on tengri.sub to tengriadm;
As cache manager user I perform insert query:
Command> insert into tengri.sub values (1, '1', '1', 1, '1', '1', 1, 1, 1, 1, 1, 1);
1 row inserted.
And check it on Oracle
select count(*) from sub;
it returns me 1
Then I perform insert on Oracle
insert into tengri.sub values (2, '2', '1', 1, '1', '1', 1, 1, 1, 1, 1, 1);
And perform select on TimesTen
Command> select count(*) from tengri.sub;
< 1 >
1 row found.
Still 1 entry. My first mind was about commit issue but I double checked it on Oracle, executed commit command explicitly and still don't see any changes on TimesTen. Could anyone clarify this behavior?
Thanks in advance!

Answer 1

For local dynamic cache groups, dynamic load is only possible for SQL statements that include a full key equality predicate on a defined primary key or foreign key. For statements that meet these requirements TimesTen will first try and access the requested data locally. If no matching rows are found then it will try in Oracle. If the data is found in Oracle it will be retrieved, inserted into the cache tables in TimesTen (ready for the next access to it) and then the application SQL will execute against the local data and return its result. This works for SELECT, UPDATE, INSERT and DELETE operations.
For global dynamic cache groups TimesTen tracks, at a cache instance level, whether data is al;ready present somewhere in the grid (and if so where it is located). For SQL that qualifies for dynamic load, if no matching rows are found locally then they will be retrieved (moved) from another grid member (if the data is already present in the grid) but if not it will be loaded dynamically from Oracle as for the local cache group case.
In the current implementation of Cache Grid Oracle serves many functions and the concept is of a ;cache' grid. It is not currently possible to use Cache Grid without a backend Oracle database. This may change in a future release.
Chris