Wisteria leaves in winter.
SQL Server has a process called replication, whereby you can automatically copy records from one database to another, and keep them in-sync. One use for this is to have one database as the transactional database, and another to report from, with the reporting database having indexes and constraints tailored more toward faster reporting (reads) than fast input.
Sometimes replication gets a little behind, and if you are running reports on the database that is a little behind, you might like to know.
The stored procedure sp_replcounters will tell you the count of transactions awaiting transfer to the distribution database (which lies between the transaction database and the destination database in a replication process). You can call this stored procedure, but you want it to return the result set to Java.
One way to achieve this is to wrap your own stored procedure around it, put the records into a temp table and query the temp table to return the result set. This only works if you specify SET NOCOUNT ON, otherwise the Java Persistence API (JPA) gets confused by the multiple queries and you don’t get the result set in your Java code.
CREATE PROCEDURE GetReplicationLatency AS --This is important. Results from multiple queries within stored procedures throw JPA off unless SET NOCOUNT ON is used. SET NOCOUNT ON declare @db varchar(50) set @db = db_name() create table #tempTable ([database] varchar(50), [replicated transactions] int, [replication rate trans/sec] int, [replication latency (sec)] decimal(16,6), replbeginlsn varchar(40), replnextlsn varchar(40)) insert into #tempTable exec sp_replcounters select * from #tempTable where [database] = @db drop table #tempTable
Then your Java code looks like this:
private static final String REPLICATION_LATENCY_QUERY = "exec GetReplicationLatency ";Query query = getEntityManager().createNativeQuery(REPLICATION_LATENCY_QUERY);
Query query = getEntityManager().createNativeQuery(REPLICATION_LATENCY_QUERY); List<Object> results = query.getResultList();