Maximum secondary node quantity in star tolopogy

Seniru

is there a recommended limit on the secondary node quantity in star topology?

Bernardo

It depends on the total amount of writes per second

If the app has low amount of writes, then it can have thousands of secondary nodes. We have not tested it yet for this case to discover the approximate number.

But if there are many writes, then the limit may be lower otherwise it will not be able to handle the throughput

We suggest to join SQL commands in transactions as much as possible and avoid unnecessary writes to increase the amount of nodes possible (when reaching the limit)

Seniru

Thank you for your quick response!

I’d like to know more about the commercial version of LiteSync:
1. How many tables can be created in a single database, is there a certain limit?
2. Is the license a one-time payment, or are there recurring fees?

Bernardo

There is no limit of tables, unless set by SQLite itself

The license is a one-time purchase

Seniru

Great, Thank you

In this topology with a primary handling occasional bursts of 1000 writes per second, connected to a large number of secondaries, remain manageable? The secondaries only replicate from the primary but do not write back to it. Any insights?

Bernardo

What do you mean by "the secondaries only replicate from the primary but do not write back to it"?
So the secondary nodes are read-only?
If all writes will be made on the primary node, then I suspect you do not need LiteSync. A solution that replicates the WAL or db pages would do the job. There are some free and open-source ones, but I never used them. You would need to check if some of them fit your requirements.

Bernardo

Regarding the writes, if they are 1000 insertions on a single transaction, then it is fast.
If they are 1000 individual transactions, it is way slower.
It is not clear to me: you plan to make all writes directly to the primary node? If yes, then you can wrap many of them into transactions, to make replication faster. And again, you can use a simpler and free tool for this. LiteSync is for more complex cases, namely multi-master replication (writing on many nodes and sync them all) with off-line reads and writes.

Seniru

Yes, all writes happen on the primary node, while the secondaries are read-only. There are also plans to adopt a mixed topology with multiple primaries (read/write) and a large number of secondaries (read-only). Even if LiteSync might be overkill for read-only secondaries, does it ensure proper synchronization for all secondaries when they come online?

Bernardo

Yes, they will catch up. You can use the free version to test them under your conditions.