Hi Ming,
The number is connected with the main memory.
> We have totally 16 GB memory, but wir can only set the number up to max.
> 30000.
> How can we increase the -bufs-num setting in our case?
>
Sedna is a 32-bit application. It means that it can't allocate more than
2-3GB (exact number may vary depending on system configuration).
Are you sure you need buffer memory larger than 2GB (bufs-num equals 32000)?
> In our experience concurrent access in the same collection causes
> performance issurs. The access with 2 threads has just 20%-25% performance
> as with 1 thread.
> Is this a known issue?
It depends on queries you run.
However, at the moment Sedna has a bottleneck in se_sm (database instance
process). Performance degrades in some situations when you run parallel
transactions which extensively use IO.
> The speed of insert a document as xml depends on the amount of documents
> in the collection. To insert a document with 1.5 KB, it takes
> 30ms (7,000docs)/100ms(230,000docs)/730ms(660,000docs).
> Is this expected?
We will try to reproduce this issue. I'll let you know.
We are looking for a way to improve the performance. If there is no way
> to increase the speed of insert a xml document, we have to reorganise
> our data(expected ca. 5,000,000 docs), so that, there are more
> collections or sub-collections with fewer data in them.
>
I think, you can use sub-collections, or even start multiple databases.
If you are going to use multiple collections you probably need to increase
persustent heap size (see se_cdb options).
Ivan Shcheklein,
Sedna Team
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