[ http://issues.apache.org/jira/browse/DERBY-959?page=all ]
Sunitha Kambhampati updated DERBY-959:
--------------------------------------
Attachment: odbc_rowgreaterthan64k.trace
SmallRows_32kBlkSz.trace
SmallRows_64kBlkSz.trace
The new C client that I was testing the server with is sending a qryblksz of
65535 and I gathered server traces with it. I am attaching the trace files here
.
odbc_rowgreaterthan64k.trace -- using C client, trace has select of a table
with 4 rows each row having more than 64k of data. The table has 341 columns
of type char(200).
SmallRows_32kBlkSz.trace - this server trace was gathered when running with the
client driver(jdbc). query is a simple select * from tbl. where the table has
rows ~ 10k each.
SmallRows_64kBlkSz.trace - this server trace was gathered when running with
the C client that sends a qryblksz of 65535. query is a simple select * from
tbl. where the table has rows ~ 10k each.
Please let me know if you need more information to understand these traces.
Thanks.
> Allow use of DRDA QRYDTA block sizes greater than 32K
> -----------------------------------------------------
>
> Key: DERBY-959
> URL: http://issues.apache.org/jira/browse/DERBY-959
> Project: Derby
> Type: Improvement
> Components: Network Client, Performance, Network Server
> Versions: 10.1.1.0, 10.2.0.0, 10.1.1.1, 10.1.1.2
> Reporter: Bryan Pendleton
> Priority: Minor
> Attachments: 959Notes_v1.html, SmallRows_32kBlkSz.trace,
> SmallRows_64kBlkSz.trace, derby959.review.diff.txt, derby959.review.stat.txt,
> odbc_rowgreaterthan64k.trace
>
> Currently, the Network Server and Network Client use a 32K blocksize when
> returning database data in QRYDTA blocks.
> I came across the following statement in the DRDA spec (Volume 1, page 12):
> Blocking applies only to the QRYDTA reply objects. Each
> query block is a QRYDTA DSS. The maximum query block size
> value allowed in the qryblksz parameter is increased from
> 32K to 10M, thus accomodating the larger data volumes
> required by modern, more data-intensive applications.
> The importance of larger block sizes depends strong on the application
> profile.. For example, many applications perform single-record selects,
> and they are not influenced by the block size.
> But for some applications, it seems like the ability to use a larger block
> size could be quite valuable.
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