[CONJ-151] performance degraded after upgrading from 1.1.7 to 1.1.8 Created: 2015-04-24  Updated: 2015-06-23  Resolved: 2015-06-23

Status: Closed
Project: MariaDB Connector/J
Component/s: Other
Affects Version/s: 1.1.8
Fix Version/s: 1.1.9

Type: Bug Priority: Minor
Reporter: Alan Frazier Assignee: Diego Dupin
Resolution: Fixed Votes: 0
Labels: None
Environment:

Linux


 Description   

After upgrading from 1.1.7 to 1.1.8, I noticed a performance decrease. The CPU Sampler in VisualVM pointed to MySQLParameterizedQuery.toSQL2() being the issue.

I modified this method to use a StringBuilder instead of += which seems to have addressed the issue.

Updated Code:

private String toSQL2() throws UnsupportedEncodingException {
if(queryPartsArray.length == 0)

{ return ""; }

StringBuilder sb = new StringBuilder(new String(queryPartsArray[0], "UTF-8"));

for(int i = 1; i<queryPartsArray.length; i++)

{ sb.append(parameters[i-1]); if(queryPartsArray[i].length != 0) sb.append(new String(queryPartsArray[i], "UTF-8")); }

return sb.toString();
}

 Comments   
Comment by Vladislav Vaintroub [ 2015-05-10 ]

The commit https://github.com/MariaDB/mariadb-connector-j/commit/8e507c416ef17b3b556b16d4cbff0bca59ebd233 was a mistake.
Constructing query as string just to get its UTF8 length is a wrong approach

Comment by Diego Dupin [ 2015-05-29 ]

same as Vladislav, each query implementation has a write method based on byte arrays. There is no need for transformation to have the write size.

Comment by Diego Dupin [ 2015-05-29 ]

merge https://github.com/MariaDB/mariadb-connector-j/commit/a163bdbb0d01123095634593047873273fb2bb9f

Comment by Vladislav Vaintroub [ 2015-05-29 ]

Commented about the merge proposal on github.

Comment by Vladislav Vaintroub [ 2015-05-30 ]

Gave it a try here
https://github.com/vaintroub/mariadb-connector-j/commit/59f3d68c1bbd32936e631b9e533c31f45d5ec770

It turns out a bit more complicated with max_allowed_packet over 16MB, where query splits into multiple packets. In that case, terminate the connection whenever max_allowed_packet would overflow seems ok. also removed methods that materialize prepared statement toSQL() and toByteArray()as string rsp bytes in my patch, hope this is ok

Comment by Diego Dupin [ 2015-06-23 ]

method toSQL replaced, because, not only perf degradation, but buggy.

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