[GitHub] trafodion pull request #1682: [TRAFODION-3177] Error when selecting count(*)...
Github user asfgit closed the pull request at: https://github.com/apache/trafodion/pull/1682 ---
[GitHub] trafodion pull request #1682: [TRAFODION-3177] Error when selecting count(*)...
Github user zellerh commented on a diff in the pull request: https://github.com/apache/trafodion/pull/1682#discussion_r213034998 --- Diff: core/sql/sqludr/SqlUdrPredefLogReader.cpp --- @@ -1311,17 +1362,19 @@ bool ReadCppEventsUDFInterface::validateEvent(const UDRInvocationInfo , // All other comparisons are assumed to be string compares else { - // convert predicate value + // convert and trim predicate value temp = constStr; constStr.clear(); for(size_t j = 0; j < temp.size(); ++j) constStr += (std::toupper(temp[j])); + constStr.erase(constStr.find_last_not_of(" ")+1); --- End diff -- Actually, changing the code and debugging again made me realize what happens: For a string with something other than blanks, this will always return something other than string::npos. If the string contains all blanks or is empty, it will return -1 (string::npos), and adding 1 will give 0 and erase the entire string, which is again what we want. But it's ugly to rely on string::npos + 1 = 0, so I'll change it anyway. The resulting code looks ugly as well. It's disappointing that std::string makes it so hard to do a simple operation like trim. ---
[GitHub] trafodion pull request #1682: [TRAFODION-3177] Error when selecting count(*)...
Github user zellerh commented on a diff in the pull request: https://github.com/apache/trafodion/pull/1682#discussion_r213030480 --- Diff: core/sql/sqludr/SqlUdrPredefLogReader.cpp --- @@ -1311,17 +1362,19 @@ bool ReadCppEventsUDFInterface::validateEvent(const UDRInvocationInfo , // All other comparisons are assumed to be string compares else { - // convert predicate value + // convert and trim predicate value temp = constStr; constStr.clear(); for(size_t j = 0; j < temp.size(); ++j) constStr += (std::toupper(temp[j])); + constStr.erase(constStr.find_last_not_of(" ")+1); --- End diff -- That's a very good point. Actually, when I made the change I googled "trim string C++" and found something like this: https://stackoverflow.com/questions/216823/whats-the-best-way-to-trim-stdstring. Then I just copied the solution without thinking too much of it. When I debug it, it works fine and does not delete the entire string, but I'm not sure why. Adding 1 to string::npos clearly doesn't seem like a good idea. I'll change the code. ---
[GitHub] trafodion pull request #1682: [TRAFODION-3177] Error when selecting count(*)...
Github user DaveBirdsall commented on a diff in the pull request: https://github.com/apache/trafodion/pull/1682#discussion_r210397770 --- Diff: core/sql/sqludr/SqlUdrPredefLogReader.cpp --- @@ -1311,17 +1362,19 @@ bool ReadCppEventsUDFInterface::validateEvent(const UDRInvocationInfo , // All other comparisons are assumed to be string compares else { - // convert predicate value + // convert and trim predicate value temp = constStr; constStr.clear(); for(size_t j = 0; j < temp.size(); ++j) constStr += (std::toupper(temp[j])); + constStr.erase(constStr.find_last_not_of(" ")+1); --- End diff -- What happens when find_last_not_of returns string::npos? (that is, when there are no trailing blanks?) It seems string::npos is defined as -1 (unsigned), so adding 1 to it would get zero and we'd do erase(0) which erases the whole string? ---
[GitHub] trafodion pull request #1682: [TRAFODION-3177] Error when selecting count(*)...
GitHub user zellerh opened a pull request: https://github.com/apache/trafodion/pull/1682 [TRAFODION-3177] Error when selecting count(*) from event_log_reader UDF See the JIRA for a description of the issues. - Removed code that required usage of a set of output columns to evaluate code. This check caused the error described in the test case, and I think it is no longer necessary. Removing it can speed up some cases where we now evaluate predicates in the UDF, for example: ``` select count(*) from udf("_LIBMGR_".event_log_reader('f')) where log_file_node = 0; ``` - Added predicate evaluation code for MESSAGE, LOG_FILE_NODE, LOG_FILE_LINE, and PARSE_STATUS columns. You can merge this pull request into a Git repository by running: $ git pull https://github.com/zellerh/trafodion bug/R23a Alternatively you can review and apply these changes as the patch at: https://github.com/apache/trafodion/pull/1682.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #1682 commit 5ecb6890cb9fc381bca7c4f5c93ea8a28ed9fd31 Author: Hans Zeller Date: 2018-08-07T01:20:09Z [TRAFODION-3177] Error when selecting count(*) from event_log_reader UDF See the JIRA for a description of the issues. - Removed code that required usage of a set of output columns to evaluate code. This check caused the error described in the test case, and I think it is no longer necessary. Removing it can speed up some cases where we now evaluate predicates in the UDF, for example: select count(*) from udf("_LIBMGR_".event_log_reader('f')) where log_file_node = 0; - Added predicate evaluation code for MESSAGE, LOG_FILE_NODE, LOG_FILE_LINE, and PARSE_STATUS columns. ---