There are several compiler warnings being generated when building qserv that should be fixed. Most should be considered bugs, but there are a few non-bugs such as intentional missing breaks. It is possible to squash warnings by line, which might be the right approach. More information here:
https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html

The warnings:

Catching by reference is recommended 'UserQueryError' UserQuery.cc
/qserv_a/core/modules/ccontrol line 247 Code Analysis Problem

Class 'Checker' has virtual method 'operator ()' but non-virtual
destructor ResourceUnit.h /qserv_a/core/modules/global line
103 Code Analysis Problem

Class 'ResRowBuffer' has virtual method 'fetch' but non-virtual
destructor RowBuffer.cc /qserv_a/core/modules/mysql line 110
Code Analysis Problem

Class 'RowBuffer' has virtual method 'fetch' but non-virtual
destructor RowBuffer.h /qserv_a/core/modules/mysql line 68 Code
Analysis Problem

Invalid project path: Include path not found
(/afs/slac.stanford.edu/u/sf/jgates/work/qserv/$LOG_DIR/include).
qserv_a pathentry Path Entry Problem

Member '_dirty' was not initialized in this constructor
QuerySession.h /qserv_a/core/modules/qproc line 157 Code
Analysis Problem

Member '_fieldOffset' was not initialized in this constructor
RowBuffer.cc /qserv_a/core/modules/mysql line 131 Code Analysis
Problem

Member '_hasChunks' was not initialized in this constructor
QuerySession.h /qserv_a/core/modules/qproc line 157 Code
Analysis Problem

Member '_hasMerge' was not initialized in this constructor
QuerySession.cc /qserv_a/core/modules/qproc line 86 Code
Analysis Problem

Member '_hasSubChunks' was not initialized in this constructor
QuerySession.h /qserv_a/core/modules/qproc line 157 Code
Analysis Problem

Member '_hasSubChunks' was not initialized in this constructor
QuerySession.h /qserv_a/core/modules/qproc line 157 Code
Analysis Problem

Member '_limit' was not initialized in this constructor SelectStmt.cc
/qserv_a/core/modules/query line 92 Code Analysis Problem

Member '_order' was not initialized in this constructor
OrderByClause.h /qserv_a/core/modules/query line 66 Code
Analysis Problem

Member '_request' was not initialized in this constructor
QueryResource.h /qserv_a/core/modules/qdisp line 53 Code
Analysis Problem

Member '_requestType' was not initialized in this constructor
QservPath.h /qserv_a/core/modules/obsolete line 39 Code
Analysis Problem

Member '_session' was not initialized in this constructor
QueryResource.h /qserv_a/core/modules/qdisp line 53 Code
Analysis Problem

Member '_sessionId' was not initialized in this constructor
UserQuery.cc /qserv_a/core/modules/ccontrol line 261 Code
Analysis Problem

Member 'bufferSize' was not initialized in this constructor
TransactionSpec.h /qserv_a/core/modules/qdisp line 52 Code
Analysis Problem

Member 'chunkCount' was not initialized in this constructor
QueryContext.h /qserv_a/core/modules/query line 64 Code
Analysis Problem

Member 'counter' was not initialized in this constructor
testProtocol.cc /qserv_a/core/modules/proto line 47 Code
Analysis Problem

Member 'metaSession' was not initialized in this constructor
testPlugins.cc /qserv_a/core/modules/qana line 51 Code Analysis
Problem

Member 'needsMerge' was not initialized in this constructor
QueryContext.h /qserv_a/core/modules/query line 64 Code
Analysis Problem

No break at the end of case MergingRequester.cc
/qserv_a/core/modules/ccontrol line 113 Code Analysis Problem

No break at the end of case SchemaFactory.cc
/qserv_a/core/modules/mysql line 168 Code Analysis Problem

No break at the end of case ValueFactorFactory.cc
/qserv_a/core/modules/parser line 118 Code Analysis Problem

No break at the end of case ValueFactorFactory.cc
/qserv_a/core/modules/parser line 166 Code Analysis Problem

Statement has no effect 'GOOGLE_PROTOBUF_VERIFY_VERSION'
testProtocol.cc /qserv_a/core/modules/proto line 112 Code
Analysis Problem

Suspicious semicolon AggregatePlugin.cc /qserv_a/core/modules/qana
line 83 Code Analysis Problem