IMPALA-1272: fix crash when compression codec is invalid for parquet

Defer resizing the columns_ vector until we are sure we will initialize it.
Downstream code doesn't expect any NULLs.

Change-Id: I250cceee5181428fcd3cd1a8b021edb7187ae888
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4465
Reviewed-by: Daniel Hecht <dhecht@cloudera.com>
Tested-by: jenkins
Bug fixes in null-aware anti-join

This commit fixes issue IMPALA-1215 where NOT IN subqueries return wrong
results in the presence of null values.

Change-Id: I97e41c8df8ba864d0189595d670b3f0349fcad36
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4467
Reviewed-by: Dimitris Tsirogiannis <dtsirogiannis@cloudera.com>
Reviewed-by: Nong Li <nong@cloudera.com>
Tested-by: Nong Li <nong@cloudera.com>
FE changes for a disable_unsafe_spills query option.

A new disable_unsafe_spills query option allows Impala to internally
disable spilling for potentially disastrous query plans. Impala will
excercise this option if a query has no plan hints, and at least one
table is missing relevant stats.

The explain plan will display a warning that spilling is disabled.

Change-Id: I78c182ff2c7f236be31870123e752370be2ed748
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4429
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins
IMPALA-1111: 16-byte align DecimalVal allocas

Change-Id: Ibc03c1286eb583ad2e7958d8ef9579171defb223
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4483
Reviewed-by: Nong Li <nong@cloudera.com>
Tested-by: jenkins
Unpin blocks form the tuple stream from the back.

We read from the front so this maximizes the chance the block is not
evicted.

Change-Id: I6d8c6c6c1ec7f9ce34633b1d8d9cdeef16c9045f
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4488
Tested-by: jenkins
Reviewed-by: Nong Li <nong@cloudera.com>