From 179ffe409f8030e98ab99c4ec558779b3d2764da Mon Sep 17 00:00:00 2001
From: Piotr Findeisen <piotr.findeisen@gmail.com>
Date: Tue, 28 May 2019 10:56:46 +0200
Subject: [PATCH] Fix getting views for Hive 2.3+ metastore

Hive 2.3 metastore provides more space for table parameter values. On
certain databases (e.g. Derby, Oracle) it uses CLOB and these databases
disallow `=` predicates over CLOB values. At the same time, they allow
`LIKE` predicates over them.

This fixes `SHOW TABLES` and queries over `information_schema.tables`.
---
 .../metastore/thrift/ThriftHiveMetastore.java | 50 +++++++++++++++++--
 1 file changed, 46 insertions(+), 4 deletions(-)

diff --git a/presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/thrift/ThriftHiveMetastore.java b/presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/thrift/ThriftHiveMetastore.java
index 363339ca8a601..9671008cd4dfe 100644
--- a/presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/thrift/ThriftHiveMetastore.java
+++ b/presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/thrift/ThriftHiveMetastore.java
@@ -117,6 +117,9 @@ public class ThriftHiveMetastore
     private final Duration maxRetryTime;
     private final int maxRetries;
 
+    private volatile boolean metastoreKnownToSupportTableParamEqualsPredicate;
+    private volatile boolean metastoreKnownToSupportTableParamLikePredicate;
+
     @Inject
     public ThriftHiveMetastore(MetastoreLocator metastoreLocator, ThriftHiveMetastoreConfig thriftConfig)
     {
@@ -722,10 +725,7 @@ public Optional<List<String>> getAllViews(String databaseName)
                     .stopOn(UnknownDBException.class)
                     .stopOnIllegalExceptions()
                     .run("getAllViews", stats.getGetAllViews().wrap(() -> {
-                        try (ThriftMetastoreClient client = clientProvider.createMetastoreClient()) {
-                            String filter = HIVE_FILTER_FIELD_PARAMS + PRESTO_VIEW_FLAG + " = \"true\"";
-                            return Optional.of(client.getTableNamesByFilter(databaseName, filter));
-                        }
+                        return Optional.of(getPrestoViews(databaseName));
                     }));
         }
         catch (UnknownDBException e) {
@@ -739,6 +739,48 @@ public Optional<List<String>> getAllViews(String databaseName)
         }
     }
 
+    private List<String> getPrestoViews(String databaseName)
+            throws TException
+    {
+        /*
+         * Thrift call `get_table_names_by_filter` may be translated by Metastore to a SQL query against Metastore database.
+         * Hive 2.3 on some databases uses CLOB for table parameter value column and some databases disallow `=` predicate over
+         * CLOB values. At the same time, they allow `LIKE` predicates over them.
+         */
+        String filterWithEquals = HIVE_FILTER_FIELD_PARAMS + PRESTO_VIEW_FLAG + " = \"true\"";
+        String filterWithLike = HIVE_FILTER_FIELD_PARAMS + PRESTO_VIEW_FLAG + " LIKE \"true\"";
+
+        if (metastoreKnownToSupportTableParamEqualsPredicate) {
+            try (ThriftMetastoreClient client = clientProvider.createMetastoreClient()) {
+                return client.getTableNamesByFilter(databaseName, filterWithEquals);
+            }
+        }
+        if (metastoreKnownToSupportTableParamLikePredicate) {
+            try (ThriftMetastoreClient client = clientProvider.createMetastoreClient()) {
+                return client.getTableNamesByFilter(databaseName, filterWithLike);
+            }
+        }
+
+        try (ThriftMetastoreClient client = clientProvider.createMetastoreClient()) {
+            List<String> views = client.getTableNamesByFilter(databaseName, filterWithEquals);
+            metastoreKnownToSupportTableParamEqualsPredicate = true;
+            return views;
+        }
+        catch (TException | RuntimeException firstException) {
+            try (ThriftMetastoreClient client = clientProvider.createMetastoreClient()) {
+                List<String> views = client.getTableNamesByFilter(databaseName, filterWithLike);
+                metastoreKnownToSupportTableParamLikePredicate = true;
+                return views;
+            }
+            catch (TException | RuntimeException secondException) {
+                if (firstException != secondException) {
+                    firstException.addSuppressed(secondException);
+                }
+            }
+            throw firstException;
+        }
+    }
+
     @Override
     public void createDatabase(Database database)
     {