Fix max encoded size estimate in RLE encoding.

Nong Li · Nong Li · commit 846e6b4622f4 · 2014-05-27T10:36:04.000-07:00
diff --git a/src/impala/rle-encoding.h b/src/impala/rle-encoding.h
@@ -144,7 +144,8 @@ class RleEncoder {
     int bytes_per_run = BitUtil::Ceil(bit_width * MAX_VALUES_PER_LITERAL_RUN, 8.0);
     int num_runs = BitUtil::Ceil(num_values, MAX_VALUES_PER_LITERAL_RUN);
     int literal_max_size = num_runs + num_runs * bytes_per_run;
-    return std::max(MinBufferSize(bit_width), literal_max_size);
+    int min_run_size = MinBufferSize(bit_width);
+    return std::max(min_run_size, literal_max_size) + min_run_size;
   }
 
   // Encode value.  Returns true if the value fits in buffer, false otherwise.

Original file line number	Diff line number	Diff line change
`@@ -144,7 +144,8 @@ class RleEncoder {`
`144`	`144`	`int bytes_per_run = BitUtil::Ceil(bit_width * MAX_VALUES_PER_LITERAL_RUN, 8.0);`
`145`	`145`	`int num_runs = BitUtil::Ceil(num_values, MAX_VALUES_PER_LITERAL_RUN);`
`146`	`146`	`int literal_max_size = num_runs + num_runs * bytes_per_run;`
`147`		`- return std::max(MinBufferSize(bit_width), literal_max_size);`
	`147`	`+ int min_run_size = MinBufferSize(bit_width);`
	`148`	`+ return std::max(min_run_size, literal_max_size) + min_run_size;`
`148`	`149`	`}`
`149`	`150`
`150`	`151`	`// Encode value. Returns true if the value fits in buffer, false otherwise.`