官网地址
https://impala.apache.org/docs/build/html/topics/impala_batch_size.html
Number of rows evaluated at a time by SQL operators. Unspecified or a size of 0 uses a predefined default size. Using a large number improves responsiveness, especially for scan operations, at the cost of a higher memory footprint.
This option is primarily for testing during Impala development, or for use under the direction of the appropriate support channel.
翻译，sql执行过程中每次处理的行数。默认是=0，其实是1024.使用更大的值可以提高响应能力，尤其是扫描操作，但代价是使用更多内存。
Type: numeric
Default: 0 (meaning the predefined default of 1024)
Range: 0-65536. The value of 0 still has the special meaning of "use the default", so the effective range is 1-65536. The maximum applies in Impala 2.11 and higher.
实战！！！
这里可惜的是，我在impala set结果没有这个参数。。。
impala版本 impalad version 3.2.0-cdh6.3.2 RELEASE (build 1bb9836227301b839a32c6bc230e35439d5984ac)
set 参数 无batch_size。 单独设置了1和65535 也感觉不到查询区别。全当了解了。
[test-flimpala.woa.com:25003] odsiadata> set ;
Query options (defaults shown in []):
ABORT_ON_ERROR: [0]
COMPRESSION_CODEC: []
DISABLE_CODEGEN: [0]
DISABLE_ROW_RUNTIME_FILTERING: [0]
DISABLE_STREAMING_PREAGGREGATIONS: [0]
DISABLE_UNSAFE_SPILLS: [0]
EXEC_TIME_LIMIT_S: [0]
EXPLAIN_LEVEL: [STANDARD]
IDLE_SESSION_TIMEOUT: [0]
MAX_ROW_SIZE: [524288]
MEM_LIMIT: [0]
MT_DOP: []
NUM_SCANNER_THREADS: [0]
OPTIMIZE_PARTITION_KEY_SCANS: [0]
PARQUET_ARRAY_RESOLUTION: [THREE_LEVEL]
PARQUET_FALLBACK_SCHEMA_RESOLUTION: [POSITION]
QUERY_TIMEOUT_S: [0]
REQUEST_POOL: []
RUNTIME_FILTER_MODE: [GLOBAL]
RUNTIME_FILTER_WAIT_TIME_MS: [0]
S3_SKIP_INSERT_STAGING: [1]
SCRATCH_LIMIT: [-1]
SYNC_DDL: [0]
THREAD_RESERVATION_AGGREGATE_LIMIT: [0]
THREAD_RESERVATION_LIMIT: [3000]
TIMEZONE: [Asia/Shanghai]
Advanced Query Options:
APPX_COUNT_DISTINCT: [0]
BUFFER_POOL_LIMIT: []
CLIENT_IDENTIFIER: Impala Shell v3.2.0-cdh6.3.2 (1bb9836) built on Fri Nov 8 07:22:06 PST 2019
COMPUTE_STATS_MIN_SAMPLE_SIZE: [1073741824]
DEFAULT_JOIN_DISTRIBUTION_MODE: [BROADCAST]
DEFAULT_SPILLABLE_BUFFER_SIZE: [2097152]
DISABLE_CODEGEN_ROWS_THRESHOLD: [50000]
ENABLE_EXPR_REWRITES: [1]
EXEC_SINGLE_NODE_ROWS_THRESHOLD: [100]
HBASE_CACHE_BLOCKS: [0]
HBASE_CACHING: [0]
KUDU_READ_MODE: [DEFAULT]
MAX_ERRORS: [100]
MAX_MEM_ESTIMATE_FOR_ADMISSION: [0]
MAX_NUM_RUNTIME_FILTERS: [10]
MIN_SPILLABLE_BUFFER_SIZE: [65536]
NUM_REMOTE_EXECUTOR_CANDIDATES: [3]
NUM_ROWS_PRODUCED_LIMIT: [0]
PARQUET_ANNOTATE_STRINGS_UTF8: [0]
PARQUET_DICTIONARY_FILTERING: [1]
PARQUET_FILE_SIZE: [0]
PARQUET_READ_STATISTICS: [1]
PREFETCH_MODE: [HT_BUCKET]
REPLICA_PREFERENCE: [CACHE_LOCAL]
RESOURCE_TRACE_RATIO: [0.000000]
RUNTIME_BLOOM_FILTER_SIZE: [1048576]
RUNTIME_FILTER_MAX_SIZE: [16777216]
RUNTIME_FILTER_MIN_SIZE: [1048576]
SCAN_BYTES_LIMIT: [0]
SCHEDULE_RANDOM_REPLICA: [0]
SHUFFLE_DISTINCT_EXPRS: [1]
SUPPORT_START_OVER: [false]
TOPN_BYTES_LIMIT: [536870912]
Shell Options
WRITE_DELIMITED: False
VERBOSE: True
LIVE_SUMMARY: False
OUTPUT_FILE: None
DELIMITER: \t
LIVE_PROGRESS: False
Variables:
No variables defined.
