Github user jianqiao commented on a diff in the pull request:
https://github.com/apache/incubator-quickstep/pull/19#discussion_r66470811
--- Diff: relational_operators/TextScanOperator.cpp ---
@@ -155,116 +63,50 @@ bool TextScanOperator::getAllWorkOrders(
InsertDestination *output_destination =
query_context->getInsertDestination(output_destination_index_);
- if (parallelize_load_) {
- // Parallel implementation: Split work orders are generated for each
file
- // being bulk-loaded. (More than one file can be loaded, because we
support
- // glob() semantics in file name.) These work orders read the input
file,
- // and split them in the blobs that can be parsed independently.
- if (blocking_dependencies_met_) {
- if (!work_generated_) {
- // First, generate text-split work orders.
- for (const auto &file : files) {
- container->addNormalWorkOrder(
- new TextSplitWorkOrder(query_id_,
- file,
- process_escape_sequences_,
- storage_manager,
- op_index_,
- scheduler_client_id,
- bus),
- op_index_);
- ++num_split_work_orders_;
- }
- work_generated_ = true;
- return false;
- } else {
- // Check if there are blobs to parse.
- while (!text_blob_queue_.empty()) {
- const TextBlob blob_work = text_blob_queue_.popOne();
- container->addNormalWorkOrder(
- new TextScanWorkOrder(query_id_,
- blob_work.blob_id,
- blob_work.size,
- field_terminator_,
- process_escape_sequences_,
- output_destination,
- storage_manager),
- op_index_);
- }
- // Done if all split work orders are completed, and no blobs are
left to
- // process.
- return num_done_split_work_orders_.load(std::memory_order_acquire)
== num_split_work_orders_ &&
- text_blob_queue_.empty();
- }
- }
- return false;
- } else {
- // Serial implementation.
- if (blocking_dependencies_met_ && !work_generated_) {
- for (const auto &file : files) {
+ // Text segment size set to 256KB.
+ constexpr std::size_t kTextSegmentSize = 0x40000u;
+
+ if (blocking_dependencies_met_ && !work_generated_) {
+ for (const std::string &file : files) {
+ // Use standard C libary to retrieve the file size.
+ FILE *fp = std::fopen(file.c_str(), "rb");
+ std::fseek(fp, 0, SEEK_END);
+ const std::size_t file_size = std::ftell(fp);
+ std::fclose(fp);
+
+ std::size_t text_offset = 0;
+ while (text_offset < file_size) {
container->addNormalWorkOrder(
new TextScanWorkOrder(query_id_,
file,
+ text_offset,
+ std::min(kTextSegmentSize, file_size -
text_offset),
field_terminator_,
process_escape_sequences_,
output_destination,
storage_manager),
op_index_);
+ text_offset += kTextSegmentSize;
--- End diff --
Yes alternatively we can do
```
std::size_t text_segment_size = std::min(kTextSegmentSize, file_size -
text_offset);
... // addNormalWorkOrder
text_offset += text_segment_size;
```
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