Now Env has unify all environment operation, such as file operation.
However some of our old functions don't leverage it. This change unify
FileUtils::scan_dir to use Env's function.
When making snapshot for incremental clone, missed singleton versions may have been compacted.
So get_rowset_by_version() will not acquire any rowset.
This rowset should be acquired from _inc_rs_version_map.
In Storage Engine GC, TabletManger use std::regex to extract tablet id
and schema hash from path. But it will construct regex pattern for
every path to check, this is a huge waste. This change list make this
pattern a global static pattern, and replace it with RE2, which has
better performance.
This commit enable the avg operator in fe instead of converting the avg function into sum/count.
Also, this commit fix the bug of deciamlv2 avg which cause the core in be.
The int128 could not be assinged directly.
The speed of avg function is similar to sum function after enhancement.
Leverage gitattributes to enable auto convert end-of-line to LF when
checking in. Convert already exist CRLF to LF by removing all files and
checking out with new .gitattributes file. Except .gitattributes, all
files are only modified at the end of line.
major change
change data format of binary dict page, appending (dict page data) and (dict page offset) to binary dict page;
add new decoding method for new binary dict page format
add ut for segment test
set the elements of initial array to 0 ,when calling arena.AllocateNewBlock
hard code way to choose dict coding for string
0919 commit major change
change dict file format:when saving binary dict page, separate dict page from dict page,one dict page may have multi data pages;when reading a binary dict page,one ColumnReader keeps one dict page
loading dict when calling column_reader._read_page
3.rollback BinaryDictPage
no longer using memset(0) to inital column_zonemap.max_value
0926 17 commit major change
init column_zone_map min value column_zone_map slice's data array;
set char/varchar column_zone_map'max value size to 0
add ut for char column zone map query hit/miss
0929 10 commit major change
allocate mem for column_zone_map 's max and min value
direct copy content to column_zone_map's max and min value
Remove the default constructor for UniqueID
Add a gen_uid method in UniqueId. If need to generate a new uid, users should call this api explicitly.
Reuse boost random generator not generate a new one every time.
In this change list
1. validate HLL column when loading data, if data is invalid, this row
will be filtered.
2. seems as empty HLL when serializing invalid type of HLL data, with
this change, all ingested data will be valid.
3. seems as empty HLL when deserializing nullptr or invalid type of HLL data.
With this change, dirty data can be handled normally.
4. rename function empty_hll to hll_empty.
5. disable memtable_flush_execute_test because this will fails
sometimes. When tearing down, some thread is not joined, and they will
visit destroyed resource, which is invalid.
Sometime the broker writer failed to close, but we do not handle this failure.
This may create an empty file on remote storage but be treated as normal.
Also enhance some usabilities:
1. getting latest 2000 transactions instead of getting the earliest.
2. Show backend which download and upload tasks are being executed.
Fix direct compilation failed：
fix compile thirdparty in ubuntu will install libs to lib dir instead of lib64
fix compile error in gcc5 due to the defect of c++11 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60970)
fix gcc version check will not work on some OS
In previous compaction, only rowsets will be taken into consideration.
Doing streaming load, the singleton rowset may is made up of many overlapping segments.
Scanning these overlapping segments will result in read amplification.
To address this problem, overlapping segments should be taken into consideration
when doing cumulative compaction to reduce read amplification.
The current load process is:
Tablet Sink -> Tablet Channel Mgr -> Tablets Channel -> Delta Writer -> MemTable -> Flush to disk
In the path of Tablets Channel -> DeltaWriter -> MemTable -> Flush to disk, the following operations are performed:
Insert tuple into different memtables according to tablet ID
When the memtable size reaches the threshold, it is written to disk.
The above operations are equivalent to single thread execution for a single load task.
In fact, the insertion of memtable and the flush of memtable can be executed synchronously.
Perform these operation in single thread prevents the insertion of memtable from being delayed due to slow disk writing.
In the new implementation, I added a MemTableFlushExecutor class with a set of flush queues and corresponding worker threads.
By default, each data directory uses two worker threads for flush, which can be modified by the parameter flush_thread_num_per_store of BE.
DeltaWriter will push the full memtable to MemTableFlushExecutor for flush operation and generate a new memtable for receiving new data.
This design can improve the performance of load large files.
In single host testing, the time to load a 1GB text file is reduced from 48 seconds to 29 seconds.
