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98e3a99a88
Since this hides real problems, since destructor does final flush and if
it fails, then data will be lost.
One of such examples if MEMORY_LIMIT_EXCEEDED exception, so lock
exceptions from destructors, by using
MemoryTracker::LockExceptionInThread to block these exception, and allow
others (so std::terminate will be called, since this is c++11 with
noexcept for destructors by default).
Here is an example, that leads to empty block in the distributed batch:
2021.01.21 12:43:18.619739 [ 46468 ] {7bd60d75-ebcb-45d2-874d-260df9a4ddac} <Error> virtual DB::CompressedWriteBuffer::~CompressedWriteBuffer(): Code: 241, e.displayText() = DB::Exception: Memory limit (for user) exceeded: would use 332.07 GiB (attempt to allocate chunk of 4355342 bytes), maximum: 256.00 GiB, Stack trace (when copying this message, always include the lines below):
0. DB::Exception::Exception<>() @ 0x86f7b88 in /usr/bin/clickhouse
...
4. void DB::PODArrayBase<>::resize<>(unsigned long) @ 0xe9e878d in /usr/bin/clickhouse
5. DB::CompressedWriteBuffer::nextImpl() @ 0xe9f0296 in /usr/bin/clickhouse
6. DB::CompressedWriteBuffer::~CompressedWriteBuffer() @ 0xe9f0415 in /usr/bin/clickhouse
7. DB::DistributedBlockOutputStream::writeToShard() @ 0xf6bed4a in /usr/bin/clickhouse
33 lines
701 B
C++
33 lines
701 B
C++
#pragma once
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#include <memory>
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#include <IO/ReadBuffer.h>
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namespace DB
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{
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struct IReadableWriteBuffer
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{
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/// At the first time returns getReadBufferImpl(). Next calls return nullptr.
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inline std::shared_ptr<ReadBuffer> tryGetReadBuffer()
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{
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if (!can_reread)
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return nullptr;
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can_reread = false;
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return getReadBufferImpl();
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}
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virtual ~IReadableWriteBuffer() = default;
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protected:
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/// Creates read buffer from current write buffer.
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/// Returned buffer points to the first byte of original buffer.
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/// Original stream becomes invalid.
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virtual std::shared_ptr<ReadBuffer> getReadBufferImpl() = 0;
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bool can_reread = true;
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};
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}
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