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https://www.cnblogs.com/abclife/p/15968628.html
根据这篇文档中的脚本,在我们自己的环境中跑了下,第一次跑的结果如下:
运行完上面跑出的split脚本后,还是存在jumbo块,第二次跑出的结果:
从上面结果可以看出,chunks的数量增加了,但jumbo chunks的数量没有减少很多。
也和阿里云后台沟通,jumbo chunk不能分裂的原因:
因为大部分jumbo chunk是相同shard key组成的,所以无法继续分割。
不知道有没有通过这种方法分割成功的案例。
具体运行脚本如下:
1、使用以下脚本找出未被检测到的Jumbo块,并生成相关命令:
var allChunkInfo =
function
(ns){
var chunks = db.getSiblingDB(
"config"
).chunks.find({
"ns"
: ns}).sort({
min
:1}).noCursorTimeout(); //this will
return
all
chunks
for
the ns ordered
by
min
var totalChunks = 0;
var totalJumbo = 0;
var totalSize = 0;
var totalEmpty = 0;
chunks.forEach(
function
printChunkInfo(chunk) {
var db1 = db.getSiblingDB(chunk.ns.split(
"."
)[0]) // get the
database
we will be running the command against later
var
key
= db.getSiblingDB(
"config"
).collections.findOne({_id:chunk.ns}).
key
; // will need this
for
the dataSize call
// dataSize
returns
the info we need
on
the data, but using the estimate
option
to
use counts
is
less intensive
var dataSizeResult = db1.runCommand({datasize:chunk.ns, keyPattern:
key
,
min
:chunk.
min
,
max
:chunk.
max
, estimate:
false
});
if(dataSizeResult.
size
> 67108864) {
totalJumbo++;
print(
'sh.splitFind("'
+ chunk.ns.toString() +
'", '
+ JSON.stringify(chunk.
min
) +
')'
+
' // '
+ chunk.shard +
' '
+ Math.round(dataSizeResult.
size
/1024/1024) +
' MB '
+ dataSizeResult.numObjects );
}
totalSize += dataSizeResult.
size
;
totalChunks++;
if (dataSizeResult.
size
== 0) { totalEmpty++ }; //
count
empty chunks
for
summary
}
)
print(
"***********Summary Chunk Information***********"
);
print(
"Total Chunks: "
+totalChunks);
print(
"Total Jumbo Chunks: "
+totalJumbo);
print(
"Average Chunk Size (Mbytes): "
+(totalSize/totalChunks/1024/1024));
print(
"Empty Chunks: "
+totalEmpty);
print(
"Average Chunk Size (non-empty): "
+(totalSize/(totalChunks-totalEmpty)/1024/1024));
}
2、脚本必须通过mongos router进行调用:
mongos> allChunkInfo(
"db.test_col"
)
3、 生成如下结果
sh.splitFind(
"db.test_col"
, {
"_id"
:
"jhxT2neuI5fB4o4KBIASK1"
}) // shard-1 222 MB 7970
sh.splitFind(
"db.test_col"
, {
"_id"
:
"zrAESqSZjnpnMI23oh5JZD"
}) // shard-2 226 MB 7988
sh.splitFind(
"db.test_col"
, {
"_id"
:
"SgkCkfSDrY789e9nD4crk9"
}) // shard-1 218 MB 7986
sh.splitFind(
"db.test_col"
, {
"_id"
:
"X5MKEH4j32OhmAhY7LGPMm"
}) // shard-1 238 MB 8338
...
***********Summary Chunk Information***********
Total Chunks: 5047
Total Jumbo Chunks: 120
Average Chunk
Size
(Mbytes): 19.29779934868946
Empty Chunks: 1107
Average Chunk
Size
(non-empty): 24.719795257064895
4、运行上一步骤的split命令
备注:阿里云分片集群介绍
什么是MongoDB分片集群_云数据库 MongoDB 版(MongoDB)-阿里云帮助中心
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