How loading process works internally
Details on load (pass 1 and pass 2 )
A load process consists of the following steps:
a) read data from file
b) convert data from ascii to binary format
c) assign rowid to each row of data
d) insert data into index
e) performing referential integrity checks
f) evaluating table and column check constraints
The logic exercised in step (d) varies from index to index.
- For FP(NBit), DATE, DTTM, and TIME indexes, data is inserted directly into the index.
- For HG and WD indexes, data is sorted prior to inserting the data into the index.
- Steps (e) and (f) are performed as required.
The above steps are exercised as follows relative to pass 1 and pass 2
steps (a), (b), (c)
step (d) - for FP(NBit), DATE, DTTM, and TIME indexes, data inserted into the index
- for HG and WD, data put into a sort
step (d) - for HG and WD indexes, data is retrieved from the sort and inserted into the index
step (e) - perform referential integrity checks
step (f) is performed after Pass 2 is completely finished.
IQ Large memoy (or Virtual memory) is used to store both the data manipulated in step (a) and step (b).
The amount of virtual memory can be controlled using the "-iqlm" start-up parameter option.
The sorting done for HG and WD indexes uses IQ temp cache.
Different thread pools are used for Pass 1 and Pass 2. The load process ideally assigns one thread to every IQ index.
"Load process" ; "Bulk load" ; , KBA , BC-SYB-IQ , Sybase IQ , How To
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