Hi, I have 3 questions here:
1. I see comments in but_internals.h below:
* Also, in places we do one-time reads of the flags without bothering to
* lock the buffer header; this is generally for situations where we don't
* expect the flag bit being tested
> 2023年11月10日 22:31，jacktby jacktby 写道：
>
> In the bus_internal.h,I see
>
> Note: Buffer header lock (BM_LOCKED flag) must be held to examine or change
> tag, state or wait_backe
In the bus_internal.h,I see
Note: Buffer header lock (BM_LOCKED flag) must be held to examine or change
tag, state or wait_backend_pgprocno fields.
As we all know, this buffer header lock is
Hi, postgres hackers, I’m studying postgres buffer cache part. So I open this
thread to communicate some buffer cache codes design and try to improve some
tricky codes.
For Buffer Cache, we know it’s a buffer array, every bucket of this array is
consist of a data page and its header which is us
> 2023年9月28日 12:26，David G. Johnston 写道：
>
> On Wednesday, September 27, 2023, jacktby jacktby <mailto:jack...@gmail.com>> wrote:
>> postgres=# SET enable_seqscan = off;
>> SET
>> postgres=# explain select * from t;
>>
> 2023年9月28日 01:07，Andres Freund 写道：
>
> Hi,
>
> On 2023-09-28 00:37:41 +0800, jacktby jacktby wrote:
>> postgres=# SET enable_seqscan = off;
>> SET
>> postgres=# explain select * from t;
>>
> 2023年9月28日 01:07，Andres Freund 写道：
>
> Hi,
>
> On 2023-09-28 00:37:41 +0800, jacktby jacktby wrote:
>> postgres=# SET enable_seqscan = off;
>> SET
>> postgres=# explain select * from t;
>>
> 2023年9月28日 01:07，Andres Freund 写道：
>
> Hi,
>
> On 2023-09-28 00:37:41 +0800, jacktby jacktby wrote:
>> postgres=# SET enable_seqscan = off;
>> SET
>> postgres=# explain select * from t;
>>
postgres=# SET enable_seqscan = off;
SET
postgres=# explain select * from t;
QUERY PLAN
-
Seq Scan on t (cost=100.00..123.60 rows=1360 width=32)
(
> 2023年9月27日 18:08，Matthias van de Meent 写道：
>
> On Wed, 27 Sept 2023 at 05:03, jacktby jacktby <mailto:jack...@gmail.com>> wrote:
>>
>>
>>
>>> 2023年9月27日 00:45，Matthias van de Meent 写道：
>>>
>>> On Tue, 26 Sept
> 2023年9月27日 00:45，Matthias van de Meent 写道：
>
> On Tue, 26 Sept 2023 at 18:38, jacktby jacktby wrote:
>>
>> typedef bool (*aminsert_function) (Relation indexRelation,
>> Datum *values,
>> bool *isnull,
>> ItemPointer heap_tid,
>> Relation h
typedef bool (*aminsert_function) (Relation indexRelation,
Datum
*values,
bool *isnull,
ItemPoint
/* Typedef for callback function for table_index_build_scan */
typedef void (*IndexBuildCallback) (Relation index,
ItemPointer tid,
Datum
*values,
I find this in source code
#define ShareLock 5 /* CREATE INDEX
(WITHOUT CONCURRENTLY) */
I think if there is no CONCURRENTLY, so why we need a lock, I think that’s
unnecessary. What’s the point?
typedef struct TupleDescData
{
int natts; /* number of attributes
in the tuple */
Oid tdtypeid; /* composite type ID
for tuple type */
int32 tdtypmod; /* typmod for tuple type */
typedef struct TupleDescData
{
int natts; /* number of attributes
in the tuple */
Oid tdtypeid; /* composite type ID
for tuple type */
int32 tdtypmod; /* typmod for tuple type */
> 2023年9月15日 20:31，jacktby jacktby 写道：
>
> I’m trying to implement a new column store for pg, is there a good example to
> reference?
That’s too complex, I just need to know the interface about design a column
store. In fact, I just need a simple example, and I will implement i
I’m trying to implement a new column store for pg, is there a good example to
reference?
In buffer README, I see “Pins may not be held across transaction boundaries,
however.” I think for different transactions, they can pin the same buffer
page, why not? For concurrent read transactions, they could read the one and
the same buffer page.
A normal LRU cache or implement it reference to a research paper?
> 2023年9月12日 00:34，Chapman Flack 写道：
>
> On 2023-09-11 12:28, jacktby jacktby wrote:
>>> 2023年9月11日 23:51，Aleksander Alekseev 写道：
>>> often better) add a corresponding extension to /contrib/. You can find
>>> a complete example here [1] for instance, se
> 2023年9月11日 23:51，Aleksander Alekseev 写道：
>
> Hi,
>
>> I only add below:
>>
>> Datum fake_dinstance2(PG_FUNCTION_ARGS)
>> {
>>PG_RETURN_INT16(0);
>> }
>> in src/backend/utils/adt/int8.c, and the I run “make install”,
>> But I can’t find the fake_distance2 in src/backend/utils/fmgrta
I only add below:
Datum fake_dinstance2(PG_FUNCTION_ARGS)
{
PG_RETURN_INT16(0);
}
in src/backend/utils/adt/int8.c, and the I run “make install”,
But I can’t find the fake_distance2 in src/backend/utils/fmgrtab.c which is
generated by src/backend/utils/Gen_fmgrtab.pl. What else do I need t
> 2023年9月6日 18:50，jacktby jacktby 写道：
>
>
>
>> 2023年9月6日 18:19，jacktby jacktby 写道：
>>
>>
>>
>>> 2023年9月6日 01:47，David G. Johnston 写道：
>>>
>>> OIDs don't exist independently of the data they are associated with. Giv
> 2023年9月6日 18:19，jacktby jacktby 写道：
>
>
>
>> 2023年9月6日 01:47，David G. Johnston 写道：
>>
>> OIDs don't exist independently of the data they are associated with. Give
>> more context if you want a better answer. Or just go look at the sourc
> 2023年9月6日 01:47，David G. Johnston 写道：
>
> OIDs don't exist independently of the data they are associated with. Give
> more context if you want a better answer. Or just go look at the source code
> commits for when the last time something needing an OID got added to the core
> catalog.
>
> 2023年9月5日 22:29，jacktby jacktby 写道：
>
I’m trying to add a new data type for my pg. How to do that? Can you give me
more details or an example?
> 2023年8月6日 13:18，Julien Rouhaud 写道：
>
> On Sun, 6 Aug 2023, 12:34 jacktby jacktby, <mailto:jack...@gmail.com>> wrote:
>> I’m trying to add a new operator for my pg application like greater_equals
>> called “<~>", how many files I need to
>&
I’m trying to add a new operator for my pg application like greater_equals
called “<~>", how many files I need to
modify and how to do it? Can you give me an example?
32 matches
Mail list logo
